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Isochronal maps of ventricular activation were analyzed in dogs 3-5 days after ligation of the left anterior descending coronary artery utilizing a 64-channel multiplexer. Isochronal maps of the effective refractory period were determined from 62 epicardial sites and correlated with the activation maps. The ischemia occurring in the surviving epicardial(More)
We studied isochronal maps of ventricular activation during ventricular arrhythmias induced by programmed premature stimulation in dogs 3-5 days after ligation of the left anterior descending coronary artery. The entire epicardial surface and selective intramural sites were recorded using a computerized multiplexing technique. The electrophysiologic data(More)
BACKGROUND The ability of intermittent or symptom-based monitoring to accurately identify patients with atrial tachycardia/atrial fibrillation (AT/AF) and to quantify AT/AF burden is not well established. OBJECTIVES The purpose of this study was to compare intermittent and symptom-based monitoring to continuous monitoring for (1) identification of(More)
Continuous long-term monitoring of atrial fibrillation (AF) and tachycardia (AT) is an unmet clinical need, which could be met with a chronically-implanted monitor. Improved therapeutic decisions based on accurate monitoring of parameters, such as daily AF/AT burden (hours/ day) may lead to improvements in clinical outcomes such as reduction in(More)
Triggered activity developed in depolarized Purkinje fibers (maximum diastolic potential -59.3 +/- 9.9 mV) during superfusion with normal Tyrode's solution in 84% of subendocardial preparations from 1-day-old canine infarct. Triggered activity occurred when a delayed afterdepolarization attained threshold potential and spontaneously terminated after a(More)
INTRODUCTION Previous reports demonstrate that individual patients may have distinctive electrocardiographic patterns preceding atrial fibrillation (AF) onset. However, these observations are based on single recordings, and are thus limited by their "snapshot" derivation; it is unclear whether patterns observed on these recordings are consistent over time.(More)
OBJECTIVES This study investigated the effects of hormonal therapy on large arterial properties. BACKGROUND Arterial stiffness is an emerging risk marker for coronary heart disease and is potentially modifiable. Postmenopausal use of hormonal therapy is associated with a lower risk of coronary heart disease. METHODS Total systemic arterial compliance(More)
OBJECTIVES We investigated 1) the feasibility, safety and efficacy of multisite right atrial pacing for prevention of atrial fibrillation (AF); and 2) the ability of atrial pacing in single- and dual-site modes to increase arrhythmia-free intervals in patients with drug-refractory AF. BACKGROUND We recently developed and applied a novel technique of(More)
The place of pacemakers in the treatment of tachyarrhythmias has expanded far beyond the initial role in the brady-tachy syndrome, of providing a "minimum guaranteed rate" while medications suppress the tachycardia. Techniques have been developed for prevention, termination, and duplication of a patient's spontaneous tachycardia under safe catheterization(More)
BACKGROUND Transvenous implantable cardioverter-defibrillators provide significant advantages in the treatment of patients with life-threatening ventricular arrhythmias. However, present technology requires considerable electrophysiology expertise, multiple incisions, and long operative times for successful implementation. METHODS AND RESULTS In this(More)