ReachPR Trial Resynchronization Therapy in Heart Failure Patients With Prolonged PR Interval

Rationale: Prolongation of the electrocardiographic PR interval (PR interval \> 200ms; also known as first-degree atrioventricular block) is frequently encountered in clinical practice and is generally considered as a benign sign. However, there is increasing evidence that a prolonged PR interval results in poor hemodynamic performance with elevated left ventricular (LV) end-diastolic pressures evidenced by diastolic mitral regurgitation. Previous studies have also associated a prolonged PR interval with a substantially increased risk of future atrial fibrillation (AF) and pacemaker-implantation, and increased risk of heart failure (HF) hospitalization and death. These risks stress the importance of proper atrioventricular (AV) coupling. Shortening of the PR interval may be especially important in heart failure patients and can be obtained by atrioventricular pacing. A possible adverse effect of ventricular pacing is that it results in ventricular dyssynchrony which may lead to worsening cardiac function. This effect may be prevented by applying atrio-biventricular pacing. Data from several previous (sub)studies have suggested this. Objective: The purpose of this study is to investigate the acute hemodynamic effects of restoration of atrioventricular coupling by atrio-biventricular pacing in patients with heart failure and prolonged PR interval. Study design: This study will be a multi-center, exploratory, prospective interventional, nonrandomized acute hemodynamic study, using patients as their own controls. Study population: The study will enroll 26 patients with symptomatic heart failure, reduced left ventricular ejection fraction (LVEF) (\230ms), but without seriously prolonged QRS duration (\<150ms) or left bundle branch block (LBBB) QRS pattern, who are candidates for an implantable cardioverter defibrillator (ICD) device according to current guidelines. Main study parameters/endpoints: The main study parameter will be t