A prospective study of supraventricular activity and incidence of atrial fibrillation.
BACKGROUND
Atrial fibrillation (AF) episodes are thought to be started by an electrical trigger reaching susceptible atria. Such a trigger could be present long before the occurrence of sustained symptomatic arrhythmia.


OBJECTIVE
We sought to determine whether supraventricular extrasystoles (SVESs) and supraventricular tachycardias (SVTs) measured at 24-hour Holter electrocardiogram were associated with an increased incidence of AF.


METHODS
In 1998-2000, 389 individuals (44% men; mean age 65 years) were examined using 24-hour Holter electrocardiogram. Six individuals with known prevalent AF were excluded. After a mean follow-up of 10.3 years, there were 45 cases of incident AF. Hazard ratios (HRs) were computed using multivariable Cox regression adjusting for age, sex, systolic blood pressure, height, weight, smoking, and homeostatic model assessment of insulin resistance.


RESULTS
Frequency of SVESs as well as SVT episodes per hour were independent predictors of incident AF (HR per log unit 1.38; 95% confidence interval 1.14-1.68; P = .001 and HR 1.95; 95% confidence interval 1.21-3.13; P = .006, respectively). Further adjustment for education level, alcohol use, use of medication, and physical activity did not substantially alter the results, nor did analysis using competing risks regression accounting for a competing risk of death. The maximum duration of SVT or the heart rate at SVT was not significantly associated with the incidence of AF.


CONCLUSION
SVESs and SVTs independently predict AF. The prognostic significance was similar for SVESs, SVTs, and a combination of the two. Repeated efforts to detect AF could be of merit in individuals with frequent supraventricular activity.