Left Atrial Relaxation and Left Ventricular Systolic Function Determine Left Atrial Reservoir Function

• DOI: 10.1161/01.cir.100.4.427
• Publication Date: 2012-06-12T00:42:29Z
• Authors: Paolo Barbier; Steven B. Solomon; Nelson B. Schiller; Stanton A. Glantz
• Keywords: Ventricular Function

Background —Determinants of left atrial (LA) reservoir function and its influence on ventricular (LV) have not been quantified. Methods Results —In an open-pericardium, paced (70 90 bpm) pig model LV regional ischemia (left anterior descending coronary constriction), with high-fidelity LV, LA, RV pressure recordings, we obtained the LA area 2D automated border detection echocardiography, pressure-area loops, Doppler transmitral flow. We calculated τ, relaxation (a−x difference divided by time, normalized a pressure), stiffness (slope between x v points loop). Determinants total (maximum−minimum area, cm 2 ) were identified multiple regression analysis. Different mean rates increase consecutive (early rapid late slow) phases. During ischemia, long-axis shortening (LAS, base systolic descent) change decreased (7.3±0.3 [SEM] versus 5.6±0.3 , P <0.001) increased (1.6±0.3 3.1±0.3 mm Hg/cm =0.009). Early depended ejection rate (LA at ECG wave minus minimum time; coefficient=0.9; (coefficient=4.9 ×ms/s; <0.001). Late LAS (coefficient=8 cm/s; Total filling (coefficient=−0.31 4 /mm Hg; =0.001) cardiac output (coefficient=0.001 ×min/L; =0.002). The strongest predictor was (coefficient=301 L/min×cm ; loop determined output, early Conclusions —Two late) phases are contraction descent. Acute increases impairs reducing