Detecting long QT syndrome early could help reduce the impact of sudden infant death

A team led by Dra. Georgia Sarquella (IRSJD) and Drs. Ramon Brugada and Oscar Campuzano (IDIBGI) provide new diagnostic measures to prevent sudden infant death from long QT syndrome. The paper was recently published in the scientific journal Frontiers in Pediatrics.

The health of newborns and children is one of the priorities of current health systems and the World Health Organization (WHO). For this reason, it is important to be able to identify those children at risk of suffering from a certain disease and thus be able to treat them early. In the case of SADS (Sudden Arrhythmia Death Syndromes) to be able to make this detection could prevent severe arrhythmias and sudden deaths. It is estimated that about 1 in 2500 children may be carriers of diseases that can trigger what is known as SADS.

"SADS is a lethal pathology that includes different heart disorders that can cause sudden death in children and/or adults. SADS is mostly associated with inherited diseases, such as channelopathies, and sudden death is often the first manifestation of the disease within the family. SADS can also occur in the first months of life, being the cause of sudden death in infants, 15% of these children have long QT syndrome," Dr. Georgia Sarquella, pediatrician in the Cardiology Service of the SJD Barcelona Children’s Hospital and head of the Cardiovascular Diseases in Development group at the Institut de Recerca Sant Joan de Déu, says.

Long QT syndrome is a rare inherited cardiac disease with a prevalence of 1 in 2,000 newborns. Canalopathies are characterized by pathogenic alterations in the genes encoding cardiac ion channels or associated proteins. Currently, the detection of this syndrome is performed through an electrocardiogram, which records a longer QT interval than usual due to a delay in ventricular repolarization.

The clinical manifestations of this syndrome range from asymptomatic people to ventricular tachycardias that can cause sudden death. Currently, pharmacological therapies have reduced the mortality of this syndrome and hundreds of pathogenic variants have been identified in 15 genes that explain the disease.

"Long QT syndrome can be detected through an electrocardiogram, so we thought it would be interesting to study whether this tool could help us diagnose the syndrome early, so we could start treatment earlier," Dr. Sarquella, first author of the paper published in Frontiers in Pediatrics, says.

The team studied 684 babies born at Hospital Sant Joan de Déu and Hospital Clínic for 3 years. Of the 684 infants, there was a 0.14% of the cases with long QT syndrome without a prior family diagnosis, and of these, eight cases required drug treatment due to their severity. In addition, a new genetic variant associated with the syndrome was also identified.

"Given these results, we believe that assessing the incorporation of electrocardiograms in neonatal screening protocols may be a feasible and non-invasive tool for assessing the QT interval. That way we would have an indicator to predict the susceptibility to cardiac arrhythmias, and we could detect those infants who are likely to suffer a sudden death and be able to perform an early intervention," the research team concludes.

"Despite this, it is very important to provide professionals with tools that allow the proper interpretation of electrocardiograms, to avoid false positives, and not to make patients and families go through unnecessary stressful situations," Dr. Georgia Sarquella says.

On the other hand, the team also emphasizes the importance of performing genetic studies in those cases where the QT interval is greater than 480ms in order to find the mutations that explain the pathology. Finally, they emphasize the importance of these tests for the whole family as it is an inherited disease.

The paper has been published in the journal Frontiers in Pediatrics and has had the participation of researchers from the Institut de Recerca Sant Joan de Déu · Hospital Sant Joan de Déu Barcelona, ​​the Girona Biomedical Research Institute, el BCNatal, and the Hospital Josep Trueta de Girona.

Reference paper

Sarquella-Brugada G, García-Algar O, Zambrano MD, Fernández-Falgueres A, Sailer S, Cesar S, Sebastiani G, Martí-Almor J, Aurensanz E, Cruzalegui JC, Merchan EF, Coll M, Pérez-Serra A, Del Olmo B, Fiol V, Iglesias A, Ferrer-Costa C, Puigmulé M, Lopez L, Pico F, Arbelo E, Jordà P, Brugada J, Brugada R, Campuzano O. Early Identification of Prolonged QT Interval for Prevention of Sudden Infant Death. Front Pediatr. 2021 Jul 29;9:704580. doi: 10.3389/fped.2021.704580. PMID: 34395343; PMCID: PMC8358435.