ICD Shock therapy – What is the cause?
Highly Specialised Cardiac Physiologist, Mid and South Essex NHS Foundation Trust
Disclosure: The author has no conflict of interests to declare.
A remote alert was received from a 65-year-old male with a primary prevention dual chamber ICD for ‘shock delivered for an episode’. Previous medical history included an ischemic cardiomyopathy and paroxysmal atrial fibrillation. Figure 1 displays the electrogram (EGM) at the time of the episode. There was a single VF therapy zone programmed with a rate cut of at 200 bpm with 30/40 intervals to detection
Figure 1: The recorded EGM at the time of the ICD shock therapy. Channels top to bottom: near-field atrial EGM, near-field ventricular EGM, marker channel