[Relationship between reference point potential and potential distribution of normal electrocardial field on the thoracic surface of healthy individuals].

Objective: To explore the effect of reference point on the potential distribution of normal cardioeleclric field of healthy individuals.

Methods: Two different reference points including central terminal and right forehead were applied to record electrocardiogram simultaneously from 15 testing points (V(1)-V(6), V(7)-V(9), V(3R)-V(8R)) of Wilson lead (RL) and the same testing points (HV(1)-HV(9), HV(3R)-HV(8R)) of head-chest (HC) lead around the torso of healthy individuals. Chi-square test was performed to observe statistical difference between the HCECGs and RLECGs according to different shapes of QRS and T waves.

Results: Among 120 healthy individuals, deformed ECGs appeared in V(1) and HV(3R)-HV(8R) leads, with 20% (24/120) inverted T wave in V(1) lead, 100% (120/120) in V(3R)-V(8R) leads, wide or deep Q wave 100% (120/120) in V(4R)-V(8R) leads. However, in the corresponding HC-lead system, T waves were all positive, and QRS waves were upright as the pattern of rs, RS or qRs. There was statistical difference in the form of ECG between V(1), V(3R)-V(8R) of Wilson lead and the corresponding HC-lead (P<0.05). The distribution of normal cardioeleclric field related to QRS-T wave was of all-round outward shape by HC-lead, and of roughly bipolar shape by Wilson lead for inverted QRS-T wave on the right thoracic surface.

Conclusion: The normal distribution of electrocardial field is determined by the potential of the reference point. The forehead of HC-lead seems to be better than the central terminal as the reference point of the lead system.