A possible role of hypokalemia in the manifestation of high QRS voltage and sinus bradycardia in patients with primary aldosteronism.

We analyzed electrocardiograms obtained from 29 Japanese patients with primary aldosteronism (PA) and in 106 patients with essential hypertension (EHT). QRS voltage was higher (p less than 0.05) and heart rate was slower (p less than 0.01) in cases of PA. A significant reduction in QRS voltage and a significant increase in heart rate were observed after short-term potassium replacement or after short-term administration of spironolactone, preoperatively, and within 2 to 4 weeks after the removal of aldosteronoma. These significant changes in QRS voltage and heart rate were always accompanied by significant increases in the serum potassium concentration but not always by a reduction in blood pressure. The long-term follow-up of EHT-patients showed a slower reduction in their high QRS voltage, despite effective antihypertensive therapy. Thus, hypokalemia, in addition to hypertension, may be relevant to the high QRS voltage in PA. There also appeared to be a relationship between hypokalemia and bradycardia.