Influence of advancing age on fractionated right atrial endocardial electrograms

The influence of advancing age on atrial endocardial electrograms recorded during sinus rhythm in humans who do not have atrial fibrillation has not been assessed thus far. The prevalence of atrial arrhythmias has been reported to increase with advancing age. Right atrial endocardial catheter mapping during sinus rhythm was performed in 106 patients who had normal sinus node function and no paroxysmal atrial fibrillation to evaluate the influence of advancing age on atrial endocardial electrograms. The bipolar electrograms were recorded at 12 sites in the right atrium, and an abnormal atrial electrographic result was defined as lasting > or =100 ms and/or showing > or =8 fragmented deflections. A total of 1,272 right atrial endocardial electrograms was assessed and quantitatively measured. The mean number of abnormal atrial electrograms per patient (0.61 vs 0.14, p <0.02) and the incidence of abnormal atrial electrograms (11% vs 30%, p <0.02) were significantly greater in patients who were >60 years of age than in younger patients. The longest duration (r = 0.24, p <0.02) and the maximal number of fragmented deflections (r = 0.28, p <0.005) of atrial electrograms among the 12 right atrial sites showed a slight positive correlation with age. The process of aging modifies the electrophysiologic properties of the atrial muscle. There is a progressive increment in the extension of altered atrial muscle with advancing age in humans who do not have atrial fibrillation. Patients who are >60 years of age have significantly greater abnormalities on atrial endocardial electrograms than do younger patients.