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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)
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)
We have previously shown that left-sided vagus nerve stimulation results in cessation of induced spinal cord seizures. To test our hypothesis that right-sided vagus nerve stimulation will also abort seizure activity, we have initiated seizures in the spinal cord and then performed right-sided vagus nerve stimulation in an animal model. Four pigs were(More)
It has been hypothesized that during ventricular fibrillation (VF), the fastest activating region, the dominant domain, contains a stable reentrant circuit called a mother rotor. This hypothesis postulates that the mother rotor spawns wavefronts that propagate to maintain VF elsewhere and implies that the ratio of wavefronts propagating off a region to(More)
During internal defibrillation, potential gradients greater than 100 V/cm occur near defibrillation electrodes. Such strong fields may cause deleterious effects, including arrhythmias. This study determined 1) the effects of such strong fields on the propagation of activation and 2) whether these effects were different for monophasic and biphasic shocks.(More)
INTRODUCTION The purpose of this investigation was to study the transmembrane potential changes (delta Vm) during extracellular electrical field stimulation. METHODS AND RESULTS Vm was recorded in seven guinea pig papillary muscles in a tissue bath by a double-barrel microelectrode with one barrel in and the other just outside a cell while shocks were(More)
BACKGROUND Electrical mapping studies indicate an interval of 40 to 100 ms between a defibrillation shock and the earliest activation that propagates globally over the ventricles (globally propagated activation, GPA). This study determined whether activation occurs during this interval but propagates only locally before being blocked (locally propagated(More)
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)
Fourty-eight fasciotomies performed for conventional indications were analyzed, focusing primarily on the reliability of clinical diagnosis and the effectiveness of the operative technique. Decompression was accomplished immediately after hospital admission or arterial repair in 27 patients and deferred until the appearance of signs and symptoms in 21(More)
Fifty-four patients underwent 56 profundaplasties for limb salvage. All had stenosis greater than 50% in diameter of the deep femoral artery and associated superficial femoral artery occlusive disease. After profundaplasty, ischemic ulcers healed in 9 of 17 (53%) patients. Rest pain was relieved in 6 of 19 (32%) and areas of ischemic necrosis healed in 7 of(More)