Electrocardiographic screening in psychiatric patients

Present recommendations vary regarding the use of screening ECGs in psychiatric patients; therefore, this study was undertaken to determine the utility of routine screening electrocardiograms (ECGs) in hospitalized psychiatric patients.

Twelve-lead ECGs were obtained on 1006 consecutive admissions to an academic freestanding 250-bed public psychiatric hospital over a period of 2 years.

Tracings were read as normal in 765 of 1006 cases. Tracings of 148 patients were considered to be equivocal, mainly due to nonspecific T wave abnormalities seen in 118 patients. In 29 patients, no ostensible cause for the T wave abnormalities was found. Among the remaining 80 instances, abnormalities were attributed to drug abuse. Especially prevalent was recent cocaine abuse, often with concurrent alcohol abuse (N = 30); recent alcohol abuse alone (N = 10); or concurrent psychotherapeutic drugs (lithium, N = 19; thioridazine, N = 9; and miscellaneous drugs, N = 12). Subclinical hypothyroidism was found in 5 and borderline hypokalemia in 4 patients. Ninety-three tracings were definitely abnormal; one half of these were among patients over 50 years of age. Only 5 of 162 tracings in patients under 20 years of age were abnormal; one of these (incomplete right bundle branch block) might have mattered had the patient been considered for treatment with drugs that lengthen intraventricular conduction times, such as tricyclic antidepressants or thioridazine.

Routine screening ECGs done on psychiatric patients yielded relatively few abnormalities except in those over the age of 50 years, confirming the experience with such surveys in the general population. The prevalence of abnormalities among these patients was frequent enough to merit routine screening. For other patients regardless of age, ECGs are indicated whenever a history or physical findings suggest cardiovascular disease or whenever it is proposed to treat these patients with psychotherapeutic drugs known to increase cardiac conduction times or otherwise alter cardiac function.