Clinical trial NCT03189134
Conditions: Atrial Septal Defect
Sponsor: Aditya Kaza
Start date: 2018-04-02; Completion date: 2019-04-26
Enrollment: 6 participants; Allocation: NA; Intervention model: SINGLE_GROUP

Brief summary:
The investigators propose to translate confocal microscopy for use during open heart surgery. This tool will help discriminate between various types of tissues in the heart during surgery. One of the most feared complication after heart surgery is heart block. This flexible fiberoptic confocal microscope will help discriminate between the various types of tissues in the heart and thus help avoid injury to the conduction tissue during surgery.

Detailed description:
This is an interventional pilot study that proposes to evaluate the safety, logistical feasibility, and technological feasibility of using Fluorescite with fiberoptic confocal microscopy during cardiac surgery to discriminate between cardiac tissue and conduction tissue. During surgery to repair atrial septal defect, diluted Fluorescite will be added to the surface of the heart. The fiberoptic confocal microscope (Cellvizio 100 Series System with Confocal Miniprobe) will be used to record images in several different locations of the heart. The image files will be provided to blinded raters who will attempt to identify whether they contain cardiac tissue or conduction tissue. All subjects will be monitored while they are inpatient after surgery for any adverse events.

Arms: arm 1: Up to 5mL of 1:1000 dilute FLUORESCITE will be applied to cardiac tissue prior to imaging with Cellvizio 100 Series System with Confocal Miniprobes
Interventions: intervention 1: Fluorescite intervention 2: Cellvizio 100 Series System with Confocal Miniprobes
Intervention descriptions: intervention 1: Dilute fluorescite will be applied to cardiac tissue prior to imaging intervention 2: Microscopy system will image cardiac tissue.

Protocol documents:
ICF_000.pdf: 
 
Page 1 of 8 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed Consent Form 
 
Protocol Title: Utilization of Confocal Microscopy During Cardiac Surgery 
 
Document Date: October 19, 2018 
 
IRB Approval Date: October 31, 2018 
 
NCT Number: NCT03189134


 
 
 
DO NOT PLACE IN 
MEDICAL RECORD 
Protocol Title: Utilization of Confocal 
Microscopy During Cardiac Surgery. 
 
Principal Investigator: Aditya K. Kaza, MD 
 
RESEARCH CONSENT FORM 
 
Use Plate or Print: 
 
MRN#: 
 
DOB: 
 
Subject’s Name:  
 
Gender: 
 
 
 
Page 2 of 8 
 
Why is this research study being conducted? What is its purpose? 
 
The research study is being done to establish the effectiveness of using a specific type of microscope and a special dye 
called fluorescein for identifying different tissue types in the heart during heart surgery. The purpose of this project is to 
develop a new system to avoid injury to the electrical pathways in the heart. These electrical pathways are what help the 
heart beat with the right rhythm.  Any injury to these pathways could require placement of a permanent pacemaker (a 
device to help the heart beat in the right rhythm). 
 
Fluorescein is approved by the Food and Drug Administration (FDA) for use in eye imaging and angiography.  In this 
study, the use of fluorescein is investigational.   This means that the drug has not yet been approved by the FDA for the 
purpose we are studying, imaging during cardiac surgery. 
 
The microscope we are using in this study, the Cellvizio Imaging System, is cleared by the Food and Drug Administration 
(FDA) for use during endoscopy.  In this study, the use of the Cellvizio Imaging System is investigational.   This means 
the device has not yet been approved by the FDA for the purpose we are studying, imaging during cardiac surgery. 
 
 
Who is conducting this research study, and where is it being conducted? 
 
The Principal Investigator, Dr. Aditya Kaza, is a cardiac surgeon at Boston Children’s Hospital. The study will be 
conducted at Boston Children’s Hospital, and is funded by the National Heart, Lung, and Blood Institutes (NHLBI). 
 
How are individuals selected for this research study? How many will participate? 
 
Any subject who is scheduled for isolated atrial septal defect closure is eligible to participate in the study. We will enroll a 
total of six subjects for this study. 
 
What do I have to do if I am in this research study? 
 
If you choose to participate or have your child participate in the study, we will use a microscope during your/your child’s 
heart surgery to help determine its usefulness in identifying tissue which makes the heart beat.  This microscope is used 
with a special dye (fluorescein) which will shine when a bright light (laser) from the microscope hits the tissue.  While the 
laser is shining on the heart tissue, pictures will be taken with the microscope.   This will only add about three minutes to 
surgery time. The information obtained from the study will be used to develop a microscope system to assist during heart 
surgery.   
 
There will be no other tests required of you or your child, specifically for research.  We would also like to look through 
your/your child’s medical record and collect existing information about tests you/your child has done clinically.   


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 3 of 8 
 
If you choose not to participate in the study, you/your child will receive his/her routine care and no further action will be 
needed. 
 
What are the risks of this research study? What could go wrong? 
 
We will discuss the three different potential risks related to the device, laser energy, and the fluorescent dye utilized. 
 
The microscope system has been FDA cleared for imaging of the intestines and lungs. We will use it to image the tissue 
inside the heart and do not expect any additional risks. There is a small risk of prolonging the procedure because of the 
imaging process; this additional time will be less than three minutes.  
 
The laser used for the project has been approved by the FDA for use in human beings to help identify various body tissues 
including the intestines, bladder, and lungs. Using the established safety guidelines, the laser strength generated by this 
device is 80% less than the approved exposure. Other organ systems will not be exposed to the laser source. 
 
The dye which will be used for this study is FDA approved, but the way we are using it in this study is not FDA approved.  
Fluorescein sodium (dye) will be diluted and only a small amount of the diluted dye will be used.  A small amount of the 
diluted dye will be applied to the surface of the heart as needed for imaging. There is a possibility of an allergic reaction 
to the dye, however this chance is very low because we are not administering this dye directly into your/your child’s 
bloodstream; instead we are using it locally on the surface of the heart. Once the imaging is completed, the remaining dye 
will be rinsed and suctioned from the heart surface. In the rare chance that an allergic reaction occurs, this would be 
treated by flushing the area with fluids immediately.  
 
What are the benefits of this research study? 
 
There are no immediate benefits to you or your child. However, the study may help us better understand the ability of the 
imaging system to help identify different types of heart tissue, especially the electrical pathways during open heart 
surgery. If we can develop a way of identifying tissue during heart surgery, we can reduce the risk of injuring the 
electrical pathways and ultimately reducing pacemaker placement for future patients undergoing heart surgery. 
 
Are there costs associated with this research study? Will I receive any payments? 
 
There are no extra costs to you. You will not receive any payments related to the study. 
 
We will offer you the care needed to treat any injury that directly results from taking part in this research. We reserve the 
right to bill your insurance company or other third parties, if appropriate, for the care you get for the injury. We will try to 
have these costs paid for, but you may be responsible for some of them. For example, if the care is billed to your insurer, 
you will be responsible for payment of any deductibles and co-payments required by your insurer.  
 
Injuries sometimes happen in research even when no one is at fault. There are no plans to pay you or give you other 
compensation for an injury, should one occur. However, you are not giving up any of your legal rights by signing this 
form. If you think you have been injured or have experienced a medical problem as a result of taking part in this research, 


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 4 of 8 
tell the person in charge of the research as soon as possible. The researcher's name and phone number are listed in this 
consent form. 
 
If you go to the Emergency Room or to another hospital or doctor it is important that you tell them that you are in this 
research.  If possible, you should give them a copy of this consent form. 
 
If I do not want to take part in this research study, what are the other choices? 
 
You may choose not to participate. The decision whether or not you wish to participate in this study will not affect your or 
your child’s relationship or care received at Boston Children’s Hospital. There are no alternate studies related to 
intraoperative microscope imaging currently available for your child to participate in. 
 
What are my rights as a research participant? 
 
Participation in the study is completely voluntary and refusal to participate or withdraw from the study will not affect the 
medical care you receive at Boston Children’s Hospital. If you choose to participate in the study, a summary of the 
research findings will be provided to you at the completion of the research project.  
 
Why would I be taken off the study early? 
 
 The research investigator may take you out of this study at any time. This would happen if: 
 
The study is cancelled by the sponsor. 
 
Withdrawal of parent/legal guardian permission. 
 
Other information that may help you 
 
Boston Children’s Hospital has recently developed a web-based, interactive educational program for parents called “A 
Parent’s Guide to Medical Research.”  To find out more about research at Children’s Hospital, please visit the program at 
www.researchchildren.org.  
 
Boston Children’s Hospital is interested in hearing your comments, answering your questions and responding to any 
concerns regarding clinical research at Children's Hospital. If you would like further information about the type of clinical 
research performed at the hospital or have suggestions, questions or concerns regarding clinical research you may send an 
email to cci@childrens.harvard.edu or call 617 355-7052 between the hours of 8:30and 5:00. 
 
Who may see, use or share your health information?  
 
A copy of this consent form will be placed in your child’s medical record.  
 
The results of the tests performed for research purposes will not be placed in your child’s medical record. In this manner it 
will be unlikely that others within the hospital, an insurance company or employer would ever learn of such results. 
 


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 5 of 8 
You/your child’s health information is protected by a law called the Health Information Portability and Accountability act 
(HIPAA). In general, anyone who is involved in this research including those funding and regulating the study may see 
the data, including information about you.  For example, the following people might see information about you: 
 
 
Research staff at Boston Children’s Hospital involved in this study. 
 
Medical staff at Boston Children’s Hospital directly involved in your care that is related to the research or arises 
from it. 
 
Other researchers and centers that are a part of this study, including people who oversee research at that hospital. 
 
People at Boston Children’s Hospital who oversee, advise, and evaluate research and care. This includes the 
ethics board and quality improvement program. 
 
People from agencies and organizations that provide accreditation and oversight of research. 
 
People that oversee the study information such as data safety monitoring boards, clinical research organizations, 
data coordinating centers, and others.  
 
Sponsors or others who fund the research, including the government or private sponsors. 
 
Companies that manufacture drugs or devices used in this research. 
 
Federal and state agencies that oversee or review research information, such as the Food and Drug 
Administration, the Department of Health and Human Services, the National Institutes of Health, and public 
health and safety authorities. 
 
People or groups that are hired to provide services related to this research or research at Boston Children’s 
Hospital, including services providers, such as laboratories, and others. 
 
Your health insurer for portions of the research and related care that are considered billable. 
 
If some law or court requires us to share the information, we would have to follow that law or final ruling. 
 
Some people or groups who get your health information might not have to follow the same privacy rules. Once your 
information is shared outside of Boston Children’s Hospital, we cannot promise that it will remain private. If you/your 
child decide to share private information with anyone not involved in the study, the federal law designed to protect 
privacy may no longer apply to this information. Other laws may or may not protect sharing of private health information. 
If you have a question about this you may contact the Boston Children’s Hospital Privacy Office at 857-218-4680 which 
is set up to help you understand privacy and confidentiality. 
 
Because research is ongoing we cannot give you an exact time when we will destroy this information.  Researchers 
continue to use data for many years so it is not possible to know when they will be done. 
 
We will also create a code for the research information we collect about you so identifying information will not remain 
with the data and will be kept separately. The results of this research may be published in a medical book or journal or be 
used for teaching purposes. However your name or identifying information will not be used without your specific 
permission.  
 
Your privacy rights 
 
If you or your child do not want to participate in this study, you do not have to.  If you do want to participate, however, 
you must sign this form.   
 


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 6 of 8 
If you do not sign this form, it will not affect your care or your child’s care at Boston Children’s Hospital now or in the 
future and there will be no penalty or loss of benefits.  You/your child can withdraw from the study and end your 
permission for Boston Children’s Hospital to use or share the protected information that was collected as part of the 
research; however you cannot get back information that was already shared with others. Once you remove your 
permission, no more private health information will be collected. If you wish to withdraw your health information will 
need to do so in writing.   
 
You/your child may have the right to get some the information that was shared with others for research, treatment or 
payment.  This information is available after the study analysis is done.  To request the information, please contact the 
Hospital’s Privacy Officer at 857-218-4680. 
 
The National Institutes of Health has issued a Certificate of Confidentiality for this research. 
This adds special protection for the research information and specimens that may identify 
you. The researchers may not disclose information that may identify you, even under a court 
order or subpoena unless you give permission.  However, a Certificate of Confidentiality 
does not prevent researchers from disclosing information about you if required by law (such 
as to report child abuse, communicable diseases or harm to self or others); if you have 
consented to the disclosure (such as for your medical treatment); or if it is used for other 
research as allowed by law. In addition the Certificate cannot be used to refuse a request if a 
governmental agency sponsoring the project wants to audit the research.  Any research 
information that is placed in your medical record would not be covered under this 
Certificate.   The Certificate will not be used to prevent disclosure for any purpose you have 
consented to in this informed consent document.  The Certificate does not stop you from 
voluntarily releasing information about yourself or your involvement in this research. If 
others obtain your written consent to receive research information, then the researchers may 
not use the Certificate to withhold that information. 
 
Contact Information 
I understand that I may use the following contact information to reach the appropriate person/office to address any 
questions or concerns I may have about this study.  I know: 
  I can call… 
 At 
 If I have questions or concerns about 
Investigator: 
Phone: 617-355-7932 
  General questions about the study 
  Research-related injuries or emergencies 
  Any research-related concerns or complaints 
Aditya K. Kaza, MD 
Pager: 
617-355-7243  
9183 
Research Nurse 
Phone: 617-919-4457 
  General questions about the study 
 Research-related injuries or emergencies 
  Any research-related concerns or complaints 
Breanna Piekarski, RN, 
BSN 
Pager: 
617-560-4694  
7200 
Office of 
Clinical Investigations 
Phone: 617-355-7052 
 Rights of a research subject 
 Use of protected health information. 
 Compensation in event of research-related injury 
 Any research-related concerns or complaints. 
 
 


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 7 of 8 
 If investigator/study contact cannot be reached. 
 If I want to speak with someone other than the 
Investigator, Study Contact or research staff. 
 
Documentation of Informed Consent and Authorization 
 I have read this consent form and was given enough time to consider the decision to participate in this study. 
 This research study has been satisfactorily explained to me, including possible risks and benefits. 
 All my questions were satisfactorily answered.  
 I understand that participation in this research study is voluntary and that I can withdraw at any time. 
 I am signing this consent form prior to participation in any research activities. 
 I give permission for my/my child’s participation in this research study and for the use of associated protected health 
information as described above (HIPAA).  
 
Parent/Legal Guardian Permission (if applicable)  
If the child to be involved in this research study is a foster child or a ward of the state please notify the researcher or their 
staff who is obtaining your consent. 
 
  __________________ 
____________________________________________ 
_________________  
   Date (MM/DD/YEAR) 
Signature of Parent #1 or Legal Guardian 
Relationship to child 
 
  __________________ 
____________________________________________ 
_________________  
    Date (MM/DD/YEAR) 
Signature of Parent #2   
 
Relationship to child 
 
 CHECK if 2nd parent signature not obtained above.  The PI must document in research records, the reason and/or all 
attempts made before concluding 2nd parent was not ‘reasonably available’. 
 
Child Assent (if applicable)  
 
 __________________ 
____________________________________________ 
 
    Date (MM/DD/YEAR) 
Signature of Child/Adolescent Subject  
 
 
 If child/adolescent’s assent is not obtained above, please indicate reason below (check one):  
 Assent is documented on a separate IRB-approved assent form 
 Child is too young 
 Other reason (e.g. sedated), please specify: ____________________________________________ 
 
Adult Participant (if applicable)  
 
 


 
 
 
RESEARCH CONSENT FORM 
MRN: _________________________ 
Pt Name: ______________________ 
 
 
 
Page 8 of 8 
 __________________ ____________________________________________ 
 
    Date (MM/DD/YEAR) Signature of Adult Participant (18+ years) 
 
 
Investigator or Associate’s Statement & Signature 
 I have fully explained the research study described above, including the possible risks and benefits, to all involved 
parties (subject/parents/legal guardian as applicable).  
 I have answered and will answer all questions to the best of my ability.  
 I will inform all involved parties of any changes (if applicable) to the research procedures or the risks and benefits 
during or after the course of the study.  
 I have provided  a copy of the consent form sign by the subject/ parent / guardian and a copy of the hospital’s 
privacy notification  (if requested) 
 
 
 __________________ 
____________________________________________ 
 
    Date (MM/DD/YEAR) 
Signature of Investigator or Associate 
 
Witness Statement & Signature 
A witness must be present for the entire consent process in the following situations (please check the appropriate 
box)  
 The individual cannot read and this consent document was read to the participant or legal representative, or 
 The individual has certain communication impairments that limit the participant’s ability to clearly express 
consent or  
 Situations where the IRB requests a witness be present: please specify _____________________ 
 
 I confirm that the information in this consent form was accurately explained to the participant, parent or legally 
authorized representative, the individual appeared to understand the information and had the opportunity to ask 
questions, and that informed consent was given freely. 
    __________________          ____________________________________________             
 
        Date (MM/DD/YEAR)              Signature of Witness 
 

Prot_001.pdf: 
Version 4.0 -- 19 Oct 2018 
 
 
Page 1 of 13 
 
 
 
 
 
 
 
 
 
Study Protocol 
Protocol Title: Utilization of Confocal Microscopy during Cardiac Surgery 
Document Date: October 19, 2018 
IRB Approval Date: October 31, 2018 
NCT Number: NCT03189134  


Version 4.0 -- 19 Oct 2018 
 
 
Page 2 of 13 
Utilization of Confocal Microscopy during Cardiac Surgery 
A. 
Specific Aims/Objectives  
This is a pilot study, exploring the safety and feasibility of using diluted fluorescein sodium with 
fiberoptic confocal microscopy during cardiac surgery.   
 
The primary aim of this study is to evaluate the safety of using diluted fluorescein sodium 
during cardiac surgery.   
 
A secondary aim of this study is to evaluate the feasibility of using this imaging modality.  
Feasibility will be evaluated in two ways: logistically and technologically. 
o Logistical feasibility will be evaluated by measuring increased time on bypass, rate of 
enrollment, and the ability to incorporate this imaging modality into standard OR 
procedures. 
o Technological feasibility will center on the ability to capture quality image files.  A 
quality image file is defined as an image file where a rater can visualize the 
distinguishable features of the tissue type (cardiac tissue, conductive tissue) in order to 
classify that tissue type correctly. 
 
B. 
Background and Significance  
 
Congenital heart disease is the most common type of birth defect. Approximately 32,000 new cases of 
congenital heart disease occur in the US every year, and there are approximately 1.5 million new 
cases annually worldwide.1, 2 More than 20,000 pediatric cardiac operations are performed each year 
in the US.3 Over the past two decades, emphasis has been on the complete repair of the congenital 
cardiac defects in infancy. This paradigm shift has improved the surgical outcomes and 
neurodevelopmental progress of these infants. Without surgical intervention, these defects are 
uniformly lethal.4 However, there are several complications associated with surgical intervention, 
including dysfunction of sino-atrial and atrio-ventricular conduction pathways. Despite the complexity 
and individual variations in cardiac conductive pathways, tissue discrimination during surgery is 
currently limited to the use of anatomic landmarks and measurements of local electrical activity, so 
accurate surgical intervention is therefore challenging and risky. In addition, there are only sparse 
data on the location and development of these pathways in pediatric hearts with congenital defects.5 
One of the perioperative complications that can be induced during these procedures is complete heart 
block purportedly associated with interruption of cardiac conduction pathways, which can occur due to 
damage to conductive tissues from clamping, suturing, or other procedures. Complete heart block 
contributes significantly to increased morbidity and mortality.6 Once complete heart block has 
occurred and there has been no recovery by the patient, a permanent cardiac pacemaker must be 
implanted.7 This creates a lifetime dependence on the pacemaker along with the associated lead and 
generator changes.8 A study involving 497 patients over a 22-year period showed that lead failure 
occurred in 155 leads (15%) and 115 patients (23%), with a higher incidence of lead failures in 
pediatric patients.9 With more complex procedures, the risk of complete heart block or sinus node 
dysfunction increases accordingly. Lifetime costs and morbidity associated with pacemaker 
implantation in pediatric patients are very high.8 The economic burden of this rhythm management 
therapy is significant, especially when considering the average lifespan of these young patients.10 
There is also a societal burden, as evidence points to long-term morbidity associated with surgical 
correction of congenital heart defects.11 Despite the significant improvement in surgical results, there 
is still a critical barrier that needs to be overcome, which is to avoid preventable causes of conduction 
defects. 
 
The Cellvizio 100 Series System with Confocal Miniprobes is a confocal laser system with fiber optic 
probes that has been approved by the FDA to allow real-time imaging of the internal microstructure of 
tissues in anatomical tracts. This system is capable of acquiring and displaying microscopic images 


Version 4.0 -- 19 Oct 2018 
 
 
Page 3 of 13 
directly after tissue contact with a rate of up to one image every 5 milliseconds (200 images per 
second). Preliminary studies (described in more detail below) suggest that image data obtained by 
this system allows for discrimination of the cardiac conduction system. We hope to develop a system 
for intraoperative identification of tissue of the conduction system, which could potentially decrease 
the incidence of preventable causes of conduction delays in the operating room. Reducing the 
damage to the conduction system tracts may preserve autonomic nervous activity and lead to 
improved short and long term outcomes for these patients.12 Furthermore, this technology could be 
utilized not only for reconstructive pediatric heart surgery, but also for other corrective surgeries where 
detailed tissue discrimination would improve patient outcomes. 
 
C. 
Preliminary Studies  
 
In a recently published study, we established an approach based on fluorescent labeling, conventional 
confocal microscopy, and image analysis to characterize cardiac tissue types.13 Tissue preparations 
from adult rat hearts were dissected using anatomical landmarks such as the superior vena cava and 
coronary sinus. The tissue preparations were labeled with 4’,6-diamidino-2-phenylindole (DAPI) to 
identify nuclei, wheat germ agglutinin (WGA) conjugated Alexa 488 to define the extracellular space, 
antibodies for hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4) to 
identify nodal myocytes14-17 and sarcomeric α-actinin to identify cardiomyocytes. Conventional 
confocal microscopy of the tissue preparations yielded 3D distributions of the four labels at a high 
resolution.   
 
Using this method, we were able to characterize the microstructure of various cardiac tissue types. 
Atrial working myocardium (AWM) was characterized by a dense and aligned arrangement of 
myocytes that were covered by an epicardial layer with a thickness of 8.26±3.60 µm. Sino-atrial node 
(SAN) was characterized by three distinct layers comprised of epicardium, SAN cells, and subjacent 
myocytes of the AWM. The epicardial and nodal layers had thicknesses of 10.38±4.79 µm and 
10.26±3.33 µm, respectively. SAN cells formed a highly irregular reticulum and had notably smaller 
diameters than myocytes of the AWM. The extracellular space in the SAN layer was also more 
prominent than in AWM and was comprised of oval shaped clearings of variable size. Atrio-ventricular 
node (AVN) and Bundle of His tissue presented a microstructural arrangement similar to SAN. It 
exhibited major differences from AWM tissue, in particular, an irregular reticulum of cells with ample 
extracellular space. The epicardial layer of AVN tissue had a thickness of 2.84±1.25 µm. 
 
Following the investigations using conventional confocal microscopy, we investigated the hypothesis 
that fiberoptic confocal microscopy (FCM) technology could be used to identify the differences in 
tissue microstructure between nodal tissue and working myocardium in living Langendorff perfused rat 
hearts. An aqueous solution of 10 kDa dextran-conjugated Alexa 488 was pipetted to the tissue 
surface. It has previously been shown that dextran-conjugates of this molecular weight penetrate 
endothelial endocardium, endothelial epicardium, and myocardial capillary endothelium in rat, but do 
not penetrate intact cell membranes, and thus label specifically the extracellular space.18 We found 
that FCM images from the dextran-labeled AWM and nodal regions resembled images obtained using 
conventional confocal microscopy.  
 
The FCM images were of high enough quality to visually distinguish tissue types. We also explored 
approaches for automated image analysis of the conventional microscopy and FCM images. We 
evaluated the ability of two methods of 2D texture analysis to discriminate between AWM and nodal 
tissue using images of the extracellular space. The first method measured the texture orientation from 
Fourier transformed images.19 The second method characterized texture orientation from second 
order image moments of image regions.19 Both methods of 2D texture analysis yielded a larger 
magnitude of our defined measure of orientation in AWM in comparison to SAN and AVN tissue. 
 


Version 4.0 -- 19 Oct 2018 
 
 
Page 4 of 13 
In further studies, we demonstrated that fluorescein sodium (Fluorescite®) is an equally reliable label 
of extracellular space. Fluorescite® is approved by the FDA for intravenous administration for use in 
ophthalmic angiography, and its toxicity has been extensively studied.20 Fluorescite® is also used in 
gastrointestinal endoscopic imaging. The incidence of adverse reactions following intravenous 
administration of fluorescein is 1.1-4.8% for retinal fluorescein angiography and 1.4% for 
gastrointestinal endoscopic imaging.21-23 In these studies, adverse reactions including dizziness, 
nausea, vomiting, and transient hypotension have been reported. However, there were no serious 
adverse reactions or deaths. For our purposes, we determined that localized, topical delivery of the 
dye would allow us to use a smaller amount and be equally effective.24 Human examiners were able 
to classify FCM images obtained using fluorescein delivered by dye carrier as either AWM or nodal 
tissue with high degrees of sensitivity (99.2%±0.3) and specificity (98.0%±0.7). In further studies, we 
showed that topical delivery of the dye by pipette or surgical swab was equally effective to the dye 
carrier method, and allowed us to use a concentration of dye that is 1000 times more dilute than what 
is approved by the FDA. 
 
Our research team is currently conducting experiments in sheep, but the data have not been 
published. In these studies, 3 sheep have been anesthetized and placed on cardiopulmonary bypass. 
Between 5-7mLs of 1:1000 diluted Fluorescite® was applied to the epicardium and endocardium, and 
images were obtained using the Cellvizio Imaging system. After the images were obtained, the 
animals were taken off bypass. ECGs were obtained at baseline, after re-perfusing the hearts, and 
after the animals were taken off bypass. The ECGs confirmed that after the procedure, the hearts 
resumed normal baseline cardiac activity. Visual examination of the hearts also confirmed normal 
ventricular function and vigorous activity. Furthermore, preliminary imaging data from these studies 
confirms that we are able to discriminate conduction tissue from the images taken. 
D. Design and Methods  
(1) 
Study Design 
 
We propose a descriptive pilot study to assess the safety and feasibility of using fiber-optic 
confocal microscopy during cardiac surgery to image the endocardium and epicardium. 6 
patients undergoing surgery for closure of atrial septal defect will be enrolled in this study.  
 
All enrolled subjects will receive standard of care for cardiac surgery and the operation will be 
conducted according to routine procedure. After the sternotomy, the subject will be placed on 
cardiopulmonary bypass. After cardioplegic infusion and cardiac arrest, the right atrium will be 
opened to visualize the atrial septal defect.  
 
At this juncture, fluorescein sodium at a concentration of 100ug/ml in sterile saline will be 
applied topically to the myocardium, where it will diffuse into the endocardium and epicardium. 
A total volume of 5ml will be applied. The surgeon will confirm there are no visual indicators of 
an allergic reaction to the fluorescein study drug.  As long as there is no appearance of tissue 
damage, the imaging will proceed. If any signs of allergy or intolerance occur, the dye will be 
immediately flushed out and no images will be obtained. 
 
The imaging probe of the Cellvizio system will then be applied in direct contact to the region of 
interest with minimal pressure for approximately 90 seconds. During this period, Cellvizio 
Software and Viewer will be used to obtain images. The total additional time on bypass will be 
approximately 3 minutes. 
 
Once the imaging procedure has been completed, the heart surface will be washed with saline 
and evacuated using a suction apparatus, to ensure all fluorescein has been removed and will 


Version 4.0 -- 19 Oct 2018 
 
 
Page 5 of 13 
not enter the circulatory system.  After that, the remainder of the operation will proceed in the 
usual fashion. As per standard of care for patients undergoing cardiac surgery, an 
intraoperative echocardiogram will be performed after the subject is separated from bypass. 
 
The expected hospitalization for the Atrial Septal Defect (ASD) is 3-5 days post-operation. It is 
not expected that participation in this study will increase the post-operative hospital stay or 
post-hospitalization recovery.  The principal investigator (PI) and research team will monitor 
clinical labs, electrocardiograms (EKGs), and echocardiograms for any evidence of adverse 
events.  No additional follow-up testing, outside of standard clinical monitoring, are planned. In 
accordance with standard of care, all subjects will receive a pre-discharge EKG and trans-
thoracic echocardiogram.   
 
Image files will be exported out from the Cellvizio system, de-identified, and provided to the 
blinded raters. The image files will be assessed for quality and the ability to discriminate tissue 
types. 
 
(2) 
Patient Selection and Inclusion/Exclusion Criteria  
 
Patients undergoing cardiac surgery for ASD repair at Boston Children’s Hospital will be 
enrolled in this study. Surgery for ASD repair exposes the conduction system of the heart, 
allowing access to the AWM and nodal tissue for image capture by the Cellvizio system. 
Congenital heart defects such as ASD are most often diagnosed and repaired in infants and 
children, which is why conducting this study in a pediatric population is appropriate.  
Additionally, the FCM has a pre-defined field of focus, with a depth ranging from 55 to 65 µm. 
Therefore, this technology is more suited to pediatric hearts, as adult hearts are thicker and 
the conductive tissue may be too deep to be identified using this method. 
 
Inclusion criteria: 
 
Males and females between 30 days and 21 years old 
 
Undergoing elective surgery for closure of isolated secundum atrial septal defect 
 
Both parents attend pre-operative clinic appointment, to provide 2 parent consent, or 
an adult participant (age 18-21) may provide consent for him/herself 
 
Exclusion criteria: 
 
Prior history of adverse reaction to fluorescein sodium 
 
Prior history of renal failure or abnormal renal function 
 
Baseline PR interval > 220 msec or 98% for age 
 
Baseline HR > 98% for age 
 
Underlying genetic syndrome associated with progressive AV block of sinus node 
dysfunction (e.g. Holt-Oram or NKX2.5) 
 
(3) 
Description of Study Treatments or Exposures/Predictors  
 
(3.1) Investigational Agent 
 
Fluorescite® (fluorescein injection, USP) 10% contains fluorescein sodium (equivalent to 
fluorescein 10% w/v) (Alcon). Fluorescite® is commercially available, a supply of which will be 
purchased for the sole purpose of this study. The Boston Children’s Hospital (BCH) research 
pharmacy will be responsible for the receipt and accountability of study agent. The pharmacy 
will maintain accountability logs with quantities received and dispensed, specifying the 
corresponding dates, and the identification code of the study subject. 


Version 4.0 -- 19 Oct 2018 
 
 
Page 6 of 13 
 
The research pharmacy will dilute 1mL of the study drug into 1L of saline. A 5mL syringe of the 
1:1000 diluted solution will then be dispensed to the OR. Any unused prepared study drug will 
be recorded, and then discarded or destroyed according to Boston Children’s Hospital policy.  
The vial of undiluted Fluorescite® will also be discarded or destroyed according to BCH policy. 
 
(3.2) Device 
 
The Cellvizio 100 Series System and the Gastroflex UHD probe (Mauna Kea Technologies) 
will be used for imaging in this study. This instrument has been approved by the FDA for 
gastrointestinal, urologic, gynecologic, and pulmonary applications. This device will be 
provided by the manufacturer for the purposes of this study, along with the associated control 
and acquisition software. The PI has been thoroughly trained on the use of this hardware and 
software. The cardiac surgery operating room will be responsible for the receipt, 
accountability, and return of the microscope tower and imaging console. The imaging console 
will be stored in the cardiac operating room. The microprobes will be sterilized according to 
standard protocol and stored in a sterile pouch in the operating room. The imaging console is 
password protected and will only be accessed by the PI. 
 
The probe will be used in direct contact with the cardiac tissue with a pressure of 
approximately 0.7 mmHg, which is less than 1% of diastolic blood pressure. The maximum 
laser energy that the system is capable of delivering is 15 mW at 480 nm. This power and 
wavelength has been approved by the FDA for direct in-vivo imaging for various body tissues, 
including gastrointestinal, urogenital, and pulmonary. The proposed application is 
approximately 80% less than the maximum allowable retinal exposure, according to the IEC 
60825-1 standard. 
 
(4) 
Definition of Primary and Secondary Outcomes/Endpoints  
 
Primary Outcome: All adverse events will be collected and relatedness to study participation 
will be determined. Complications will be compared to average complication rates for ASD 
repairs. 
 
Hypothesis: Subjects will not experience a higher rate of adverse events than is expected in a 
clinical setting (<3-4% for all types of adverse events). 
 
Secondary Outcome: The logistical feasibility of conducting FCM imaging during cardiac 
surgery. 
 
Hypothesis: The study procedure will be logistically feasible in terms of added time on bypass 
and the ability to incorporate FCM imaging into standard cardiac surgery OR procedures.  The 
rate of enrollment will be evaluated separately. 
 
Secondary Outcome: The quality of the FCM image files collected, defined as the ability of 
observers to distinguish features and discriminate between working myocardium and nodal 
tissue.  
 
Hypothesis: Blinded raters will be able to use the FCM image files to distinguish features and 
discriminate between working myocardium and nodal tissue. 
 
(5) 
Data Collection Methods, Assessments, Interventions and Schedule (what 
assessments performed, how often)  


Version 4.0 -- 19 Oct 2018 
 
 
Page 7 of 13 
 
Standardized demographic and clinical assessments of all study participants will be performed 
via medical record review prior to and after surgery until the subject is discharged from the 
hospital. Images will be obtained during surgery and saved using Cellvizio Software and 
Viewer. The image files will be de-identified and provided to blinded raters for analysis. 
Medical records of enrolled subjects will be reviewed post-surgery while the subject is inpatient 
in the hospital.  Adverse events will be abstracted from the record and recorded on a CRF and 
input into an InForm database. 
 
(6) 
Study Timeline 
 
With several patients eligible weekly, it should be feasible to complete subject recruitment, 
enrollment, and follow-up within 6 months after study activation. Lead time will be needed to 
secure FDA and BCH Institutional Review Board (IRB) approval. 
E. Adverse Event Criteria and Reporting Procedures  
(1) 
Specification of Safety Parameters 
 
Comprehensive assessments of any apparent toxicity experienced by the study subject will be 
performed throughout the course of the study. All safety events experienced by study subjects 
for the duration of the study will be documented. The types of adverse events that must be 
reported and procedures for appropriately recording, grading and reporting are outlined in this 
section. 
 
(2) 
Definition of an Adverse Event (AE) or Medical Event 
 
According to FDA regulations, an adverse event (AE) is any undesirable, noxious, or 
pathological change compared to preexisting conditions occurring to or in a study subject 
enrolled in a clinical trial, whether or not the event is considered related to the test drug. This 
includes the time periods during which no medication is administered to a study subject, such 
as run-in or follow-up periods. An adverse event is further defined as any change in structure 
(signs) or function (symptoms) of the body that occurs while the study subject is receiving 
study drug/placebo. AEs include the following types of changes: 
 
 
Suspected adverse drug reactions, which are any adverse events for which there is a 
reasonable possibility that the drug caused the adverse event. A reasonable possibility 
implies that there is evidence that the drug caused the event. 
 
 
Other medical experiences regardless of their relationship to the test drug, such as 
injury, surgery, accidents, extensions of symptoms or apparently unrelated illnesses, 
and significant abnormalities in clinical laboratory values, physiological testing, or 
physical examination findings. 
 
 
(3) 
Definition of Serious Events (Serious Adverse Events, Serious Suspected 
Adverse Reactions or Serious Adverse Reactions)  
 
A serious adverse event including a serious suspected adverse reaction or serious adverse 
reaction as determined by the Investigator or the sponsor is any event that results in any of the 
following outcomes: 
 


Version 4.0 -- 19 Oct 2018 
 
 
Page 8 of 13 
1. Death. This includes any death that occurs during the conduct of a clinical study, 
including deaths that appear to be completely unrelated to the test drug (e.g., a car 
accident). If a study subject dies during the study and an autopsy is performed, the 
autopsy results will be attached to the study subject’s Case Report Form (CRF). 
Possible evidence of organ toxicity and the potential relationship of the toxicity to the 
test drug are of particular interest. The autopsy report should distinguish the 
relationship between the underlying diseases, their side effects, and the cause of 
death. 
 
2. Life-threatening adverse drug experience. This includes any AE during which the study 
subject is, in the view of the investigator, at immediate risk of death from the reaction 
as it occurred. This definition does not include any event that may have caused death if 
it had occurred in a more serious form. For example, drug-induced hepatitis that 
resolved without evidence of hepatic failure would not be considered a life-threatening 
event, even though drug-induced hepatitis can be fatal. 
 
3. Persistent or significant disability or incapacity or substantial disruption of the ability to 
conduct normal life functions. 
 
4. Inpatient hospitalization or prolongation of existing hospitalization, except for admission 
for elective surgery. 
 
5. Important medical event that may not result in one of the above outcomes, but may 
jeopardize the health of the study subject or require medical or surgical intervention to 
prevent one of the outcomes listed in the above definition of serious event.  
 
(4) 
Definition of Unexpected Adverse Events 
 
An adverse event is “unexpected” when its nature (specificity) or severity is not consistent with 
applicable product information, such as safety information provided in the package insert, the 
investigational plan, the investigator’s brochure or the protocol. 
 
In addition, an adverse event is “unexpected” when not one of the most common 
complications that typically arise post-operation for ASD repair such as: rhythm disturbances, 
arrhythmia, pericarditis, cardiac tamponade, bleeding, residual holes requiring a re-operation, 
transfusion associated diseases, stroke, and brain damage. These adverse events will be 
considered expected and unrelated to the study drug.    
 
(5) 
Toxicity Grading 
 
We will assign toxicity grades to indicate the severity of adverse experiences and toxicities. 
Toxicity grading consistent with NCI-CTCAE v 4.03 will be used for this protocol. The purpose 
of using the NCI-CTCAE system is to provide standard language to describe toxicities and to 
facilitate tabulation and analysis of the data and assessment of the clinical significance of 
treatment-related toxicities. 
 
Adverse events not included in the NCI-CTCAE listing will be recorded and graded 1 to 5 
according to the General Grade Definition provided below:  
 


Version 4.0 -- 19 Oct 2018 
 
 
Page 9 of 13 
Grade 1 
Mild 
Transient or mild discomforts (< 48 hours), no or minimal 
medical intervention/therapy required, hospitalization not 
necessary (non-prescription or single-use prescription therapy 
may be employed to relieve symptoms, e.g., aspirin for simple 
headache, acetaminophen for post-surgical pain). 
Grade 2 
Moderate 
Mild to moderate limitation in activity, some assistance may be 
needed; no or minimal intervention/therapy required, 
hospitalization possible.   
Grade 3 
Severe 
Marked limitation in activity, some assistance usually required; 
medical intervention/therapy required, hospitalization possible.   
Grade 4 
Life-threatening 
Extreme limitation in activity, significant assistance required; 
significant medical/therapy intervention required, 
hospitalization, or hospice care probable. 
Grade 5 
Death 
Death 
 
 
 
For additional information and a printable version of the NCI-CTCAE v. 4.03 manual, consult 
the NCI-CTCAE website, http://ctep.cancer.gov/reporting/ctc.html. 
 
(6) 
Guidelines for Determining Causality of an Adverse Event 
 
The Investigator will use the following question when assessing causality of an adverse event 
to study drug:  Is there a reasonable possibility that the drug caused the event? An affirmative 
answer designates the event as a suspected adverse reaction. 
 
If there is any doubt as to whether a clinical observation is an AE, the event should be 
reported.  All AEs must have their relationship to study product assessed using the terms 
related or not related.  In a clinical trial, the study product must always be suspect.  To help 
assess, the following guidelines are used: 
 
 
Related – Related means there is evidence to show a causal relationship between the 
study product and the adverse event. 
 
 
Possibly Related – There is a reasonable possibility that the study product caused the 
adverse event. Reasonable possibility means that there is evidence to suggest a 
causal relationship between the study product and the adverse event. 
 
Specific adverse events considered related or possibly related to study participation 
have been identified as: myocarditis or ventricular dysfunction, as measured by 
ejection fraction and fractional shortening.  These will be reported to the FDA in an IND 
Safety Report, per discussion with the FDA.   
 
Specific ECG and rhythm abnormalities requiring DSMB review prior to enrollment of 
next patient: 
1.    AV block > the a PR interval > 220 msec lasting more than 2 hours post 
completion of cardiopulmonary bypass.  This does not include transient 
Wenkebach with sleep/rest/hypothermia.   
2.    Need for atrial pacing or junctional rhythm lasting more than 6 hours post 
completion  
3.    Hypotension or ventricular dysfunction requiring pressor support > 5mcg/kg/min of 
dopamine more than 4 hours post completion of cardiopulmonary bypass.  


Version 4.0 -- 19 Oct 2018 
 
 
Page 10 of 13 
 
 
Not Related – There is not a reasonable possibility that the administration of the study 
product caused the event, and/or there is a more plausible explanation for the adverse 
event than administration of the study product. 
 
(7) 
Recording and Reporting Procedures  
 
Reporting Adverse Events and Serious Adverse Events 
 
All AEs will be followed until the time the event is resolved or medically stable, or until subject 
is discharged from hospital, whichever comes first. AEs may be discovered through any of 
these methods: 
 
 
Observing the subject 
 
Questioning the subject, which should be done in an objective manner 
 
Receiving an unsolicited complaint from the subject 
 
Review of medical records/source documents 
 
All AEs must be recorded accurately on the Adverse Event log for each study subject. The 
date of onset and duration of the AE, grade, whether it was expected or unexpected, action 
taken, date of resolution (if applicable) and outcome of the event must be recorded. The 
investigator will treat subjects experiencing adverse events appropriately and observe them at 
suitable intervals until their symptoms resolve or their status stabilizes or they are discharged 
from the hospital.  
 
SAEs and unexpected problems will be reported promptly to BCH IRB according to local 
regulations and guidelines. 
 
The PI and delegates are responsible for notifying the DSMB chair of all SAEs. DSMB panel 
will evaluate the relationship of the SAE to the underlying disease.  The PI, in cooperation with 
the DSMB panel, will determine whether the SAE is unexpected in nature and make a 
recommendation for any further action. The primary consideration is the study subjects’ safety. 
 
(8) 
Regulatory Reporting 
 
The PI will report events that are both serious and unexpected and that are associated with 
Study Agent/Intervention to the FDA and other applicable health authorities within the required 
timelines as specified in 21 CFR 312.32: fatal and life threatening events within 7 calendar 
days (by phone /fax/electronic communication) and all other serious adverse events in writing 
within 15 calendar days.  All serious events designed as “not associated” to Study 
Agent/Intervention, will be reported to the FDA at least annually. 
 
Given the low dose and method of delivery of fluorescein sodium, serious adverse events 
related to the study drug are not anticipated. Subjects will be monitored at the time of dye 
application to observe for signs of allergy or intolerance. If any signs of allergy or intolerance 
occur (as evidenced by discoloration of tissue or other signs of allergic reaction), the dye will 
be immediately flushed out and no images will be obtained. As per standard of care for 
patients undergoing cardiac surgery, subjects will receive an intraoperative echocardiogram 
after being separated from bypass, and will be monitored closely post-surgery. Before being 
discharged, all subjects will receive an electrocardiogram and trans-thoracic echocardiogram, 
in accordance with standard of care.  


Version 4.0 -- 19 Oct 2018 
 
 
Page 11 of 13 
F. Data Management Methods  
Study specific case report forms (CRFs) will be completed and the case report forms will be stored in 
individual subject binders. Data will be transcribed to a secure research data management system 
(InForm database). All hardcopies will be kept in a locked file cabinet accessible by authorized study 
staff only. Subject confidentiality will be maintained by recording subject data using a unique subject 
identifier. Identifiable linking data, such as contact information and medical record numbers, will be 
recorded and stored separately from the clinical study data.  
 
FCM image files obtained for the study will be stored on a password-protected hard drive connected 
to the Cellvizio system. The image files will be exported, labeled only with the subject’s study ID 
number, and provided to the blinded raters for analysis. 
 
G. Quality Control Method  
All study related tasks will follow Good Clinical Practice guidelines. A manual of operations (MOO) will 
be developed to detail the specific procedures to be conducted and data to be collected. Any 
significant deviations or exceptions to the protocol will be reported to the IRB and FDA in addition to 
being discussed among the investigators, and the PI will develop and implement a plan of action as 
needed (e.g. modification to MOO, study amendment, etc.). The PI will ensure the retention of all 
necessary records and reports for a minimum of 2 years after the discontinuation of the IND.  The 
FDA will be allowed access to these records.  A record of accountability of all investigational drug 
dispositions will be maintained, including batch and lot numbers and storage records. 
 
H. Data Monitoring 
 
Monitoring and auditing procedures as outlined in the Monitoring Plan will be followed to ensure that 
the entire study is conducted, documented, and reported in accordance with the IRB approved 
protocol, the International Conference on Harmonization (ICH) Good Clinical Practice (GCP) 
Guidelines, and applicable regulatory requirements of Boston Children’s Hospital. 
 
Monitors will review and verify protocol compliance with particular focus on AE/SAE reporting, CRF 
data, source documentation, informed consents, and any other study-related documentation, including 
review of hospital pharmacy procedures, drug accountability documentation, and drug storage 
facilities and records. 
 
I. Data Analysis Plan  
 
The FCM image files will be provided post-surgery to blinded raters, who will attempt to categorize the 
image files as either myocardium or nodal tissue. The raters will note if the image quality is not high 
enough to discriminate tissue types.  
J. Statistical Power and Sample Considerations  
This is a single site, descriptive, pilot study, so no power calculations have been performed.  Six 
subjects will provide enough images to determine the feasibility of a larger randomized trial, to be 
performed in the future. 
K. Study Organization  
This is a single site pilot study.  Dr. Kaza will perform all study drug administration and image 
acquisition.  BCH research team members will assist in data abstraction and analysis. 


Version 4.0 -- 19 Oct 2018 
 
 
Page 12 of 13 
L. References 
1. 
Moller JH, Taubert KA, Allen HD, Clark EB, Lauer RM. Cardiovascular health and disease in 
children: Current status. A special writing group from the task force on children and youth, 
american heart association. Circulation. 1994;89:923-930 
2. 
Hoffman JI. Congenital heart disease: Incidence and inheritance. Pediatr Clin North Am. 
1990;37:25-43 
3. 
Moodie DS. Adult congenital heart disease. Curr Opin Cardiol. 1994;9:137-142 
4. 
Gross GJ, Chiu CC, Hamilton RM, Kirsh JA, Stephenson EA. Natural history of postoperative 
heart block in congenital heart disease: Implications for pacing intervention. Heart Rhythm. 
2006;3:601-604 
5. 
Anderson RH, Ho SY, Becker AE. The surgical anatomy of the conduction tissues. Thorax. 
1983;38:408-420 
6. 
Wolff GS, Rowland TW, Ellison RC. Surgically induced right bundle-branch block with left 
anterior hemiblock: An ominous sign in postoperative tetralogy of fallot. Circulation. 
1972;46:587-594 
7. 
Weindling SN, Saul JP, Gamble WJ, MayerJr JE, Wessel D, Walsh EP. Duration of 
complete atrioventricular block after congenital heart disease surgery. Am J Cardiol. 
1998;82:525-527 
8. 
Thomson JD, Blackburn ME, Van Doorn C, Nicholls A, Watterson KG. Pacing activity, 
patient and lead survival over 20 years of permanent epicardial pacing in children. Ann 
Thorac Surg. 2004;77:1366-1370 
9. 
Fortescue EB, Berul CI, Cecchin F, Walsh EP, Triedman JK, Alexander ME. Patient, 
procedural, and hardware factors associated with pacemaker lead failures in pediatrics and 
congenital heart disease. Heart Rhythm. 2004;1:150-159 
10. 
Anderson JB, Czosek RJ, Knilans TK, Meganathan K, Heaton P. Postoperative heart block in 
children with common forms of congenital heart disease: Results from the kid database. J 
Cardiovasc Electrophysiol. 2012;23:1349-1354 
11. 
Silka MJ, Bar-Cohen Y. A contemporary assessment of the risk for sudden cardiac 
death in patients with congenital heart disease. Pediatr Cardiol. 2012;33:452-460 
12. 
Lin A, Mahle WT, Frias PA, Fischbach PS, Kogon BE, Kanter KR, Kirshbom PM. Early 
and delayed atrioventricular conduction block after routine surgery for congenital heart 
disease. The Journal of thoracic and cardiovascular surgery. 2010;140:158-160 
13. 
Huang C, Kaza AK, Hitchcock RW, Sachse FB. Identification of nodal tissue in the 
living heart using rapid scanning fiber-optics confocal microscopy and extracellular 
fluorophores. Circulation. Cardiovascular imaging. 2013;6:739-746 
14. 
Chandler NJ, Greener ID, Tellez JO, Inada S, Musa H, Molenaar P, DiFrancesco D, 
Baruscotti M, Longhi R, Anderson RH, Billeter R, Sharma V, Sigg DC, Boyett MR, 
Dobrzynski H. Molecular architecture of the human sinus node: Insights into the function 
of the cardiac pacemaker. Circulation. 2009;119:1562-1575 
15. 
Yoo S, Dobrzynski H, Fedorov VV, Xu S-Z, Yamanushi TT, Jones SA, Yamamoto M, Nikolski 
VP, Efimov IR, Boyett MR. Localization of na+ channel isoforms at the atrioventricular junction 
and atrioventricular node in the rat. Circulation. 2006;114:1360-1371 
16. 
Yamamoto M, Dobrzynski H, Tellez J, Niwa R, Billeter R, Honjo H, Kodama I, Boyett 
MR. Extended atrial conduction system characterised by the expression of the hcn4 
channel and connexin45. Cardiovasc Res. 2006;72:271-281 
17. 
Brioschi C, Micheloni S, Tellez JO, Pisoni G, Longhi R, Moroni P, Billeter R, Barbuti A, 
Dobrzynski H, Boyett MR, DiFrancesco D, Baruscotti M. Distribution of the pacemaker hcn4 
channel mrna and protein in the rabbit sinoatrial node. J Mol Cell Cardiol. 2009;47:221-227 
18. 
Andries LJ, Brutsaert DL. Endocardial endothelium in the rat: Junctional organization and 
permeability. Cell Tissue Res. 1994;277:391-400 
19. 
Gonzalez RC, Woods RE. Digital image processing. Reading, MA: Addison-Wesley; 1992. 


Version 4.0 -- 19 Oct 2018 
 
 
Page 13 of 13 
20. 
Alford R, Simpson HM, Duberman J, Hill GC, Ogawa M, Regino C, et al. Toxicity of organic 
fluorophores used in molecular imaging: literature review. Mol Imaging. 2009 Dec;8(6):341–
54. 
21. 
Kwiterovich KA, Maguire MG, Murphy RP, Schachat AP, Bressler NM, Bressler SB, et al. 
Frequency of adverse systemic reactions after fluorescein angiography. Results of a 
prospective study. Ophthalmology. 1991. July;98(7):1139–42. 
22. 
Kwan AS, Barry C, McAllister IL, Constable I. Fluorescein angiography and adverse drug 
reactions revisited: the Lions Eye experience. Clinical & experimental ophthalmology. 2006. 
Jan-Feb;34(1):33–8. 
23. 
Wallace M. B., Meining A., Canto M. I., Fockens P., Miehlke S., Roesch T., et al. The safety 
of intravenous fluorescein for confocal laser endomicroscopy in the gastrointestinal tract. 
Aliment. Pharmacol. Ther. 2010. 31, 548–552 
24. 
Huang C, Sachse FB, Hitchcock RW, Kaza AK. Sensitivity and Specificity of Cardiac Tissue 
Discrimination Using Fiber-Optics Confocal Microscopy. PLoS One. 2016; 11(1): e0147667