Compensatory responses of left atrial conduit flow to atrial fibrillation with acute myocardial infarction in a canine model

The aim of this study was to examine the interaction of acute atrial fibrillation (Af) and acute myocardial infarction (AML) on left atrial (LA) and left ventricular (LV) filling in atrioventricular (A-V) sequential paced, open chest, anesthetized dogs. Left atrial conduit function was determined from pulmonary venous flow (PVF) and detailed analysis of early diastolic flow with the use of micromanometers and transmitral Doppler echocardiography. We studied 8 dogs with regular ventricular rates to avoid the confounding effect of ventricular arrhythmia in Af. In the control stage, Af increased the diastolic PVF volume to the left atrium compared with that during regular AN pacing (from 0.58 ± 0.11 mL/beat to 0.70± 0.13 mL/beat, P P P P