Takashi Nirei

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) Induced by Amiodarone: A Report on Two Cases

Background: Amiodarone is an effective antiarrhythmic agent for life-threatening arrhythmias but has some noncardiac toxicity. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) induced by amiodarone during long-term therapy seems to be rare among adverse effects. Subjects and Results: We report on two elderly cases that developed hyponatremia caused by SIADH occurring during the initial loading period of amiodarone therapy. Both cases improved within 3 weeks after reduction of the dose, although amiodarone was continued. Conclusions: Amiodarone-induced SIADH may occur during the initial loading period, and it may be improved by reduction of the dose without discontinuation of the drug.

Cardiac memory in patients with intermittent Wolff-Parkinson-White syndrome.

This study used body surface mapping to evaluate the ventricular repolarization process in the absence of delta waves in 13 patients with the intermittent Wolff-Parkinson-White (WPW) syndrome. The findings were compared with data from 30 normal individuals and 50 patients with the overt WPW syndrome. The QRST isointegral maps of patients with the overt WPW syndrome exhibited abnormal areas and the QRST departure maps showed a peculiar distribution to each accessory pathway site. The QRST isointegral map exhibited abnormal areas in 11 of the 13 cases (85%) of the intermittent WPW syndrome in the absence of delta waves. In 8 of these 11 cases (73%), the distribution of the departure map resembled that in the overt WPW syndrome. These findings suggest that abnormal ventricular repolarization due to cardiac memory is present in patients with the intermittent WPW syndrome even in the absence of delta waves.