Atrial Tracking with a Single ICD Lead in the Ventricle

摘要

A 68-year-old male with ischemic cardiomyopathy was admitted to hospital with decompensated heart failure. Echocardiogram showed an ejection fraction of 20% with moderate mitral regurgitation. Medical history was significant for coronary artery bypass grafting in 2003, paroxysmal atrial fibrillation, chronic renal failure, obstructive sleep apnea, type 2 diabetes, and possible amiodarone lung toxi-city. He had undergone explanation of a left-sided defibril-lator system after a diagnosis of site sepsis 2 months prior to hospitalization, with subsequent implantation of a new Medtronic C-174AWK Concerto biventricular pacemaker and cardioverter-defibrillator on the right side with one RV lead. The admission ECG (Fig. 1) is shown below. Although this patient only has a single ventricular lead, the ventricular pacing appears to be tracking his atrium. What is the explanation and what are the clinical implications