Prof. Christian Wolpert,
The objective of this session was to improve understanding of the different entities encompassing the J wave syndromes and to focus on epidemiological, genetic and also practical aspects such as risk stratification by electrophysiological study. Prof. Goette introduced the session with a presentation on the mechanisms that can lead to the various electrocardiographic changes seen in Early Repolarisation Syndrome and Brugada syndrome by showing data on ion current alterations, such as an increase of the effect of the Ito-current, decrease of L type calcium currents and the potential role of IkATP. He described the proposed mechanism by which mainly the group of Antzelevitch was able to demonstrate repolarisation changes with induction of ventricular fibrillation in canine wedges as well as the data from the Amsterdam group that postulates that at least in large part depolarization changes are responsible for ST segment elevation in Brugada syndrome. He also presented new data on the effect of ajmaline to suppress J waves in early repolarisation. The discussion made clear that there is still a lot of phenomena that have to be elicited and that we may deal with different mechanisms in the various types of J wave alterations.His talk was followed by a very elegant presentation by Porf Probst who focused on genetic aspects in J wave syndromes. He first discussed recent data that could demonstrate that early repolarisation seems to be a heritable trait. In an investigation of 15,000 European individuals from a large population study there was evidence for heritability of ER. However, no genetic locus could be identified that may be associated with this genetic determination. He also presented data showing that J waves are more frequent in sudden death survivors, although there was no difference between patients or relatives in whom a channelopathy was causal compared to those who died from other reasons or those in whom no final diagnosis could be established. Prof. Probst also discussed the fact that males and younger individuals present more frequently with early repolarisation. Finally, he concluded that genetic testing and modifier gene search is still incomplete and that up to now, it has been extremely difficult to base clinical decisions on genetic test results. Prof Viskin had the task of putting ER into a broader perspective of epidemiology and risk assessment. He showed the growing amount of literature describing different kinds and degrees of early repolarisation and warned to be very correct with the recording and definitions of the continuum of ECG phenomena. He also showed that in the various population studies, the prevalence of the different types of ER was so high that specificity will remain low. He elegantly summarized the literature on the importance of ascending and descending ST segments and ER and placed a word of caution for risk stratification by making calculations on the potential risk of dying suddenly in relation to the presence of ER. Based on the currently available literature, he said that the risk of dying suddenly during lifetime is 10 times higher compared to the normal population when an individual has a J wave with horizontal ST segment morphology. The final talk of this very exciting session was given by Dr Derval who gave an excellent overview on the value and use of electrophysiological study with programmed stimulation both for Brugada syndrome and ERS. He presented the Bordeaux experience, where inducibility of ventricular fibrillation was low and the positive predictive value was also low in ERS. For Brugada syndrome he presented the large registries that come to a different conclusion when talking about the role of programmed stimulation. In one registry, the negative predictive value is very high and in their series they still see also a role for risk prediction, whereas in the other large registry with > 1000 patients, inducibility of VF is not predictive for sudden death or future ventricular fibrillation. In summary, the session gave a great overview on the most recent data and revealed again how much there is still to be learned in this still quite young field of research.
From bench to practice: J-wave syndromes
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