Author + information
- Gaetano A. Lanza, MD⁎ ()
- ↵⁎Istituto di Cardiologia, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma, Italy
I have read with interest the report by Noseworthy et al. (1) on the prevalence and heritability of the early repolarization pattern (ERP) in the general population. The ERP has for a long time been considered a benign electrocardiographic finding, but recent studies have challenged this view by reporting a significant association with ventricular tachyarrhythmias and sudden cardiac death (2–5). Thus, knowledge of its prevalence and determinants in the general population is relevant for putting ERP in the right clinical perspective. There are 2 major points in Noseworthy et al.'s study, however, that, in my opinion, deserve comment.
The ERP in this study was defined as “J-point elevation of ≥0.1 mV in ≥2 leads in the inferior or lateral territory, or both” (1), a definition similar to that applied in recent studies (2–5). However, how the J point was identified on the electrocardiogram was not specified in any of these studies. I think this issue is relevant, because identification of the J wave cannot be taken for granted. A careful reading of previous studies, indeed, leaves doubts regarding how the J point was located, in particular in the presence of prominent notched or slurred J waves (2–5), and inevitably, a similar concern holds true for the present study (1). Moreover, the definition of the ERP given in this and in recent studies does not fit with what clinical cardiologists usually diagnose as the ERP in their routine clinical practice. In the classic definition of the ERP, the presence of typical up-sloping ST-segment elevation is specifically required (6,7), but this is not taken into any account in the definition adopted in this and in previous studies (1–5).
A second questionable point of the study by Noseworthy et al. (1) is the conclusion that the ERP “has a heritable basis.” Indeed, this conclusion does not seem to be supported by the results, as the investigators' Table 5 clearly shows that there was no statistically significant increase in the prevalence of the ERP in siblings of carriers of the electrocardiographic pattern, when data were corrected for age and sex, a crucial statistical adjustment considering the heavy dependence of ERP prevalence on these 2 variables (1). Moreover, the demonstration that a higher prevalence of the ERP in siblings of ERP carriers is related to heritability should exclude that some common acquired condition in siblings (e.g., common intense physical activity, which would portend a higher prevalence of the ERP) (8), may have contributed to the association.
In summary, I believe that there is an urgent need for a clear and shared definition of the ERP and related electrocardiographic findings to put them in the correct clinical perspective. Furthermore, a careful assessment of studies on this topic is required to avoid biased conclusions that might feed confusion in this complex field.
- American College of Cardiology Foundation
- Noseworthy P.A.,
- Tikkanen J.T.,
- Porthan K.,
- et al.
- Rosso R.,
- Kogan E.,
- Belhassen B.,
- et al.