Moderate intensity supine exercise causes decreased cardiac volumes and increased outer volume variations: a cardiovascular magnetic resonance study

Abstract

BackgroundThe effects on left and right ventricular (LV, RV) volumes during physical exercise remains controversial. Furthermore, no previous study has investigated the effects of exercise on longitudinal contribution to stroke volume (SV) and the outer volume variation of the heart. The aim of this study was to determine if LV, RV and total heart volumes (THV) as well as cardiac pumping mechanisms change during physical exercise compared to rest using cardiovascular magnetic resonance (CMR).Methods26 healthy volunteers (6 women) underwent CMR at rest and exercise. Exercise was performed using a custom built ergometer for one-legged exercise in the supine position during breath hold imaging. Cardiac volumes and atrio-ventricular plane displacement were determined. Heart rate (HR) was obtained from ECG.ResultsHR increased during exercise from 60±2 to 94±2 bpm, (p<0.001). LVEDV remained unchanged (p=0.81) and LVESV decreased with −9±18% (p<0.05) causing LVSV to increase with 8±3% (p<0.05). RVEDV and RVESV decreased by −7±10% and −24±14% respectively, (p<0.001) and RVSV increased 5±17% during exercise although not statistically significant (p=0.18). Longitudinal contribution to RVSV decreased during exercise by −6±15% (p<0.05) but was unchanged for LVSV (p=0.74). THV decreased during exercise by −4±1%, (p<0.01) and total heart volume variation (THVV) increased during exercise from 5.9±0.5% to 9.7±0.6% (p<0.001).ConclusionsCardiac volumes and function are significantly altered during supine physical exercise. THV becomes significantly smaller due to decreases in RVEDV whilst LVEDV remains unchanged. THVV and consequently radial pumping increases during exercise which may improve diastolic suction during the rapid filling phase.

Rest and exercise hemodynamic and metabolic findings in active duty soldiers referred for cardiac catheterization to exclude heart disease: Insights from past invasive cardiopulmonary exercise testing using multisensor high fidelity catheters

“…In the current study, at the work load = 50 watts, both heart rate and SVi increased with heart rate being the greater contributor to increased blood flow and stroke index more variable. These results are consistent with others reporting supine exercise in the catheterization laboratory (dye) and with other imaging modalities used in current practice to dynamically assess cardiac function .…”

Alterations in ventricular pumping in patients with atrial septal defect at rest, during dobutamine stress and after defect closure

“…Also there is a mismatch in inflow and outflow from the heart and a deviation from the near constant volume of the pericardial sac, presenting as increased total heart volume variation as was observed during dobutamine stress in both ASD patients and controls. The results are in line with our previous findings in healthy volunteers during supine exercise (Steding‐Ehrenborg et al ., ) where longitudinal contribution to LVSV was reduced, but not to RVSV. The difference may be explained by a lower maximum heart rate reached during supine exercise compared to dobutamine stress (94 ± 2 bpm vs 130 ± 12 bpm in healthy controls) or by differences in systemic venous return between physical exercise and dobutamine stress.…”

Heart filling exceeds emptying during late ventricular systole in patients with systolic heart failure and healthy subjects – a cardiac MRI study

“…Notably, the late‐systolic net inflow must be located in the atria because the AV valves are closed during this time period of ongoing ventricular ejection. This late‐systolic atrial filling is caused by flow of blood in the pulmonary and caval veins which is accelerated into the atria due to the suction of ventricular systole (Zhang et al ., ; Steding‐Ehrenborg et al ., ,b). Furthermore, the systolic longitudinal AVPD must be the primary cause of the late‐systolic net inflow as systolic radial function does not cause atrial filling because of the closed AV‐valves (Carlsson et al ., ,b).…”

“…However, in the present study, there was no difference in phase shift between inflow and outflow using adenosine vasodilatation to pharmacologically achieve increased flow and thus no difference in outer heart volume variations. Interestingly, previous findings during exercise in fact showed increased outer heart volume variations, meaning larger phase shifts between inflows and outflows are present during exercise compared to rest (Steding‐Ehrenborg et al ., ,b).…”

“…The total heart volume (THV) has been shown to decrease during systole by 4%–11% in man (Bowman & Kovacs, ; Carlsson et al ., , ; Steding‐Ehrenborg et al ., ,b). There is a decrease in the content of the pericardial sac during systole, the so‐called total heart volume variation (THVV), caused by the difference in flow between blood ejected into the great arteries and the blood drawn into the atria from the caval and pulmonary veins by the atrioventricular plane displacement (AVPD) (Lundback, ; Carlsson et al ., ,b; Steding‐Ehrenborg et al ., ,b) (Waters et al ., ). In other words, the ejecting ventricles manage to eject a greater volume than what the descent of the closed AV‐plane pulls into the atria.…”