What is the topic of this review? This review concerns the negative impact of pulmonary hypertension (PH) on the pulmonary haemodynamic and gas exchange responses to exercise, considering the mechanisms by which PH plays a role in exercise intolerance in heart failure (HF) patients. What advances does it highlight? The hallmark limited pulmonary vascular ‘reserve’ and impaired pulmonary gas exchange responses to exercise in HF are further worsened by the development of PH; these are key determinants of exercise intolerance. Even HF patients who present with ‘normal’ pulmonary vascular function experience exercise-induced PH which plays a role in exercise intolerance.
Patients with heart failure universally complain of exertional intolerance, but the underlying cause(s) of this intolerance may differ between patients with different disease phenotypes. Exercise introduces an impressive stress to the lungs, where elevations in venous return and cardiac output engender substantial increases in pulmonary blood volume and flow. Relative to healthy individuals, the pulmonary vascular reserve to accept this increase in pulmonary perfusion is compromised in heart failure with a growing body of evidence suggesting that the development of pulmonary hypertension (PH), particularly a pre-capillary component of PH, further worsens the pulmonary haemodynamic response to exercise in these patients. Characterised by an exaggerated increase in pulmonary arterial pressure and an elevation in pulmonary vascular resistance, this dysfunctional pulmonary haemodynamic response plays a role in exercise intolerance likely through an impairment in right ventricular function, under perfusion of the pulmonary circulation, and a subsequent reduction in systemic blood flow and oxygen delivery. The hallmark ventilatory and pulmonary gas exchange abnormalities that accompany heart failure, including a greater ventilatory equivalent for carbon dioxide (V̇ /V̇CO ), are also further worsened by the development of PH. This raises the possibility that measures of exercise pulmonary gas exchange may help ‘describe’ underlying PH in heart failure; however, several fundamental issues and questions need to be addressed before such gas exchange measures could truly be considered efficacious measures used to differentiate PH type and track PH severity in heart failure. heart failure, pulmonary hypertension, pulmonary haemodynamics, pulmonary gas exchange, exercise intolerance This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.