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Circulation. 2018;138:e272–e391. DOI: 10.1161/CIR.0000000000000549 September 25, 2018 e329 CLINICAL STATEMENTS AND GUIDELINES that promote depletion are encountered is an important component of management. Rare case reports exist of fever prolonging the QT interval in patients with long QT syndrome type 2; fever should be reduced with antipyreticsS7.9.1.1-61 (Table 10). 7.9.1.2 Catecholaminergic Polymorphic Ventricular Tachycardia Recommendations for Catecholaminergic Polymorphic Ventricular Tachycardia References that support the recommendations are summarized in Online Data Supplement 41. COR LOE Recommendations I B-NR 1. In patients with catecholaminergic polymorphic ventricular tachycardia, a beta blocker is recommended.S7.9.1.2-1,S7.9.1.2-2 I B-NR 2. In patients with catecholaminergic polymorphic ventricular tachycardia and recurrent sustained VT or syncope, while receiving adequate or maximally tolerated beta blocker, treatment intensification with either combination medication therapy (eg, beta blocker, flecainide), left cardiac sympathetic denervation, and/or an ICD is recommended.S7.9.1.2-2–S7.9.1.2-6 IIa B-NR 3. In patients with catecholaminergic polymorphic ventricular tachycardia and with clinical VT or exertional syncope, genetic counseling and genetic testing are reasonable.S7.9.1.2-7 Recommendation-Specific Supportive Text 1. Catecholaminergic polymorphic ventricular tachycardia is characterized by exertion-related polymorphic or bidirectional VT (Figure 13), associated with syncope and SCA. SCA/SCD is reported in 3% to 13% of patients.S7.9.1.2-1,S7.9.1.2-2,S7.9.1.2-8 Treatment with beta blockers is associated with a reduction in adverse cardiac events.S7.9.1.2-1,S7.9.1.2-2 Some experts prefer the use of nadolol over other types of beta blockers; direct comparison data among beta blockers are unavailable. Use of a maximally tolerated dose of a beta blocker is important. Small observational studies suggest possible benefit of nondihydropyridine calcium channel blockers in the treatment of catecholaminergic polymorphic ventricular tachycardia.S7.9.1.2-9,S7.9.1.2-10 2. Flecainide in combination with a beta blocker can suppress ventricular ectopy by as much as 76% in patients with catecholaminergic polymorphic ventricular tachycardia during exercise testing or clinical follow-up.S7.9.1.2-2,S7.9.1.2-6,S7.9.1.2-11 For refractory VA, verapamil or propafenone may also be effective.S7.9.1.2-9,S7.9.1.2-10,S7.9.1.2-12 ICD implantation in patients with catecholaminergic polymorphic ventricular tachycardia should be reserved for patients with prior SCA, or patients with refractory VAs on combination medical therapy. Inappropriate shocks are reported in 20% to 30% of catecholaminergic polymorphic ventricular tachycardia patients with ICDs.S7.9.1.2-2,S7.9.1.2-13–S7.9.1.2-16 ICD programming in patients with catecholaminergic polymorphic ventricular tachycardia should be optimized to deliver therapy for VF and to minimize inappropriate shocks and the risk of potentially fatal electrical storms.S7.9.1.2-13,S7.9.1.2-15 Left cardiac sympathetic denervation for catecholaminergic polymorphic ventricular tachycardia may reduce the frequency of recurrent ICD shocks by 32% to 75%S7.9.1.2-3–S7.9.1.2-5,S7.9.1.2-17,S7.9.1.2-18 although recurrent syncope, SCA, or SCD is reported in 9% to 32% of patients, with other minor complications in 20% to 70% of patients. It is best if the left cardiac sympathetic denervation is performed in centers with expertise in this procedure. Intensification of medical therapy or left cardiac sympathetic denervation is important in treating patients who present with recurrent appropriate ICD shocks.S7.9.1.2-19 3. Genetic testing may be useful to confirm the diagnosis of catecholaminergic polymorphic ventricular tachycardia, which is suggested by the development of bidirectional VT with exertion or stress. Recognition of catecholaminergic polymorphic ventricular tachycardia as the cause for exertional symptoms should prompt aggressive therapy to prevent the significant risk of SCD. Therapy for catecholaminergic polymorphic ventricular tachycardia is not guided by genotype status, but screening of first-degree relatives may be facilitated with genetic testing.S7.9.1.2-20 Ryanodine receptor mutations have been reported in 47% of probands, which were de novo mutations in >70%.S7.9.1.2-7 Ryanodine genotype status has not correlated with disease severity or response to medications.S7.9.1.2-7 In very young patients presenting with idiopathic VF, mutations in calmodulin have been identified and are associated with high lethality.S7.9.1.2-21–S7.9.1.2-24 Studies of proposed pathogenic mutations in catecholaminergic polymorphic ventricular tachycardia genes report up to 15% of variants were present in exome databases of the general population, raising questions as to the monogenic cause of catecholaminergic polymorphic ventricular tachycardia.S7.9.1.2-20,S7.9.1.2-25 Downloaded from http://ahajournals.org by on October 7, 2026