Ambulatory Blood Pressure Characteristics and Long-Term Risk for Atrial Fibrillation.

BACKGROUND: We hypothesized that elevated nighttime systolic ambulatory blood pressure (ABP) yields additional information compared with daytime systolic ABP for the long-term risk of atrial fibrillation (AF) and perhaps should be taken into account in treatment strategies for preventing the increasing burden of AF during aging.

METHODS: A total of 903 subjects with or without hypertension aged 40 to 59 years, who were recruited to the Oulu Project Elucidating Risk of Atherosclerosis (OPERA) study, underwent ABP monitoring, thorough clinical examinations and laboratory tests.

RESULTS: After an average of 16.4 ± 3.6 years of follow-up, 91 (10%) of the study subjects had experienced a new-onset AF requiring a hospital emergency room or hospital visit. Of the components of baseline ABP, the nighttime mean systolic blood pressure had the strongest univariable association with the occurrence of AF (120.8 ± 15.9 vs. 116.4 ± 14.1 mm Hg, P = 0.006, in subjects with vs. without the occurrence AF). When the univariable predictors of AF, such as age, sex, body mass index, height, smoking history, alanine aminotransferase, uric acid, and fasting plasma glucose, were entered in the multivariable Cox hazards model, age (P < 0.001), and body mass index (P = 0.014) retained their significant predictive power. After adjustments in this clinical hazards model, the nighttime mean systolic blood pressure still predicted the occurrence of AF (hazards ratio = 1.07 per every 5 mm Hg increase, 95% confidence intervals = 1.004-1.15, P = 0.038).

CONCLUSION: Of the baseline ABP characteristics, the nighttime systolic blood pressure is a significant independent contributor to the long-term risk of new-onset AF requiring a hospital visit.