Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
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We assessed the effects of cardiac re-synchronization therapy (CRT) in patients who developed otherwise unexplained heart failure (HF) during right ventricular apical (RVA)-pacing for acquired complete atrioventricular block (CAVB). ⋯ CRT-upgrade improves the cardiac function and symptoms in CAVB patients with HF progression related to RVA-pacing. Because adverse LV-remodelling may be partly irreversible, consideration should be given to BiV- and LV-pacing upgrade as soon as possible after the indications appear, and prospective studies of the optimal timing of CRT-upgrade may be useful.
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One of the most feared potential adverse effects of many drugs is life threatening or fatal arrhythmia--particularly torsade de pointes (TdP) ventricular tachycardia in conjunction with QT prolongation. To fully understand the implications of QT prolongation, it is essential to have an understanding of the ion currents that comprise repolarization and their relation to electrophysiological abnormalities associated with TdP. Also, the QT interval is subject to patient-specific and sometimes idiosyncratic variability. ⋯ Repolarization reserve is also discussed. Suggestions for refining the understanding of drug-induced QT prolongation, TdP, and shortcomings of some current definitions are outlined. We speculate on possible future developments in understanding this relationship.
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Review
Drug-induced QT-interval prolongation and proarrhythmic risk in the treatment of atrial arrhythmias.
Despite the large number of available antiarrhythmic agents, significant QT-interval prolongation and risk of severe proarrhythmia, including torsade de pointes, limit pharmacological opportunities in the management of atrial arrhythmias. The risk of proarrhythmia has been demonstrated in class I and class III drugs, but significant variability has been observed between agents of the same class. ⋯ Interestingly, less proarrhythmic potential is seen or anticipated with agents that are able to block multiple ion channels and those with atrial selectivity, despite moderate QT prolongation. This observation has helped steer the development of newer drugs, with some promising preliminary results.
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Case Reports
Direct intracardiac placement of an automatic implantable cardioverter defibrillator coil lead in a small child.
A 3.5-year-old child with hypertrophic obstructive cardiomyopathy and recurrent syncope underwent surgical left-ventricular outflow tract myectomy and implantation of a single-chamber automatic cardioverter defibrillator. A single-coil active fixation lead was introduced via a purse-string suture in the right atrial appendage and the lead tip positioned and fixed in the right-ventricular apex under direct visualization via a small right atriotomy incision. Described configuration may be considered in small children undergoing intracardiac surgery at the time of defibrillator implantation.