Irregularity of the heart beat is observed usually in association with organic cardiac disease but occurs not infrequently as a functional disturbance in the absence of structural lesions. It is due either to faulty initiation of the cardiac impulse or to its defective conduction through the heart. The arrhythmia may be transient or permanent. Effective treatment depends primarily on recognition of the cause. Drug therapy often brings about marked clinical improvement and, on occasion, may save life.
The use of medicinal remedies is not indicated in every disorder of rhythm or under all circumstances. For example, sinus irregularity, often marked in children, is of no pathologic significance. Premature contractions due to tobacco disappear when smoking is stopped. Auricular fibrillation, occurring in the course of hyperthyroidism, may terminate spontaneously after subtotal thyroidectomy. Five of the more important arrhythmias have been chosen for consideration because in each, as a rule, appropriate treatment