Evaluation of Myocardial Systolic Global and Segmental Function by Strain and Strain Rate Imaging in Patients with Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is a genetic cardiovascular disease with tremendous heterogeneity in its phenotypic expression. Global systolic function measured by ejection fraction (EF) does not seem to be a reliable marker for myocardial contractility in these patients. Tissue Doppler Imaging (TDI) indices, strain, and strain rate (SR) may be helpful in discriminating HCM from other mimetics. We decided to measure the regional myocardial function by strain and SR imaging to determine whether the regional myocardial function is related to the global systolic function and whether systolic strain and SR are reduced in all types of HCM. Method Forty-one consecutive patients (20 women, mean age ± SD = 41 ± 13.0 years) with HCM were included. All the patients underwent complete clinical and echocardiographic evaluations. The global systolic function was measured visually and by Simpson’s method. The strain and strain rate of 6 different basal and 6 mid-myocardial segments were measured offline by TDI. The mean values of these parameters were compared with normal reference values using one sample T-test leading to a significant reduction (P<0.05). Result The most common symptom was dyspnea. Nineteen (46.3%) patients were in NYHA function class II and 10 (24.4%) patients had a history of syncope. Mean left ventricular ejection fraction was 55% ± 4.9%. Considering an LVOT gradient >30mmHg, HCM was found in 18 (43.9%) patients. The mean myocardial wall thickness was 2 ± 0.7 cm. Mean of strain and strain rate were significantly reduced compare with normal values (P < 0.001). In all of the 12 segments, mean ± SD of strain was -10.6 ± 3.8 and that of strain rate was -0.73 ± 0.73. Conclusion TDI, strain, and SR analysis have better diagnostic yield in HCM patients. They are significantly reduced in all HCM patients, even in patients with a normal global systolic function.