ORIGINAL RESEARCH article
Front. Endocrinol.
Sec. Clinical Diabetes
Changes of the cardiac electrical cycle in type 1 diabetes during hypoglycaemia – a prospective observational study
Provisionally accepted
Árpád Kézdi1
Viktor J. Horváth1
Viktor Vass2Márk M. Svébis1
Győző Kocsis1Viktória Ferencz1Tamás Jávorfi1Beatrix A. Domján1
Adam G Tabak1,3*- 1Semmelweis University, Budapest, Hungary
- 2Jahn Ferenc Del-pesti Korhaz es Rendelointezet, Budapest, Hungary
- 3University College London Faculty of Brain Sciences, London, United Kingdom
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Introduction: The 'dead-in-bed' syndrome is thought to be a consequence of hypoglycaemia induced QTc prolongation in type 1 diabetes. Thus, we characterized electrocardiogram (ECG) changes during hypoglycaemia in healthy, free-living type 1 diabetes patients. Methods: A cohort of n=23 type 1 diabetes patients wore continuous subcutaneous glucose and ECG monitors for ~7 days. We compared the frequency of ventricular premature beats (VPBs), the mean and SD of heart rate and ECG intervals during hypoglycaemic and their respective control episodes (n=226 episodes, n=1,697,205 beats) using linear mixed models. Results: The mean duration of hypoglycaemic episodes was 159 (95%CI: 128-192) minutes at night and 66 (95%CI: 57-75) minutes during the day. No difference in any of the investigated parameters were found between hypoglycaemic and control episodes during the day as well as in the frequency of nighttime VPBs. In contrast, mean corrected QT (QTc) (mean difference (MD): 5, 95%CI: 2-9 ms) and the SDs of RR (MD: 17, 95%CI: 4-31), P-wave (MD: 2, 95%CI: 0-4), PQ (MD: 3, 95%CI: 1-6), QT (MD: 4, 95%CI: 2-7), and QTc intervals (MD: 5, 95%CI: 2-8) increased during nighttime hypoglycaemia. Discussion: Daytime hypoglycaemia is an unlikely cause of malignant arrhythmias in healthy type 1 diabetes patients. The minimal increase of QTc interval by itself does not suggest an increased risk of malignant arrhythmias. The increase in the mean of QTc together with an increase in its SD during nighttime hypoglycaemia are compatible with the extremely rare occurrence of the 'dead-in-bed' syndrome.
Keywords: cardiac arrhythmias, Continuous glucose monitoring, 'Dead-in-bed' syndrome, Hypoglycaemia, QTc interval, type 1 diabetes
Received: 26 Aug 2025; Accepted: 28 Nov 2025.
Copyright: © 2025 Kézdi, Horváth, Vass, Svébis, Kocsis, Ferencz, Jávorfi, Domján and Tabak. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Adam G Tabak
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.