Earlier stud- ies reported benefit of antibradycardia pacing, Table 10. Commonly Used QT-Prolonging MedicationsS7.9.1.1-59,S7.9.1.1-62 Examples of QT Prolonging Medications* Antiarrhythmic Medications Psychotropic Medications Antibiotics Others Disopyramide Haloperidol Erythromycin Methadone Procainamide (N-acetylprocainamide) Phenothiazines Pentamidine Probucol Quinidine Citalopram Azithromycin Droperidol Dofetilide Tricyclic Chloroquine Ondansetron Dronedarone antidepressants Ciprofloxacin Ibutilide Fluconazole Sotalol Levofloxacin Amiodarone Moxifloxacin Clarithromycin Itraconazole Ketoconazole *A more complete list is maintained at: www.crediblemeds.org.S7.9.1.1-59 Amiodarone rarely causes torsades de pointes. CLINICAL STATEMENTS AND GUIDELINES with recurrent syncope or cardiac arrest reported In high-risk patients, observational studies sup- port effectiveness of the ICD in preventing SCD, with consideration of left cardiac sympathetic denervation to reduce the frequency of ICD Left cardiac sympa- thetic denervation can reduce VA burden, but up to 27% of high-risk patients experience at least Left cardiac sympathetic denervation may be more effective in patients with long QT syndrome type 1 and long QT syndrome type 3.S7.9.1.1-16 Complications related to left cardiac sympathetic denervation Syncope in patients with long QT syndrome may occur due to vasovagal syncope, noncompliance with medications, or proarrhythmia from concur- Clinical evaluation that incorporates consideration of genotype, QTc inter- val, medication compliance, and shared decision- making regarding the need to change or escalate therapy is important. Use of additional medica- tions is guided by long QT syndrome type. In long Figure 9. Prevention of SCD in patients with long QT syndrome. Colors correspond to Class of Recommendation in Table 1. See Section 7.9.1.1 for discussion. *ICD candidacy as determined by functional status, life expectancy, or patient preference. High-risk patients with LQTS include those with QTc >500 ms, genotypes LQT2 and LQT3, females with genotype LQT2, <40 years of age, onset of symptoms at <10 years of age, and patients with recurrent syncope. ICD indicates implantable cardioverter-defibrillator; LQTS, long QT syndrome; VT, ventricular tachycardia. Figure 10. 