MP-453086-1 THE USEFULNESS OF EPS TO PREDICT APPROPRIATE THERAPIES IN PRIMARY PREVENTION ICD PATIENTS

Abstract

Current guidelines recommend ICD implantation for primary prevention in patients with LVEF ≤35% of both ischemic and nonischemic etiology, regardless of the results of the electrophysiological study. Some studies recently questioned this policy. We aimed to access the value of the EP study in long term prediction of the arrhythmic events in patients with reduced EF (≤35%) who underwent EPS and ICD implantation. We compared the risk for all-cause mortality in patients with negative EPS with and without ICD implantation and compared the risk for appropriate therapy according to the results of the EP study of patients who underwent ICD implantation in our institution. The median follow-up was 84 months. Of 293 patients, who underwent EPS, 159 had negative result (noninducible to VT). These patients were more likely to be female and have nonischemic etiology than patients with positive EPS. Patients did not differ in presence of diabetes, atrial fibrillation or ejection fraction. Kaplan-Meier survival analysis showed that there was no difference in mortality between the 2 groups (44.9% vs 42.0%, p=0.672). This was also true in both ischemic (53.2% vs 49.6%, p=0.554) and nonischemic (27.3% vs 27.3%, p=0.974) patients. Of 212 patients who underwent ICD implantation, 90 had negative EPS. Kaplan-Meier survival analysis showed that these patients were significantly less likely to receive appropriate therapy (5.7% vs 23.9%, p<0.0001) and appropriate shock (0% vs 9.7%, p=0.002), all appropriate shocks happened in the ischemic subgroup (0% vs 10.9%, p=0.004). The time to first appropriate ICD therapy was significantly longer in EPS negative patients (111 vs 92 months, p=0.001). The incidence of inappropriate therapies was similar in both groups (6.7% vs 5.8%, p=0.792). Age, gender, ischemic etiology, coronary disease risk factors, EF and NYHA class were not significantly associated with appropriate ICD therapy. ICD implantation did not reduce mortality in patients with reduced EF and negative EPS. Patients with negative EPS and implanted ICD had much lower incidence of appropriate ICD therapies and no appropriate shocks. EP study is useful to guide decisions about ICD implantation in patients with EF≤35%.