67-year-old man implanted with a Lumax 540 VR-T single-chamber ICD for ischemic cardiomyopathy with ejection fraction of 20%; event report (yellow color) in the setting of a classified VT2.
3 channels are available: the markers with the time intervals, the shock channel (FF: far field) between the ventricular lead coil and the pulse generator, the right ventricular sensing channel (RV).
Programmer tracing (same episode)
The 3 channels are the same as for the telecardiology tracing.
The maximal duration of EGMs transmitted by telemedicine is 30 seconds before the initial classification, followed by a maximum of 10 seconds before the end of episode classification; only a maximum amount of information can be transmitted which means that, at times, these values may be lower; the transmitted EGMs correspond to the EGMs retrieved on the programmer albeit with a filtering of the baseline to limit the amount of transmitted information. The duration of the EGMs retrieved on the programmer does not exceed 3 minutes 30 seconds per episode; the EGM recording begins 5 seconds before the sudden onset diagnosis or 30 seconds before classification if the sudden onset criterion is not met. If the episode lasts more than 3 minutes 30 seconds, the recording is interrupted with systematic visualization of the beginning and the end of the episode.
This tracing demonstrates an example of a VT terminated by an antitachycardia pacing burst which represents first-line therapy for VT <200 beats/minute. Indeed, a priority of the programming of an implantable defibrillator is to minimize as much as possible the number of shocks delivered without compromising patient safety. Ideally, this entails terminating the tachycardia with the least aggressive and least painful therapy possible. Antitachycardia pacing thus represents the first line therapy for organized tachycardias comparatively to electric shocks, the former being less painful and limiting battery consumption and wear. Moreover, the deleterious effect of electric shocks has been clearly demonstrated. The principle behind antitachycardia pacing is to capture the arrhythmia and terminate an organized VT by penetrating its propagation circuit through the ventricles. The ventricle must therefore be paced at a faster rate than that of the tachycardia. The efficacy of this type of therapy has been demonstrated for a wide range of ventricular tachycardia rates up to 250 beats/minute. Antitachycardia pacing reduces nearly 90% of ventricular tachycardias with a rate <200 beats/minute with a moderate risk of acceleration of 1 to 5%. These observations have repositioned the implantable “ICD” as a first-line treatment of arrhythmias by rapid pacing with the possibility of defibrillation only as “backup”.
