Left atrial pump function in acute tests in congestive heart failure evaluated by left atrial pressure-dimension relation

The following Abstracts were omitted from the Abstract Supplement of the XVIIIth Congress of the European Society of Cardiology. To analyse left atrial (LA) systolic function in patients with congestive heart failure LA dimension (aortic-root echogram) and pulmonary capillary wedge pressure (PCWP) (balloon-tipped flow-directed catheter) were simultaneously recorded in 23 patients E.F. (33·4±9·1), (18 with ischaemic heart disease and 5 with dilated cardiomyopathy). LA pressure-dimension curve was constructed and was composed of 2 loops the A loop (expressing the pump function of the left atrium) and the V loop (expressing the reservoir function). The area of A-loop (AAL, in mm.mmHg) which reflected LA stroke work and the area of V loop (AVL) were measured. The difference between these (AAL-AVL, in mm mmHg) which reflected net atrial work was calculated before and after esmolol (E) administration, normal saline (S) infusion, dobutamine (D) and isosorbide dinitrate (N) administration. AAL significantly increased after E (20·6±6·6 mm.mmHg, p<0·05) and after S (25·7±8·6 mm.mmHg, p<0·001) and decreased after N (12·4±4·3, p<0·1) while was similar after D (14·9±4·6 mm.mmHg, NS) compared with rest (15±3·7 mm.mmHg). AAL-AVL significantly increased after E (13·9±7·4 mm.mmHg, p<0·05) and decreased after N (6·8±3·7 mm.mmHg, p<0·1) while was similar after D (8·6±4·9 mm.mmHg, NS) and after S (10·7±5·1 mm.mmHg, NS) compared with rest (8·6±4·2 mm.mmHg) The AAL was proportional to the PCWP at the beginning of LA systole (Pa) (r=0·93, p<0·001). The AAL was inversely correlated with the E.F. (r=0·43, p<0·05). With E and S the LA pressure dimension curve shifted up and rightward With N shifted down and leftward and with D up and leftward. Changes in left ventricular function by drug administration significantly influence the pump function of the left atrium in patients with congestive heart failure. LA function is attributed to Starling's mechanism