Usefulness of Doppler Echocardiography in Cardiac Pacing: Assessment of Mitral Regurgitation, Peak Aortic Flow Velocity and Atrial Capture

Doppler echocardiographic studies were performed in 14 patients with dual chamber pacemakers. Transmitral flow studies (12 patients) revealed absence of mitral regurgitation (MR) or no change in MR severity in 6, new development or increased MR during VVI and/or short or long AV interval lengths compared to more normal AV intervals (150-160 ms) in 5, and appearance of MR when the pacing mode was changed from VVI to DVI with a fixed AV interval of 250 ms in 1 patient. Aortic peak flow velocity measurements (7 patients) showed significant increases in stroke volume (range 9 to 25%, mean 19.5%) in all patients with DVI/VDD pacing compared to VVI pacing (4 patients) or to shortest available AV interval (3 patients). Presence of Doppler left atrial systolic flow correlated with evidence of atrial depolarization in all 7 patients in whom high quality 12-lead surface electrocardiograms were obtained. Our preliminary study demonstrates the value of Doppler echocardiography in the "fine tuning" of cardiac pacemaker parameters by assessment of presence, absence, or change in severity of MR, estimation of relative changes in stroke volume, and determination of atrial capture in different pacing modes and at various AV intervals.