Evaluation of subtle left ventricular systolic abnormalities in adult patients with hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM), an auto-somal dominant disorder due to mutation of genes encoding sarcomeric proteins, leads to left ventricular diastolic dysfunction. Recently, the research in this area suggests that systolic dysfunction exists in the patients with HCM even though traditional measures of systolic dysfunction are normal. So, we carried out this study to determine global systolic dysfunction in patients with HCM.

MATERIALS AND METHODS: A total of 18 patients, diagnosed with HCM according to echocardiography parameters, that is thickness of interventricular septum/posterior wall thickness >1.3 or hypertrophy involving apex only with or without left ventricular outflow tract obstruction, were included in the study and were compared with normal age-matched controls. We measured torsion and strain imaging by 2-dimensional echocardiography as well as strain imaging by tissue Doppler echocardiography.

RESULT: The results of the study showed that there was considerable increased torsion in patients with HCM as compared to normal subjects (16.61±7.43 vs. 10.42±4.73, p=0.006). Tissue Doppler indices-systolic annular velocity (7.7±0.7 vs. 8.7±1.00, p=0.012) and lateral wall E/E' (12.52±5.27 vs. 6.66±1.67, p<0.001) were significantly different in patients with HCM and normal subjects. The average systolic strain and strain rate as well as diastolic strain rate were significantly different in both the groups when strain imaging was performed by tissue Doppler echocardiography. We also observed significantly reduced global longitudinal, circumferential and radial strain in patients with HCM when strain analysis was carried out with 2-dimensional speckle tracking echocardiography.

CONCLUSION: The global subtle systolic dysfunction, as measured by left ventricular torsion and strain imaging, is present in patients with HCM even though traditional measure of systolic dysfunction is normal.