Assessment of myocardial work in sarcomere gene mutation carriers, healthy controls and overt nonobstructive hypertrophic cardiomyopathy.

Abstract

Background: Hypertrophic cardiomyopathy (HCM) is defined by unexplained hypertrophy and often characterized by diastolic and systolic dysfunction. HCM patients are known to have impaired left ventricular (LV) myocardial work (MW), a more load-independent parameter compared to global longitudinal strain (GLS). We hypothesized that impaired MW might occur in sarcomere mutation carriers without LV hypertrophy.

Methods and results: A single centre study with a case-control design. Patients with overt nonobstructive HCM and a causal sarcomere gene variant (n = 44), carriers (n = 51) and age and sex matched (to the carriers) healthy controls (n = 32) underwent a transthoracic echocardiogram including myocardial deformation analysis to calculate GLS and MW. Global work index (GWI) (1695 ± 332mmHg% vs. 1881.50 ± 490mmHg%, p = 0.001) and global constructive work (GCW) (2017.78 ± 323.05mmHg% vs. 2329.31 ± 485.44 mmHg%, p = 0.002) were lower in sarcomere mutation carriers compared to controls. LV ejection fraction and GLS were similar between these two groups. GWI (1209 ± 735mmHg% vs. 1695 ± 332mmhg%, p < 0.001), GCW (1456 ± 703mmHg% vs. 1993 ± 389mmHg%, p < 0.001), global wasted work (GWW) (117 ± 148mmHg% vs. 96 ± 69mmHg%, p = 0.006) and global work efficiency (GWE) (89 ± 7% vs. 95 ± 3%, p < 0.001)] were worse in overt non-obstructive HCM patients.

Conclusion: We show for the first time that MW indexes were significantly worse in sarcomere mutation carriers compared to controls, suggesting that MW is more sensitive to early changes than GLS and could have a significant role in the evaluation and follow-up of carriers.