Abstract
BACKGROUND: The main objective of this study was to determine whether myocardial strain and myocardial work are altered in hypertension and whether the strain is independent of hypertension-induced left ventricular hypertrophy. METHODS: Two systematic literature searches were conducted using Medline and EMBASE through to June 30, 2022. In the first, search terms left ventricular strain or speckle tracking AND hypertension and left ventricular hypertrophy were used in conjunction with Boolean operators to identify articles reporting left ventricular strain in patients with hypertension. In the second, the terms Global cardiac or myocardial work AND hypertension were used to identify articles. Publication bias was assessed by examination of funnel plots and calculation of the Failsafe N and Duval and Tweedie's Trim and fill. The results were presented as Forrest plots. RESULTS: Global longitudinal strain (GLS) was significantly lower in patients with hypertension compared to those without hypertension with a mean difference of 2.0 ± 0.1 (standard error of mean(SEM)) in the fixed effect model. Global circumferential strain (GCS) was significantly lower in hypertension. The mean difference between the hypertensive and non-hypertensive groups was 1.37 ± 0.17. Global radial strain (GRS) was significantly (p < 0.05) greater in hypertension. However, this difference was significant in only 3 and of borderline significance in 3 of 14 studies where GRS was measured. The mean difference between the hypertensive and non-hypertensive groups was 1.5 ± 0.5 using the fixed effects model. There was a significant relationship between GLS and GCS as well as between GCS and GRS but no significant relationship between GLS and GRS. There was no significant difference in left ventricular ejection fraction (LVEF) between the hypertension and no hypertension groups. There was no significant relationship between LVEF and either GLS or GCS but a significant negative correlation was found between LVEF and GRS. GLS was further reduced in persons with hypertension and left ventricular hypertrophy (LVH) compared to hypertension without LVH. In contrast, there were no or minimal differences in GCS and GRS for individuals with hypertension and LVH compared to those without LVH. Global myocardial work index (GWI) and Global constructive work (GCW) were significantly greater in patients with hypertension compared to controls. Global wasted work (GWW) indicated significantly less wasted work in controls compared to hypertension. In contrast, Global work efficiency (GWE) was significantly lower in hypertension compared to the control. CONCLUSIONS: There was a significant reduction in GLS and GCS in hypertension while GRS was increased. The reduction in GLS in hypertension was not dependent on the presence of LVH. GLS was further reduced in persons with hypertension when LVH was present. In contrast, there were no or minimal differences in GCS and GRS for individuals with LVH compared to those without LVH. GLS was independent of left ventricle (LV) ejection fraction. GWI, GCW and GWW were greater in hypertension while GWE was lower in hypertension compared to controls. These data support the contention that GLS and indices of global work are early markers of hypertensive heart disease.