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Hypertrophic cardiomyopathy (HC) is the most common inherited cardiomyopathy, with varied timing of phenotypic and clinical presentation. Literature describing cardiac magnetic resonance (CMR) imaging and late gadolinium enhancement (LGE) in young patients with HC is limited. This study included patients diagnosed with HC at young age (<21 years) between January 1990 and January 2015 who underwent transthoracic echocardiography and CMR with assessment of LGE at a single tertiary referral center. LGE was quantified via a method of 6 standard deviations and patients were grouped based upon presence or absence of LGE (≤1% and >1% LGE, respectively). Sudden cardiac death (SCD) risk was assessed in patients >16 years of age using the European SCD risk score. A composite outcome of New York Heart Association class III-IV symptoms, aborted SCD, heart transplantation, and all-cause mortality was assessed via Kaplan-Meier curves with log-rank analysis. Overall, 126 patients were included (78 male; 62%). Median age of diagnosis was 15 (12 to 18) years. LGE was present in 81 (64%) patients, although only 4 (3%) patients had LGE >15%. Median age at CMR imaging was 19 (15 to 23) years. Patients with LGE had greater wall thickness (25 ± 8 mm vs 22 ± 7 mm, p = 0.01). Median European SCD risk score was 4.7 (2.9 to 6.5). Median follow-up was 6.5 (2.5 to 13) years with 26 patients (21%) meeting the composite outcome. There were no significant differences in composite outcome since age of diagnosis when stratified by presence/absence of LGE (p = 1.0). The presence of LGE in young HC patients was not an independent risk factor for cardiovascular morbidity and mortality. Wall thickness was greater in patients with LGE. There remains a need for further evaluation of this unique HC cohort., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Because myocyte dysfunction and disarray are early abnormalities in hypertrophic cardiomyopathy (HC), we tested if Doppler myocardial imaging (DMI) could identify systolic and diastolic dysfunction in mutation carriers (MC) (genotype positive patients without hypertrophy, defined as phenotype negative after conventional screening tests). In a single family with a missense mutation in the myosin binding protein C gene (Arg 502 Gln) we identified 5 MCs; these subjects were asymptomatic and had normal physical examination, normal electrocardiogram, treadmill stress test, ambulatory Holter electrocardiogram, and normal conventional M-mode, 2-dimensional, and Doppler echocardiography. In each patient we performed a DMI study and measured the peak velocities of the systolic (S), rapid filling (E), and atrial contraction (A) waves in the 4 sides of the mitral annulus, in 8 left ventricular segments (apical views), in the tricuspid annulus, and in 2 right ventricular segments. These data were compared with those from 10 normal volunteers matched for sex, age, and body surface. Compared with the normal volunteers, the MCs had lower left ventricular systolic velocities and higher right ventricular systolic velocities; lower diastolic rapid filling velocities; higher or similar atrial contraction velocities; reduced E/A; lower percentage of annular sides and segments with E/A >1 and lower average number of sides and/or segments with E/A >1 per patient; similar right ventricular rapid filling velocities; and similar or higher atrial contraction wave velocities. Thus, DMI detects important left and right ventricular annular and regional myocardial contraction and relaxation abnormalities independently of the presence of hypertrophy, in HC. These results show that DMI is more sensitive than conventional echocardiography and establishes a new and highly accurate method for the noninvasive screening of MCs of the disease.