Pseudo-loss of left ventricular capture due to interventricular crosstalk.

An 82-year-old man was admitted to our clinic for evaluation of chronic heart failure (CHF) often punctuated by acute exacerbations. The patient had undergone placement of a biventricular implantable cardioverter-defibrillator (ICD) capable of cardiac resynchronization therapy (CRT-D; Unify Quadra 3251-40Q; St. Jude Medical, St Paul, MN) six years ago in a tertiary centre due to nonischemic cardiomyopathy, left bundle branch block (LBBB) QRS pattern of QRS duration 250 ms and drug refractory congestive heart failure with left ventricular ejection fraction (LVEF) of 25%. St. Jude Medical leads had been implanted using an Durata™ 7120Q passive right ventricular (RV) lead in the apex, an Tendril™ 1888 bipolar screw-in lead in the right atrium (RA) and an Quartet™ 1458Q quadripolar LV lead in an anterolateral coronary vein. Follow-up in-person outpatient visits occurred regularly at another hospital. Overall, the non-pacemaker dependent patient had unchanged NYHA functional class III-IV symptomatology and similar LVEF. This article is protected by copyright. All rights reserved.