Left ventricle automatic pacing threshold management in CRT systems: A comprehensive review

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Modern cardiac resynchronization therapy (CRT) devices aim for consistent left ventricular (LV) pacing while managing battery consumption.
• Current automatic LV capture confirmation often relies on evoked response or specific pacing-to-sensing algorithms.
• LV pacing percentage counters can overestimate CRT delivery due to pacing inhibition or inadequate capture.

Purpose of the Study:

• To review emerging challenges in the automatic management of LV pacing in CRT.
• To discuss the significance of LV threshold at implant and its temporal changes as an indicator of electrical viability.
• To address issues related to ineffective CRT, including subthreshold stimulation and concealed loss of capture.

Main Methods:

• Review of current technologies for LV capture automatic confirmation.
• Analysis of algorithms used for LV pacing management in CRT devices.
• Discussion of factors affecting CRT delivery accuracy and effectiveness.

Main Results:

• Existing LV capture confirmation methods have limitations.
• Pacing inhibition and inadequate capture can lead to overestimated CRT delivery.
• LV threshold behavior over time is crucial for assessing electrical viability and CRT effectiveness.

Conclusions:

• New challenges in automatic LV pacing management require further investigation.
• Accurate assessment of LV capture and threshold is essential for optimizing CRT.
• Addressing subthreshold stimulation and concealed loss of capture is key to improving CRT outcomes.