Objectives Postoperative atrial fibrillation (POAF) is the most common complication following cardiac surgery. A variety of POAF risk factors has been reported, but study results have been inconsistent or contradictory, particularly in patients with preexisting atrial fibrillation. The incidence of POAF was evaluated in a group of 10,390 cardiac surgery patients among a comprehensive range of risk factors to identify reliable predictors of POAF. Methods This 20-year retrospective study examined the relationship between POAF and demographic factors, preoperative health conditions and medications, operative procedures, and postoperative complications. Multivariate logistic regression models were used to evaluate potential predictors of POAF. Results Increasing age, mitral valve surgery (OR=1.91), left ventricular aneurysm repair (OR=1.57), aortic valve surgery (OR=1.52), race (Caucasian) (OR=1.51), use of cardioplegia (OR=1.36), use of an intra-aortic balloon pump (OR=1.28), previous congestive heart failure (OR=1.28), and hypertension (OR=1.15) were significantly associated with POAF. The nonlinear relationship between age and POAF revealed the acceleration of POAF risk in patients 55 or older. In patients undergoing coronary artery bypass grafting, increasing age and previous congestive heart failure were the only factors associated with a higher risk of POAF. There was no trend in incidence of POAF over time. No protective factors against POAF were detected, including commonly prescribed categories of medications. Conclusions The persistence of the problem of POAF, and the modest predictability using common risk factors, suggest that limited progress has been made in understanding its etiology and treatment.

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Vaginal herpes infections occur under low oxygen conditions, including anoxia. Using an anaerobic (0% O2) cell system, the infection rate, early protein expression, and progeny viability were determined. Anaerobic HeLa 229 cells (0% O2; anaerobic DMEM; 24h) were infected with MOI 1 of HSV1/2, then incubated under aerobic (control) and anaerobic conditions. Infectivity (6h post-infection (pi)) was assessed by ONPG activity and enumerating X-gal-stained cells. HSV1/2 viral immediate-early entry, early entry, and late entry protein expression were determined by fluorescent antibody staining followed by HSV1/2 glycoprotein B mouse monoclonal antibody and DAPI. Statistical analysis was performed using t-test and data were considered significant when p ≤ 0.05 (GraphPad Prism). HSV1/2 infection under standard aerobic conditions was approximately twice that measured for anaerobically infected cells. In addition, the level of HSV-2 infectivity was significantly (p < 0.05) higher (~8-fold) than that of HSV-1, regardless of oxygen level. HSV entry stage protein expression (ICP8, ICP27, VP5) was detected for anaerobic HSV1/2. A similar pattern was observed for anaerobically grown progeny of HSV1/2, i.e., the number of progeny was higher when anaerobic progenies were grown under aerobic conditions (anaerobic to aerobic) as compared to those grown under anaerobic conditions (anaerobic to anaerobic). In addition, the progeny levels grown solely under anaerobic conditions trended higher for HSV-1 than HSV-2 progeny but were not significantly different. These findings show that HSV1/2 can infect and replicate in anaerobically growing cells and that oxygen is not essential for productive replication.