Medicine & Science in Sports & Exercise:
E-23 Free Communication/Poster - Cardiac: JUNE 3, 2011 7:30 AM - 12:30 PM: ROOM: Hall B
West Virginia University, Morgantown, WV.
(No relationships reported)
Cardiovascular performance and aerobic capacity are influenced by the interaction of the left ventricle (LV) and the arterial system. This interaction can be indexed by the ratio of arterial elastance (EA; a measure of net arterial load), to LV end-systolic elastance (Ees; a measure of LV performance). During exercise, EA/Ees declines augmenting CV performance. Aerobic capacity is reduced in patients with the metabolic syndrome (MetS), which may in part be attributed to poor EA and Ees coupling during exercise.
PURPOSE: We examined the coupling between Ees and EA at rest and during exercise in MetS.
METHODS: MetS patients were defined according to ATPIII-NCEP. Using Doppler echocardiography we noninvasively characterized Ees (single beat elastance), and EA (end-systolic pressure/stroke volume) from which EA/ELV was calculated. Measurements were made at rest and peak exercise and adjusted for body surface area.
RESULTS: At rest, Ees, EA and EA/Ees did not differ between healthy controls (n=5; 47±8years) and MetS patients (n=11; 46±9years). However, at peak exercise MetS patients had a blunted increase in Ees (116% vs. 168%, p=0.054), a smaller increase in EA (26% vs. 56%, p=0.059), but a similar decline in EA/Ees vs. controls (44% vs. 42%). Further, Ees and VO2max were highly correlated (r=0.69; p<0.01), and VO2max was 24% smaller (p=0.057) in MetS vs. controls.
CONCLUSION: Our results suggest that patients with MetS (without diabetes) have normal LV-arterial coupling at rest, but a blunted LV performance during exercise and a reduced aerobic capacity. This blunted Ees response may in part contribute to the reduced aerobic capacity noted in MetS and may progress into EA and Ees uncoupling.