Tissue Doppler Imaging Consistently Detects Myocardial Abnormalities in Patients With Hypertrophic Cardiomyopathy and Provides a Novel Means for an Early Diagnosis Before and Independently of Hypertrophy

TLDR

Left ventricular hypertrophy, the hallmark of familial hypertrophic cardiomyopathy, is absent in many mutation carriers. The study aimed to determine whether reduced myocardial tissue Doppler velocities occur in FHCM patients regardless of hypertrophy. The authors performed 2D and Doppler echocardiography plus tissue Doppler imaging on 30 FHCM patients, 13 mutation‑positive but non‑hypertrophic individuals, and 30 matched controls. Reduced tissue Doppler velocities were observed in both FHCM patients and mutation carriers without hypertrophy, achieving 100 % sensitivity and 93 % specificity, indicating that TD imaging can identify FHCM before LVH develops.

Abstract

Background — Left ventricular hypertrophy (LVH), the clinical hallmark of familial hypertrophic cardiomyopathy (FHCM), is absent in a significant number of subjects with causal mutations. In transgenic rabbits that fully recapitulate the FHCM phenotype, reduced myocardial tissue Doppler (TD) velocities accurately identified the mutant rabbits, even in the absence of LVH. We tested whether humans with FHCM also consistently showed reduced myocardial TD velocities, irrespective of LVH. Methods and Results — We performed 2D and Doppler echocardiography and TD imaging in 30 subjects with FHCM, 13 subjects who were positive for various mutations but did not have LVH, and 30 age- and sex-matched controls (all adults; 77% women). LV wall thickness and mass were significantly greater in FHCM subjects ( P <0.01 versus those without LVH and controls). There were no significant differences in 2D echocardiographic, mitral, and pulmonary venous flow indices between mutation-positives without LVH and controls. In contrast, systolic and early diastolic TD velocities were significantly lower in both mutation-positives without LVH and in FHCM patients than in controls ( P <0.001). Reduced TD velocities had a sensitivity of 100% and a specificity of 93% for identifying mutation-positives without LVH. Conclusions — Myocardial contraction and relaxation velocities, detected by TD imaging, are reduced in FHCM, including in those without LVH. Before and independently of LVH, TD imaging is an accurate and sensitive method for identifying subjects who are positive for FHCM mutations.