Obstructive and nonobstructive hypertrophic cardiomyopathy : differences in global and segmental myocardial strain by cardiac magnetic resonance feature tracking

Purpose: To evaluate any significant differences in myocardial strain between hypertrophic obstructive cardiomyopathy (HOCM) and nonobstructive ones (HNCM), as assessed by cardiac magnetic resonance feature tracking (CMR-FT). Materials and Methods: A total of 17 patients (mean age: 54 +/- 14 y) with echocardiographic diagnosis of HOCM (left ventricular outflow tract obstruction peak gradient >= 30 mm Hg), 19 patients (mean age: 49 +/- 16 y) with HNCM (peak gradient <30 mm Hg), and 18 age-matched and gender-matched healthy controls (mean age: 42 +/- 14 y). All patients underwent cardiac MRI with SSFP-cine to assess left ventricular global and segmental strain analysis by CMR-FT. Late gadolinium enhancement (LGE) sequences were used for semiautomatic quantification of LGE volume, mass, and percentage. Results: The magnitude of global radial, circumferential, and longitudinal strain as well as strain rate were significantly lower in all patients in comparison to controls (P<0.001), except for radial and circumferential strain between HOCM and controls (P=0.270; P=0.154). The latter strain parameters were significantly higher in HOCM than HNCM (radial strain: 31.67 +/- 7.55 vs. 21.26 +/- 7.10, P<0.001; circumferential strain: -17.94 +/- 2.78 vs. -13.46 +/- 3.42, P<0.001). Radial and circumferential strain and circumferential diastolic strain rate were higher in mid-anterior (P<0.001), mid-anteroseptal (P<0.001), and all apical segments (P<0.005) between the 2 groups of patients. Moreover, longitudinal strain was higher only in apical segments in HOCM (P<0.02). Conclusions: HOCM patients showed higher left ventricular apical, mid-anterior, and mid-anteroseptal strain parameters compared with HNCM. These differences were independent of corresponding segmental thickness and LGE amount.