Role of Stress Echo on the Prognosis of Hypertrophic Cardiomyopathy

Background: Patients with hypertrophic cardiomyopathy (HCM) frequently present with confusing and misleading symptoms. In these instances stress tests may help to stratify the risk of future events.Objective: The purpose of this study was to assess the prognostic usefulness of the different variables obtained with exercise stress echo (ESE) in patients with HCM.Methods: A retrospective and observational study was performed in 110 patients evaluated with ESE. Patients were divided into 3 groups according to their left ventricular outflow tract obstruction level (LVOTO): 1) persistent LVOTO (peak instantaneous gradient at rest obtained by continuous Doppler ≥ 30 mmHg), 2) latent LVOTO (gradient ≥ 50 mmHg with exercise); and no LVOTO. Median follow-up was 2.7 years. The primary endpoint was the composite of death, sudden death, sustained ventricular tachycardia or hospitalization for heart failure.Results: Persistent LVOTO was present in 19.1% of cases, latent LVOTO in 31.8% and no LVOTO in 49.1%. Ventricular function, wall thicknesses and diameters were similar for the three groups. Poor prognostic variables were significantly higher for persistent LVOTO. The latent LVOTO group developed more symptoms, electrocardiographic changes and mitral regurgitation after exercise than the group without LVOTO, although it was not associated with a higher number of events. Variables that were associated with increased rate of events during follow-up were the presence of gradient ≥ 30 mmHg at rest (p=0.07), electrocardiographic changes during the test (p=0.020) and the inverse relationship of METs (p=0.07).Conclusions: Patients with HCM who achieved a high exercise capacity, expressed as METs ≥ 7, showed excellent mid- to long-term outcomes. LVOTO at rest and electrocardiographic changes during maximal stress exercise were associated with an increased number of events during follow-up.