Seventy-four year old man with an ischemic cardiomyopathy implanted in primary prevention with a dual chamber ICD Virtuoso DR.
In this case as for the previous one, the diagnosis of VT is obvious (AV dissociation). Again an analysis using the PR Logic algorithm would have made the correct diagnosis. Unfortunately, by programming the stability criterion « ON », the PR Logic doesn’t participate to the diagnostic process. This patient presents with irregular VT that fools the stability criterion and resets the VT counter. In this case, the best corrective measure is to turn off the stability to favor the PR logic algorithm. However, it is interesting to note that the present episode finally stopped by itself. Despite the inappropriate diagnosis, the stability criterion finally withheld a therapy that would have been given otherwise for nothing. A possible therapeutic option would be to increase the number of interval to detect (NID) to favor spontaneous conversion of the tachycardia to sinus rhythm.
Three detection zones are programmed. The 3 discriminators available are activated (sudden onset, stability, PR Logic); during this episode the stability criteria is not met (suggested diagnosis: SVT). Therefore, the therapy is not delivered.
