Diastolic function parameters in normotensive offspring of hypertensive Nigerians: Comparison with age-matched control

Abstract

Abstract Background: Systemic hypertension is associated with left ventricular systolic and diastolic dysfunction (LVD). Left ventricular diastolic dysfunction (LVDD) is present in over 25% of adults over 40 years of age and may precede the onset of systemic hypertension. Genetic predisposition may be the reason why some normotensive (NT) individuals develop systemic hypertension despite modest lifestyle modification and others do not. Aim: This study aimed to compare diastolic function parameters in NT offspring of Nigerians with systemic hypertension with those of NT offspring of NT individuals. Materials and Methods: A total of 45 NT offspring of parents with systemic hypertension (ocular hypertension [OHT]) were selected with 45 NT ONT parents, matched for age and sex. All subjects had echocardiography (echo) and electrocardiography (ECG) done. The presence and pattern of LVDD in all subjects were analyzed statistically. Analysis of data was done using the Statistical Package for the Social Sciences (SPSS) version 19. Results: This study observed a statistically significant difference in some LVDD echo parameters between OHT subjects and ONT controls. The left atrial volume (LAV: t = 2.229, P = 0.028), LAV index (LAVI: t = 2.578, P = 0.012), isovolumic relaxation time (IVRT: t = 3.630, P < 0.0001), and difference in atrial reversal and A-wave duration (Ar-A: t = 2.649, P = 0.01) had a statistically significant difference in their mean values between OHT subjects and ONT controls. The prevalence of LVDD in this study was 17.78%. Impaired relaxation (Grade I LVDD) pattern had the highest frequency compared to pseudonormal (Grade II LVDD) pattern (26.67% vs. 4.44%) in OHT subjects. There was no subject in the study population who had restrictive (Grade III or IV LVDD) pattern. It was observed that three sets of LVDD parameters were present in all subjects with LVDD and they were as follows: (1) IVRT + E/A + DT, (2) IVRT + E/A + DT + E/e’, and (3) IVRT + E/A + DT + E/e’ + S/D + Ar-A. The prevalence of abnormal LV geometric pattern was 42.2% (CR: 20%, CH: 13.3%, and EH: 8.9%) in OHT subjects, and this was about two and half times more than the prevalence in ONT controls. Furthermore, the prevalence of LV hypertrophy (CH and EH) in OHT subjects was 22.2%, while it was 14.4% in all subjects in this study. There was a significant correlation between DBP and all echocardiographic LVDD parameters in OHT subjects except A-wave, E/e’ ratio, and systolic fraction (S/D ratio). Conclusions: LVDD and abnormalities are present in NT offspring of systemic hypertensive individuals. These findings suggest that LVDD precedes the development of systemic hypertension.