Single chamber pacemakers versus dual chamber pacemakers the effect on cardiac physiology

ABSTRACT

The aim of this study was assessment of cardiac functions and quality of life in DDD versus VVI pacing modes. Thirty patients had DDD pacing with a primary diagnosis of acquired symptomatic bradycardia were reprogrammed to VVI mode for four weeks. They were followed by transthoracic echocardiographic examination during DDD pacing mode and restudied after reprogramming to VVI pacing mode. Parameters observed were chamber dimensions [MM], chamber volumes, systolic functions, cardiac output [Simpson's method],Colored jet area method to assess Mitral regurgitation [MR] and Tricuspid regurgitation [TR] and Estimated Systolic Pulmonary Artery Pressure [ESPAP]. Thirty patients were mean age [47.9 +/- 13.2], 10 males and 20 females, Three patients only were hypertensive [10%]. There were significant decrease of the following parameters including LV systolic function [EF% [P value=0.002], CO [P value=0.008]] Left ventricular end diastolic diameter [P value=0.03] and Left ventricular end diastolic volume [P value=0.04] in VVI mode. There were significant increase in Right ventricular end diastolic diameter [P value=0.004], the incidence and degree of TR [P value=0.03] in VVI mode. There were no statistically significant difference between both modes as regard; Left ventricular end systolic diameter and volume. Left atrial dimension, Incidence and degree of MR and Estimated Systolic Pulmonary artery Pressure. From the present study we concluded that; Cardiac functions and quality of life are better in DDD mode compared to VVI mode