Dual-site right ventricular and left ventricular pacing in a patient with left ventricular systolic dysfunction and atrial fibrillation using a standard CRT-D device

ABSTRACT

In patients undergoing cardiac resynchronization therapy with defibrillator [CRT-D] implantation for left ventricular systolic dysfunction [LVSD] accompanied by permanent atrial fibrillation [AF], generally, the unused atrial port is plugged at device implantation. We describe an alternative use for the atrial-port in this case report. A 43 year old gentleman with LVSD due to left ventricular non-compaction [LVNC] and AF of unknown duration underwent a CRT-D implantation after optimization of cardiac failure treatment. The atrial-port which would otherwise have been plugged was connected to a high right ventricular septal [RVS] pacing-lead and the shock-lead was positioned at the right ventricular apex [RVA]. This approach permitted modified cardiac resynchronization in a high RVS to left ventricular [LV] and RVA pacing sequence using the high RVS and LV pacing combined with a shock vector including the RV apex. A standard CRT-D device with a minimum programmable A-V delay of 30 ms [technically RVS to LV delay in the 'DDD' pacing mode] was used. The device was programmed to a 'DDD' pacing mode [sequential multi-site ventricular pacing with some programmability]. The mode switch operation was programmed 'OFF' since atrial sensing is unavailable. Device-delivered shocks did not cardiovert the patient back to sinus rhythm suggesting that the AF was permanent [no prior cardioversion attempts were made on the presumption that the chances of maintaining sinus rhythm, given the underlying cardiac condition, were low]. Subsequently, the patient required radio-frequency ablation of the atrio-ventricular node for conducted AF. Symptomatic, echocardiographic and radiological improvement preceded atrio-ventricular node ablation. Amongst AF patients with permanent AF undergoing CRT-D implantation, those patients who are likely to have the CRT-D device atrial-ports plugged could benefit from having both the options of [i] a RVA shock vector as well as [ii] a high RVS-pacing feasible, by utilizing the atrial-port of a conventional CRTD device for a RVS pacing lead, should a RVA shock-lead position be preferred. New device programming algorithms will be necessary to make patient-customized programming in this lead configuration flexible, more useful clinically and easy