Short- and long-term outcomes following atrial fibrillation in patients with acute coronary syndromes with or without ST-segment elevation.

OBJECTIVE: To assess variables associated with the occurrence of atrial fibrillation (AF) and the relation of AF with short- and long-term outcomes and with other in-hospital complications in patients with acute coronary syndromes (ACS) with and without ST-segment elevation. DESIGN: Pooled database of 120 566 patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation (NSTE) ACS enrolled in 10 clinical trials. Multivariable logistic regression and Cox proportional hazards modelling were used to identify factors associated with AF and its relation with clinical outcomes. SETTING: ACS complicated by AF. PATIENTS: 120,566 patients with STEMI and NSTE-ACS in 10 clinical trials. INTERVENTIONS: None evaluated. MAIN OUTCOME MEASURE: Short- and long-term mortality. RESULTS: Occurrence of AF was 7.5% in the overall population (STEMI 8.0% (n = 84 161); NSTE-ACS = 6.4% (n = 36,405)). Seven-day mortality was higher for patients with AF (5.1%) than for those without (1.6%). After adjusting for confounders, association of AF with 7-day mortality was present in STEMI (hazards ratio (HR) = 1.65; 95% CI 1.44 to 1.90) and NSTE-ACS (HR = 2.30; 95% CI 1.83 to 2.90; p interaction = 0.015). Risk of long-term mortality (day 8 to 1 year) was also higher in STEMI (HR = 2.37; 95% CI 1.79 to 3.15) and NSTE-ACS (HR = 1.67; 95% CI 1.41 to 1.99). AF had a larger impact in NSTE-ACS on risk of short-term mortality (p<0.001), stroke (p<0.001), ischaemic stroke (p<0.001) and moderate or severe bleeding (p<0.001). CONCLUSIONS: AF is more common in patients with STEMI. An association of AF with short- and long-term mortality among patients with STEMI and NSTE-ACS was found. Understanding these findings may lead to better care of patients with this common arrhythmia.

Observations on the transition from intermittent to permanent atrial fibrillation.

BACKGROUND: Quantitative data on the frequency with which transition from intermittent to permanent atrial fibrillation occurs are lacking. We conducted this study to determine the proportion of patients with intermittent atrial fibrillation who progress to permanent atrial fibrillation and to investigate baseline clinical characteristics that might predict such a progression. METHODS: This retrospective cohort study included 231 patients who were seen with intermittent atrial fibrillation at a university hospital-based clinic from January 1978 through December 1997. Patients' medical records and electrocardiograms were reviewed and data were collected for all clinic visits through May 1998. The proportion of patients who remained free of transition from intermittent to permanent atrial fibrillation was calculated by the Kaplan-Meier method. A Cox proportional hazards model was used to determine the effect of some baseline characteristics on this transition. RESULTS: The number of patients who remained free of transition from intermittent to permanent atrial fibrillation was 92% (95% confidence interval 88%-96%) at 1 year and 82% (95% confidence interval 75%-88%) at 4 years. Among 5 baseline characteristics (age, sex, structural heart disease, atrial fibrillation at presentation, and use of an antiarrhythmic medicine before presentation), the 2 significant predictors of progression from intermittent to permanent atrial fibrillation were age (P =.0003) and being in atrial fibrillation at presentation (P =.0006). The hazard ratio associated with 10 years of advancing age was 1.82 (95% confidence interval 1.31-2.51), and the hazard ratio associated with atrial fibrillation at presentation was 3.56 (95% confidence interval 1.73-7.34). CONCLUSIONS: Approximately 18% of patients who had intermittent atrial fibrillation were permanently in atrial fibrillation after 4 years of follow-up. Age and being in atrial fibrillation at presentation were the only 2 important clinical variables identified in predicting such a progression.

Clinical features of Wolff-Parkinson-White syndrome.

Wolff-Parkinson-White syndrome is the most common form of ventricular preexcitation. Understanding this syndrome is fundamental for anyone interested in learning about arrhythmias. This review addresses (1) the historic sequence of events that led to the understanding of this syndrome; (2) the pathologic, embryologic, and electrophysiologic properties of accessory pathways; (3) the epidemiology and genetics of this syndrome; (4) the clinical diagnosis of this syndrome, with special emphasis on the arrhythmias that patients with ventricular preexcitation are predisposed to; and (5) the therapy for patients with Wolff-Parkinson-White syndrome.