Amiodarone for refractory cardiac arrhythmias: 10-year study.

Over a 10-year period 130 patients with drug-resistant cardiac arrhythmias associated mainly with coronary artery disease and its complications were treated with amiodarone. The drug controlled all the tachyarrhythmias associated with the Wolff-Parkinson-White syndrome, 95% of the ventricular arrhythmias, including recurrent ventricular tachycardia and fibrillation, and 92% of the supraventricular arrhythmias. The maximum duration of therapy was 111 months and the mean 34 months. Side effects occurred in 34% of the patients, and there was one withdrawal from therapy per 15.3 patient-years of treatment. The commonest cause of withdrawal was nausea, which was significantly related (p less than 0.01) to a drug interaction with digoxin and diuretics. Reversible neurologic complications occurred in eight patients (6%), and acute myositis was recognized for the first time. Pulmonary infiltration developed in four patients (3%), who were receiving 600 mg of amiodarone per day. The rates of side effects and of withdrawal from therapy differed significantly between the patients whose maintenance doses were 600 and 200 mg/d, at 59% v. 6% (p less than 0.01) and 32% v. 0% (p less than 0.05) respectively. Thus, amiodarone is a very effective antiarrhythmic that can be administered over long periods with acceptable rates of side effects and withdrawal provided the minimal effective dose is used; 400 mg/d or less is desirable.

Life-threatening ventricular arrhythmias provoked by amiodarone treatment.

We report two patients who developed symptomatic life-threatening ventricular tachyarrhythmias with changing QRS axes (resembling torsades de pointes), during treatment of their supraventricular tachycardias with oral amiodarone. Like other effects of amiodarone on the body, the arrhythmias became evident several days after initiating therapy, at which time electrocardiographic QT prolongation was present. The arrhythmias subsided after amiodarone treatment was withdrawn. No other drugs or electrolyte disturbances could be incriminated as a cause.

Amiodarone pulmonary toxicity.

Numerous cytoplasmic lamellar bodies were seen in many cell types in an open lung biopsy from a patient on amiodarone therapy. These membrane-bound lamellar bodies were characterized by distinct, concentric parallel membranes and peripheral granular densities. Their morphology and distribution suggest a metabolic disorder of phospholipid degradation induced by this drug. The differential diagnosis of lamellar body accumulation in the lung is discussed. This case emphasizes the desirability for ultrastructural study of lung biopsies in such potentially reversible lung disease.

Control of refractory cardiac arrhythmias with amiodarone.

Amiodarone hydrochloride was used to treat 19 patients with symptomatic arrhythmias refractory to quinidine sulfate, procainamide hydrochloride, disopyramide phosphate, antazoline hydrochloride, lidocaine hydrochloride, bretylium tosylate, propranolol hydrochloride, phenytoin sodium, and practotol acetanilide given to the limit of tolerance. In 17 patients, attacks were completely controlled. Arrhythmias treated successfully included recurrent supraventricular tachycardias, recurrent supraventricular tachycardias with Wolff-Parkinson-White syndrome, and refractory ventricular arrhythmias including recurrent ventricular tachycardia and ventricular fibrillation complicating acute coronary heart disease. Control was confirmed by continuous ECG monitoring both in the hospital and when ambulatory and was maintained for up to four years. Attacks of supraventricular tachycardia were reduced from 7.9/mo to one attack every 53.5 months on amiodarone. Hospital admissions for arrhythmias were reduced from 34 the year before treatment to none the year after. Therefore, amiodarone is an excellent drug for control of many refractory arrhythmias, but two patients with recurrent atrial fibrillation were refractory to this treatment.

An assessment of intermediate coronary care.

The effect of intermediate coronary care, with and without ECG monitoring, was compared with general medical ward care on the basis of mortality, resuscitation, and detection and treatment of arrhythmias from days 3 to 14 after admission in 2,095 cases of acute coronary heart disease. Mortality was significantly reduced (P less than .02), and number of successful resuscitations for ventricular fibrillation was increased (P less than .05) but only in the unit with monitoring. Number of arrhythmias detected was significantly increased, particularly incidence of ventricular ectopics and heart block (P less than .02). Number of arrhythmias corrected to sinus rhythm was increased, but not significantly. Death from pulmonary embolism fell (P less than .01). Review of causes of death and autopsies showed an increased proportion of deaths due to intractable heart failure and cardiogenic shock. Not only specially trained nurses, but also ECG monitoring, were necessary to obtain the benefits of this treatment.