Global and regional atrial function after rapid atrial pacing: an echo Doppler study.

We examined diastolic transmitral, left atrial appendage, and pulmonary venous flow pulsed-wave Doppler velocities in five dogs sedated with Valium and ketamine both before and 1 week after rapid (400 beats/min) atrial pacing with transesophageal echocardiography. Left ventricular systolic function was assessed with long-axis fractional area shortening with the use of transesophageal echocardiography. Transmitral and left atrial appendage atrial systolic and pulmonary vein systolic velocities decreased significantly. The transmitral and left atrial appendage early-to-late velocity ratios increased significantly and the pulmonary venous systolic-to-diastolic velocity ratio decreased significantly after rapid atrial pacing. Thus, 1 week of rapid atrial pacing results in impaired global and regional atrial pump function and enhanced conduit function of the left atrium with preservation of left ventricular systolic function. These findings may have implications for anticoagulation therapy in patients with atrial arrhythmia.