Fullscreen Mode

The transmission includes an episode showing a ventricular tachycardia at around 210 beats per minute. The sensing of ventricular events is correct and there are no signs of noise artifacts. After a few cycles in the VF zone, the VT stabilizes in the VT zone with correct classification (VTLC marker). However, it takes over ten seconds for the VT to be treated, owing to the persistence counter being programmed at 50 cycles, instead of the 20 or 30 cycles which are recommended. The following ATP terminates the VT with success.

Next steps

Treated ventricular arrhythmias often need clinical action. After making sure the ICD and lead function properly, the clinical history of the patient should be collected to be able to understand why programming is different to the recommendations. In this case, it is because this young patient (50 years of age) implanted due to dilated cardiomyopathy is known to have asymptomatic nonsustained VTs, even at high rates. It was previously decided to program longer persistance counters, in order to allow for the VT to self-terminate, and diminish the risk of deleterious ATPs (bursts or ramps which accelerate the VT into faster VT or VF). It is however recommended to call the patient to enquire whether the episode was symptomatic (especially if loss of consciousness occurred) which may require reprogramming the ICD.

The persistance counter is a trade off between wanting to treat ventricular arrhythmia before it causes symptoms or accelerates into a more dangerous arrhythmia and wanting to decrease unnecessary treatment. It is important to note that the fact that the ATP/shock is successful does not mean that is was needed as many ventricular arrhythmia self-terminates, This is a limitation of many (older) ICD studies. The ideal persistance is probably not to be defined for all patients but rather on a patient level, based on symptoms during arrhythmia and the occurrence of nonsustained VTs.