**7. Electrophysiological testing**

Patients after MI have the highest induction rates in electrophysiological study and the pres‐ ence of ejection fraction less than 40% and asymptomatic NSVT is associated with a induci‐ bility of 20-40% [22], [61].

Programmed ventricular stimulation identifies most patients at risk for sustained monomor‐ phic ventricular tachycardia associated with reentrant circuits that result of the healing proc‐ ess after infarction [22].

Electrophysiological study was required in MADIT, MUSTT, BEST–ICD [62], but not in MADIT –II and SCD-HeFt trials.

Based on these trials, electrophysiological testing is not required before ICD implantation. It is recommended (class I) for diagnostic evaluation of symptoms suggestive of tachyarrhyth‐ mias, to guide VT ablation and for differential diagnosis of a wide-QRS-complex tachycar‐ dias of unclear mechanism [14].

Electrophysiological study is also reasonable for risk stratification in patients with NSVT, and LVEF equal or less than 40% (Class IIa). Inducibility of VT in patients with NSVT is as‐ sociated with a high risk for VT/FV and the characteristics of NSVT could not predict the inducibility [63].
