In healthy subjects the arterial system and the left ventricle (LV) are tightly coupled at rest to optimize cardiac performance. Systolic hypertension (SH) is a major risk factor for heart failure and is associated with structural and functional alterations in the arteries and the LV. The effects of SH and resting systolic blood pressure (SBP) on arterial-ventricular coupling (E(a)I/E(LV)I) at rest, at peak exercise, and during recovery are not well described. We noninvasively characterized E(a)I/E(LV)I as end-systolic volume index/stroke volume index in subjects who were normotensive (NT, n = 203) or had SH (brachial SBP > or =140 mmHg, n = 79). Cardiac volumes were measured at rest and throughout exhaustive upright cycle exercise with gated blood pool scans. E(a)I/E(LV)I reserve was calculated by subtracting peak from resting E(a)I/E(LV)I. At rest, E(a)I/E(LV)I did not differ between SH and NT men but was 23% (P = 0.001) lower in SH vs. NT women. E(a)I/E(LV)I did not differ between SH and NT men or women at peak exercise or during recovery. Nevertheless, E(a)I/E(LV)I reserve was 61% (P < 0.001) lower in SH vs. NT women. Similarly, resting SBP (as a continuous variable) was not associated with E(a)I/E(LV)I in men (beta = -0.12, P = 0.17) but was inversely associated with E(a)I/E(LV)I in women (beta = -0.47, P < 0.001). SH and a higher resting brachial SBP are associated with a lower E(a)I/E(LV)I at rest in women but not in men, and SH women have an attenuated E(a)I/E(LV)I reserve. Whether a smaller E(a)I/E(LV)I reserve leads to functional limitations warrants further examination. (Am J Physiol Heart Circ Physiol. 2008;295(1):H145-153). Understanding the performance of the left ventricle requires not only examining the properties of the left ventricle itself, but also investigating the modulating effects of the arterial system on left ventricular (LV) performance. The interaction of the left ventricle with the arterial system, termed arterial-ventricular coupling, is a central determinant of cardiovascular performance and cardiac energetics. Arterial-ventricular coupling (EA/ELV) can be indexed by the ratio of effective arterial elastance (EA; a measure of the net arterial load exerted on the left ventricle) to LV end-systolic elastance (ELV; a load independent measure of LV chamber performance). At rest, in healthy individuals, EA/ELV is maintained within a narrow range, which allows the cardiovascular system to optimize energetic efficiency at the expense of mechanical efficacy. During exercise, an acute mismatch between the arterial and ventricular systems occurs, due to a disproportionate increase in ELV (from an average of 4.3 to 13.2, and 4.7 to 15.5 mmHg/ml/m(2) in men and women, respectively) vs. EA (from an average of 2.3 to 3.2, and 2.3 to 2.9 mmHg/ml/m(2) in men and women, respectively), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. As a result EA/ELV decreases from an average of 0.58 to 0.34, and 0.52 to 0.27 in men and women, respectively. In this review, we provide an overview of the concept of arterial-ventricular coupling, and examine the effects of age, hypertension, and heart failure on EA/ELV and its components (EA and ELV) in men and women. We discuss these effects both at rest and during exercise, and highlight the mechanistic insights that can be derived from studying arterial-ventricular coupling. (J Appl Physiol. 2008 Jul 10. Epub ahead of print).
