BJSM In some cases, IRBBB may be confused with a Brugada-ECG diomyopathy (ARVC).21 However, in ARVC, the IRBBB pattern pattern, which is characterised by a high take-off and downslop-is usually associated with other ECG abnormalities, such as T ing ST segment elevation followed by a negative T wave in ≥2 wave inversion involving the mid-precordial leads beyond V2, leads in V1–V3.22 Unlike the R0 wave in Figure 10 (A) Brugada-ECG pattern mimicking IRBBB. The ‘Jwave’ (arrows) of Brugada-ECG is confined to right precordial leads (V1 and V2) without reciprocal ‘Swave’ (of comparable voltage and duration) in leads I and V6 (arrowheads). (B) IRBBB in a trained athlete. The RV conduction interval is mildly prolonged (QRS duration=115 ms) with a typical rSR0 pattern in V1 (arrow). Note also the reciprocal ‘Swave’ in V6 (arrow). IRBBB, the ‘Jwave’ seen in a Brugada-ECG pattern does not indicate delayed RV activation, but reflects early repolarisation with J point elevation and a high take-off with downsloping ST segment followed by a negative T wave (figure 10). Early repolarisation Early repolarisation is an ECG pattern consisting of STelevation and/or a J wave (distinct notch) or slur on the downslope of the R wave (figure 11). Traditional examples of early repolarisation referred to ST elevation, but newer definitions also include J waves or terminal QRS slurring (figure 12).23 Early repolarisation is a common finding in trained athletes and considered a benign ECG pattern in apparently healthy, asymptomatic individuals.24 25 Depending on how it is defined, early repolarisation is reported in up to 35–91% of trained athletes and is more prevalent in young males and black/ Africans.12 13 25 26 precordial leads but can be present in any lead.27–29 Early repolarisation is most common in the CommerFigure 11 ECG from a 29-year-old asymptomatic soccer player demonstrating early repolarisation ( J-point and ST elevation) in I, II, aVF, V2–V6 (arrows) and tall, peaked T waves (circles). These are common, training-related findings in athletes and do not require more evaluation. This figure is only reproduced in colour in the online version. cially available computer diagnostic ECG programmes commonly misreport early repolarisation patterns in athletes as acute ischaemia/myocardial infarction or pericarditis. The early repolarisation pattern in athletes typically involves a concave and ascending/upward ST segment elevation.24 28 Late QRS slurring or notching with horizontal ST segment elevation in the inferolateral leads has been associated with an increased risk of arrhythmic death in one study of middle-aged, nonathletic Finnish citizens.30 HoweFigure 12 (A and B) Classic definition of early repolarisation based on ST elevation at QRS end ( J-point). Examples without (A) and with (B) a J wave. (C and D) New definitions of early repolarisation showing slurred QRS downstroke (C) and J-wave (D) without ST elevation. 30 Sport & Geneeskunde | mei 2013 | nummer 2 ver, a significant percentage of young competitive athletes (25–30%) show early repolarisation with similar morphological features in either the inferior or lateral leads.27–29 These findings are more common in athletes at times of peak fitness, suggesting early repolarisation is a dynamic process and is at least in part a direct result of exercise training.29 To date, no data support the presence of an association between early repolarisation and SCD in athletes. Although further investigation is warranted to fully characterize the prognostic implications of early repolarisation in competitive athletes, all patterns of early repolarisation, including inferolateral subtypes, should be considered normal variants in athletes.24 Pagina 29
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