Comparison of 50% Tilt and Tuned Waveforms in 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amplified at high impedance levels with tuned waveforms being superior (unpublished).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