High output heart failure in group 1 pulmonary hypertension and clinical outcomes

Extract This letter is in response to an interesting article published in a recent issue of the European Respiratory Journal by Reddy et al. [1]. The findings of this study are interesting and noteworthy. However, a few physiological justifications are needed to derive a meaningful interpretation. All three pulmonary hypertension phenotypes (low, normal and high cardiac output) had normal ejection fractions and nearly similar mean arterial pressure. In a subset of patients, pulmonary vasodilator therapy increased cardiac output solely by reducing systemic vascular resistance (SVR).