How to Image Hypertrophic Cardiomyopathy.

A 48-year-old man, with only a history of mild systemic hypertension, was initially evaluated after presenting with symptoms of exertional dyspnea occurring predominantly with inclines. At that time, an abnormal 12-lead ECG was obtained demonstrating left ventricular hypertrophy by conventional voltage criteria, prompting additional testing with a 2-dimensional echocardiogram that showed normal systolic function (ejection fraction=65%), with 14-mm ventricular septal thickness and 12 mm in the posterolateral wall, and mild systolic anterior motion (SAM) of the mitral valve (bend of anterior leaflet into outflow tract without septal contact). A stress nuclear stress test showed no myocardial ischemia at rest or at peak exercise with a normal blood pressure response and no arrhythmias or ST-T changes during exercise or in recovery. The patient was prescribed a β-blocker for treatment of systemic hypertension. During the next 2 years, the patient developed more limiting exertional symptoms with routine activities. β-Blocker dosage was increased, and a repeat echocardiogram demonstrated similar findings to the initial study, borderline left ventricular (LV) wall thickness despite well-controlled blood pressure. The abnormal ECG, and mild SAM at rest, raised consideration for a diagnosis of hypertrophic cardiomyopathy (HCM) and management for limiting heart failure symptoms. HCM is often suspected in a patient based on the presence of cardiovascular symptoms, detection of abnormal ECG, systolic ejection murmur on routine examination, or as part of pedigree screening.1,2 Abnormalities on ECG are present in >90% of patients with HCM, although no specific ECG pattern is pathognomonic.1 Clinical diagnosis of HCM can reliably be made in the majority of patients with 2-dimensional transthoracic echocardiography by imaging increased LV wall thickness (≥15 mm) with a nondilated cavity in the absence of any disease known to cause LV hypertrophy of that magnitude (ie, systemic hypertension or aortic stenosis).1–5 In …