QT interval in patients with primary aldosteronism and low-renin essential hypertension.
BACKGROUND
QT interval prolongation increases the risk of sudden death in several medical conditions. Patients with primary aldosteronism and salt-sensitive hypertension experience more cardiovascular events than those with normal-renin essential hypertension. QT interval prolongation might represent one of the risk factors for cardiovascular events in these patients. The aim of the present study was to evaluate the QT interval in patients with primary aldosteronism and low-renin essential hypertension (LREH).


METHODS
Twenty-seven patients with primary aldosteronism, 17 patients with LREH, 117 patients with essential hypertension and 25 healthy individuals were studied. Plasma aldosterone, plasma renin activity, and aldosterone to plasma renin activity ratio (ARR) were determined. Corrected QT intervals (QTcs) were measured from a 12-lead electrocardiogram.


RESULTS
The QTc was longer in primary aldosteronism (434 +/- 23 ms) and LREH (430 +/- 18 ms) compared with essential hypertension (419 +/- 22 ms) and healthy controls (412 +/- 19 ms) (P = 0.0004). The prevalence of QTc longer than 440 ms was higher in primary aldosteronism (48%) and LREH (23%) compared with essential hypertension (11%) and healthy controls (4%) (P < 0.0001). QTc correlated with plasma aldosterone (P = 0.01), ARR (P = 0.02), and diastolic blood pressure (P = 0.01). ARR (P = 0.01) and systolic blood pressure (P = 0.01) were identified as independent predictors of QTc.


CONCLUSIONS
We postulate that the elevated aldosterone secretion contributes to the prolongation of the QT interval in patients with primary aldosteronism and LREH through both a depletion of intracellular potassium concentration and higher blood pressure values. QTc measurement might represent one simple, non-invasive and reproducible index to characterize the cardiovascular risk in patients with primary aldosteronism and LREH.
Maule
Simona
S
Autonomic Unit and Hypertension Unit, Department of Medicine and Experimental Oncology, S. Vito Hospital, University of Turin, Turin, Italy. simmaule@tin.it
Mulatero
Paolo
P
Milan
Alberto
A
Leotta
Giannina
G
Caserta
Mimma
M
Bertello
Chiara
C
Rabbia
Franco
F
Veglio
Franco
F
D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D006929:Hyperaldosteronism / Q000503:physiopathology*; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000378:metabolism*
D012083:Renin