Normalization of increasing shocking coil impedance with full output synchronized shock

Area of Science:

• Cardiovascular implantable electronic devices (CIEDs)
• Electrophysiology
• Biomedical engineering

Background:

• Impedance monitoring is critical for CIED function.
• Low voltage sub-threshold measurement (LVSM) is commonly used for impedance assessment.
• LVSM of shock impedance (LVSM-SI) may become inaccurate due to peri-lead tissue changes.

Observation:

• A case of elevated LVSM-SI was observed 8 years post-lead implantation.
• This elevation was potentially caused by right ventricular lead coil encapsulation.
• High voltage shock impedance (HVSI) measured after a test shock was normal.

Findings:

• A full output synchronized shock test accurately assessed HVSI.
• Post-test shock, LVSM-SI normalized and remained stable during follow-up.
• This suggests a method to correct inaccurate LVSM-SI readings.

Implications:

• Consider a full output synchronized shock test for abnormal LVSM-SI in remote post-ICD implantation phases.
• This approach may help normalize LVSM shock impedance measurements.
• Ensures reliable impedance monitoring for CIEDs.