Paul A. Belk

Learn More
OBJECTIVES The purpose of this study was to characterize interactions between normal pacing system operation and the initiating sequence of ventricular tachycardia (VT)/ventricular fibrillation (VF). BACKGROUND Abrupt changes in ventricular cycle lengths (short-long-short, S-L-S) might initiate VT/VF. The S-L-S sequences might be passively permitted or(More)
While radio frequency (RF) catheter ablation (RCA) procedures for treating ventricular arrhythmias have evolved significantly over the past several years, the use of RCA has been limited to treating slow ventricular tachycardias (VTs). In this paper, we present preliminary results from computer and animal studies to evaluate the accuracy of an algorithm(More)
OBJECTIVES The purpose of this study was to compare an ascending ramp waveform (RAMP) with a standard, clinically available biphasic truncated exponential waveform (BTE) for defibrillation in humans. BACKGROUND In animal studies, RAMP had a lower defibrillation threshold (DFT) than BTE. METHODS We studied 63 patients at implantable(More)
OBJECTIVE We hypothesized that a new minimal ventricular pacing mode (MVP) that provides AAI/R pacing with ventricular monitoring and back-up DDD/R pacing as needed during AV block (AVB) would significantly reduce cumulative percent ventricular pacing compared to DDD/R. BACKGROUND Conventional DDD/R mode often results in high cumulative percent(More)
BACKGROUND With the development of left ventricular pacing for cardiac resynchronization, there is an interest in the possibility of improving ventricular antitachycardia pacing (ATP) efficacy by pacing from the LV electrode(s). OBJECTIVE This study assessed the efficacy of pacing delivered from the left coronary vein (LCV) compared to that delivered from(More)
UNLABELLED AV Decoupling During Enhanced AAIR Pacing. BACKGROUND Enhanced AAI/R pacing minimizes right ventricular pacing but may permit or induce AV decoupling (AV-DC) due to unrestricted AV intervals (AVIs). The purpose of this study was to characterize and quantify AVI behavior in a randomized trial of enhanced AAI/R pacing in ICD patients. METHODS(More)
BACKGROUND Ventricular fibrillation (VF) is induced during implantable cardioverter-defibrillator (ICD) implantation to ensure that the ICD will sense, detect, and defibrillate VF. ICD implant guidelines state that the amplitude of the sinus rhythm R wave recorded from the ventricular electrogram should have amplitude ≥5 mV. No study has tested the(More)
BACKGROUND Implantable cardioverter defibrillator (ICD) implant testing based on the upper limit of vulnerability, or vulnerability testing, permits assessment of defibrillation safety margins without inducing ventricular fibrillation (VF) in most patients. Vulnerability testing requires that T-wave shocks be timed at the most vulnerable intervals of the(More)
A quantitatively-reliable computer model of the human heart could be a very useful tool for the analysis and development of potential tachyarrhythmia therapies. In this article, we present a new discrete cellular automata (CA) model of the human ventricle that allows representation of important quantitative aspects of cardiac excitation waves. We use this(More)
We have fabricated AlGaAs/GaAs split-gate field-effect transistors with different lengths and widths in order to establish geometric design criteria for one-dimensional (1D) transport. The experiments show a more negative 1D threshold voltage for zero length split-gate devices (constrictions) than finite length split-gate devices for the same given width.(More)
  • 1