[The detection of changes in intra-atrial conductivity (based on enhanced ECG data)]. / Vyiavlenie izmenenii vnutripredserdnoi provodimosti (po dannym usilennoi EKG).

The 20-fold enhanced ECG (without frequency filtration of the signal) was recorded in 30 normal men aged 18 to 36 years. A study was made of the constancy of the P wave forms on the ECG. The P wave form underwent changes in 8 test subjects: in 5 during breathing retention on expiration and in 3 during superficial breathing. The changes indicated are viewed as a manifestation of intraatrial conduction disorders. It is assumed that the changes in the tone of the autonomic nervous system and myocardial hypoxia may contribute to the detection of latent disorders in the cardiac activity.