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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Grace J. 1, Duvenage E. 2, Jordaan J. P. 2
1 School of Health Sciences, Discipline of Biokinetics, Exercise and Leisure Sciences, University of Kwazulu Natal, Durban, South Africa;
2 Faculty of Science and Agriculture, Department of Biokinetics & Sport Science, University of Zululand, Kwadlangezwa, South Africa
AIM: There is concern over the effect of training on heart function of athletes as recorded by 12-lead electrocardiography (ECG). Although ECG abnormalities with respect to ethnic origin of black athletes from the Caribbean, West Africa and East Africa have been reported, black athletes from southern Africa, specifically participating in different sports, have never been investigated before. The purpose of this study was to analyze the ECG patterns in South African students of Zulu descent, who represented our university in boxing (endurance modality) and body building (resistance modality) at a regional level.
METHODS: Fifteen subjects each were assigned to an endurance (E), resistance (R) or control (C) group, respectively. ECG patterns were recorded with a 12-lead ECG.
RESULTS: Our subjects indicated no significant differences in ECG patterns in relation to whether they participate in strength or endurance related sport. However, 80% of the endurance group and 67% of the resistance displayed ECG criteria indicative of left ventricular hypertrophy (LVH), group E displays higher R5/S1-wave voltages (E=43.3 mm; R=36.8 mm; C=37.1 mm) as well distinctly abnormal ECG patterns (E=87%; R=73%; C=53%), raising clinical suspicion of structural heart disease. Our cohort presented with non-significant, marked ST-segment elevation (53% of both the E and R groups) and inverted T-waves in 27% of the E group.
CONCLUSION: Similar to findings in other ethnic Africans, a large proportion of our Zulu study population displayed ECG criteria indicative of LVH on the evidence of a marked increase of R5/S1-wave voltage and ST/T-segment changes with no differences in relation to whether they participate in strength or endurance related sport.