Device rounds: T-wave oversensing: A cause of loss of cardiac resynchronization therapy

A CRT-D patient presented with loss of biventricular pacing associated with heart failure symptoms. The electrocardiogram showed sinus rhythm with alternating wide unpaced and narrower paced QRS complexes. Device interrogation showed T-wave oversensing on all paced biventricular beats, with the following sinus P-wave not tracked due to it falling in the post-ventricular atrial refractory period, leading to intrinsic conduction. Device reprogramming from true bipolar (RV tip to RV ring) sensing to integrated bipolar (RV tip to RV coil) resolved the problem without having to decrease sensitivity values, allowing biventricular pacing close to 100% to resume with improvement of symptoms. T-wave oversensing is a frequently recognised cause of inappropriate therapy in implantable cardioverter defibrillators, but less frequently as a cause of loss of biventricular pacing in CRT-Ds. We review the different non-invasive strategies to overcome this problem.