TY  - BOOK
AU  - Najjar, Samer S
TI  - Use of the Frank-Starling mechanism during exercise is linked to exercise-induced 130912s in arterial load
SN  - 0363-6135
KW  - *Exercise/ph [Physiology]
KW  - *Hemodynamics
KW  - *Models, Cardiovascular
KW  - *Muscle Contraction
KW  - *Muscle, Skeletal/bs [Blood Supply]
KW  - Adult
KW  - Aged
KW  - Analysis of Variance
KW  - Arteries/ph [Physiology]
KW  - Baltimore
KW  - Blood Pressure
KW  - Cardiac Output
KW  - Compliance
KW  - Exercise Test
KW  - Female
KW  - Heart Rate
KW  - Humans
KW  - Longitudinal Studies
KW  - Male
KW  - Middle Aged
KW  - Stroke Volume
KW  - Time Factors
KW  - Vascular Resistance
KW  - Ventricular Function, Left
KW  - MedStar Heart & Vascular Institute
KW  - Journal Article
KW  - Research Support, N.I.H., Extramural
KW  - Research Support, N.I.H., Intramural
KW  - Research Support, Non-U.S. Gov't
N1  - Available online through MWHC library: 2008-2010
N2  - Effective arterial elastance(E(A)) is a measure of the net arterial load imposed on the heart that integrates the effects of heart rate(HR), peripheral vascular resistance(PVR), and total arterial compliance(TAC) and is a modulator of cardiac performance. To what extent the 130912 in E(A) during exercise impacts on cardiac performance and aerobic capacity is unknown. We examined E(A) and its relationship with cardiovascular performance in 352 healthy subjects. Subjects underwent rest and exercise gated scans to measure cardiac volumes and to derive E(A)[end-systolic pressure/stroke volume index(SV)], PVR[MAP/(SV*HR)], and TAC(SV/pulse pressure). E(A) varied with exercise intensity: the E(A) between rest and peak exercise along with its determinants, differed among individuals and ranged from -44% to +149%, and was independent of age and sex. Individuals were separated into 3 groups based on their E(A)I. Individuals with the largest increase in E(A)(group 3;E(A)>=0.98 mmHg.m(2)/ml) had the smallest reduction in PVR, the greatest reduction in TAC and a similar increase in HR vs. group 1(E(A)<0.22 mmHg.m(2)/ml). Furthermore, group 3 had a reduction in end-diastolic volume, and a blunted increase in SV(80%), and cardiac output(27%), during exercise vs. group 1. Despite limitations in the Frank-Starling mechanism and cardiac function, peak aerobic capacity did not differ by group because arterial-venous oxygen difference was greater in group 3 vs. 1. Thus the 130912 in arterial load during exercise has important effects on the Frank-Starling mechanism and cardiac performance but not on exercise capacity. These findings provide interesting insights into the dynamic cardiovascular alterations during exercise
UR  - http://dx.doi.org/10.1152/ajpheart.00147.2011
ER  -