Abstract 3004: Assessment of Left Atrial Volume in Resistant Hypertension by Cardiac Magnetic Resonance Imaging
Introduction: Increased left atrial (LA) volumes are associated with impaired diastolic properties of the left ventricle (LV) and have been shown to predict cardiovascular events in a wide spectrum of patients. A relation between LA volume and aldosterone has been reported in idiopathic dilated cardiomyopathy, but this relationship has not been evaluated in resistant hypertensive subjects.
Hypothesis: We hypothesized that patients with elevated plasma aldosterone concentration (PAC) have greater LA volumes. We compared LA volumes in normal subjects and mildly hypertensive patients (Controls) and patients with resistant hypertension.
Methods: 71 patients (55 resistant hypertensive (51% male, age 57±12 y) and 16 Controls (62% men, age 54±11 y, p=ns) were studied. Clinic blood pressure (BP), plasma levels of B-type natriuretic peptide (BNP), PAC, plasma renin activity (PRA), serum cortisol, and 24 hour urinary aldosterone and sodium excretion were determined. Cardiac magnetic resonance imaging was performed in all patients and LA volumes were measured using a biplane length-area method and indexed for the body surface area.
Results: Results are summarized in the Table⇓. Resistant hypertensives had significantly higher systolic and diastolic BP compared to Controls. There was a trend towards higher PAC in hypertensives that did not reach statistical significance. BNP levels also were not different between the groups but we found a relationship between BNP and LA volume index (r=0.43, p=0.003). Hypertensives also exhibited increased LV mass and LA volume index compared to Controls. No relation between LA volume index and PAC was found. PRA, cortisol, and 24 hour urinary aldosterone and sodium excretion also had no relation to LA volume index.
Conclusions: LA volume index is higher in resistant hypertension and shows positive correlation with BNP levels in all subjects but is not related to PAC in either the Control or Resistant hypertension groups.