Pediatric/Adult Congenital Heart Disease -> Pediatric Cardiology D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-033 - Efficacy Of Intentional Permanent Atrial Pacing In The Long-term Management Of Congenital Long Qt Syndrome (ID 422)

 G.N. Kowlgi: Nothing relevant to disclose.


Background: Beta-blockers, left cardiac sympathetic denervation (LCSD), and implantable cardioverter-defibrillator (ICD) therapy represent the core components of a long QT syndrome (LQTS) treatment program. Unfortunately, some patients with LQTS experience breakthrough cardiac events (BCEs) despite maximal therapy. Small studies have shown that these refractory LQTS cases may benefit from intentional permanent atrial pacing (IPAP).
Objective: To determine the genotype-specific utilization and efficacy of adjunctive IPAP in a large single-center LQTS registry.
Methods: In this retrospective study, available electronic medical records from 1,062 patients diagnosed with LQTS between 01/2000 and 11/2019 were used to identify all individuals that received a permanent pacemaker. After excluding patients with non-IPAP related device implants, pre- and post-IPAP heart rate, heart rate-corrected QT (QTc) values, annual BCE rate, and IPAP-related serious adverse events were assessed and compared between genotypes. BCEs were defined as LQTS-associated syncope/seizures, ventricular fibrillation (VF)-terminating ICD therapies, and sudden cardiac arrest/death (SCD).
Results: Overall, 52/1062 LQTS patients (7 LQT1, 28 LQT2, 12 LQT3, and 5 minor/multisystem LQTS) received adjunctive IPAP therapy (77% female; median age at implant (IQR) 18.5 (1-35.5) years; 73% with prior VT/VF). Over an average IPAP follow-up duration of 121 ± 82 months, the average sinus rate increased from 65.8 ± 20.4 bpm to 78.9 ± 17.1 bpm; (p<0.01) and the average QTc decreased from 533.4 ± 66.6 ms to 488.3 ± 52.4 ms; (p < 0.01). Importantly, the mean BCE rate dropped from 0.88 to 0.19 BCEs per patient-year following IPAP (p=0.01), driven largely by a marked decrease in BCEs in patients with LQT2 (1.01 BCE/year to 0.02; p=0.003). Lastly, no serious IPAP-related complications were observed.
Conclusion: In a sample of high-risk LQTS patients, namely those with recalcitrant LQT2, IPAP appears to be a safe and efficacious adjunct therapy. Consistent with prior studies, the beneficial effects of IPAP may stem from attenuating the QTc and circumventing a pause-dependent trigger. Whether IPAP might obviate the need for an ICD in some of these high-risk patients warrants further scrutiny.