Unmasking Obstruction in Hypertrophic Cardiomyopathy With Postprandial Resting and Treadmill Stress Echocardiography

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Latent left ventricular outflow tract obstruction (LVOTO) is an important cause of symptoms in patients with hypertrophic cardiomyopathy (HCM) but can be challenging to provoke. To examine the value of postprandial resting and stress echocardiography and utilization of invasive or enhanced drug therapies (surgical myectomy, alcohol septal ablation, disopyramide, and mavacamten) in patients with postprandial LVOTO. Consecutive HCM patients without LVOTO underwent routine and postprandial echocardiography at rest, with provocation (Valsalva and standing) and after symptom-limited treadmill stress. Among 252 patients (mean age, 58years, 39% women), postprandial LVOT gradients were higher compared with routine echocardiography at rest (median, 9.0 [0-38.0] vs 0 [0-14.0] mm Hg; P<.0001) and with provocation (18.5 [0-70.3] vs 1.5 [0-41.0] mm Hg; P<.0001). Postprandial exercise stress echocardiogram (PPXSE) gradients were higher in a subset of 44 patients who underwent both postprandial and fasting stress echocardiography (47.0 [5.3-81.0] vs 17.5 [0-46.0] mm Hg; P<.0001). In total, 49 (19.5%) patients achieved the ≥50mm Hg threshold under routine conditions (rest/provocation); 90 (35.7%) additional patients achieved postprandial gradients ≥50mm Hg (rest/provocation/exercise), 38 (15.1%) with PPXSE alone. A total of 71 patients were treated with 91 invasive or enhanced drug therapies, 32 (45.1%) of whom had gradients ≥50mm Hg only after eating (rest/provocation) and 8 (11.3%) only with PPXSE, with symptom relief in the majority. Postprandial echocardiography was useful at unmasking LVOTO in more than one-third of patients who did not have high gradients otherwise. Eating before echocardiography is a powerful provocative tool in the evaluation of patients with HCM.