Ageing Alters Right Ventricular But Not Left Ventricular Myocardial Mechanics

Abstract

Introduction: Ageing is associated with a progressive stiffening of the pulmonary vasculature that causes an increase in pulmonary vascular resistance and a decrease in compliance. It remains unclear if right ventricular myocardial mechanics adapt in response to age-related remodeling in the pulmonary vasculature.

PURPOSE: Accordingly, this study examined global and transmural longitudinal myocardial tissue deformation (strain) in a cohort of healthy young and middle-aged men to characterize age-related changes in myocardial tissue mechanics.

METHODS: Two-dimensional echocardiography was used to measure left (LV) and right (RV) ventricular strain in 10 young men (YM; Age: 27 ± 2yr, BMI: 23.2 ± 2.4m2) and 10 middle aged men (MAM; Age: 61 ± 7yr, BMI: 25.9 ± 3.2m2). A transmural strain gradient was calculated as the difference between endocardial and epicardial strain as an index of regional non-uniformity.

RESULTS: Systemic blood pressure was similar in young and middle aged men (YM: 118 ± 4mmHg vs MAM: 122 ± 4mmHg, p > 0.05), while echocardiographic estimates of pulmonary blood pressure via the tricuspid regurgitation pressure gradient were greater in middle aged men (YM: 17 ± 4mmHg vs MAM: 25 ± 6mmHg, p < 0.05). LV and RV dimensions were similar (p > 0.05) in young (LV EDV: 118 ± 19mL; RV EDA: 18.3 ± 2.2cm2) and middle aged men (LV EDV: 118 ± 17mL; RV EDA: 17.3 ± 3.8cm2). LV global longitudinal strain (YM: -17.5 ± 1.0% vs MAM: -18.0 ± 1.0%, p > 0.05) was similar in young and middle aged men, while RV global longitudinal strain (YM: -27.3 ± 1.8% vs MAM: -22.5 ± 1.7%, p<0.01) was lower in middle aged men. LV transmural strain gradient (YM: -4.6 ± 0.4% vs MAM: -4.6 ± 0.4%, p > 0.05) was similar in young and middle aged men, while RV transmural strain gradient (YM: -1.1 ± 0.4% vs MAM: -5.5 ± 0.5%, p<0.01) was higher in middle aged men.

CONCLUSION: Ageing was associated with global and regional alterations in RV myocardial mechanics, while LV function was unaltered. Specifically, ageing resulted in a decrease in RV global strain and an increase in transmural non-uniformity (i.e., increased transmural strain gradient). Differences in LV and RV myocardial architecture and age-related changes in the pulmonary vasculature are possible explanations for opposing LV and RV functional remodeling in response to ageing.