The transmission has a yellow alert: measurement of a high LV threshold (3V), which surpasses the 2.5V value and therefor triggers and alert. The impedance is normal, the EGM looks normal and before and after this measurement, the LV threshold values are normal. Since there is a single abnormal threshold and no other signs of lead failure, it is probable that the LV threshold test failed to find the actual threshold due to technical error or changes in the signal (fusion, extrasystole, …).

Next steps

When there is a slight suspicion of lead dysfonction without significant clinical risks, intensified remote monitoring is recommended. In this case, we asked the patient to perform a manual tranmission a few weeks later which is shown here:

As the Autothreshold graph shows, there are no new abnormal thresholds during the follow-up. This confirms that the high threshold is due to technical error, and not due to lead failure.

Decrease %CRT

While not the topic of this case, there is a significant decrease in %CRT since implantation. This is due to the occurrence of atrial fibrillation directly after implantation. The patient was treated with amiodarone but as the transmission shows, the treatment is not effective. The patient, less symptomatic than before implantation, was planned for electrical cardioversion.