[Analysis of right electrocardiographic leads in 195 normal subjects]

The aim of the present study was to analyse age-related differences in the morphology of QRS complex and ST-T segment of right-sided chest ECG leads (V3R-V6R) in normal subjects.

One hundred ninety-five subjects evaluated for competitive sport training were divided into 2 groups according to age: group A (18-35 years) 77 subjects; group B (36-65 years) 118 subjects. All subjects underwent a complete clinical examination, conventional 12-lead ECG with right-sided chest leads, spirometric tests, a maximal stress-test (Bruce protocol), and a cardiac ultrasound study. None had signs or symptoms of cardiopulmonary disease nor of thoracic abnormalities, and all had normal standard ECGs.

An rS morphology in V3R-V4R was observed in 92%-84% and 92%-81% of subjects in groups A and B, respectively (p = NS). The QS morphology in V6R was observed in 15% of subjects in group A and in 11% in group B (p = NS). Negative T-waves in V6R were more often observed in group A than B (94% vs 85%, p < 0.03). Isoelectric T-waves in V3R were found in 10% of subjects in group A and 21% in group B (p < 0.04). The amplitude of R-wave was always higher in group A (p < 0.01). An upsloping ST-T segment (0.5-1 mm) was observed only in V3R-V4R, with a prevalence of 23% in group A and 13% in group B in V3R (p < 0.05).

No significant differences were observed between the 2 groups as to QRS complex of the right-sided ECG leads. A QS morphology may be observed even in normal subjects. The polarity of T-wave is quite variable, but in V6R it is most often negative among young people. Elevation of ST-T segment may be observed only in V3R and V4R, and more often in young subjects in the former lead.