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BACKGROUND Shocks that have defibrillated spontaneous ventricular fibrillation (VF) during acute ischemia or reperfusion may seem to have failed if VF recurs before the ECG amplifier recovers after shock. This could explain why the defibrillation threshold (DFT) for spontaneous VF appears markedly higher than for electrically induced VF. METHODS AND(More)
The ultimate value of profundaplasty in the management of lower extremity ischemia was determined by multifactoral analysis of 239 operated limbs in 209 patients followed up to 110 months. In patients who underwent operation for claudication (n=83), patency without the need for subsequent revision or distal bypass was achieved in 77% at 5 years. By(More)
BACKGROUND In this study, we examined the effect of changing capacitor values between phases of a biphasic waveform with the goal of lowering leading edge voltage (LEV), total delivered energy (TDE), and total stored energy (TSE). METHODS Defibrillation thresholds were determined in 18 open-chest swine using epicardial patch electrodes. In part I, three(More)
While it has been shown that pacing during ventricular fibrillation (VF) can capture a portion of the epicardium, little is known about the characteristics of the area captured or about whether adaptively changing the pacing rate during VF will increase the area captured. In six open-chested pigs, pacing during VF was performed from the center of a plaque(More)
INTRODUCTION Recent studies showed that pacing atrial and ventricular fibrillation (VF) is possible. The studies presented here determined which parameters influence the efficacy of a pacing train to capture fibrillating ventricular myocardium. Electrode type, current strength, order of pacing trains, polarity, and VF morphology preceding the pacing trains(More)
An intelligent multichannel stimulator (IMS) has been designed and built for use in a cardiac research environment. The device is capable of measuring and responding to cardiac electrophysiological phenomena in real time with carefully timed and placed electrical stimuli. The system consists of 16 channels of sense/stimulation electronics controlled by a(More)
The concept of the profunda artery as a collateral system is very useful in determining which patients may benefit from profundaplasty. When hemodynamic profunda stenosis is associated with combined aortoiliac and superficial femoral artery occlusive disease, profundaplasty as an adjunct to an arterial inflow procedure is highly successful. It is most(More)
This study determined the response of action potentials during ventricular fibrillation (VF) to timed monophasic and biphasic shocks. A floating glass microelectrode was used to record intracellularly from the anterior right ventricle in 10 open-chest dogs. After 10 seconds of electrically induced VF, 5-millisecond monophasic and 2.5/2.5-millisecond(More)
Recent studies suggest that 1) electrically induced fibrillation and defibrillation involve prolongation of refractoriness by the shock in addition to stimulation and 2) biphasic waveforms are more efficient for defibrillation than are comparable monophasic waveforms. The purpose of this study was to compare prolongation of action potential duration at 50%(More)
The characteristics of spontaneous cardiac arrhythmias leading to sudden cardiac death are largely unknown. To study arrhythmias in animal models, an eight-channel implantable radio telemetry system has been developed to record continuously cardiac electrograms over a period of weeks to months, with maintenance restricted to changing batteries. The inputs(More)