Abstract 12804: The Relation between Left Atrial Function and Cardiac Output During Exercise in Left Heart Disease Patients: Insights by Combining Cardiopulmonary Exercise Testing With Stress Echo

Abstract

Background: The hemodynamic response to exercise in left heart disease in relation to left atrial mechanics has never been studied. We aimed at investigating the link between left atrial function and cardiac output (CO) response during exercise in different cardiac disorders. Methods: 73 heart failure with reduced (n=51) and preserved (n=21) ejection fraction, 53 aortic stenosis, 27 primary mitral regurgitation, 14 hypertrophic cardiomyopathy, and 42 control subjects underwent cardiopulmonary exercise testing evaluation combined with Echo-Doppler with assessment of left atrial strain (LAS) and were divided into 4 groups according to LA volume index (LAVI) and LAS at rest. Results: In group D (LAVI ≥34 ml/m 2 , LAS ≤23%, n=80) compared to group A (LAVI <34 ml/m 2 , LAS >23%, n=78) and group C (LAVI ≥34 ml/m 2 , LAS >23%, n=31), peak CO (6.2 ± 2.2 vs 8.5 ± 2.9 and 7.8 ± 2 L/min, P <0.05, respectively) and peak VO 2 (15.3 ± 4.1 vs 18.2 ± 6.3 and 18.1 ± 6.1 ml/kg/min, P <0.05, respectively) were significantly lower and the minute ventilation-carbon dioxide production (VE/VCO 2 ) slope were significantly higher (33.2 ± 9.5 vs 27.1 ±3.7 and 27 ± 3.1, P <0.05, respectively). There were correlation between LAS both at rest and exercise vs peak VO 2 and VE/VCO 2 slope (R=0.41 and R=-0.53 at rest, R=0.44 and R=-0.45 at exercise, P <0.05, respectively, Figure A). In group B (LAVI <34 ml/m 2 , LAS ≤23%, n=19) and D, LAS both at rest and exercise significantly correlated with CO and stroke volume index (R=0.34 and R=0.38 at rest, R=0.35 and R=0.44 at exercise, P <0.05, respectively) and not in Group A and C (Figure B). Conclusions: In left heart disease patients, irrespective of etiology, an impaired LAS performance at rest is associated with a leftward shifted LAS vs CO response during exercise. Among this group of patients LA reservoir function is a key element of increasing CO during exercise.