Heart rhythm : the official journal of the Heart Rhythm Society
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Action potential duration is widely used as a measure of refractory period in ischemia. Although the end of repolarization closely corresponds to the end of refractoriness in the well-perfused, well-oxygenated myocardium, it is no longer true for the ischemic myocardium, in which the recovery of excitability lags behind full repolarization. ⋯ The findings showed that although postrepolarization refractoriness is profoundly proarrhythmic during ischemia, it may protect the heart from reentrant arrhythmias in the absence of depolarization of the resting membrane. An increase in postrepolarization refractoriness induced by sodium-channel-blocking drugs may exert an antifibrillatory action.
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Multicenter Study Comparative Study
Should all individuals with a nondiagnostic Brugada-electrocardiogram undergo sodium-channel blocker test?
The diagnostic Brugada-electrocardiogram (Br-ECG) is characterized by "coved-type" ST-segment elevation (type 1) in V(1) to V(2)/V(3). The sodium-channel blocker test is clinically used to unmask diagnostic Br-ECG in patients with nondiagnostic "saddle-back" Br-ECG (type 2 and type 3). ⋯ In asymptomatic individuals with a nondiagnostic Br-ECG, the incidence of events is low regardless of the sodium-channel blocker test result while in symptomatic patients a positive sodium-channel blocker test result is associated with an adverse arrhythmic outcome and may contribute to risk stratification.
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Multicenter Study Comparative Study Clinical Trial
The durability of pulmonary vein isolation using the visually guided laser balloon catheter: multicenter results of pulmonary vein remapping studies.
The visually guided laser ablation (VGLA) catheter is a compliant, variable-diameter balloon that delivers laser energy around the pulmonary vein (PV) ostium under real-time endoscopic visualization. While acute PV isolation has been shown to be feasible, limited data exist regarding the durability of isolation. ⋯ In this multicenter, multioperator experience, VGLA resulted in a very high rate of durable PV isolation with a clinical efficacy similar to that of radiofrequency ablation.
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Comparative Study
Value of right ventricular mapping in patients with postinfarction ventricular tachycardia.
Postinfarction ventricular tachycardia (VT) typically involves the left ventricular endocardium. Right ventricular involvement in the arrhythmogenic substrate of postinfarction VT is considered unusual. ⋯ Right ventricular mapping and ablation may be necessary in order to eliminate all inducible VTs in patients with postinfarction VT. More than half the patients with septal myocardial infarction have right ventricular septal areas that are critical for postinfarction VT and that cannot be eliminated by left ventricular ablation alone.
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Comparative Study
Electrophysiologic characteristics and catheter ablation of ventricular tachyarrhythmias among patients with heart failure on ventricular assist device support.
Ventricular tachyarrhythmias (VT) are common among ventricular assist device (VAD) recipients, yet electrophysiologic (EP) characteristics and catheter ablation outcomes remain uncharacterized. ⋯ Catheter ablation of VT is effective among recipients of VAD. Intrinsic myocardial scar, rather than the apical device cannulation site, appears to be the dominant substrate.