LV Dysfunction Following Pacemaker Placement

Overview

Several studies have confirmed the link between chronic RV apical pacing and the development of heart failure and LV systolic dysfunction in some patients 1,2. However, questions continue to remain unanswered in regard to the adverse effects of RV pacing such as the exact amount of RV pacing that is detrimental to cardiac function and which subsets of patients are most at risk for developing cardiac dysfunction from chronic RV pacing. Rates of permanent pacemaker implantation have been increased over the last twenty years with expanding indications to include permanent pacing after AV node ablation for the treatment of drug refractory atrial fibrillation and other atrial tachy-arrhythmias. The current standard of practice is to minimize RV pacing however in patients that have had an AV node ablation right ventricular pacing cannot be avoided therefore it is important to identify if this particular group of patients is at an increased risk for developing worsening cardiac function. The purpose of this study is to compare cardiac function over time between patients that have undergone AV node ablation versus patients that have had pacemaker implantation for AV node dysfunction.

Study Design This is a retrospective chart review of patients that have undergone permanent pacemaker implantation by the electrophysiology group at Oregon Health and Sciences University Hospital during the period between 01/2003 and 01/2013 for chronic RV pacing after AV node ablation or for AV node dysfunction. Goal The goal of this study is to determine if patients requiring RV pacing after AV nodal ablation are at increased risk for developing worsening cardiac function secondary to chronic RV pacing compared to patients requiring RV pacing for AV node dysfunction. Specific Objectives * To determine the number of patients that have a permanent pacemaker implanted after AV node ablation and for AV node dysfunction within the last 10 years at OHSU Hospital. * To determine the number of patients that have a biventricular pacemaker implanted with or without an implantable cardiac defibrillator within the last 10 years at OHSU Hospital (control group). * Amongst those patients identified determine (1) left ventricular ejection fraction prior to permanent pacemaker or biventricular pacemaker implantation and over time (2) left ventricular volume and/or diameter prior to permanent pacemaker placement and over time (3) all cause mortality * Amongst those patients identified determine incidence of new onset atrial fibrillation after permanent pacemaker or biventricular pacemaker implantation * Amongst those patients identified determine incidence of inpatient admission of heart failure exacerbation defined as presenting symptoms of dyspnea, orthopnea, paroxysmal nocturnal dyspnea, increased lower extremity edema requiring IV diuretics Methods This is a retrospective chart review of patients that have undergone permanent pacemaker medical record system used at OHSU Hospital) with the help of an EPIC representative. If the patient was referred for permanent pacemaker or biventricular pacemaker implantation from a physician or medical group outside of OHSU records will be requested from that physician or medical group.