Predictors of high defibrillation threshold in patients with implantable cardioverter-defibillator using a transvenous dual-coil lead

Background: Defibrillation testing (DT) is considered a standard procedure during implantable cardioverter-defibrillator (ICD) implantation. However, little is known about the factors that are significantly related to patients with high defibrillation threshold (DFT) using the present triad system.

Methods and Results: We examined 286 consecutive patients who underwent ICD implantation with a transvenous dual-coil lead and DT from December 2000 to December 2011. We defined patients who required 25 J or more by the implanted device as the high DFT group, and those who required less than 25 J as the normal DFT group. For each patient, assessment parameters included underlying disease, comorbidities, NYHA functional class, drugs, and echocardiographic measures. The high DFT group consisted of 12 patients (4.2%). Multivariate analysis identified 3 independent predictors for high DFT: atrial fibrillation (odds ratio (OR) 4.85, 95% confidence interval (CI) 1.24–22.33, P=0.023), hypertension (OR 4.01, 95% CI 1.08–15.96, P=0.039), thickness of interventricular septum (IVS) >12 mm (OR 4.82, 95% CI 1.17–20.31, P=0.030).

Conclusions: Atrial fibrillation, hypertension and IVS hypertrophy were significantly associated with high DFT. Identification of such patients could help to lower the risk of complications with DT.