See Sections 7.3, 7.4, electrophysiological study for specific disease states. Recommendation-Specific Supportive Text 1. A study of electrophysiological testing in patients with symptomatic NICM found inducible VT/VF in 28% of patients which was associated with a higher rate of ICD events during follow-up.S4.3.2-17 In a prospective cohort of 180 patients with isch- emic or NICM and syncope, induction of VT or VF at electrophysiological study correlated with car- diac mortality only in patients with ischemic heart disease. In patients with NICM, cardiac mortality correlated with LVEF but not with inducibility on 2. In patients who meet criteria for ICD implanta- tion (ie, HF and LVEF 35%), data do not sup- port the routine use of electrophysiological study solely for risk stratification, as such patients have been shown to derive survival benefit from the An electrophysiological study may be helpful, however, in selected patients suspected to have preexcitation or supraventricular arrhythmias as the cause of symptoms or wide complex tachycardias that warrant definitive diagnosis and management. SVT leading to VT/VF or aberrantly conducted SVT may also be suspected in younger patients or those with a preserved LVEF. Induction of SVT and ablation may then be curative, with no need for an ICD. In such cases, failure to induce VT/VF after elimination of the substrate for SVT would be expected. 3. Risk stratification for channelopathies is generally made on the basis of symptoms, the ECG,S4.3.2-13, exercise treadmill testing,S4.3.2-25 S4.3.2-27 and the results of genetic testing.S4.3.2-28 S4.3.2-32 The electrophysiological study (ie, programmed ventricular stimulation) does not have prognostic value for risk stratification in patients with these 5. THERAPIES FOR TREATMENT OR PREVENTION OF VA 5.1. 