Ablation for long QT syndrome : local or global repolarization effects?

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023001%3A_____%2F23%3A00084004" target="_blank" >RIV/00023001:_____/23:00084004 - isvavai.cz</a>

Result on the web

<a href="https://academic.oup.com/europace/article/25/7/euad196/7222339?login=true" target="_blank" >https://academic.oup.com/europace/article/25/7/euad196/7222339?login=true</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/europace/euad196" target="_blank" >10.1093/europace/euad196</a>

Result language

angličtina

Original language name

Ablation for long QT syndrome : local or global repolarization effects?

Original language description

It is amazing to see a localized substrate in the epicardium of the right ventricular outflow tract. Although the ablation of this epicardial layer with clearly abnormal electrical activities appeared highly effective in the prevention of recurrent arrhythmias, we would like to discuss the author’s observation that ablation was accompanied by a shortening of corrected QT (QTc) interval.Accurate and precise QT interval measurement is challenging even in healthy subjects, let alone in patients with T- and U-wave abnormalities. As an example, in Figure 2 (patient #4), the authors presented the procedural recordings of 12-lead electrocardiogram (ECG) before and after ablation with presumable shortening of QT interval from 489 to 439 ms and QTc interval from 525 to 482 ms. The measurement was performed on a single cardiac cycle, but the use of electronic callipers and the paper speed of 50 cm/s guaranteed the reliable detection of a potential shortening of repolarization by &gt;10 ms and definitely by ∼40 ms as suggested.We re-assessed these readings in magnified and digitized Figure 2. The original callipers were placed correctly in the baseline ECG recording, so that the baseline QT data appear realistic. In the post-ablation ECG, however, the QRS-onset calliper was placed clearly late as is evident in almost all ECG leads. On the other hand, the T-wave-offset calliper was placed too early which can be best seen in leads V5 and V6. After the elimination of this ‘bilateral’ bias of ∼20 ms in favour of QT interval shortening by 40 ms, the final correct QT interval could be 479 ms with QTc interval of 526 ms, indicating virtually no change in the duration of repolarization induced by epicardial substrate ablation. In Supplementary material online, Figure S4 for the same patient, a 9-month follow-up ECG is presented with an automated reading of QT interval (382 ms) and QTc interval (404 ms) that appear correct by the naked eye, but the comparison to former ECGs, which were acquired in the anaesthetized patient, is not relevant and standard pre-ablation ECG is not provided.We thus wonder whether Pappone et al. would admit that proposed substrate ablation may indeed modify or even shorten the repolarization of ventricular myocardium, but that this works locally, not globally. Such a conclusion would be more plausible than unsupported speculation that ‘ablation over these abnormal regions causes distal denervation that impairs repolarization of the entire heart’. In our opinion, relatively limited ablation cannot substantially affect the multiple neural inputs into the heart as well as the overall functioning of the intrinsic autonomic nervous system at the ventricular level.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

30201 - Cardiac and Cardiovascular systems

Project

—

Continuities

N - Vyzkumna aktivita podporovana z neverejnych zdroju

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Europace

ISSN

1099-5129

e-ISSN

1532-2092

Volume of the periodical

25

Issue of the periodical within the volume

7

Country of publishing house

GB - UNITED KINGDOM

Number of pages

1

Pages from-to

"art. no. euad196"

UT code for WoS article

001031635700001

EID of the result in the Scopus database

2-s2.0-85165516947