Echocardiographic Study of LV Function in Patients with Ventricular and AV Sequential Pacing

ObjectivesThis research was performed to assess systolic and diastolic left ventricular function in patients with ventricular and AV sequential pacing, placing particular emphasis on the long-term evaluation of left ventricular function in ventricular and AV sequential pacing. We also compared the short-term effects of different modes of pacing on LV function. MethodsWe conducted a prospective one-year echocardiographic study on 40 patients with ventricular and AV sequential pacemakers at our center in Tehran. Echocardiography was done before and 1 week, 2, 6 and 12 months after pacemaker implantation. Systolic and diastolic functions were assessed as well. Results12 (30%) women and 28 (70%) men aged 65.32±13.11 years were recruited in the study. 32 (80%) had advanced AV block and 8 (20%) had sick sinus syndrome. End diastolic volume, stroke volume, and ejection fraction were significantly decreased (p<0.01) in ventricular pacing group in short and long–term evaluations. In AV sequential pacing group, end diastolic volume, end systolic volume, and stroke volume were significantly decreased (p<0.01 for both). ConclusionIn spite of a decreased ejection fraction, ventricular pacing can improve cardiac output both in short and long-terms, but AV sequential pacing improves cardiac output by increasing both ejection fraction and the heart rate. Diastolic function assessment by echo is not as reliable as in systolic function. (Iranian Heart Journal. 2002; 2(4)&3(1): 6-10)