What is happening in this electrogram?
What type of device is this?
What rhythm is this? How is the rhythm terminated?
Is the device functioning appropriately?
What if any programming changes should be considered?
Answer:
The device is a dual chamber ICD. The EGM is a stored episode. There is a discrimination channel and morphology scoring. These are found in ICDs only.
The rhythm is monomorphic ventricular tachycardia at a rate of approximately 178bpm. The R waves are regular and are not associated with the P waves. This falls in the V>A rate branch. The VT was not terminated by the ICD. The artifact prior to termination is the result of successful external defibrillation.
To determine if the device is functioning appropriately, one would reference the high voltage parameters. In this case, the device is labeling the rhythm as VT in the monitor zone. Without viewing the HV settings, it can be concluded that this rate of VT is falling within the monitor zone only, therefore no therapies are delivered. For reference, this device was programmed with two zones: a monitor zone at 150bpm, and a VF zone of 222bpm. The patient presented to the ER with tightness in the chest and a fast heart rate. Upon interrogation, the patient had been in VT for over 7 hours prior to the external defibrillation.
Based on how the device was programmed, the device functioned appropriately.
Device reprogramming was discussed with the following EP. A VT2 zone was programmed in the 170-bpm range, and a monitor zone was left at 150bpm. The VF zone of 222bpm was unchanged.
