Role of Exercise Testing in Hypertrophic Cardiomyopathy

Over the last 25 years, patients with hypertrophic cardiomyopathy (HCM) have been studied with a variety of methods employing physiological exercise that have made major contributions to disease management and are performed without increased risk. Previously under-utilized in HCM, exercise (stress) echocardiography has become incorporated into the standard clinical assessment and diagnostic armamentarium of HCM using upright or supine symptom-limited treadmill or bicycle modalities. In patients without outflow gradients at rest, exercise echocardiography is the most appropriate method for provoking obstruction, with the capability of predicting future development of progressive heart failure symptoms, and differentiating patients with provocable obstruction from those without obstruction, with major implications for dictating treatment options, that is, surgical myectomy (alternatively, alcohol septal ablation) versus heart transplant. Reduced myocardial oxygen consumption with metabolic (cardiopulmonary) exercise testing provides an independent and quantitative assessment of functional limitation for individual patients when the personal history is ambiguous, and also guides eligibility for heart transplant. Hypotensive blood pressure response to exercise can be an arbitrator in risk stratification decisions. Exercise testing with a variety of methods has become an integral and powerful component of the noninvasive evaluation of HCM, and in some patients can determine treatment strategy.