Multifocal Atrial Tachycardia

Multifocal atrial tachycardia was seen in 32 elderly and severely ill patients, with a high prevalence of acute and chronic pulmonary disease and cor pulmonale. Twelve patients (37.5 per cent) died. Bronchodilators were used frequently and contributed to the rapid heart rates. The arrhythmia itself was rarely due to digitalis intoxication. Serious arrhythmias did not arise in patients receiving maintenance doses of digitalis. Increments of digitalis often produced high-grade atrioventricular block, atrial tachycardia with block, nodal rhythms and ventricular irritability. Multifocal atrial tachycardia should be carefully distinguished from other atrial arrhythmias, especially atrial fibrillation. This is particularly important for rational digitalis therapy. Control of the arrhythmia paralleled improvement in ventilation and oxygenation, control of sepsis, correction of metabolic and electrolyte derangements and reduction in chronotropic drugs used as bronchodilators. The role of antiarrhythmic agents in treatment remains unsettled.