Reference ranges for ambulatory heart rate measurements in a middle-aged population.

Background: Elevated heart rate (HR) predicts cardiovascular disease and mortality, but there are no established normal limits for ambulatory HR. We used data from the Swedish CArdioPulmonary Imaging Study to determine reference ranges for ambulatory HR in a middle-aged population. We also studied clinical correlates of ambulatory HR.

Heart rate and premature atrial contractions at 24hECG independently predict atrial fibrillation in a population-based study.

Background: Low resting heart rate and premature atrial contractions (PACs) predict incident atrial fibrillation (AF) and could be interdependent, since PACs occur in the gaps between normal beats.

Objective: To study the association between low heart rate at 24hECG, PACs and incident AF in a prospective population-based cohort.

Methods: In the Malmö Diet and Cancer study, 24hECGs were performed in 377 AF-free subjects.