Analysis of the atrial repolarisation phase of the electrocardiogram in health and in atrial fibrillation

Little is known about the atrial repolarisation phase of the ECG and it may provide a useful marker for those susceptible to atrial arrhythmia. The amplitude of the atrial repolarisation phase of the ECG and P wave was measured in five patients with healthy hearts and in five patients with paroxysmal atrial fibrillation (PAF) who were in sinus rhythm at the time of the study. Atrial repolarisation amplitude was (mean (sd)) 15 (9) muV (healthy), 17 (8) muV (PAF) and P wave amplitude was 100 (33) muV (healthy) and 102 (32) muV (PAF) with no significant differences between groups. There was a significant correlation between absolute values ofP wave amplitude and repolarisation amplitude (Pearson correlation 0.43, p < 0.05). There was a negative association between depolarisation and repolarisation in the atria, opposite to that known for the ventricles. The observable atrial repolaristion in PAF patients was no different to that in subjects with healthy hearts.