Stationarity of surface ECG atrial fibrillatory wave characteristics in the time and frequency domains in clinically stable patients

Stationarity of surface ECG fibrillatory (f) wave characteristics over 24 hours in clinically stable patients was studied. Inter- and intrapatient differences of f wave characteristics (after QRS-T cancellation) in the time and frequency domains were evaluated by ANOVA. Short-term peak frequencies of all the patients ranged from 4.6 to 8.0 Hz, while one SD for each patient ranged from 0.2-0.5 Hz. The f wave amplitude of all the patients ranged from 0.02 to 0.12 mV, while one SD of the amplitude for each patient ranged from 0.001 to 0.01 mV. For these and all other parameters tested inter-patient differences were significantly greater compared to intra-patient differences (p < 0.0001). This demonstration of stationarity provides a foundation for further study of the relationship of f wave characteristics to pathophysiology and management decisions.