Biventricular autocapture TM is feasible in chf patients with LBBB

Abstract

Background Today, St. Jude Medical offer ventricular AutoCapture with beat-tobeat capture verification in single and dual chamber devices. Increasing use of biventricular (BiV) devices has revealed a higher percentage of threshold related problems on transvenous left side electrodes compared to right side electrodes. In this study we investigated if a new capture detection method based on the paced depolarization integral (PDI) could be used for assessing left ventricular (LV) capture in BiV devices. Methods IEGMs from the RV and LV were collected during device implantation on 15 CHF patients with LBBB. A majority of patients were male (10/15), mean age was 68 ± 10 years, LVEF 28 ± 6.4 %, NYHA class II-III and 4 patients had atrial arrhythmias. Mean QRS width was 153 ± 24 ms and 4 patients had underlying ischemic heart disease. Signals were recorded for different stimulation orders (RV or LV first) with both sub and supra threshold stimulation. During offline analysis the PDI method's ability to distinguish capture from loss of capture was investigated for different VV delays and different lengths of the evoked response (ER) detection window. Results Using an ER detection window of 40 ms, the method was successful in 13/15 patients when RV was programmed as the primary channel. When the LV was set as the primary channel, the method was successful in all (12/12) analyzed patients. The results were independent of the programmed VV delay. Conclusion By using the PDI method, capture detection in the LV is feasible in a majority of patients, regardless of stimulation order or the VV delay. Hence, the PDI method enables the design of a BiV AutoCapture™ algorithm, making BiV devices safer, less power consuming and smaller.