Quinidine-induced Syncope.

Since quinidine was introduced by Frey in 1918 it has remained the drug of choice for the conversion of certain arrhythmias to sinus rhythm and for the maintenance of normal rhythm once achieved. It is commonly used in this manner for atrial fibrillation, atrial flutter, -paroxysmal tachycardia of atrial, nodal, and ventricular origin, and ventriculat fibrillation. It has also been employed as a prevesnive of extrasystoles, particularly following recent myocardial infarction. Only in the past two years has its position in the management of these arrhythmias been challenged by the development of direct-current shock therapy (Lown, Amarasingham, and Neuman, 1962).