A cardiologist revisits electroconvulsive therapy: editorial comment.

Over 16 million Americans suffer from coronary artery disease (CAD), and it is the single leading cause of death in the United States. In addition, nearly 6 million Americans have heart failure.1 Most studies support that depression is independently associated with increased cardiovascular morbidity and mortality. Meta-analyses provide strong evidence for a relationship between depression and the incidence of CAD as well as one between depression and premature mortality among patients with documented CAD. In addition, clinical depression is present in 1 of 5 patients with heart failure and is associated with poorer outcomes. For these reasons, an American Heart Association Science Advisory has recommended routine screening, referral, and treatment of all patients with coronary heart disease for depression. The association between mental health and cardiac disease dates back to the pioneering work of Friedman and Rosenman in the 1950s. The precise mechanism linking these two, however, remains elusive. Certain behaviors and social characteristics in depressed patients may lead to the development of CAD. For example, individuals with depression are more likely to smoke cigarettes and to be physically inactive compared with those without depression. Depressed patients appear to have enhanced platelet activation, which may increase their susceptibility to cardiac events. Other biologic mechanisms reported in depressed patients with CAD include reduced heart rate variability (suggesting increased sympathetic and/or reduced vagal activity), hypothalamic-pituitary-adrenal axis dysfunction, impaired vascular function, and elevated inflammatory biomarkers. The recommendation to screen, refer, and treat all patients with coronary heart disease for depression is an interesting one, particularly in light of the lack of randomized clinical trials. A review of the literature finds that treatment of depression with medication or cognitive behavioral therapy in patients with known CAD is associated with only modest improvement in depressive symptoms, but no improvement in cardiac outcomes. However, it is well known that one third of patients with major depression do not respond to antidepressant medications and may require electroconvulsive therapy (ECT). Electroconvulsive therapy is known to have cardiovascular effects, even in subjects without known cardiac disease, through the activation of the parasympathetic and later the sympathetic nervous system. During the initial parasympathetic discharge, bradycardia with or without hypotension usually occurs, and premature atrial contractions, atrial fibrillation or flutter, atrioventricular block, escape ventricular rhythms, or asystole may also occur. Pretreatment with atropine is now commonly used to decrease these arrhythmias. Following an initial increase in parasympathetic tone is the sympathetic discharge mediated by a sharp rise in plasma noradrenaline and adrenaline concentrations. This discharge may result in sinus tachycardia or, in rare instances, ventricular tachyarrhythmias, as well as a dramatic rise in blood pressure. These effects may then produce coronary ischemia and angina. This catecholamine response may be blunted by A-adrenergicYblocking agents. Given these findings, it is not surprising that early reports documented a significantly higher risk of cardiovascular complications during ECT in patients with preexisting heart disease than in those patients without known heart disease. Zielinski et al, in a retrospective study, found a 55% risk of cardiac complications in 40 patients with both major depression and preexisting cardiac disease who underwent ECT as opposed to a 7.5% risk of complications in those without known cardiac disease. Moreover, in the group without known cardiac disease, the complications were relatively benign (eg, short-lived atrial arrhythmias). Because of the findings of these early studies, most clinicians are reluctant to perform ECT in individuals with underlying heart disease. Since the time of the early description of the increased risk of complications in patients with underlying cardiac disease undergoing ECT, a number of advances in the fields of both psychiatry and EDITORIAL