Incidence of Clinically Significant Ventricular Arrhythmias in Patients on Home Inotrope Infusion in the Contemporary Era

Abstract

Approximately 6.2 million Americans live with heart failure (HF). Inotropic support is often used as bridge therapy and palliation. The incidence of events attributed to hemodynamically significant ventricular arrhythmias (VA) on current medical therapy is not well established. Establish incidence rates of clinically meaningful VA events (syncope, defibrillator therapy, sustained VA's or cardiac arrest) in the contemporary era. Consecutive charts were reviewed of patients with end-stage HF who received home inotrope therapy. ICD interrogations and history of presentation with an event in the electronic medical record were also reviewed. About 438 consecutive patients aged 68.0 ± 13.7yr (72.4% Male) were included in the analysis. Patients were on milrinone (n = 353) or dobutamine (n = 85) over 9.3 ± 11.6 months. Incidence of VA events for the overall sample was 5.66 events per 100 person-months (95% CI = 4.97 to 6.44). Patients on Milrinone (n = 353) had a VA event rate of 6.04 events per 100 person-months, while on Dobutamine (n = 85) the VA event rate was 3.79 events per 100 person-months. Incidence rate for patients with nonischemic cardiomyopathy was significantly greater than those with ischemic cardiomyopathy [difference = 2.54 events per 100-person months (95% CI = −1.09 to 3.99; p <0.001)]. Incidence rate for patients on antiarrhythmics was significantly greater than those not on antiarrhythmics [difference=5.65 events per 100-person months (95% CI = 3.71 to 7.59; p <0.001)]. In this contemporary evaluation of significant VA events in patients receiving home inotropes, overall event rates were low (∼6 per 100 person-months) in the current era. Event rates were higher in patients on Milrinone, with nonischemic cardiomyopathy or taking antiarrhythmic medications