The purpose of this study is to compare the defibrillation efficacy between the 50/50% tilt biphasic waveform and the Tuned biphasic waveform in a single coil active can configuration.

There has been one prospective study that found some benefit of using tuned waveforms over 50/50% 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.

Theoretical analysis has shown that difference between the tuned and 50% tilt waveforms is amplified at high impedance levels with tuned waveforms being superior (unpublished). Accordingly, this study has been designed to prospectively compare the DFT estimates with tuned and 50% tilt waveforms in left-sided, active pectoral defibrillation lead systems when the SVC coil has been turned OFF or is not part of the shocking circuit.

Inclusion Criteria:

• Patient meets standard indication for an ICD/ CRT-D and will be implanted with an FDA approved SJM ICD/ CRT-D and compatible defibrillation lead system in the left pectoral region.
• Patient is able to tolerate DFT testing.

Exclusion Criteria:

• Patient has the pulse generator on the right side.
• Patient is pregnant.
• Patient is less than 18 years old.
• SVC coil was turned ON during DFT testing

Patients with ICD/CRT-D indications