Phenotyping Left Ventricular Obstruction With Postprandial Re-Test Echocardiography in Hypertrophic Cardiomyopathy

Dynamic left ventricular (LV) obstruction has important clinical and therapeutic implications in patients with hypertrophic cardiomyopathy (HC). Although absent at rest, LV obstruction may be elicited using varying stressors. Meal-related hemodynamic changes may favor LV obstruction and support postprandial (PP) symptoms in HC patients. The aim of this study was to evaluate PP-LV obstruction inducibility in HC patients in comparison with fasting Valsalva maneuver and exercise test. Ninety-two HC patients without LV obstruction underwent at-rest Transthoracic Echocardiography (TTE) during Valsalva maneuver and exercise test under fasting condition followed by at-rest re-test PP-TTE 30 to 60 minutes after a standardized midday meal. LV obstruction was noted and classified as being related to systolic anterior motion (SAM) of the mitral valve (SAM-related) and/or non-SAM-related (mid-cavity or apical), and intraventricular gradient was measured. At-rest re-test PP-TTE showed significant intraventricular gradient (>30 mm Hg) in 68 patients (60 SAM-related, 8 non-SAM related, 30 combined) with a higher prevalence (74%) of HC phenotype re-classified as obstructive compared with the fasting Valsalva maneuver (23%) or exercise test (33%) (p < 0.001). At multivariate analysis, a clinical history of PP symptoms and mitral anterior leaflet length and/or LV outflow ratio >2 were independently correlated with PP-TTE obstruction. In conclusion, PP TTE re-test is a simple and effective approach to unmask latent LV dynamic obstruction in daily clinical practice over fasting Valsalva maneuver or exercise test. PP clinical phenotype refinement may be relevant in targeting and evaluating HC therapy.