Fifty-eight year old man presenting an ischemic cardiomyopathy (previous anterior myocardial infarction) and implanted with a dual chamber ICD EnTrust DR secondary to an episode of sustained ventricular tachycardia.
In the present case, the diagnosis of VT is easily made when analyzing the tracing (AV dissociation). However, the diagnostic process ran by the ICD erroneously led to the opposite diagnostic. In fact, the PR logic would have probably classified correctly this tachycardia as a VT. But the sudden onset that comes first in the hierarchic order of algorithms is fooled by the relatively slow rate of the tachycardia (that just border the inferior limit of the VT zone) and suggests that the tachycardia origin is supraventricular. In this case, the best option is to turn off the sudden onset and favor the PR logic algorithm.
Two detection zones are programmed; the three steps of the discrimination process are activated (sudden onset, stability, PR Logic); this episode is diagnosed as a SVT and the therapy is withhold because the onset of the tachycardia was considered gradual by the ICD.
