Hf-567-03 arrhythmic events in patients with cardiogenic shock on inotropic support: results of the doremi randomized trial

Inotropic support is widely used in the management of cardiogenic shock ( CS ) to improve cardiac output and organ perfusion. To characterize the incidence and clinical relevance of arrhythmic events in patients with CS on inotropic support managed by medical teams blinded to the inotrope being used. Patients with CS enrolled in the DObutamine compaREd to MIlrinone (DOREMI) trial were analyzed. Patients with and without arrhythmic events (defined as arrhythmias requiring intervention or sustained ventricular arrhythmias) were compared to (1) identify factors associated with their occurrence and (2) examine their association with in-hospital outcomes. Ninety-five patients (49.5%) had arrhythmic events, occurring equally with dobutamine and milrinone (P=0.665). A history of atrial fibrillation and need for vasopressor support at inotrope initiation were positively associated with arrhythmic events whereas predominant right ventricular dysfunction and previous myocardial infarction were negatively associated with them. Atrial arrhythmic events were associated with the need for mechanical circulatory support or cardiac transplantation (RR 3.64, 95% CI 1.35-9.83) and both intensive care unit and hospital lengths of stay (6 [IQR 4-10] vs. 4 [3-7], P=0.029, and 17 [10-31] vs. 13 [5-21] days, P=0.010, respectively). Ventricular arrhythmic events were associated with the trial’s primary composite outcome (RR 1.88, 95% CI 1.35-2.60), including all-cause mortality (RR 1.73, 95% CI 1.09-2.75), initiation of renal replacement therapy (RR 2.86, 95% CI 1.29-6.36), and need for mechanical circulatory support or cardiac transplantation (RR 4.85, 95% CI 1.46-16.16). Clinically relevant arrhythmic events occur in half of patients with CS treated with dobutamine or milrinone and are associated with poor clinical outcomes. Ventricular arrhythmic events are most strongly associated with adverse outcomes, including a 73% increase in all-cause in-hospital mortality. Clinical factors available at the time of inotrope initiation may help identify patients most at risk of arrhythmic events. Given the purported proarrhythmic effects of inotropic agents, their role in the management of patients with CS warrants critical and rigorous appraisal.