Background Cardiac-resynchronization therapy (CRT) benefits patients with left ventricular
systolic dysfunction and a wide QRS complex. Most of these patients are candidates for an …

Background Patients with heart failure who receive an implantable cardioverter–defibrillator
(ICD) for primary prevention (ie, prevention of a first life-threatening arrhythmic event) may …

Background Dual-chamber (atrioventricular) and single-chamber (ventricular) pacing are
alternative treatment approaches for sinus-node dysfunction that causes clinically significant …

Background— Some current pacing systems can automatically detect and record atrial
tachyarrhythmias that may be asymptomatic. We prospectively studied a 312-patient (pt) …

Background Atrial fibrillation is the most common type of cardiac arrhythmia and a leading
cause of cardiovascular morbidity, particularly stroke. The cardiac gap-junction protein …

Background—Establishing a diagnosis in patients with unexplained syncope is complicated
by infrequent and unpredictable events. Prolonged monitoring may be an alternative …

Background—The conventional investigation of patients who present with syncope involves
short-term ECG monitoring or provocative testing with head-up tilt and electrophysiological …

Objectives : We evaluated the ability of delayed enhancement magnetic resonance imaging
(DE-MRI) to predict clinical response to cardiac resynchronization therapy (CRT). …

Background— Cardiac arrest without evident cardiac disease may be caused by subclinical
genetic conditions. Provocative testing to unmask a phenotype is often necessary to detect …

Background Patients with syncope of unknown etiology after negative noninvasive and
electrophysiological testing may suffer from recurrent disability. Syncopal episodes are often too …