Diastolic Dysfunction and Baroreflex Sensitivity in Hypertension

Abstract

Abstract-The determinants of diastolic dysfunction in patients with systemic hypertension are not completely known. To evaluate the possible role of age, arterial blood pressure, and baroreflex heart rate response impairment in causing diastolic dysfunction, we studied 61 patients (42 male; meanϮSD age, 43.9Ϯ12 years) with newly recognized and therefore previously untreated systemic hypertension. Diastolic dysfunction was evaluated by means of Doppler echocardiography (and diagnosed as such when the early to atrial peak velocity ratio corrected to heart rate was Ͻ1), arterial blood pressure by 24-hour ambulatory monitoring, and baroreflex heart rate response by means of the spectral technique (␣ index) during paced (0.27 Hz) and spontaneous breathing (in a supine position and during tilt). Nineteen patients had diastolic dysfunction, the most powerful predictor of which was age (rϭϪ0. T he cause and time of occurrence of cardiac impairment in patients with essential hypertension are not precisely known. It has been shown that diastolic dysfunction is the earliest cardiac abnormality in this patient population 1 and may precede ventricular hypertrophy. 2 Age and pressure load are considered possible determinants, 3 whereas the role of the autonomic nervous system is still debated. Animal studies have suggested that a high sympathetic tone may favor the development of hypertrophy, 4 but the role of the autonomic nervous system in the genesis of cardiac abnormalities is unclear. Some studies have reported increased sympathetic activity in hypertensive patients with cardiac hypertrophy, 5 but this has not been confirmed by other authors. 6 Furthermore, no data are yet available concerning the role of depressed baroreflex sensitivity in determining cardiac impairment in these patients. It is possible that it is too late for any autonomic nervous system abnormalities to be detected once hypertrophy becomes evident, and therefore the early phase of essential hypertension could offer important information on the role of autonomic nervous system activity in determining the presence of cardiac involvement.The purpose of this study was to evaluate the role of pressure load and baroreflex heart rate response in determining the appearance of diastolic ventricular dysfunction in patients with previously unrecognized and untreated mild to moderate essential hypertension. Methods Study PopulationThe study involved 61 consecutive patients referred to our outpatient clinic for previously untreated mild to moderate hypertension. Only the patients whose diastolic blood pressure was Ͼ90 mm Hg at 3 different examinations were included in the study. All of the patients were asymptomatic and underwent a full medical examination, 12-lead ECG, routine laboratory tests, and a treadmill stress test to rule out neurological disease, secondary hypertension, and coronary artery disease. Obese (body mass index Ͼ30 kg/m 2 ) and diabetic patients were also excluded. The control group consisted of 15 nonhospitalized healthy volunteers (10 male; m...

Baroreflex sensitivity correlates with left ventricular morphology and diastolic function in essential hypertension

“…Our data confirm a previous study by Pitzalis et al [33], performed in a small population of hypertensive patients, which showed an association between the mitral inflow E/A ratio and BRS. A major limitation of the evaluation of diastolic function using mitral inflow is the difficulty in identifying a pseudonormal pattern, resulting in the misdiagnosis of moderate diastolic dysfunction for a normal status.…”

High circulating levels of endogenous ouabain in the offspring of hypertensive and normotensive individuals

“…Our results are also in line with previous findings that hypertensive offspring are characterized by altered indexes of diastolic function [19,20], which we found to be independently related to plasma EO levels; that is, higher EO levels correlated with lower E/A ratios and a greater IVRT. These data are particularly interesting because it is generally accepted that diastolic abnormalities precede ventricular hypertrophy and, in two separate studies, we have recently identified a specific association between EO and left ventricular mass [10,11].…”

Gene Transfer of Neuronal Nitric Oxide Synthase into Intracardiac Ganglia Reverses Vagal Impairment in Hypertensive Rats

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