From the Research
Chronaxie is a critical parameter in optimizing electrical stimulation parameters, particularly in cardiac pacing, and its understanding helps clinicians balance therapeutic effectiveness with battery longevity and minimize unwanted side effects. The concept of chronaxie is essential in neurophysiology, representing the minimum time required for an electrical current at twice the rheobase to elicit a response 1. In the context of cardiac pacing, chronaxie values can vary between different tissues, with the His bundle having a shorter chronaxie than the adjacent ventricular myocardium, which has implications for pacemaker programming 1. Key points to consider include:
- Chronaxie is used to determine the excitability of nerve or muscle tissue and represents the minimum time required for an electrical current at twice the rheobase to elicit a response.
- Different tissues have characteristic chronaxie values, with motor nerves typically having values around 50-100 microseconds, while sensory nerves and cardiac tissue have longer chronaxies.
- Understanding chronaxie helps clinicians balance therapeutic effectiveness with battery longevity in implantable devices and minimize unwanted side effects from electrical stimulation.
- In cardiac pacing, pacing at pulse durations adjusted to the chronaxie can offer the lowest current drain and promote selective capture, while longer pulse durations may provide a greater safety margin for ventricular capture 1. The most recent and highest quality study on this topic, published in 2019, highlights the importance of chronaxie in pacemaker programming, particularly in achieving selective His bundle capture and minimizing battery current drain 1. Overall, chronaxie is a vital parameter in optimizing electrical stimulation parameters, and its understanding is crucial for clinicians to provide effective and safe treatment in various medical applications.