A 59-year-old man suffering from severe dilated cardiomyopathy with a LVEF <30%, recipient of an EnTrust VR single chamber ICD for primary prevention, is seen for pre-syncope and palpitations. (Same as in tracing 22.)
A major goal, when programming ICD, is to lower the likelihood of shock delivery without compromising the patient’s safety. As mentioned earlier, a large proportion of tachyarrhythmias detected in the VF zone are organized, monomorphic and can be terminated by ATP. Its programming during charge of the capacitors does not delay the delivery of shocks, if needed. The detection of VF triggers simultaneously ATP and the charge of the capacitors. If ATP terminates the tachycardia, all other therapies are withheld, preserving the patient’s quality of life. On the other hand, the charge of the capacitors drains a fair amount of energy, which can be problematic, if frequent. A maximal charge of the capacitor corresponds typically to 15 to 30 days of battery life. In the last generation of ICD, the shock can be diverted during the charge, sparing the battery.
A single zone of detection (VF) and therapy was programmed. Instead of a “shock box” configuration of the ICD, with shocks as the only therapy, a brief burst of ATP was programmed during charge of the capacitors, which terminated the arrhythmia and aborted the delivery of shocks.
