Right Ventricular Pacing and Sensing Function in High Posterior Septal and Apical Lead Placement in Cardiac Resynchronization Therapy

BACKGROUND: The conventional right ventricular (RV) lead position in cardiac resynchronization therapy pacemakers (CRT-P) is the RV apex (RV-A). Little is known about electrophysiological stability and associated complications of pacing leads in RV high posterior septal (RV-HS) position in CRT-P. METHODS: Two hundred and thirty-five consecutive CRT-P patients were included from 1999-2010. Pacing thresholds at 0.5ms and 2.5V, sensing electrograms and lead impedances were measured at implant and repeated 1,3,6,12,18 and 24 months after CRT-P. Electrophysiological measurements of leads located in RV-A and RV-HS were analyzed retrospectively. Bipolar RV leads were used, including high impedance leads, passive fixation and active fixation. RESULTS: RV pacing leads were implanted in RV-A (n=79) and RV-HS (n=156). Average RV pacing thresholds from CRT implant procedure to 24-month follow-up at 0.5ms were 0.77±0.69V in RV-A and 0.71±0.35V in RV-HS (P=0.31), and at 2.5V were 0.06±0.08ms in RV-A and 0.07±0.05ms in RV-HS (P=0.12). Average RV electrogram amplitudes from baseline to 24 months after CRT were 15.3±6.9mV in RV-A and 12.1±6.0mV in RV-HS (P=0.55). Average RV impedances during follow-up were 850±286Ω in RV-A and 618±147Ω in RV-HS (P=0.57). Similar RV lead revisions between RV-A and RV-HS were observed after 2-year follow-up (P=0.55). CONCLUSION: The RV-HS lead position demonstrated stable and acceptable long-term pacing and sensing function, with rates of complications comparable to conventional RV-A lead position in CRT. The RV-HS lead position is feasible in CRT-P.