Effective Arterial Elastance in the Pulmonary Arterial Circulation

urrent understanding of ventricular-vascular interactions is largely based on the seminal works of (1) Guyton, 1 who developed and validated the first comprehensive models of the circulatory system; (2) Suga and Sagawa, 2 who introduced the time-varying elastance model and E es , the slope of the end-systolic pressure-volume relationship, to characterize ventricular properties; and (3) Sunagawa et al, 3 who created the concept of effective arterial elastance (E a ) to depict vascular properties on the ventricular pressure-volume diagram. These efforts advanced understanding of ventricular-vascular coupling and led to the observation that maximal transfer of mechanical stroke work from the left ventricle to the systemic arterial circulation occurs when E a E es . Furthermore, important aspects of the hemodynamic abnormalities of acute and chronic heart failure and hypertension occur when the E a /E es ratio deviates from normal-a condition commonly referred to as ventricular-vascular uncoupling or mismatch.