Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Mar 1996
Case ReportsTwo hearts beating as one: radiofrequency ablation of the His bundle in a heterotopic heart transplant patient.
We describe a 54-year-old man with heterotopic heart transplantation, who had severe exertional angina and dyspnea related to native heart ischemic disease. Because of drug resistant atrial fibrillation and atrial flutter of the native heart with fast ventricular response (130 beats/min), right-sided radiofrequency ablation of the His bundle was undertaken, followed by permanent pacemaker linkage of donor and native hearts. The procedure was successful and uneventful. Remarkable relief of symptoms was achieved.
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Pacing Clin Electrophysiol · Mar 1996
Case ReportsDefibrillator twiddler's syndrome causing device failure in a subpectoral transvenous system.
Twiddler's syndrome is well described as a complication of cardiac pacing. Defibrillator twiddler's syndrome has been recently reported with abdominal implantations of epicardial and transvenous defibrillator systems. We report a case of a patient with a transvenous defibrillator system implanted with the pulse generator placed in the subpectoral plane. ⋯ This caused inappropriate shocks due to sensing both the atrial and ventricular electrograms. While the subpectoral position leaves the generator deeper and more difficult for the patient to access, it may not lessen the chance of twiddler's syndrome. It is possible that the subpectoral position may actually predispose the patient to this malady.
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Pacing Clin Electrophysiol · Nov 1995
Use of double ventricular extrastimulation to determine the preexcitation index in atrioventricular nodal reentrant tachycardia.
The ability of single paced ventricular beats during tachycardia to penetrate the tachycardia circuit and reset the subsequent atrial depolarization (atrial preexcitation), enabling calculation of the "preexcitation index," can be helpful in analyzing supraventricular tachycardias. However, the ventricular refractory period often prevents ventricular capture of beats with the necessary prematurity to demonstrate atrial preexcitation, particularly in atrioventricular nodal reentrant tachycardia (AVNRT). We hypothesized that the use of double premature stimuli could overcome this limitation. ⋯ On the other hand, in all but 1 patient with AVRT, atrial preexcitation could be achieved with single and double extrastimuli. A formula was derived for obtaining a preexcitation index with double extrastimuli and shown to correspond closely with the preexcitation index obtained with a single extrastimulus in the 16 patients in whom atrial preexcitation could be achieved with single and double extrastimuli. Thus, this technique significantly enhances the ability to achieve atrial preexcitation and to calculate the preexcitation index in patients with AVNRT, and thus may be useful in deciphering tachycardia mechanism in some patients, as well as being a useful technique in studying the electrophysiological properties of the antegrade and retrograde limbs of AVNRT.
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Pacing Clin Electrophysiol · Oct 1995
Dynamic relationship between the Q-aT interval and heart rate in patients with long QT syndrome during 24-hour Holter ECG monitoring.
The purpose of this study was to investigate the dynamic relationship between heart rate and the Q-aT interval (the interval from the Q wave to the T wave apex) in patients with long QT syndrome. The QT to heart rate relation is useful for evaluating abnormalities of the ventricular repolarization, but its clinical application to the long QT syndrome requires accurate computer aided measurement of the QT interval and the sampling of a large number of beats. Therefore, the Q-aT interval was used on the basis of some reports that the heart rate dependency of the QT interval was concentrated in the Q-aT interval. ⋯ The patients showed morphological T wave changes associated with heart rate changes during Holter recordings and these affected the Q-aT interval. The patients showed the following characteristics in the relationship between the major T wave peak and the RR interval: (1) a modestly decreased correlation between Q-aT and RR than in the control subjects (a median r value of 0.87 vs 0.93; P = 0.001); and (2) a steeper Q-aT/RR slope than in controls (a median slope of 0.24 vs 0.16; P < 0.05). Abnormal and variable T wave morphology in the long QT patients was closely related to a modestly decreased correlation between Q-aT and RR than in the control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)