Palpitation: Extended Electrocardiogram Monitoring: Which Tests to Use and When.

Palpitation is common. It is often accompanied by dizziness, lightheadedness, near syncope, and even syncope. It may be difficult to confirm a diagnosis in patients with infrequent symptoms.

Ampere Hour as a Predictor of Cardiac Resynchronization Defibrillator Pulse Generator Battery Longevity: A Multicenter Study.

Background: Cardiac resynchronization defibrillator (CRT-D) devices improve survival for New York Heart Association classes II-IV systolic heart failure patients with QRS > 120 ms and left ventricular ejection fraction < 35%. A limitation of 100% CRT pacing is excess battery depletion and pulse generator (PG) replacement compared to VVI or dual-chamber systems. Ampere hour (Ah) measures PG battery capacity and may predict CRT-D device longevity.

Toward guidance of epicardial cardiac radiofrequency ablation therapy using optical coherence tomography.

Radiofrequency ablation (RFA) is the standard of care to cure many cardiac arrhythmias. Epicardial ablation for the treatment of ventricular tachycardia has limited success rates due in part to the presence of epicardial fat, which prevents proper rf energy delivery, inadequate contact of ablation catheter with tissue, and increased likelihood of complications with energy delivery in close proximity to coronary vessels. A method to directly visualize the epicardial surface during RFA could potentially provide feedback to reduce complications and titrate rf energy dose by detecting critical structures, assessing probe contact, and confirming energy delivery by visualizing lesion formation.

Real-time monitoring of cardiac radio-frequency ablation lesion formation using an optical coherence tomography forward-imaging catheter.

Radio-frequency ablation (rfa) is the standard of care for the treatment of cardiac arrhythmias; however, there are no direct measures of the successful delivery of ablation lesions. Optical coherence tomography (OCT) imaging has the potential to provide real-time monitoring of cardiac rfa therapy, visualizing lesion formation and assessing tissue contact in the presence of blood. A rfa-compatible forward-imaging conical scanning probe is prototyped to meet this need.

In vitro characterization of cardiac radiofrequency ablation lesions using optical coherence tomography.

Currently, cardiac radiofrequency ablation (RFA) is guided by indirect signals. We demonstrate optical coherence tomography (OCT) characterization of RFA lesions within swine ventricular wedges. Untreated tissue exhibited a consistent birefringence artifact within OCT images due to the organized myocardium, which was not present in treated tissue.

The future of fellowship training in clinical cardiac electrophysiology: Program directors' perspective 2008.

Background: At the Clinical Cardiac Electrophysiology (CCEP) program directors' annual meeting during the 2008 scientific sessions of the Heart Rhythm Society, a consensus emerged for an urgent need to strengthen and rejuvenate fellowship training in clinical cardiac electrophysiology.

Objective: A writing group of the Heart Rhythm Society Clinical Research and Training Committee was charged with defining these issues.

Methods: A comprehensive questionnaire designed by the writing group was used to conduct an on-line survey of the 101 CCEP program directors in the United States.

Rational patient selection for catheter ablation of atrial fibrillation.

During the past decade, catheter ablation of atrial fibrillation has been progressively used for the treatment of drug-refractory patients. As experience and technique have evolved, patient selection criteria have been modified to include a wider range of patients. Patients with paroxysmal, persistent, and longstanding persistent atrial fibrillation can be treated with catheter ablation.

Implantable cardioverter defibrillator (ICD) for polymorphic ventricular tachycardia (VT) due to coronary vasospasm.

We report a case of a young woman who presented with atypical angina. During an episode of chest pain she had a documented run of sustained polymorphic ventricular tachycardia (VT). In addition to medical therapy, she received an ICD to prevent future episodes of sudden cardiac death.

Intracardiac alternans compared to surface T-wave alternans as a predictor of ventricular arrhythmias in humans.

Background: Microvolt T-wave alternans (MTWA) measured from the surface electrocardiogram (ECG) is a marker of sudden cardiac death (SCD). Recently, it has been suggested that intracardiac alternans (ICA) detected from the endocardium underlies MTWA and is a marker of electrical instability leading to ventricular arrhythmias. As such, ICA may be used in future implantable cardioverter-defibrillators (ICDs) to monitor periods of electrical instability before ICD therapy.

Electrical and hemodynamic function produced by stimulation of atropine sensitive right ventricular nerves in humans.

In mammalian ventricles including humans, it is recognized that parasympathetic ganglia innervate the heart. Little is known about the location and function of right ventricular parasympathetic nerves in humans. We hypothesized that in humans: (1) there are parasympathetic ganglia that supply the right ventricle that can be stimulated via an endocardial catheter and (2) stimulation of these fibers will alter the electrical and hemodynamic function of the right ventricle.

Preservation of the anterior fat pad paradoxically decreases the incidence of postoperative atrial fibrillation in humans.

Objectives: The goal of this study was to determine if parasympathetic nerves in the anterior fat pad (FP) can be stimulated at the time of coronary artery bypass surgery (CABG), and if dissection of this FP decreases the incidence of postoperative atrial fibrillation (AF).

Background: The human anterior epicardial FP contains parasympathetic ganglia and is often dissected during CABG. Changes in parasympathetic tone influence the incidence of AF.

T-wave alternans: marker, mechanism, and methodology for predicting sudden cardiac death.

Sudden cardiac death (SCD) is a leading cause of cardiovascular mortality. Therefore, identifying patients at highest risk for SCD is crucial. Conventional noninvasive markers of SCD are inadequate because of low positive predictive value.

Biventricular pacing for congestive heart failure: early experience in surgical epicardial versus coronary sinus lead placement.

Objective: Biventricular pacing (BVP) has recently been introduced for the treatment of refractory congestive heart failure. Coronary sinus lead placement for left ventricular pacing is technically difficult, has a risk of lead dislodgement, and has long procedure times. Surgical epicardial lead placement has the potential advantage of the visual selection of an optimal pacing site, does not need exposure to ionic radiation, and allows lead multiplicity, but it does require a thoracotomy and general anesthesia.

Identification and characterization of atrioventricular parasympathetic innervation in humans.

Introduction: We hypothesized that in humans there is an epicardial fat pad from which parasympathetic ganglia supply the AV node. We also hypothesized that the parasympathetic nerves innervating the AV node also innervate the right atrium, and the greatest density of innervation is near the AV nodal fat pad.

Methods And Results: An epicardial fat pad near the junction of the left atrium and right inferior pulmonary vein was identified during cardiac surgery in seven patients.