Cardiopulmonary Exercise Testing in the Evaluation of Unexplained Dyspnea

Diagnosis of unexplained exertional dyspnea or fatigue is a significant challenge. When routine cardiac and pulmonary evaluations are unrevealing, cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring may reveal the abnormal physiology causing these symptoms. In this review, the authors describe the protocol for invasive CPET at Massachusetts General Hospital, and present cases of exercise-induced pulmonary arterial hypertension and exercise-induced heart failure with preserved ejection fraction, as well as a new entity, preload failure, to demonstrate the utility of invasive CPET in the evaluation of unexplained exertional dyspnea. Indeed, exercise-induced pulmonary hypertension may represent early disease where prompt therapeutic intervention may improve outcome. When compared to noninvasive CPET or exercise stress echocardiography, invasive CPET has significant advantages in identifying the etiology of elevated pulmonary pressures and determining the influence of central hemodynamics on exercise capacity. For this reason, we expect that invasive CPET will assume a more prominent role in the evaluation and management of pulmonary hypertension.