Atrial Fibrillation in the ICU

Abstract

Atrial fibrillation (AF) is the most common arrhythmia encountered in the ICU. Preexisting AF is highly prevalent among older patients with chronic conditions who are at risk for critical illness, whereas new-onset AF can be triggered by accelerated atrial remodeling and arrhythmogenic triggers encountered during critical illness. The acute loss of atrial systole and onset of rapid ventricular rates that characterize new-onset AF often lead to decreased cardiac output and hemodynamic compromise. Thus, new-onset AF is both a marker of disease severity as well as a likely contributor to poor outcomes, similar to other manifestations of organ dysfunction during critical illness. Evaluating immediate hemodynamic effects of new-onset AF during critical illness is an important component of rapid clinical assessment aimed at identifying patients in need of urgent direct current cardioversion, treatment of reversible inciting factors, and identification of patients who may benefit from pharmacologic rate or rhythm control. In addition to acute hemodynamic effects, new-onset AF during critical illness is associated with both short- and long-term increases in the risk of stroke, heart failure, and death, with AF recurrence rates of approximately 50% within 1 year following hospital discharge. In the absence of a strong evidence base, there is substantial practice variation in the choice of strategies for management of new-onset AF during critical illness. We describe acute and long-term evaluation and management strategies based on current evidence and propose future avenues of investigation to fill large knowledge gaps in the management of patients with AF during critical illness.

New-onset atrial fibrillation and associated outcomes and resource use among critically ill adults—a multicenter retrospective cohort study

“…Identification of these factors may also be helpful in discussions with patients and families regarding goals of care. NOAF is often thought to be a marker of illness severity [3]; however, the evidence examining the association between NOAF and hospital mortality remains uncertain [4]. In our large cohort of critically ill adults, we did not find such an association.…”

“…To adjust for measured confounders in the association between new-onset AF and outcomes of interest, we followed recommendations for observational studies in the critically ill [30]. As per these recommendations, confounders were determined a priori, on the basis of their likelihood of influencing both the presence of NOAF and mortality and not acting as mediators or colliders in the association between AF and mortality, as based upon existing clinical knowledge evaluating the association between NOAF and mortality in critically ill patients [3,4]. In accordance with these recommendations [30], we used multivariable logistic regression modeling to adjust for important continuous (age, MODS at ICU admission, Elixhauser comorbidity index) and categorical (sex, individual comorbidities, "No-CPR" directive on admission, location prior to ICU admission, and most responsible diagnosis) variables.…”

“…Development of AF has been associated with stroke, myocardial infarction, heart failure, and death [2]. In the intensive care unit (ICU), patients often present with pre-existing AF; however, some ICU patients may develop new-onset AF (NOAF) in the context of critical illness [3]. Unlike AF seen in non-critically ill patients, NOAF is often thought to be a consequence of critical illness pathophysiology and treatment, including inflammation, electrolyte disturbances, or proarrhythmic medications, namely vasopressors and inotropes [4].…”

“…Unlike AF seen in non-critically ill patients, NOAF is often thought to be a consequence of critical illness pathophysiology and treatment, including inflammation, electrolyte disturbances, or proarrhythmic medications, namely vasopressors and inotropes [4]. Incidence of NOAF in the general ICU varies markedly; however, most studies suggest that 10-15% of patients will develop this complication during their ICU stay [3][4][5].…”

Predictors of Outcomes in Patients with Prolonged Weaning with Focus on Respiratory Tract Pathogens and Infection

“…The incidence of atrial fibrillation was independently associated with mortality. Whereas atrial fibrillation is highly prevalent among elderly patients, it may also be triggered during critical illness, and it may be both a marker of disease severity and a risk factor of death [11]. …”