Bisoprolol Treatment and Adherence in Pediatric Patients With Genotype-Positive Long QT Syndrome.

Background: Non-selective beta-blockers, such as propranolol, are highly effective in reducing arrhythmia risk in long QT Syndrome (LQTS). The study aim was to evaluate the use of beta-blockers, especially beta-1-selective bisoprolol, and their efficacy in Finnish children with genotype-positive LQTS type 1 or 2. Methods: We retrospectively reviewed the medical records of children with genetically confirmed LQTS1 or LQTS2 diagnosis, who were treated at Tampere University Hospital in Finland between 2006 and 2020. Data on cardiac events, beta-blocker use and adherence, ECG, clinical exercise tests, and genetic testing were collected. Results: Eighty-eight children were diagnosed with a genotype-positive type 1 or 2 LQTS, and 84% of them had a family history of LQTS associated gene mutations. Four Finnish founder mutations accounted for 68% of the cases. At diagnosis, 63% had a normal QTc interval. No cardiac events occurred during follow-up among patients receiving beta-blocker therapy. For children aged 0-7 years, propranolol was the primary medication in 90% of cases, and for > 7-year-olds, bisoprolol was used in 77% of cases. At the last follow-up visit, 87/88 were on beta-blockers, most commonly bisoprolol (66%). Medication adherence was high, with 84% of patients using beta-blockers as prescribed. In clinical exercise tests, maximal heart rate remained < 160 beats per minute in 76% of tests, indicating effective beta-blockade. Conclusions: Cascade screening identified asymptomatic patients, most with normal QTc intervals. Bisoprolol was the most commonly used beta-blocker with good adherence, effective heart rate control, and no cardiac events observed during follow-up among these Finnish children with LQTS.