Three cases of primary aldosteronism including one case with postoperative ventricular tachycardia

Three patients with primary aldosteronism were treated surgically between February and September 1984. All patients had suffered from hypertension with U waves in ECG and laboratory examinations revealed hypokalemia, hyperaldosteronemia and suppressed plasma renin activity. The localization of the adrenal tumor was diagnosed accurately in all 3 patients by adrenal vein sampling and in 2 of the patients by PRP, CT scan, adrenal scanning with 131I-iodo cholesterol and adrenal venography. Adrenal tumors were surgically removed by unilateral adrenalectomy through the flank approach in all cases. Histological examinations of removed specimens showed adrenocortical adenoma. Removal of the adenoma caused a prompt reversal of the laboratory serum abnormalities and hypertension was normalized within 2 weeks postoperatively in all cases. Severe ventricular tachycardia (Torsades de Pointes) was observed suddenly in one of the patients after about 5 hours postoperatively. Therapy including conventional antiarrhythmic drugs, such as lidocaine or procainamide, and potassium administration failed to prevent the arrhythmia. Ventricular tachycardia was successfully treated and disappeared with the use of magnesium sulfate (MgSO4) intravenously. The serum potassium concentration was normal during the episode and the serum magnesium concentration, which was not detected before or just after the operation, was under the limit of normal range (1.4 mEq/l) after the use of magnesium sulfate. Hypomagnesemia which is retrospectively thought to be the result of primary aldosteronism may be responsible for the episode of postoperative ventricular tachycardia.