AGE AND GENDER INFLUENCES ON RATE AND DURATION OF PAROXYSMAL ATRIAL-FIBRILLATION

The influence of age and gender on the character of paroxysmal atrial fibrillation (PAF) has not been described. Methods: The heart rate (HR ) during PAF in patients receiving placebo or antiarrhythmic therapy w as analyzed. Data from 177 24-hour Holter recordings were analyzed to mark the onset and termination of PRF and converted into RR interval f iles. PAF episodes lasting at least 2 minutes and containing less than or equal to 20% noise were included. HR during the first 30-second se gment versus during the remainder of the episode, and the duration of PAF episodes were compared among groups of different ages and sex (Wil coxon test). Results: 236 episodes from 55 recordings in 32 patients ( all patients: 61.4 +/- 12.8 years; men (19): 58.5 +/- 12.6 years; wome n (13) 65.5 +/- 12.4 years, P = ns for difference in age) fulfilled th e inclusion criteria. Women had a higher mean heart rate at AF onset ( 123 +/- 35 beats/min vs 115 +/- 20 beats/min, P = 0.02) and during the remainder of the episode (120 +/- 25 beats/min vs 112 +/- 22 beats/mi n at the start, P = 0.02, and 116 +/- 26 beats/min vs 108 +/- 18 beats /min subsequently, P = 0.02). Episodes tended to be longer in women (m ean 89.8 min vs 50.5 min, P = NS) and in the aged (mean 83.8 min vs 46 .9 min, P = NS). Conclusion: PAF episodes are associated with faster h eart rates and last longer in women, which may reflect differing auton omic responses to AF. A slower ventricular rate during PAF in older pa tients probably reflects an increasing prevalence of impaired atrioven tricular conduction.