True bipolar and integrated bipolar sensing and detection by implantable defibrillators

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Implantable defibrillators utilize either true bipolar or integrated bipolar configurations for sensing and detection.
• Newer Medtronic generators offer adjustable configurations for sensing functions.

Purpose of the Study:

• To compare the sinus rhythm R-wave amplitude and ventricular fibrillation (VF) detection time between true bipolar and integrated bipolar configurations.
• To evaluate acute and chronic phase performance of these sensing configurations in implantable defibrillators.

Main Methods:

• Twenty-eight patients were assessed in the acute phase, with 15 evaluated in the chronic phase.
• R-wave amplitude and VF detection time were measured for both true bipolar and integrated bipolar configurations using specific Medtronic generators and leads.
• Electrograms were recorded, and detection time was measured from T shock to VF onset.

Main Results:

• No significant difference was observed in acute-phase R-wave amplitude (13.9 ± 7.1 mV vs. 13.6 ± 6.9 mV, p = 0.38) between the two configurations.
• Ventricular fibrillation detection times were also comparable between true bipolar (3.12 ± 0.39 seconds) and integrated bipolar (3.17 ± 0.39 seconds) configurations (p = 0.52).

Conclusions:

• Sensing and detection performance were not significantly different between true bipolar and integrated bipolar configurations.
• The findings apply to the specific leads and generators tested, indicating comparable efficacy for both configurations.