[Pathological modifications of the P wave due to probable primary changes in intra-atrial conduction]

Two cases of variable changes in ECG P oscillation not due, as is usually the case, to familiar cardiac or respiratory conditions suggested a review of the literature on the subject. It is concluded that these anomalies are the result of changes in the intra-atrial conduction of the stimulus through preferential ways or to aberrant atrial conduction. These are situations of no little practical interest because they may be precursors of major rhythm disturbances such as atrial flutter or atrial fibrillation.