Assessment of the optimal atrioventricular delay in patients with dual chamber pacemakers using impedance cardiography and Doppler echocardiography

Journal of Clinical and Basic Cardiology 1999; 2 (2): 237-240

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Keywords: AV-Überleitungszeit,  Dopplersonographie,  Impedanzkardiographie,  kardiale Hämodynamik,  Zweikammerherzschrittmacher,  AV-delay,  cardiac haemodynamics,  Doppler echocardiography,  dual chamber pacemaker,  impedance cardiography

Impedance cardiography and Doppler echocardiography are two non-invasive methods to investigate the haemodynamics in dual chamber pacing. The purpose of the study was to assess the haemodynamic effects of different atrioventricular delays (AVDs). Second aim was the comparison of these established techniques to find the easiest method for optimal AVD selection. 36 patients with dual chamber pacemakers were tested at rest and 32 of them at a higher rate (90 bpm) pacing. We measured the stroke volume by impedance cardiography at various AVDs. Doppler echocardiography was used to determine the maximum velocity of aortic flow and its velocity-time-integral. The measurements show individually different optimal AVD between 78 and 300 ms. Compared with the most disadvantageous AVD we could improve the stroke volume at optimal AVD by 30.6 ± 24.7 % (at rest) and by 43.6 ± 18.9 % (at a higher pacing rate). These optimal AVDs were confirmed by measurements of maximum aortic flow and its velocity time integral, which were found to be in good correlation to the stroke volume measured by Impedance cardiography. The aortic flow and velocity time integral significantly increased at rest by 13.3 ± 10.1 % and 12.9 ± 9.7 % at higher rate pacing by 19.9 ± 15.8 % and 25.8 ± 19.7 % respectively. The optimal AVD for haemodynamics in dual chamber pacing is always an individual value. Impedance cardiography and Doppler echocardiography both provide this optimal AVD. J Clin Basic Cardiol 1999; 2: 237-40.