Tissue tracking analysis and left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy

Abstract

Hypertrophic cardiomyopathy (HCM) is the most frequent inherited cardiomyopathy in adults and may be associated with limiting symptoms and adverse clinical evolution, especially in the obstructive forms. Cardiac magnetic resonance (CMR) is a key technique to accurately diagnose the condition and tissue tracking strain analysis, a promising new tool to better identify and understand its mechanisms. We sought to investigate the association of tissue tracking CMR deformation parameters with obstructive HCM forms. CMR deformation parameters were evaluated in a cohort of 38 obstructive and 88 non-obstructive HCM patients. Longitudinal time to peak strain (cutoff value of ≥400 ms) emerged as the best predictor of obstruction after adjusting for left ventricular ejection fraction, betablocker and calcium-channel antagonist active therapies, and corrected by heart rate (adjusted odds ratio 4.48; 95 % confidence interval 1.27-15.85; p = 0.020). In conclusion, time to peak strain is independently related to the presence of LVOT obstruction in patients with HCM, suggesting a delayed deformation in these patients and potentially identifying obstructive gradient effects on the HOCM patients' left ventricle. A threshold of longitudinal time to peak strain of >/≤ 400 ms emerges as a valuable predictor of LVOT obstruction.

Keywords: Cardiac magnetic resonance; Deformation analysis; Hypertrophic cardiomyopathy; Left ventricular outflow tract obstruction; Strain; Tissue tracking.