Compliance with the provisions in this LCD may be monitored and addressed
through post payment data analysis and subsequent medical review audits.

**History/Background and/or General Information**

Ambulatory Electrocardiograph (AECG) diagnostic procedures provide a record of
the heart rhythm during daily activities. AECG can often identify the
existence and determine the frequency of clinically significant rhythm
disturbances and waveform abnormalities that are missed on a standard
electrocardiogram (ECG).

AECG continues to advance at a rapid pace and incorporates various monitoring
devices and indications for use. These devices range from Holter Monitors,
Event Recorders/Monitors, Patch Recorders, External Loop Recorders, Mobile
Cardiovascular Telemetry, Mobile Cardiovascular Outpatient Telemetry,
Insertable Cardiac Monitor/Internal Loop Recorders, and Subcutaneous Cardiac
Rhythm Monitors. They are differentiated by capabilities and the varying
technical components among devices, such as intermittent/continuous recording,
patient/rhythm activated recording, number of leads, time frames of use and
whether the rhythm is interpreted in real time (attended surveillance) or if
it is transferred from the device and interpreted at a later time. Regardless
of the equipment, these devices provide valuable data for diagnosis of
palpitations, syncope and other signs and symptoms suggestive of cardiac
arrhythmia.

The scope of this LCD is to define the specific patient indications that
support medical necessity for this type of monitoring.

**Definitions**

**Acute Coronary Syndrome (ACS)** - applies to patients with suspicion or
confirmation of acute myocardial ischemia or infarction. It describes a large
array of signs and symptoms that range from atypical chest discomfort,
nonspecific electrocardiographic changes, normal cardiac biomarkers, non-ST-
elevation myocardial infarction (NSTEMI), large ST-segment elevation
myocardial infarction (STEMI), and cardiogenic shock.1

**Silent Myocardial Ischemia** - is defined as 'objective documentation of
myocardial ischemia in the absence of angina or anginal equivalents.'2

**24-hour Monitoring Station** (applicable only to mobile cardiac telemetry) -
is defined as a facility in operation 24-hours per day, seven days a week,
with a receiving station staffed with EKG technicians or other non-physician
staff on a 24-hour per day basis. The technicians should have immediate
24-hour access to a physician to review transmitted data that falls outside of
set parameters. The technicians should know how to contact available
facilities to assist in any cardiac emergencies.3,4,5.

**Covered Indications**

AECG monitoring, when performed with a device that has FDA clearance, will be
considered medically reasonable and necessary in the following situations:

  1. A standard 12-lead electrocardiograph (ECG), complete cardiac history and cardiac exam has not satisfactorily explained the patient's cardiac complaints and AECG testing will provide diagnostic information that will assist in developing a treatment plan or changing a treatment plan for patients that are at risk for cardiac arrythmias.3,6,7  
 **OR**

  2. For patients experiencing unexplained syncope, near syncope, episodic dizziness, chest pain, palpitations, and/or shortness of breath.6   
**OR**

  3. To assess documented or suspected bradycardia.8   
**OR**

  4. For patients experiencing nocturnal arrhythmias.6   
**OR**

  5. To assess the average heart rate and adequacy of rate control in a patient with atrial fibrillation.6   
**OR**

  6. To aid in the regulation of anti-arrhythmic drug dosage.3,6,7,9   
**OR**

  7. To assess the effectiveness of arrhythmia therapy (e.g., post ablation).6   
**OR**

  8. To evaluate prognosis following acute coronary syndrome.6,10   
**OR**

  9. Pre/Post implantable cardiac defibrillator reprogramming.7   
**OR**

  10. To assess for silent myocardial ischemia in a patient with known or suspected coronary heart disease.3,6   
**OR**

  11. To assess for asymptomatic ventricular premature beats or non-sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, dilated or restrictive cardiomyopathy, congenital heart disease, or Brugada syndrome.6,7   
**OR**

  12. To evaluate for occult atrial fibrillation (A-Fib) as a potential cause of cardio-embolism in patients with cryptogenic stroke.4,6

**Note:** A 24-48 hour monitor is most appropriate for patients with daily or
near daily symptoms.6 Otherwise, providers should order the most appropriate
type of AECG for the patient based on their evaluation of the patient, the
patient's symptoms and the devices' labeled indications.

**Note:** The duration of monitoring should be consistent with the patient's
signs and symptoms.3,6,11,12,13

**Limitations**

The following are considered not medically reasonable and necessary:

  1. Devices that do not have FDA clearance, including non-physician prescribed; hand/wrist held - smart phone based devices.
  2. AECG monitoring of potentially harmful ventricular arrhythmias requiring inpatient level of care.12,14
  3. Any 24-hour monitoring station that does not meet the definition in the definition section.3,4,5

Please refer to NCD 20.15 for additional indications and limitations.

**Provider Qualifications**

Services will be considered medically reasonable and necessary when all
aspects of care are within the scope of practice of the provider's
professional licensure, when performed according to the supervision
requirements per state scope of practice laws, and when all procedures are
performed by appropriately trained providers in the appropriate setting.

**Notice:** Services performed for any given diagnosis must meet the
indications and limitations stated in this LCD, the general requirements for
medical necessity as stated in CMS payment policy manuals, any and all
existing CMS national coverage determinations, and all Medicare payment rules.

**Clinical Practice**

Zimetbaum et al14 provides an overview and evaluation for care with patients
that present with palpitations. There are many factors to be considered in the
etiology of palpitations. Cardiac disorders are the most common cause of
palpitations and include arrhythmias, structural heart disease, conduction
system abnormalities, valvular disease, pacemaker syndrome, atrial myoma,
sympathetic stimulation and catecholamine release during exercise and high
output cardiac states. Other etiology of palpitations may include psychiatric
disorders, medication effects, substance abuse, endocrine disorders, and
metabolic disorders.

The workup for a patient who presents with palpitations typically includes an
extensive medical history along with a 12-lead ECG, physical exam and limited
laboratory testing.14(p3)

When an arrhythmia is not identified on the 12-lead ECG, the patient's medical
history can be helpful to note the age of symptom onset, duration of
palpitations, heart rate and rhythm regularity, additional symptoms that are
associated with the palpitations (pre-syncope or syncope), the onset and
resolution of the palpitations, effects of positional changes and if the
patient is able to alleviate the palpitations on their own. In addition, the
cardiac exam should include the patient's family cardiac history and co-
existing medical conditions such as pregnancy, metabolic and endocrine issues,
chronic obstructive pulmonary disease, and psychiatric disorders.14(p2)

Following an extensive cardiac exam, if the etiology of the palpitations
remains unclear limited laboratory testing for anemia, hyperthyroidism, and
toxicology testing may be indicated, as well as echocardiography for patients
with possible structural heart disease.

**Holter vs. Continuous Long-Term Electrocardiographic (LT-ECG) Monitors**

Barrett et al15 conducted a prospective analysis of cardiac arrhythmias using
the Holter monitor and the Zio patch between April 2012 and July 2012. The
goal was to compare arrhythmia detections over the course of 14 days to the
arrhythmia events detected in the first 24 hours of monitoring.

One hundred and forty-six patients between the ages of 22 and 94 participated
in the study. The average wear time of the AECG monitors ranged between one
day for the Holter monitor and eleven days for the patch monitor. Both devices
were activated simultaneously and monitored for 24 hours for the Holter
monitor and up to 14 days for the patch monitor. All arrhythmias were
evaluated by the Scripps Translational Science Institute and the McNemar's
test was implemented to compare if arrhythmias were clinically significant and
what type of arrhythmias were detected by each monitor.

Arrhythmia detection was placed into six categories: supraventricular
tachycardia (SVT) (>4 beats, not including A-Fib or A-Flutter),
A-Fib/A-Flutter (>4 beats), pause >3 seconds, atrioventricular block (Mobitz
type II or third-degree atrioventricular [AV] block), ventricular tachycardia
(VT) (>4 beats), or polymorphic ventricular tachycardia/ventricular
fibrillation.15(p14)

The results demonstrated that the "patch monitor detected 96 arrhythmia events
compared with 61 arrhythmia events by the Holter monitor ( _P_ <
.001)."15(p12) The patch monitor and Holter monitor detected the same number
of events, but "14 clinically significant arrhythmia events were detected by
the adhesive patch monitor that went undetected by the Holter monitor."15(p12)

The secondary effect was to determine the arrhythmias that were detected in
the first 24 hours. It was noted that the Holter monitor detected 61
arrhythmias compared to 52 arrhythmias detected by the patch monitor ( _P_
=.013). In review of the arrhythmia types three events were considered
'clinically significant' and were ultimately detected by the patch monitor
beyond the first 24 hours.

In conclusion, the first seven days of AECG monitoring has the greatest
detection of arrhythmias. Typically monitoring greater than seven days may
only provide an additional 3.9% chance of identifying a different diagnosis as
noted by the Zimetbaum (1998) article.

Rosenberg et al16 conducted a single-center pilot study to compare the use of
a continuous LT-ECG recorder, with a 24-hour Holter monitor in 74 patients
with paroxysmal A-Fib (AF), between April 2011 and May 2012. During the
initial 24-hour monitoring period, both the Holter monitor, and the continuous
LT-ECG recorder detected 25 AF occurrences. Patients continued to wear the
continuous LT-ECG recorder for an additional two weeks, during which 43 more
patients were diagnosed with AF. This indicates that AF episodes were detected
in significantly more patients wearing a continuous LT-ECG recorder due to the
longer duration of detection, compared with the Holter monitor. Furthermore,
in this study, the LT-ECG recorder also detected cardiac pauses after the
initial 24-hour monitoring, thus prompting physicians to review medications
and initiate pacemaker referrals for this patient group.

**Holter Monitor**

Paudel et al17 conducted a prospective, single center study that included 335
patients who had symptoms of recurrent chronic palpitations or a single
episode of palpitations. These patients were older than 18 years of age and
the study was conducted from January 2010 to May 2012.

Patients were provided a Cardio Blue 24-hour Holter monitor that recorded in
either three or five channels and allowed for recording of arrhythmias, as
defined by the American College of Cardiology (ACC)/American Heart Association
(AHA), with or without corresponding documented symptoms.

The arrhythmias that were identified via the Holter monitor were: less than
10% ventricular ectopy, 36.7% bigeminy, less than 10% supraventricular
episodes, 5.7% non-sustained VT and 12.5% sustained VT.

The study groups were noted to be statistically significant for patients that
were younger than 50 years of age and those who were 50 years of age or older.
The highest categories of arrhythmias were related to patients that were older
than 50 years of age. This study group had a 72% rate with premature
ventricular contactions (PVCs) and 44% with bigeminy as compared to 38.7%
having PVCs and 23.1% with bigeminy that were younger than 50 years of age.

The authors reviewed literature provided by Mayet (1995) and Stein (2010). The
conclusion of those two articles determined that Holter monitors detect
arrhythmias such as ventricular bigeminy, VT, SVT, AV blocks, and silent
ischemia in older patients who are more at risk of sudden cardiac death.

**Event Recorders/Intermittent Monitors**

Fredriksson et al18 studied intermittent AECG recordings versus continuous
event recording in detecting A-Fib for patients 75-76 years of age. Two-
hundred and sixty-nine patients that were included in this analysis were from
the STROKESTOP II study from Europe. This study was conducted over a two-week
period with 55 days on average for the intermittent recorders and 13 days on
average for the continuous recorders. The devices were R-test 4 and Novocaor
(for continuous recording) and a 30 second handheld device Zenicor II (for
intermittent recording). All devices had activation buttons for symptomatic
arrhythmias, and patients were given a symptom diary as well. Within the
study, A-Fib was defined by the European Society of Cardiology (ESC) as
"absolute irregular rate-to-rate intervals, no discernable distinct p-waves,
and duration of at least 30 seconds" and recordings were manually inspected
and validated on computerized algorithms.18(p360)

After the review of data, it was determined that continuous event recordings
identified three times more cases of A-Fib (6%; n=15/269) than the
intermittent AECG recordings (2%; n=5/269) ( _p_ =.002). On average,
continuous recordings identified a 1-8 interquartile range (IQR) on day four
and a 4-14 IQR on day eight for intermittent monitoring ( _P_ =.135). These
IQR's were analyzed using the Mann-Whitney U test and Chi-square tests in
relation to proportions. While comparisons between the two monitoring methods
were performed, the use of the McNemar's test resulted in P< .05, which was
considered significant when testing for dichotomous variables and paired
sample t-test for continuous variables.18(p356)

Surprisingly, only six percent of the patients reported symptoms within their
diaries when having verified A-Fib and none of the patients had reported
palpitations. Limitations of the study include: patients that were part of a
larger study (STROKESTOP II) and were thus highly motivated and possibly
healthier than peers, use of one-lead AECGs that potentially complicate the
analysis of the p-waves, possible bias by misclassification case, and
conflicts of interest for those study team members receiving grants from
companies such as Bayer, Pfizer, Sanofi, AstraZeneca, and Medtronic.

**External Loop Recorders/Mobile Cardiovascular Outpatient Telemetry**

Favilla et al19 provides a retrospective cohort study of 227 patients with
cryptogenic stroke (179 patients) or transient ischemic stroke (48 patients).
These patients underwent a 28-day mobile cardiac outpatient telemetry (MCOT),
post cryptogenic or transient ischemic stroke. Of the 277 patients, 14% had
A-Fib detected on MCOT, 58% of which was  30 seconds in duration. It was
determined that age and prior cortical or cerebellar infarctions were
independent predictors of A-Fib.

Rothman et al20 provided a prospective clinical trial of randomized patients
that were evaluated with the CardioNet system in 17 multicenter facilities.
Two-hundred and sixty-six patients who had palpitations, presyncope, and/or
syncope were included. The goal was to confirm or exclude the etiology of
arrhythmias that caused patient symptoms. All patients had previously
undergone 24 hours of monitoring with a Holter monitor, which failed to
provide diagnostic information. These patients were placed in two groups for
30 days of monitoring with either the MCOT or with an external looping event
monitor (ELM).

During monitoring, clinically significant arrhythmias were detected in 55
(41%) patients with the MCOT versus 19 (15%) patients with the ELM ( _P_ <
0.001). For patients who had prior syncope or presyncope, clinically
significant arrhythmias were detected in 52% of patients with MCOT and in 16%
of patients with loop recorders ( _P_ < 0.001). In most cases, the arrhythmias
detected were A-Fib, atrial flutter, or ventricular tachycardia. There were
two subgroups noted in the study. For one subgroup of patients presenting with
"syncope or presyncope, a diagnosis was made in 89% of MCOT subjects versus
69% of LOOP subjects ( _P_ =0.008)."20(p243) A second subgroup analysis was
performed at the centers that used auto-triggered loop monitoring rather than
patient-activated monitoring. For this subgroup, a definitive diagnosis was
obtained for 88% of MCOT patients and only 46% ( _P_ =0.002) of the ELM
patients; however, this subgroup analysis involved only 50 of the 266
patients.

**Insertable Cardiac Monitor/Subcutaneous Cardiac Rhythm Monitors**

Nadkarni21 provides an overview of subcutaneous cardiac rhythm monitors
(SCRMs) with the high diagnostic yield for "cryptogenic stroke, syncope,
palpitation and AF [A-Fib] Monitoring."21(p588) It has long been noted that
there is no established guideline for the use of SCRMs and the rate of false-
positive transmissions has been the 'Achilles heel' of AECG. The author
determines that the indications for use, techniques used in implantation,
programming, and connectivity determine the clinical benefits for patients.
Within this overview the author cites the ABACUS prospective randomized
control trial by Kapa et al. This trial noted that SCRMs "led to more
actionable events and higher rates of antiarrhythmic discontinuation when
compared with other forms of rhythm monitoring in a post AFib ablation
population."21(p588)

The versatility of the SCRM allows for adjustments in tachycardia and
bradycardia thresholds, minimum episode durations, and the detection of atrial
tachycardia and atrial fibrillation. Along with the versatility is the ability
to transmit data in two ways: alert notifications and manual downloads by the
patient via their home or cell phone application. With that noted and
continual advancements, SCRMs have proven to be beneficial for patients.

SCRMs remain a valuable tool in the diagnosis of cardiac events.

**Professional Societies and Associations**

_American College of Cardiology (ACC)/American Heart Association (AHA) Task
Force on Clinical Practice Guidelines_

Kusumoto8 provides a consensus statement on behalf of the ACC/AHA and the task
force for clinical practices. The statement provides an overview and
recommendations regarding appropriate use of AECG monitoring, particularly in
the context of diagnosing bradyarrhythmia, and patients with bradycardia and
cardiac conduction delays, patients can be managed with a 24-to-48-hour
continuous AECG. For patients that present with symptoms that are greater than
30 days between symptoms, the use of a broad array of modalities, such as
long-term monitors, implantable cardiac monitors, etc., would be appropriate
if the initial non-invasive evaluation was not diagnostically conclusive. The
guideline indicates that the "Choice of device is predicated on frequency of
symptoms and the degree to which symptoms incapacitate the patient" and that
regardless of the monitoring system, it is important for the system to notify
health care providers in a timely fashion, especially in regard to identifying
potentially dangerous arrhythmias.8(p399)

_American Heart Association /American College of Cardiology/ Heart Rhythm
Society Clinical Practice Guidelines_

Al-khatib9 provides clinical guidelines for the use of AECG monitoring
indicating that suspected arrhythmias, the frequency of arrhythmias, and the
associated symptoms dictate monitor type. For example, event or 'Looping'
monitors are more appropriate and have greater diagnostic yields for sporadic
symptoms. It further explains that when ventricular arrhythmias are identified
and potentially harmful, AECG may not be appropriate. Further information upon
the use of AECG monitoring is indicated when assessing medical therapy
response.

_International Society for Holter and Noninvasive Electrocardiology (ISHNE),
and the Heart Rhythm Society (HRS) expert consensus statement_

Steinberg7 provides a consensus statement that outlined the limitations,
clinical indications, pharmacological treatment of arrhythmias, and the use of
external monitoring for pacemaker malfunctioning/placement. It is noted that
for the selection of specific AECG monitors, one must consider the diagnostic
power, the monitoring capability and the accuracy, local availability, symptom
frequency, patient compliance and the condition of the patient. Within the
article there are descriptions of advantages and limitations associated with
each AECG monitor. The clinical indications for use of the various types of
monitors can include the following: syncope, bradyarrhythmia, tachyarrhythmia,
palpitations, chest pain and coronary ischemia, ischemic heart diseases and
postinfarction, hypertrophic cardiomyopathy, arrhythmic right ventricular
dysplasia/cardiomyopathy, Wolff-Parkinson-White syndrome, inherited primary
arrhythmic diseases, Short or Long QT syndrome, Brugada syndrome,
catecholaminergic polymorphic ventricular tachycardias, early repolarization
syndromes, idiopathic ventricular fibrillation with nonischemic dilated
cardiomyopathy, dialysis and chronic kidney disease associated arrhythmias. It
is noted that the use of monitoring with AECG for neurological and muscular
disease is controversial. The article further indicates an appropriate
clinical assessment may include a continuous AECG, and if unsuccessful,
additional monitoring should include an intermittent external loop recording.
If patients remain undiagnosed after prolonged noninvasive monitoring, an
internal loop recorder (ILR) may be necessary.

Coverage of items and services in the Medicare program is provided based on
what is medically reasonable and necessary. This concept is operationalized by
the application of evidentiary standards, clinical validity, and clinical
utility. Over the years, AECG monitoring has advanced and evolved to include a
spectrum of technology, from the long standing Holter monitors to the present-
day Bluetooth enabled AECG monitors that allow for increased functionality and
patient convenience. Arrhythmias often remain unpredictable in onset, vary in
duration and the episodes can be incapacitating and life threatening for the
patient. The evidence thresholds for coverage are a careful balance of
benefits and harms in the consideration of net health outcomes.

The FDA provides controls and guidance in relation to AECG's through the FDA
510(k) device approval. There are over 400 approved AECG monitoring devices
aimed at improving the recognition, interpretation, and etiology of various
arrhythmias. With these devices, health care professionals have many choices
for obtaining the necessary diagnostic information.

In review of these clinical trials, randomized controlled trials (RCTs), meta-
analyses, societal recommendations, and literature it is noted that there are
different standards for AECG based on patient symptoms, antiarrhythmic
regulation, post internal cardiac defibrillator insertion, cryptogenic stroke,
cardio-embolism, transient ischemic stroke, silent myocardial ischemia,
conduction disorders, and the evaluation of A-Fib/A-Flutter. It is generally
expected that through a detailed exam that is based on patient signs and
symptoms, a thorough cardiac exam, review of the patient medical/family
histories to assess for conduction system abnormalities, valvular disease,
metabolic disorders, endocrine issues, chronic obstructive pulmonary disease,
structural heart disease, toxicology, and physiological disorders, the
practitioner will be able to diagnose and treat the patient. If further
diagnostic information is needed, a 12-lead EKG is appropriate and when
combined with the patient's capability and potential compliance, will aid the
healthcare provider in determining if AECG monitoring is appropriate and which
AECG monitoring device should be used.

Societal evidence provides the support for the use of AECG when evaluating for
effective use of antiarrhythmic drugs, in the context of pre/post operative
re-programing of defibrillators, to assess for known or suspected coronary
artery disease, for evaluation and assessment of asymptomatic ventricular
premature beats, and for evaluation and assessment of non-sustained
ventricular tachycardia in patients with hypertrophic cardiomyopathy,
arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, dilated or
restrictive cardiomyopathy, congenital heart disease, or Brugada syndrome.

The progression of non-invasive diagnostics to more invasive diagnostics is
the standard of care taking into consideration benefits versus harm to
patients while determining the etiology and treatment options for patients
with arrhythmias. With the advancements in monitoring capabilities the
ordering provider has multiple available alternatives to determine the type of
monitoring needed for the individual needs of the patient.

After review of the available literature, it has been determined that limited
coverage for AECG is medically reasonable and necessary when a 12-lead EKG
does not provide an adequate diagnosis. It is expected that providers will use
the most appropriate AECG device consistent with the patients' signs and
symptoms.