Defibrillation threshold testing: is it necessary during implantable cardioverter-defibrillator implantation?

Defibrillation threshold (DFT) testing has traditionally been a routine part of implantable cardioverter-defibrillator (ICD) implantation. DFT testing was developed in the early days of the ICD when failure of defibrillation was common, recipients had a high-risk of ventricular tachycardia (VT) or ventricular fibrillation (VF), and the only therapy for rapid VT or VF was a shock. However, modern ICD systems have such a high rate of successful defibrillation that many electrophysiologists now question whether DFT testing is still worthwhile. Studies found that long-term mortality was not higher among patients not undergoing DFT testing. Moreover, there was no survival difference between patients with a lower DFT and a higher DFT. Other studies have demonstrated that DFT testing poses some risk to the patient such as myocardial damage, embolic stroke in patient with atrial fibrillation and DFT testing-related death. If DFT testing is abandoned, more patients may have the opportunity to be treated with ICD, especially in regions with few or no electrophysiologists. It may be argued that other physicians, such as those currently implanting pacemakers, would more readily implant ICDs if not for the requirement of DFT testing.