ABSTRACT
<p><b>BACKGROUND</b>Cardiac resynchronization therapy (CRT) could improve heart function, symptom status, quality of life and reduce hospitalization and mortality in patients with severe heart failure (HF) with optimal medical management. However, the possible adverse effects of CRT are often ignored by clinicians.</p><p><b>METHOD</b>A retrospective analysis of CRT over a 6-year period was made in a single cardiac center.</p><p><b>RESULTS</b>Fifty-four patients were treated with CRT(D) device, aged (57 ± 11) years, with left ventricular ejection fraction of (32.1 ± 9.8)%, of which 4 (7%) developed ventricular tachycardia/ventricular fibrillation (VT/VF) or junctional tachycardia after operation. Except for one with frequent ventricular premature beat before operation, the others had no previous history of ventricular arrhythmia. Of the 4 patients, 3 had dilated cardiomyopathy and 1 had ischemic cardiomyopathy, and tachycardia occurred within 3 days after operation. Sustained, refractory VT and subsequent VF occurred in one patient, frequent nonsustained VT in two patients and nonparoxysmal atrioventricular junctional tachycardia in one patient. VT was managed by amiodarone in two patients, amiodarone together with beta-blocker in one patient, and junctional tachycardia was terminated by overdrive pacing. During over 12-month follow-up, except for one patient's death due to refractory heart and respiratory failure in hospital, the others remain alive and arrhythmia-free.</p><p><b>CONCLUSIONS</b>New-onset VT/VF or junctional tachycardia may occur in a minority of patients with or without prior history of tachycardia after biventricular pacing. Arrhythmia can be managed by conventional therapy, but may require temporary discontinuation of pacing. More observational studies should be performed to determine the potential proarrhythmic effect of CRT.</p>