Eur J Clin Invest 2011; 41 (7): 743–750

Background  Primary aldosteronism (PA) is associated a worse cardiovascular outcome than essential hypertension. Hypokalemia, which is one major characteristic of PA, can affect both cardiac structure and function. The goal of this study is to evaluate the influence of serum potassium level on left ventricular (LV) mass and function in PA patients.

Materials and methods  We prospectively analysed 85 PA patients from October 2006 to September 2008 and 27 essential hypertension patients as the control group (group 1). Thirty‐two patients with serum potassium < 3·5 mmol L⁻¹ were defined as hypokalemia (group 2), and 53 patients with serum potassium ≥ 3·5 mmol L⁻¹ were defined as normokalemia (group 3). Echocardiography including tissue Doppler image (TDI) recordings was performed in all patients.

Results  Group 2 patients had significant higher systolic and diastolic blood pressure (DBP), log‐transformed plasma aldosterone concentration, log‐transformed aldosterone‐to‐renin ratio and lower serum potassium level than groups 1 and 3. In echocardiographic measurement, group 2 patients had higher LV mass index (LVMI) than groups 1 and 3. In multivariate analysis for factors affecting LVMI in PA patients, only serum potassium level (P = 0·001), use of spironolactone (P = 0·004) and DBP (P = 0·005) were independent factors. In the TDI study, both groups 2 and 3 had lower e′ and E/e′ values than group 1.

Conclusions  Serum potassium level is significantly associated with LVMI in PA patients. Compared with essential hypertensive patients, PA patients had a greater impairment of cardiac diastolic function.