title: Left cardiac sympathetic denervation in long QT syndrome: analysis of therapeutic nonresponders.
abstract: BACKGROUND
  Long QT syndrome (LQTS) is a potentially lethal but highly treatable cardiac channelopathy. Treatment options include pharmacotherapy, device therapy, and left cardiac sympathetic denervation (LCSD). Here, we sought to determine the characteristics of LQTS patients who have had ≥1 LQTS-related breakthrough cardiac event (BCE) after LCSD.
  
  
  RESULTS
  We performed retrospective chart review for 52 consecutive patients (24 males; mean age at diagnosis, 10.0±10 years; mean QTc, 528±74 ms) with LQTS who underwent LCSD between 2005 and 2010 (mean age at LCSD, 14.1±10 years) and have been followed up for 3.6±1.3 years. A BCE was defined as either (1) an appropriate ventricular fibrillation-terminating implantable cardioverter defibrillator shock or (2) arrhythmogenic syncope, seizures, or aborted cardiac arrest after LCSD. Thirty-three patients (61%) had LCSD as primary prevention because of either high-risk assessment or β-blocker intolerance. So far, 12 of 52 (23%) patients (7 males) have experienced ≥1 BCE post LCSD. The clinical phenotype of patients with BCEs was significantly more severe than patients without a BCE. No BCEs were seen in patients undergoing LCSD for β-blocker intolerance (0/12 versus 17/40; P<0.001).
  
  
  CONCLUSIONS
  Although a marked reduction in number of cardiac events is usually seen after LCSD, ≈50% of high-risk LQTS patients have experienced ≥1 post-LCSD breakthrough. Therefore, LCSD must not be viewed as curative or as an alternative in implantable cardioverter defibrillator for high-risk patients. Prophylactic LCSD may provide another option to counter a suboptimal quality of life resulting from medication-related side effects.
authors.affiliation: Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology & Experimental Therapeutics, Division of Pediatric Cardiology, Department of Pediatric & Adolescent Medicine, Division of Pediatric Surgery, Department of Surgery, and Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: Bos
authors.forename: Katy M
authors.initials: KM
authors.lastname: Bos
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Johnson
authors.forename: Christopher
authors.initials: C
authors.lastname: Moir
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D017147:Defibrillators, Implantable; D018572:Disease-Free Survival; D004554:Electric Countershock / Q000295:instrumentation; D005260:Female; D006321:Heart / Q000294:innervation*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D008133:Long QT Syndrome / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013562:Sympathectomy / Q000009:adverse effects; D013564:Sympathetic Nervous System / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: arrhythmias, cardiac; death sudden, cardiac; left cardiac sympathetic denervation; long QT syndrome; syncope