The relationship between diastolic dysfunction and level of blood pressure in Blacks

Abstract

Introduction and objective: Patients with essential hypertension are predisposed to impaired left ventricular relaxation, and consequently, diastolic dysfunction. Because diastolic dysfunction is an early marker of the pathological effects of hypertension on the heart, evaluating the relationship between the development of diastolic dysfunction and the level of blood pressure becomes pertinent. The aim of our study was to evaluate this relationship.

Patients and methods: Between November 1998 and January 2000, 692 consecutive hypertensive patients, all Blacks, attending the medical outpatient and cardiac clinics of the University of Nigeria Teaching Hospital, Enugu, Nigeria were screened for the study. One hundred five of them, divided into 3 groups of 35 each according to levels of blood pressure, met the inclusion criteria. Thirty-five age and sex-matched normotensives were used in the control group. Clinical parameters, including systolic and diastolic blood pressures, and echocardiographic indices, were measured.

Results: A definite positive relationship between diastolic dysfunction and the level of the blood pressure was established, with the degree of diastolic dysfunction proportionate to increasing level of blood pressure (P<.001). A significant difference between the mean values of the diastolic dysfunction index (A/E ratio) in the hypertensive groups was evident (P<.05). While there was virtually no correlation found between normotensives and diastolic dysfunction (r=0.07), direct relationships existed between moderate and severe hypertensives and diastolic dysfunction (r=0.24 and 0.39 respectively).

Conclusion: This study has demonstrated that diastolic dysfunction was significantly and progressively higher in the hypertensive groups when compared to the normotensive control group. Further studies, with a large number of patients, are recommended to determine population-based data on diastolic dysfunction and its other confounding variables in our environment, independent from the level of blood pressure.