Ethnic variation in prevalence of end QRS notching and slurring in apparently healthy populations

The presence of end QRS notching or slurring (a characteristic of early repolarization) has been the subject of much recent study with new guidelines being developed for its identification. The aim of the present study was to examine the prevalence of end QRS notching or slurring in apparently healthy populations of different races. New criteria for the detection of end QRS notching and slurring were implemented in the Glasgow resting ECG analysis program. 4223 ECGs from Caucasian, Black, Chinese and Indian cohorts were analysed and the interpretations examined for the presence of end QRS notching and slurring. Counts were obtained and categorised by age, gender and race. The site of the notching/slurring, e.g. inferior, etc. was also recorded and analysed. Comparisons of proportions were made using a Chi-squared test. There is a high prevalence of end QRS notching/slurring in normal populations with a significantly higher prevalence in Blacks. The prevalence in Black women, and in particular, in young Black women, was significantly higher than in other races. End QRS notching/slurring was most evident in the inferior leads.