Implantable cardioverter-defibrillator therapy in patients with congenital long-QT syndrome: a long-term follow-up.
OBJECTIVE
The purpose of this study was to evaluate retrospectively a single-center experience with the use of ICDs in patients with long QT syndrome (LQTS) concerning outcome, complications, and optimal programming.


BACKGROUND
Use of implantable cardioverter-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, 1 LQT3, 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).


CONCLUSIONS
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.
Mönnig
Gerold
G
Department of Cardiology and Angiology, University Hospital Münster, Münster, Germany. moennig@uni-muenster.de
Köbe
Julia
J
Löher
Andreas
A
Eckardt
Lars
L
Wedekind
Horst
H
Scheld
Hans H
HH
Haverkamp
Wilhelm
W
Milberg
Peter
P
Breithardt
Günter
G
Schulze-Bahr
Eric
E
Böcker
Dirk
D
D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D017147:Defibrillators, Implantable / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008133:Long QT Syndrome / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome
D000319:Adrenergic beta-Antagonists