Journal of cardiovascular electrophysiology
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J. Cardiovasc. Electrophysiol. · Mar 1998
Clinical TrialEndocardial and epicardial ablation guided by nonsurgical transthoracic epicardial mapping to treat recurrent ventricular tachycardia.
An epicardial site of origin of ventricular tachycardia (VT) may explain unsuccessful endocardial radiofrequency (RF) catheter ablation. A new technique to map the epicardial surface of the heart through pericardial puncture was presented recently and opened the possibility of using epicardial mapping to guide endocardial ablation or epicardial catheter ablation. We report the efficacy and safety of these two approaches to treat 10 consecutive patients with VT and Chagas' disease. ⋯ Epicardial mapping does not enhance the effectiveness of endocardial pulses of RF. Epicardial applications of RF energy can safely and effectively treat patients with VT and Chagas' disease.
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J. Cardiovasc. Electrophysiol. · Dec 1997
The effects of ventricular fibrillation duration and a preceding unsuccessful shock on the probability of defibrillation success using biphasic waveforms in pigs.
While the defibrillation threshold has been reported to increase with ventricular fibrillation (VF) duration for monophasic waveforms, the effect of VF duration for biphasic waveforms is unknown. ⋯ (1) As opposed to monophasic shocks, ED 50 is significantly lower for biphasic shocks delivered after 20 seconds of VF compared with shocks delivered after 10 seconds of VF in pigs. (2) An unsuccessful biphasic shock in pigs does not affect the defibrillation efficacy for a subsequent shock. (3) ED 50 for a biphasic shock delivered after 20 seconds of VF is linearly related to ED 50 for a shock delivered after 10 seconds of VF.
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J. Cardiovasc. Electrophysiol. · Dec 1997
Low-energy impedance-compensating biphasic waveforms terminate ventricular fibrillation at high rates in victims of out-of-hospital cardiac arrest. LIFE Investigators.
New automatic external defibrillators (AEDs), which are smaller, lighter, easier to use, and less costly make the goal of widespread AED deployment and early defibrillation for out-of-hospital cardiac arrest feasible. The objective of this study was to observe the performance of a low-energy impedance-compensating biphasic waveform in the out-of-hospital setting on 100 consecutive victims of sudden cardiac arrest. ⋯ Low-energy impedance-compensating biphasic waveforms terminate long-duration VF at high rates in out-of-hospital cardiac arrest. Use of this waveform allows AED device characteristics consistent with widespread AED deployment and early defibrillation.
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J. Cardiovasc. Electrophysiol. · Aug 1997
ReviewThe seventh annual Gordon K. Moe Lecture. Atrial fibrillation: from cell t bedside.
Atrial fibrillation is the most common sustained tachyarrhythmia and, as such, has become the recent focus of intense clinical and experimental interest. Because of its associated morbidity and mortality, there is a multidisciplinary effort to understand the pathophysiology that may ultimately lead to improved therapeutic options. This review concentrates on three aspects of atrial fibrillation that influence contemporary choices for treatment: an electrophysiologic basis for initiation of atrial fibrillation, anatomic and electrophysiologic remodeling, and concepts regarding its termination or prevention.
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J. Cardiovasc. Electrophysiol. · Jul 1997
High-rate atrial pacing as an innovative bridging therapy in a neonate with congenital long QT syndrome.
The neonatal presentation of the long QT syndrome is rare, although it is frequently accompanied by life-threatening arrhythmias. Infants may not survive childhood despite traditional management with beta-adrenergic blockade and pacing. ⋯ High-rate atrial pacing with 2:1 AV block is presented as a novel and "bridging" therapy for neonatal long QT syndrome and 2:1 AV block with ventricular arrhythmias. Definitive therapy with ICD implantation was then possible when patient size was substantially increased. The electrophysiologic response to intentional elevation of the serum potassium suggests a genetic defect in an inward potassium channel and demonstrates a possible therapy of long QT syndrome in some future patients.