Near-fatal ventricular arrhythmia related to V undersensing


This 81 old patient was implanted years ago for bradycardia associated with permanent AF. He was hospitalized for acute left-sided abdominal pain. Two days after, during the ultrasound examination, he had a cardiac arrest which was treated by 10 min CPR and 2 external shocks. The final diagnosis for the abdominal pain was splenic infarction (subtherapeutic anticoagulation).

The device interrogation revealed a ventricular undersensing resulting in a VF induction by asynchronous pacing. The same day the device had measured a sudden drop in both intrinsic amplitude and impedance associated with a sudden increase in pacing threshold.

No electrolyte perturbation was present and a coronarography excluded any coronary artery stenosis. A new lead was inserted and the patient went home with a new PM.

Asynchronous pacing is a classical although rarely documented cause of life threathening arrhythmia.

S Ploux

Physician advice: 

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Nicolas Clementy's picture

Beautiful tracings.

ICDs may kill...

Impressive EGM!

Lucky patiënt to have VF while he was in the hospital!

The graphs show that R-wave amplitude was already low a few days before the event, is there a pacemaker alert for this problem in Boston Scientific devices?

Sylvain Ploux's picture

Thanks guys for the comments.

@Nicolas: this was a PM...not an ICD.

@Marc: The patients was not under Latitude at that time. Yes there is a specific alert for right ventricular intrinsic amplitude out of range.