Implantable cardioverter-defibrillator therapy in patients with congenital long-QT syndrome:: A long-term follow-up

OBJECTIVES The purpose of this study was to evaluate retrospectively a single-center experience with the use of ICIs in patients with long QT syndrome (LQTS) concerning outcome, complications, and optimal programming. BACKGROUND Use of implantable card i overter-defibrillator (ICD) in patients with congenital LQTS is controversial but is generally accepted in high-risk patients. METHODS We enrolled 27 symptomatic patients with LQTS undergoing ICD therapy (QTc 540 +/- 64 ms (1/2); 85% female, 63% cardiac arrest; 33% syncope despite beta-blockers; 4% with severe phenotype) and 81 genotyped patients with LQTS undergoing conventional drug therapy (28 LQT1, 39 LQT2, ILQT3, 13 LQT5). During a mean follow-up of 65 +/- 34 months, one death occurred in the ICD group that was not LQTS related. A total of 178 appropriate shocks were observed in 10/27 patients (37%), mostly in Survivors of cardiac arrest (in 58% of cardiac arrest patients vs. in 20% of non-cardiac arrest patients). RESULTS In a logistic regression analysis, only QTc interval (121/178 shocks (68%) for QTc > 500 ms (1/2)) and "survived cardiac arrest" were prognostic for ICD shocks. In 30% of patients in the ICD group, multiple shocks occurred and could be reduced after increase of antibradycardia pacing rate, adding beta-blocker therapy, or starting the rate-smoothing algorithm (average 7.1 shocks before to 0.75 shocks after additional intervention annually). CONCLUSION ICD therapy is a safe and useful tool in high-risk patients with LQTS. QTc interval and cardiac arrest survivors were prognostic factors for appropriate ICD shocks. The results of this large single-center experience suggest that beta-blockers should always be added to ICD therapy. In addition, some patients might benefit from additional antibradycardia pacing, prolonged detection time, and a rate-smoothing algorithm to prevent recurrent episodes.