 There has been one prospective study that found some benefit of using tuned waveforms over 5050 tilt waveforms.11 Other studies have failed to show much change in defibrillation efficacy with different duration biphasic waveforms. A vast majority of patients in these studies were tested with dual coil leads. Although dual coil leads can lower defibrillation thresholds, it is known that dual coil leads can make the lead extraction difficult, lead to venous obstruction and are more prone to failure. Results from a recent study showed that that a single coil configuration is adequate in a vast majority of patients when DFT testing was performed with tuned waveforms. This makes the use of single-coil leads during ICD CRT-D implants an attractive option. 