Usefulness of Magnetic Resonance Imaging to Distinguish Hypertensive and Hypertrophic Cardiomyopathy

Abstract

Different pathophysiologic pathways in the development of left ventricular (LV) hypertrophy can be reflected in phenotypical differences. A total of 119 subjects (39 with hypertension [HTN]; 43 with nonobstructive hypertrophic cardiomyopathy [HC], and 37 control subjects) underwent a standardized cardiac magnetic resonance imaging protocol for assessment of global and regional morphology and function using balanced steady-state free precession sequences and late gadolinium enhancement studies. Compared to controls, both hypertrophic groups had significantly greater maximal wall thickness and LV mass index (p <0.01). The patients with HTN had reduced ejection fraction, increased heart cavities, and increased LV wall stress (p <0.01). The HC group had supernormal ejection fraction and reduced LV wall stress (p <0.01). The HTN group had reduced anteroseptal systolic strains (p <0.02), and the HC group displayed a marked decrease in longitudinal systolic strain (p <0.01). In the HC group, an inverse relation was seen between a globally increased late gadolinium enhancement score and the ejection fraction (r = -0.5, p = 0.01), and between regional late gadolinium enhancement scores and regional systolic strain in the inferoseptal segments. Increased LV wall stress was identified as the hallmark of HTN (odds ratio 1.2, p = 0.002), while HC was best characterized by reduced total longitudinal strain (odds ratio 1.3, p = 0.002). In conclusion, our findings indicate the presence of distinctive hypertrophic phenotypes detectable by means of multiparametric magnetic resonance imaging. In HTN, impaired deformation follows the distribution of LV wall stress. On the contrary, HC is characterized by reduced global and regional deformation, in association with fibrosis.