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Figure 3 Indications for Device Implantation

The most common indication for device implantation was syncope despite beta-blocker therapy. There were 13 patients in this group. Devices were placed in 4 patients with documented torsades de pointes (TdP) or ventricular tachycardia (VT) and in 3 who presented with resuscitated sudden death. A family history of sudden death caused by long QT syndrome (LQTS) was the sole indication in 3 additional patients. A pacemaker was placed in an infant with LQTS and 2:1 atrioventricular block (AVB), and an implantable cardioverter-defibrillator (ICD) was placed in an asymptomatic patient with an SCN5A mutation. A device was placed in 1 patient with syncope and a QTc interval of >600 ms who was later identified as a compound heterozygote having both SCN5A and KCNQ1 mutations. BB = beta-blockers; FH = positive family history of long QT syndrome; SD = sudden death.