bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accelerometer‐Derived Time Intervals during Various Pacing Modes in Patients with Biventricular Pacemakers: Comparison with Normals
Authors: MARCUS FRANK I. , SORRELL VINCENT , ZANETTI JOHN , BOSNOS MIKE , BAWEJA GURPREET , PERLICK DOUG , OTT PETER , INDIK JULIA , HE DING SHENG , GEAR KATHY 
Published: August 2010

Introduction:

Changes due to biventricular pacing have been documented by shortening of QRS duration and echocardiography. Compared to normal ventricular activation, the presence of left bundle branch block (LBBB) results in a significant change in cardiac cycle time intervals.
Some of these have been used to quantify the underlying cardiac dyssynchrony, assess the effects of biventricular pacing, and guide programming of ventricular pacing devices. This study evaluates a simple noninvasive method using accelerometers attached to the skin to measure cardiac time intervals in biventricularly paced patients.
Methods:

Ten patients with biventricular pacemakers previously implanted for congestive heart failure were paced in the AAI mode, then in atrioventricular (AV) sequential mode from the right and left ventricles followed by biventricular pacing. Simultaneous recordings were obtained by 2D, Doppler echocardiography as well as by accelerometers. Similar recordings were obtained from 10 gender, aged matched, normal controls during sinus rhythm.
Results:

Compared to normals, heart failure patients paced in AAI mode had prolonged isovolumetric contraction time (IVCT), shorter ventricular ejection time (LVET), and prolonged isovolumetric relaxation (IVRT). With biventricular pacing the IVCT decreased, but the LVET and IVRT did not change significantly. There was excellent correlation between the echo and accelerometer‐measured intervals.
Conclusions:

Shortening of the IVCT measured by an accelerometer is a consistent time interval change due to biventricular pacing that probably reflects more rapid acceleration of left ventricular ejection. The accelerometer may be useful to assess immediate efficacy of biventricular pacing during device implantation and optimize programmable time intervals such as AV and interventricular (VV) delays.
Comparison of Microvolt T‐Wave Alternans Measurements Using Atrial Pacing Compared to Atropine Administration
Authors: WEBER STEFAN , SCHWAB JÖRG O. 
Published: August 2010

Background:

Microvolt T‐wave alternans (MTWA) has been associated with malignant ventricular arrhythmias in patients (pts) with structural heart disease. MTWA has been shown to be a strong heart rate‐dependent arrhythmia marker. However, in clinical practice some pts in which MTWA should be assessed are unable to perform physical exercise to increase heart rate due to various reasons.
Methods:

In this study, we investigated the feasibility of noninvasive MTWA measurement by using intravenous atropine to increase heart rate and compared the results to MTWA measurement by right atrial (RA) pacing during electrophysiologic (EP) study in 27 consecutive pts (53 ± 14 years; nine women). Determining the arrhythmia event‐rate, a follow‐up of 18 months was performed in all pts.
Results:

Using atropine, five pts (18%) did not reach the target heart rate (105 bpm). In the remaining group of pts, concordant results for MTWA assessment could be found in 21 pts (96%). Comparing MTWA positive tests there were slightly higher amplitudes using right atrial (RA) pacing than atropine (7.0 ± 2.3μV vs 6.3 ± 2.2μV, P = 0.03; r = 0.97). During follow‐up all pts with a positive MTWA test had documented ventricular arrhythmias. There were no arrhythmic events in the MTWA negative group.
Conclusion:

Whenever target heart rate for MTWA evaluation is obtained by intravenous atropine, the results are comparable to RA pacing. In using atropine there has been observed no pharmacologically influenced increase of MTWA voltage leading to false positive MTWA results. Therefore the use of atropine can be recommended as a safe, non‐invasive, and reliable method for MTWA assessment.
Exercise Does Not Increase QTcmax and QTcd in Diabetic Patients with Autonomic Neuropathy
Authors: YAZICI MEHMET , OZDEMIR KURTULUS , ALTUNKESER BULENT BEHLUL , YAZICI RAZIYE , KAYRAK MEHMET , ULGEN MEHMET SIDDIK , ALIHANOGLU YUSUF , GOK HASAN 
Published: August 2010

Background:

The purpose of this study was to examine the effects of exercise on maximum QTc interval (QTcmax) and QTc dispersion (QTcd) in diabetic patients without clinically evident heart disease.
Methods

: Seventy‐six diabetic patients who had no coronary artery disease or hypertension (group I; mean age 48 ± 9 years old) and 40 healthy volunteers (group II; mean age 46 ± 13 years old) were enrolled in the study. Cases with clinically evident heart disease were excluded from the study. Resting 12‐lead electrocardiogram (ECG) and maximal treadmill exercise test (according to Bruce protocol) were performed in all cases. The QTcmax interval was determined at rest (RQTcmax) and during peak exercise (PQTcmax). Also, the QTcd was measured at rest (RQTcd) and during peak exercise (PQTcd). Autonomic neuropathy was assessed by measuring the heart rate variability (HRV).
Results

: There was no significant difference between clinical characteristics of two groups. In group I, HRV parameters were significantly lower than group II. RQTcd, PQTcd, RQTcmax, and PQTcmax were significantly longer in group I (56 ± 16 vs 34 ± 11; P< 0.001, 62 ± 22 vs 40 ± 15; P < 0.001, respectively). In diabetic patients, there was no significant difference between RQTcmax and PQTcmax (428 ± 19 vs 420 ± 31; P > 0.05), and no significant difference was present between RQTcd and PQTcd (56 ± 16 vs 62 ± 22; P > 0.05, respectively).
Conclusion

: Exercise does not affect QTcd in patients with diabetes mellitus and without clinically evident heart disease.
Tilt Training: Does It Have a Role in Preventing Vasovagal Syncope?
Authors: GUREVITZ OSNAT , BARSHESHET ALON , BAR‐LEV DAVID , ZIMLICHMAN EYAL , ROSENFELD GAIL F , BENDERLY MICHAL , LURIA DAVID , AMITAL HOWARD , KREISS YITSHAK , ELDAR MICHAEL , GLIKSON MICHAEL 
Published: August 2010

Background:

Vasovagal syncope is one of the most common medical conditions in young adults. Previous trials have shown effectiveness of tilt training in treating this condition. We conducted a prospective, randomized study in order to evaluate the role of tilt‐training in young adults with vasovagal syncope.
Methods:

Forty‐six soldiers (mean age 19.4 ± 0.8 years, 25 males), with a clinical diagnosis of vasovagal syncope supported by positive tilt test, were randomized to either three months of daily tilt training (treatment group), or no training (control group). Patients in both groups were instructed to increase fluid and salt intake, and to refrain from syncope‐inducing situations, such as prolonged standing.
Results:

Compliance, defined as performing 50% or more of the tilt training daily sessions, was 91% during the first month, and declined to 58% during three months. Treatment group patients had a median (interquartile range) of 5.0 (0.5–16.0) syncope episodes during one‐year follow up, compared to a median of 2.0 (0–6.0) episodes in the control group (P = 0.737). Also, there was no difference in time to first syncope after randomization between groups: a median of 1.0 (0.5–2.0) month in the treatment group, compared to 0.8 (0.5–2.0) month in the control group (P = 0.336).
Conclusions:

Adding daily three‐month tilt training to modifications in lifestyle does not improve treatment results in young adults with vasovagal syncope. Good compliance is difficult to achieve in a tilt training program.
Spatial and Topologic Distribution of Verapamil‐Sensitive Atrial Tachycardia Originating from the Vicinity of the Atrioventricular Node
Authors: KOYAMA JUNJIROH , YAMABE HIROSHIGE , TANAKA YASUAKI , MORIHISA KENJI , UEMURA TAKASHI , KAWANO HIROAKI , OGAWA HISAO , ODAGAWA YUKINARI , HONDA TOSHIHIRO , HONDA TAKASHI 
Published: August 2010

Background:

Little information exists regarding the precise distribution of verapamil‐sensitive atrial tachycardia originating from the vicinity of the atrioventricular node (V‐AT).
Methods:

In 12 patients with V‐AT, we examined the spatial and topologic distribution of tachycardia origin relative to the His bundle (HB) site. The V‐AT origin was divided into six areas: anterior (A‐HB), posterior (P‐HB), superior (S‐HB), inferior (I‐HB), lateral (L‐HB), and septal (SP‐HB) portion of HB catheter. Three dimensional distance between the distal pair of the electrodes of HB catheter and that of V‐AT origin (DIS) was obtained by calculating the distances on the right and left anterior fluoroscopic images. Topologic distribution was expressed as the interval between the onset of the atrial electrogram of V‐AT origin and that of HB catheter (INT).
Results:

The tachycardia origin was observed at the P‐HB in four, S‐HB in two, I‐HB in two, SP‐HB in three, and L‐HB in one patient. The tachycardia cycle length, DIS, and INT were 369 ± 67 ms, 12 ± 3 mm, and −12 ± 8 ms, respectively. After successful ablation of initial V‐AT (1st V‐AT), V‐AT with a different origin (2nd V‐AT) was induced in five patients. The tachycardia origin, tachycardia cycle length, DIS, and INT of the 2nd V‐AT (P‐HB in three, S‐HB in one, and SP‐HB in one patient; 333 ± 66 ms, 8 ± 3 mm, and −11 ± 4 ms, respectively) were not different from those of 1st V‐AT.
Conclusions:

V‐AT often shows a shift in tachycardia origin to another site where the spatial and topologic distributions are similar to those of 1st V‐AT.
Psychological Intervention Following Implantation of an Implantable Defibrillator: A Review and Future Recommendations
Authors: PEDERSEN SUSANNE S. , VAN DEN BROEK KRISTA C. , SEARS SAMUEL F. 
Published: August 2010

Background:

The medical benefits of the implantable cardioverter defibrillator (ICD) are unequivocal, but a subgroup of patients experiences emotional difficulties following implantation. For this subgroup, some form of psychological intervention may be warranted. This review provides an overview of current evidence on the efficacy of psychological intervention in ICD patients and recommendations for future research.
Methods:

We searched the PubMed and PsycInfo databases in the period between January 1980 and April 2007, using a set of a priori determined keywords. Based on the search and a hand search of the reference lists of the included articles, we identified nine studies that fulfilled the inclusion criteria.
Results:

The majority of studies used a randomized controlled trial design, but studies varied considerably in sample size, response, attrition rate, and type of intervention. However, most interventions were multifactorial, using cognitive behavioral therapy as one of the mainstays of treatment. Overall, psychological interventions seem to have little impact on shocks and heart rate variability. Some studies found a decrease in depressive symptoms and gains in quality of life, but the most notable effects are seen in improved exercise capacity and reductions in anxiety. Effect sizes for changes in anxiety in the intervention group ranged from small to large compared to small in the usual care group, using Cohen's effect size index.
Conclusions:

Preliminary evidence from small‐scale intervention trials suggests that psychological intervention is worthwhile in ICD patients. Nevertheless, large‐scale, well‐designed trials are warranted to substantiate these findings. A multifactorial approach using a cognitive behavioral component paired with exercise training is likely to be the most successful.
Characterization of Human Coronary Sinus Valves by Direct Visualization during Biventricular Pacemaker Implantation
Authors: ANH D.J. , EVERSULL CHRISTIAN S. , CHEN HENRY A. , MOFRAD PIROOZ , MOURLAS NICHOLAS J. , HARDWIN MEAD R. , ZEI PAUL C. , HSIA HENRY H. , WANG PAUL J. , AL‐AHMAD AMIN 
Published: August 2010

Background: The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus.
Objectives: The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices.
Methods: The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC).
Results: The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization.
Conclusions: Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.
Mechanisms of Ventricular Fibrillation Initiation in MADIT II Patients with Implantable Cardioverter Defibrillators
Authors: ANTHONY RYAN , DAUBERT JAMES P. , ZAREBA WOJCIECH , ANDREWS MARK L. , McNITT SCOTT , LEVINE ETHAN , HUANG DAVID T. , HALL W. JACKSON , MOSS ARTHUR J. ,   For The Multicenter Automatic Defibrillator Implantation Trial‐II (MADIT‐II) Investigator
Published: August 2010

Background:

The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics.
Methods:

Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index.
Results:

Sixty episodes of VF among 29 patients (mean age 64.4 ± 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short‐long‐short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS‐initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 ± 104 ms for SLS and 744 ± 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on β‐blockers compared to 83% of the VPC patients.
Conclusion:

Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause‐dependent arrhythmias are unlikely to decrease the incidence of VPC‐initiated episodes of VF.
Risk of Interference from Transcutaneous Electrical Nerve Stimulation on the Sensing Function of Implantable Defibrillators
Authors: HOLMGREN CHRISTINA , CARLSSON TOBIAS , MANNHEIMER CLAS , EDVARDSSON NILS 
Published: August 2010

Background:

The use of transcutaneous electrical nerve stimulation (TENS) for pain relief is increasing. At the same time the implantable cardioverter defibrillator (ICD) is a routine treatment for malignant tachyarrhythmias. Today patients often need devices for more than one condition, and consideration must be given to the interaction between them. We studied the risk of interference between TENS and the ICD function.
Methods and Results:

Thirty patients who had received an ICD underwent a test protocol including TENS at the mammilla and hip levels, at two energy levels, and at the highest comfortable stimulation level. The effects of TENS on the electrocardiogram lead II, intracardiac electrograms, and the ICD marker channels were analyzed. Disturbance from TENS on the sensing function was seen at all stimulation attempts. Interference between the systems was observed in 16 patients. In eight patients (27%) the interpretation was VT/VF and in 14 patients (47%) as ventricular premature extra beats. Other kinds of interactions were seen in five patients (16%). Each patient could have more than one kind of interference.
Conclusions:

Noise reversion and undersensing might prevent the ICD from delivering shock when it should and the interpretation as VT/VF could result in inappropriate shocks. Because of the potentially serious consequences of interference we do not recommend the use of TENS in patients with ICD.
Left Ventricular Dysfunction after Cardiac Resynchronization Therapy in Congenital Heart Disease Patients with a Failing Systemic Right Ventricle
Authors: KIESEWETTER CHRISTOPH , MICHAEL KEVIN , MORGAN JOHN , VELDTMAN GRUSCHEN R 
Published: August 2010

Background:

Cardiac resynchronization therapy is rapidly emerging as an effective strategy for managing ventricular dysfunction and heart failure associated with congenital heart disease. Indications for therapy, optimal lead placement, and late outcomes are however lacking.
Methods:

We present three patients, one with Mustard procedure and two with congenitally corrected transposition of great arteries, who developed subpulmonic ventricular dysfunction 3–6 months after biventricular pacing ± implantable cardioverter defibrillator implantation, despite initial favorable result of resynchronization therapy. Possible factors for adverse outcome are relatively high pacing rate, unfavorable alteration of torsional contraction, and increased atrioventricular valve regurgitation due to suboptimal placement of larger diameter defibrillation leads.
Results:

Careful evaluation of patients, particularly indications for therapy, need to be rigorous; assessment of hemodynamic response at the time of implant and appropriate programming may improve the effectiveness of cardiac resynchronization therapy (CRT) in this patient population.
Conclusion:

Our case series emphasizes the need for a registry in the absence of randomized controlled trials, in order to identify patients who benefit most from CRT, and, importantly, recognize subgroups that respond poorly.
Rate Responsive Pacemakers: A Rapid Assessment Protocol
Authors: SHABER JUSTIN D. , FISHER JOHN D. , RAMACHANDRA INDIRESHA , GONZALEZ CHRISTIAN , ROSENBERG LAUREN , FERRICK KEVIN J. , GROSS JAY N. , KIM SOO G. 
Published: August 2010

Background:

Rate responsive (RR) pacemakers are commonly implanted with nominal conservative factory‐set responsiveness, which is usually accepted because established exercise protocols are time‐consuming. We aimed for efficient assessment of RR pacemaker settings.
Methods:

We tested exercise heart rates in controls and paced patients using a brief exercise test that approximates real‐life levels of exertion. The test used a nonmotorized treadmill: 30 seconds walking at patient‐determined speed followed by 15 seconds brisk exertion. Subjects totaled 110: 26 with RR pacemakers; 22 with non‐RR pacers; 27 “sick” nonpaced control patients; and 35 healthy controls. Heart rate (HR) was measured prior to exercise, after 30 seconds of casual walk, after 15 seconds of brisk walk, and 1 minute into recovery. Testing required <5 minutes from set‐up to recovery.
Results:

The 26 RR pacer patients had a mean HR at rest = 74 ± 10 beats per minute (bpm), walk = 87 ± 14, and brisk = 94 ± 18 (increase 27%). Non‐RR pacer patients (n = 22): rest = 73 ± 12 bpm, walk = 88 ± 14, and brisk = 94 ± 17 (increase 24.3%, P = 0.60 vs RR patients). “Sick” controls (n = 27): rest = 78 ± 14 bpm, walk = 102 ± 17, and brisk = 117 ± 18 (increase 51.9%, P< 0.001 vs RR pts). For the healthy controls, HRs were at rest 83+/11 bpm, walk = 104 ± 12, and brisk = 117 ± 13 (P< 0.001 compared to both paced groups; P = NS vs sick controls).
Conclusions:

Nominal RR settings may be suboptimal for many patients. The nonmotorized treadmill test allows quick and inexpensive assessment of RR programming, with the potential for efficient RR optimization.
Evaluation of Fractal‐Coated Temporary Pacing Leads in the Early Postoperative Course
Authors: MELLERT FRITZ , KONIETZKO PETER , SCHNEIDER CHRISTIAN , GERSING EBERHARDT , KREUZ JENS , BALTA OSMAN , PREUSSE CLAUS J. , WELZ ARMIN 
Published: August 2010

Background:

The performance of temporary pacing wires is still limited by capture and sensing problems. Fractal coating can enhance electrical properties and reliability. We therefore investigated fractal‐laminated wires in comparison with conventional wires.
Methods:

In 21 patients two unipolar, fractal‐coated pacing wires (fe) and one conventional bipolar electrode (se) were implanted in ventricular position. Afterward pacing threshold (V), R‐wave sensing (mV), lead impedance (ohm), and slew‐rate (mV/s) were measured. Loss of capture or sensing and dislocation was documented. fe wires were examined with energy dispersive x‐ray diffraction (EDX)‐analysis and scanning electrode microscopy (SEM).
Results:

Failure in pacing was less frequent in fe wires. Also fe leads had lower pacing thresholds at implantation (0.76 ± 0.15 V vs 1.51 ± 0.95 V, P< 0.0001) and afterward. Furthermore fe wires showed lower increase of pacing threshold/time (0.25 V/day vs 0.42 V/day). R‐wave sensing and slew‐rate values in the fe group on day of operation (5.81 ± 4.80 mV; 0.63 ± 0.71 V/s) were lower than in the se group (10.37 ± 6.89 mV; 1.85 ± 1.71 V/s P< 0.0001) and afterward. Nevertheless, decrease of amplitude/time was lower in fe wires (0.17mV/day vs 0.46 mV/day). fe wires always had lower impedance values.
Conclusions:

Lower pacing threshold and increase of threshold/time in fe wires indicate more reliable function. Initial lower sensitivity values are still not understandable and must be investigated. However, fe wires, constancy of sensing and impedance values was more stable, so fe epicardial wires can be recommended for safe and feasible use.
Indications for Pacing in Patients with Congenital Heart Disease
Authors: Villain Elisabeth 
Published: August 2010

Background: Advances in pacing technology have increased indications for antibradycardia pacing and new indications have appeared for treatment of atrial tachycardia and cardiac failure in patients with congenital heart disease (CHD).
Methods and Results: Implantation of a pacemaker is mandatory for symptomatic children with complete atrio‐ventricular block (CAVB). In asymptomatic neonates and infants, prophylactic pacing is indicated when the ventricular rhythm is <55 beats per minute (bpm) or 70 bpm in case of significant cardiac malformations. Beyond one year of age, PM implantation is recommended in children with an average heart rate <50 bpm or long pauses on 24‐hour recordings. Post‐operative block that persists 7 days after cardiac surgery is a class I indication for pacing. Postoperative heart block may also be transient, but patients with residual conduction abnormalities and a long HV interval have a high risk of late sudden death and should be paced. After cardiac surgery, atrial pacing may also be considered, in patients with severe sinus bradycardia and symptoms, or in those requiring antiarrhythmic drugs for tachy‐bradycardia syndrome; in case of failure of antiarrhythmic drugs, antitachycardia atrial pacing now appears to be safe and efficacious. Finally, cardiac resynchronization therapy may apply to children with congenital heart block and cardiomyopathy, as well as to the population with CHD. Methods and results are described in the section dedicated to resynchronization.
Conclusion: Cardiac pacing indications have extended beyond prevention of sudden death and pacemaker implantation is now indicated to improve quality of life of patients with CHD and as a bridge to cardiac transplantation.