Relationship between myocardial microcirculation perfusion and myocardial mechanics in nonobstructive hypertrophic cardiomyopathy at rest

Abstract

Abstract Objective To quantitatively analyze myocardial microcirculation perfusion in nonobstructive hypertrophic cardiomyopathy (HCM) patients, evaluate myocardial mechanics characteristics in nonobstructive HCM and explore the relationship between microcirculation perfusion and myocardial mechanics in nonobstructive HCM patients. Methods Twenty-eight healthy volunteers and twenty-eight nonobstructive HCM patients were recruited as the case group. All subjects underwent two-dimensional echocardiography, contrast-enhanced myocardial ultrasound (MCE), and two-dimensional speckle tracking imaging (2D-STI).The nonobstructive HCM patients were divided into a hypertrophic segmental myocardium (HS) group and a nonhypertrophic segmental myocardium (NHS) group according to the degree of myocardial hypertrophy. Results (1) There were no statistically significant differences in age, height, weight, body surface area, systolic blood pressure, diastolic blood pressure, or heart rate between the nonobstructive HCM and control groups (P > 0.05). Myocardial thickness (MT), tricuspid regurgitation (TR), E/e', the left atrial volume (LAV) and the left atrial volume index (LAVI) increased in the nonobstructive HCM group, while stroke volume (SV), end-diastolic volume (EDV), end-systolic volume (ESV) and E/A decreased, and the differences were statistically significant (P < 0.05). (2) Compared with those in the control group, peak intensity (PI) and area under the curve (AUC) in the nonobstructive HCM group decreased, s-RS, s-PI, s-TTP and s-AUC in the HS group decreased, and s-PI and s-AUC in the NHS group decreased. The differences were statistically significant (P < 0.05). (3) The nonobstructive HCM group showed a significant decrease in GLS compared with the control group (P < 0.05), although the change in GCS was not significant (P > 0.05), and GLS and GCS were not significantly different between the HS and NHS groups (P > 0.05). (4) In the HS group, PI, AUC, s-PI, s-AUC and GLS were positively correlated, s-TTP was negatively correlated with GLS and GCS (P < 0.05), and RS and s-RS had no correlation with GLS and GCS. Conclusion In nonobstructive HCM patients, myocardial microcirculation perfusion and longitudinal strain of the myocardium were impaired in both hypertrophic and nonhypertrophic segmental myocardium. Hypertrophic myocardial segments in nonobstructive HCM patients have more significant damage and close correlations with changes in myocardial mechanics.