Significance of aborted cardiac arrest and sustained ventricular tachycardia in patients referred for treatment therapy of advanced heart failure

Abstract

Cardiac arrest in patients with heart failure may be the result of remediable factors such as pulmonary edema, drug toxicity, or electrolyte abnomalities, or it may be due to primary arrhythmias. The relation of prior aborted cardiac arrest or sustained ventricular tachycardia to subsequent prognosis was assessed in 458 consecutive patients referred for management of advanced heart failure (left ventricular ejection fraction 0.2 ± 0.07). All patients received tailored vasodilator and diuretic therapy and were then followed as outpatients. Patients were divided into four groups: 388 patients (85%) with no prior cardiac arrest or sustained ventricular tachycardia, 31 patients (7%) with a primary arrhythmia cardiac arrest, 22 patients (5%) with a secondary cardiac arrest, and 17 patients (4%) with sustained ventricular tachycardia without cardiac arrest. Patients with cardiac arrest resulting from a primary arrhythmia were usually treated with antiarrhythmic drugs (25 patients), and five patients received an implantable defibrillator. After hospital discharge actuarial 1-year sudden death risk (17%) and total mortality (24%) rates for the group with primary arrhythmia were similar to corresponding values in patients with no history of cardiac arrest or sustained ventricular tachycardia (17% and 30%, respectively). In patients with a secondary cardiac arrest as a result of exacerbation of heart failure (11 patients), torsade de pointes (10 patients), or hypokalemia (one patient), therapy focused on removal of aggravating factors. Actuarial 1-year sudden death (39%) and total mortality (54%) rates for the group with secondary arrest were higher than for patients without a history of cardiac arrest ( p = 0.003 and 0.005, respectively). Patients with sustained ventricular tachycardia without cardiac arrest tended to have less severe heart failure, and only 1 of these 17 patients died suddenly for an actuarial 1-year mortality rate of 6%. Multivariate Cox analysis identified a history of secondary cardiac arrest as a predictor of sudden death and total mortality independent of left ventricular ejection fraction, pulmonary capillary wedge pressure, atrial fibrillation, type of vasodilator, and serum sodium level. Thus the prognosis for survivors of life-threatening arrhythmias who have advanced heart failure varies. Patients who have had primary arrhythmias treated with available therapies have a prognosis similar to that in patients without prior cardiac arrest who have a comparable severity of heart failure. Cardiac arrest as a result of remediable factors is indicative of a high risk despite attempts to control the precipitating factors. Patients with heart failure who have sustained ventricular tachycardia without cardiac arrest have a relatively favorable outcome.