Spectrum and prevalence of side effects and complications with guideline-directed therapies for congenital long QT syndrome

BACKGROUND beta-Blockers (BBs), sodium channel Mockers (SCBs), left cardiac sympathetic denervation (LCSD), and implantable cardioverter-defibrillators (ICDs) are used to prevent or counter long QT syndrome (LQTS)-triggered syncope, seizures, and sudden cardiac death. The spectrum and extent of side effects/complications associated with these guideline-directed therapies (GDTs) remain unknown. OBJECTIVE The purpose of this study was to identify the types/prevalence of treatment-associated side effects/complications for patients with the most common LQTS subtypes after GDT. METHODS Retrospective analysis was performed on 1310 patients with type 1,2, or 3 LQTS evaluated in Mayo Clinic's Windland Smith Rice Genetic Heart Rhythm Clinic (average age at the time of diagnosis 22 +/- 18 years; average length of follow-up 5 +/- 5 years) and treated with >= 1 of the common GDTs for LQTS. RESULTS BBs were used in 1102 (84%), SCBs in 104 (8%), LCSD in 197 (15%), and an ICD was used in 251 (19%) patients. Overall, 727 (55%) patients reported at least 1 treatment-associated side effect/ complication. complication. A total of 490 of 1102 patients treated with BBs (44%) reported side effects, with fatigue (381 [35%]) being the most common; 28 of 104 SCB-treated patients (27%) reported side effects, most common being gastrointestinal distress/vomiting (18 [17%]); 80 of 197 patients (41%) reported side effects after LCSD, most reporting neuropathic pain (57 [29%]); and 129 of 251 patients (51%) experienced >= 1 complication after ICD implantation, including inappropriate shocks (46 [18%]). CONCLUSION Although LQTS-triggered sudden cardiac death is uncommon in the properly treated patient, this study demonstrates that contemporary GDTs for LQTS are not innocuous. Their treatment-related side effects are not trivial and should compel an ongoing quest for new LQTS therapies.

Automated summary

This study aimed to identify the types and prevalence of treatment-associated side effects and complications in patients with the most common subtypes of long QT syndrome (LQTS) after guideline-directed therapies (GDTs). The results showed that the treatments for LQTS were not without side effects, and new therapies should be explored.