title: Quinidine therapy and digitalis toxicity.
abstract: In a 90-year-old man undergoing prolonged digitalis therapy, digitalis toxicity was precipitated by the administration of quinidine. The electrocardiogram revealed supraventricular bidirectional tachycardia, a rare but characteristic arrhythmia associated with digitalis toxicity. Upon withdrawal of digoxin, the clinical and ECG signs disappeared. A diagnosis of digitalis toxicity rather than quinidine intolerance led to appropriate treatment.
mesh_terms: D000368:Aged; D004077:Digoxin / Q000009:adverse effects*; D004347:Drug Interactions; D004562:Electrocardiography; D006801:Humans; D008297:Male; D011802:Quinidine / Q000008:administration & dosage*; D013610:Tachycardia / Q000139:chemically induced*
chemical_list: D004077:Digoxin; D011802:Quinidine