Factors influencing pacemaker generator longevity: results from the complete automatic pacing threshold utilization recorded in the CAPTURE Trial.

OBJECTIVES: The CAPTURE study evaluated the accuracy of automated atrial and right ventricular (RV) threshold algorithms. BACKGROUND: Modern pacemakers include many added features designed to improve the ease of patient follow-up, as well as algorithms to reduce pacing outputs and/or reduce the atrial or ventricular pacing percentages, thus improving longevity. METHODS: Automated atrial and RV threshold measurements were assessed versus manual measurements at 6 months. The projected longevity was assessed and compared between subjects with the threshold-tracking feature On versus Off. In addition, the projected longevity effect of device features to reduce atrial pacing and reduce ventricular pacing, and device characteristics such as battery size and high impedance leads (> or =1,000 ohms), was investigated. RESULTS: Atrial and RV manual versus automatic measurements were equivalent in 683 of 691 subjects (98.8%) and 736 of 746 subjects (98.7%), respectively. Thresholds were stable with 99.6% of atrial and 99.2% of RV consecutive measurements within +/-0.25V. Algorithms for threshold tracking, reducing ventricular pacing, and reducing atrial pacing were associated with 0.8, 0.9, and 0.2 years projected longevity improvements. High impedance leads were associated with a 0.8-year projected longevity improvement. Approximately 2 years of longevity improvement was projected for a 1-cc increase in device size. CONCLUSIONS: The atrial and RV algorithms were accurate and reliable in all leads tested. Threshold tracking, reduced ventricular pacing, and high impedance leads result in increased device longevity. Battery capacity was the strongest determinant of increased projected longevity.

Aortoscopy: a less invasive intraoperative method to assess the aortic valve.

Surgical management of mild aortic stenosis coexisting with severe coronary artery disease remains controversial. Direct examination of the aortic root under these circumstances may be decisive. At present, intraoperative assessment of the aortic valve requires an aortic incision which, in itself, may increase the risk of intraoperative complications, particularly when this portion of the aorta is needed to construct proximal graft anastomoses. We present a simple aortoscopic method for direct intraoperative assessment of the aortic valve while performing coronary bypass grafting that obviates the need for aortic incisions.