<![CDATA[Background: The use of dual-chambers (DDD) pacemakers is steadily increasing a year after year and oneof the programmable settings for these pacemakers is the duration of the atrioventricular interval (AVI).AVI manipulation is justified for a variety of reasons including better hemodynamic stability and extendingthe battery life of the pacemaker. Since plasma NT-proBNP level reflects the myocardial wall tension, wehypothesized that different durations of AVI may have an effect on cardiomoycytes stretch and myocardialwall tension and hence an effect on plasma NT-proBNP level. So we tried to use plasma NT-proBNP as amarker for that strain, if present. Also, we tried to explore the effect of DDD pacemakers on both the systolicand the diastolic functions of the heart using conventional echocardiographic parameters.Methods: 52 patients with permanent dual-chambers pacemaker were recruited. We exclude those withheart failure, renal impairment, and major valvular or coronary vessels disease. All patients had a thoroughmedical history and examination, ECG, echocardiography (2-D, M-mode, and Doppler) as well as bloodsampling for NT-proBNP. Based on the shape of their E-A waves by pulsed-wave Doppler of transmitralflow, they were grouped in 3 categories. Group-A included those with truncated A-wave, group-B comprisedthose with separated E and A waves, and group-C involved those with fused E-A waves with or withoutdiastolic mitral regurgitation.Results: there was statistically significant difference in the duration of AVI among the 3 groups (p <0.001)with patients having fused E-A waves recorded the longest AVIs. Plasma NT-proBNP levels were significantlyhigher when E-A waves were fused (p <0.001). The systolic parameters such as the cardiac output, the strokevolume and the ejection fraction were higher when there was neither A-wave truncation nor E-A wavefusion (p <0.001). All patients showed evidences of diastolic dysfunction.Conclusion: despite the fact that DDD pacemakers are more physiological mode of pacing, neverthelessthey induce some grade of diastolic heart failure. Manipulating the AVI into longer than the device`s defaultvalues should be carefully judged since it is associated with higher levels of plasma NT-proBNP levels thatreflect cardiac wall tension and strain which in turn may progresses in future into another cardiac problemssuch as atrial fibrillation.]]>
