Chronic heart failure is a complex syndrome in which the pumping function of the heart fails to meet the metabolic demands in the muscles of the body. As the heart pumps less blood each beat, the blood flow to exercising skeletal muscles will be reduced. This is the reason most patients with chronic heart failure experience a reduced exercise tolerance.
The main focus of cardiovascular research in chronic heart failure has been on the arterial side of the circulation, with less attention paid to the venous side, despite evidence of changes in venous structure and function in subjects with a failing heart. The venous system plays an important role in the circulation by removing metabolic waste and ensuring venous return and optimal heart function. Therefore, one would think that a decrease in venous return would reduce the minute volume, and ultimately also physical performance, as seen in patients with chronic heart failure.
Red for arteries, blue for veins
In an article published in the Journal of Cardiopulmonary Rehabilitation and Prevention, Welsch and colleagues examined the vascular function and exercise intolerance in twenty patients with chronic heart failure, and compared them to ten healthy subjects. They examined the relationship between arterial and venous function, and exercise tolerance, and found that impaired venous function was associated with reduced exercise performance (measured as 6 minute walking distance in heart failure patients when compared to healthy aged-matched subjects). Based on these results, one may suggest that exercise intolerance in heart failure may be a result of insufficiency in the venous circulation, as well as dysregulation on the arterial side.
Future research on heart failure and venous function is warranted, as improved knowledge about the contribution of venous function or impaired function may help to establish original and novel diagnostic and therapeutic tools for prevention and treatments of heart failure.
Written by Ingeborg Leinan, PhD Candidate at CERG.
Cardiac Exercise Research Group 