Transmission

L'alerte indique que la valeur du seuil LV est supérieure à l'amplitude maximale testée (5,0 V) et nous observons que la sortie est programmée à 4V. En regardant les courbes Autothreshold, nous pouvons voir que le seuil pour la dérivation LV a toujours été élevé mais qu'il a augmenté encore plus ces derniers jours. Le %biV (CRT) est proche de 100%, ce qui signifie que la sonde LV est en train de stimuler, mais cela ne signifie pas que la sonde LV est en train de capturer. Sur l'EGM en temps réel, nous ne pouvons pas distinguer la capture biventriculaire de la capture d'un seul site (RV).

Prochaines étapes

There is a suspected LV lead dysfunction but we cannot guarantee the proper functioning of the LV lead using remote medicine. These patients are known with heart failure and the clinical condition can deteriorate quickly when the LV is not captured. While the percentage of CRT may seem normal, the percentage of actual CRT may be a lot lower, increasing the risk of decompensated heart failure and LV remodeling. Therefore the patient should be called to the clinic to perform manual LV capture tests. In this patient, the 12-lead ECG confirmed loss of LV capture; ECG was identical during biventricular pacing and RV pacing only. The vector was changed from LV-ring-to-R-coil to RV-tip-to-RV-ring which resulted in a high but acceptable pacing threshold. The 12-lead ECG confirmed biventricular capture and the patient was discharged. The patient has been informed that the LV lead is at risk, meaning that in the future it a new LV lead may have to be implanted. With a correctly working LV lead in place, even with elevated thresholds, it is often decided to postpone this invasive procedure, as it is not without risk. Remote monitoring (with LV autothreshold on auto or monitoring) is essential in order to precede symptoms of LV lead failure through alerts.