0022: Incidence and predictors of new-onset atrial fibrillation in septic shock patients in a medical ICU: data from 7-day Holter ECG monitoring

Abstract

New-onset atrial fibrillation (NAF) is a common complication of septic shock and incidence is underestimated. We sought to investigate the real incidence, associated risk factors for NAF, and its prognostic impact during septic shock in patients hospitalized in a medical Intensive Care Unit (ICU). Prospective, single-center, observational study. Medical ICU in a large university teaching hospital. All consecutive patients presenting between March 2011 and May 2013 with septic shock were eligible for inclusion, with the following exclusion criteria: patients aged <18 years, prior history of AF (paroxysmal or sustained), and patients transferred from another ICU with prior septic shock. After inclusion, all patients were equipped with long-duration Holter ECG monitoring for 7 days. NAF was defined as an AF episode lasting more than 30 seconds. Patient characteristics, infection criteria, cardiovascular parameters, severity of illness, medical and technical support therapies were recorded. Among 66 patients, 29 (44%) developed NAF; 10 of which (34%) would not have been diagnosed without Holter ECG monitoring. NAF patients were older, and more often presented markers of heart failure, i.e. higher troponin and NT-pro-BNP levels associated with lower left ventricular ejection fraction (LVEF), as compared to patients who remained in sinus rhythm. NAF patients also had longer QRS duration and more often presented nonsustained supra ventricular arrhythmias (<30s) on the first day. In a multivariate model, only age (OR: 1.06; p=0.01) and LVEF<45% (OR: 13.01, p=0.03) remained associated with the occurrence of NAF. However, NAF was not an independent predictor of 28 or 90 day mortality. This is the first study to examine the exact incidence and risk factors of NAF in septic shock patients. NAF is common, especially in older patients, and is associated with low ejection fraction. We did not find NAF to be independently associated with higher mortality in this study.