Upgrade of a chronic unipolar pacemaker to a biventricular pacemaker system

With the development of cardiac resynchronization for patients with symptomatic heart failure and electrical dyssynchrony, there are patients with chronic pacemakers that meet the indications for biventricular pacing. Typically, this involves placement of the left ventricular lead with generator change to a dual chamber biventricular pacemaker, maintaining use of the right-sided leads. There are patients with older pacemaker systems that have unipolar leads with 5/6-mm pin connectors. These patients present challenges to upgrade that are separate from typical IS-1 system upgrades. Currently there are no pacemakers manufactured that accept the chronic 5/6-mm unipolar leads directly with the additional IS-1 left heart lead. This report presents one such case in which a combination of adaptor and lead replacement resulted in upgrade to a biventricular system.