The Changing Clinical Picture of Digitalis Intoxication

Twenty-four recent cases of digitalis toxicity were characterized by 4 salient points: Nine cases, or 37%, were identified electrocardiographically by atrioventricular dissociation with an AV nodal rate above 70. The average age in this group was 69.7 years. Twenty cases, or 83%, were induced by digoxin. Nineteen patients, or 79%, were on chlorothiazide or mercurial diuretics. All hospitalized cases of digitalis excess were recorded during a 12-month period. Since the average age was in the seventh decade, it must be assumed that the aging patient is the most likely candidate for such toxicity. It is a particularly tragic parodox that those who must require the unique action of digitalis are the most intolerant to slight variations in dosage. 1 Indeed, in repeated cases, as the ratio between therapeutic and toxic dosage narrowed, it was impossible for the aged heart to tolerate any therapeutic amount of digitalis.