Triggers of Atrial Fibrillation in the Geriatric Medical Intensive Care Unit: An Observational Study.

Background: Atrial fibrillation (AF) is a common arrhythmia in the non-cardiac intensive care unit (ICU). However, data concerning AF incidence and predictors in such populations are scarce and controversial. The study aimed to investigate the contributing factors of new-onset AF in elderly patients within the medical intensive care setting.

Methods: Patients admitted to ICU during a 6-month period were prospectively studied. Patients admitted for short period postoperative monitoring and patients with chronic or paroxysmal AF were excluded. The conditions involved as AF risk factors or "triggers" from demographic data, history, and echocardiography were recorded. Acute Physiology and Chronic Health Evaluation II score was calculated. Electrolytes including some trace elements (zinc, copper, and magnesium) were analyzed.

Results: The study included 142 patients (49% females). Mean age was 69.5 ± 7.3 years. AF was observed in 12%. Diagnosis of pneumonia (P < 0.001), low copper (P < 0.0001) and low zinc levels (P < 0.0001) was significantly associated with the occurrence of AF. By multivariate analysis, they remained statistically significant (odds ratio, 7.0; 95% confidence interval, 2.0 - 24.6; P < 0.01).

Conclusions: A significant fraction of ICU elderly patients manifests AF. The relevant factors contributing to AF incidence in the elderly are pneumonia and low zinc and low copper.