The Usefulness of Electrophysiological Test (EPS) for Implantable Cardioverter Defibrillator (ICD) Therapy in Patients with Hypertrophic Cardiomyopathy (HCM)

Background: Patients with HCM are at substantial risk for sudden cardiac death (SCD). There are observational studies that show HCM patients with inducible arrhythmias are at increased risk for SCD, however, the usefulness of EPS, which predicts the necessity of preoperative management for ICD therapy, is not established. Method: In 76 patients with HCM implanted ICD between May 2000 and August 2010 followed for mean (±SD) of 38.3 +⁄− 3.2 months, consists of 50 patients implanted ICD for primary prevention and 26 patients for secondary prevention, 9 patients (18%) in primary prevention group and 10 patients (38%) in secondary prevention group have received appropriate ICD therapies. Arrythmogenic risk was assessed by occurrence of NSVT in Holter ECG and induced Sustained Ventricular tachycardia (SVT) and fibrillation (VF) in EPS. Results: In the primary prevention group, all patients has a history of NSVT on Holter ECG, of which max beats are significantly higher (17.22/8.357 P=0.0017) in therapy group. EPS shows there is no tendency to the occurance of SVT/VF in therapy group (P=0.17). In therapy group, SVT/VF had induced by double ventricular extrastimuli in only 2 patients (25%), triple entricular extrastimuli in 5 patients (62%). In non-therapy group, SVT/VF had induced by double ventricular extrastimuli in 37 patients (51%), triple ventricular extrastimuli in 14 patients (37%). Conclusion: In HCM patients, EPS suggest not to be the prior predictor for the indication of primary ICD implantation.