What is it about?

A young female patient- suffering from multifocal ectopic Purkinje related premature contraction syndrome (MEPPC)- had an inappropriate shock after an improper SMARTPass filter (SP) deactivation of her subcutaneous ICD. Interrogation demonstrated a shock during sinus tachycardia, resulting most likely from the SP that was unexpectedly found deactivated.Post-shock chest x-rays evidenced no generator's or electrodes' displacement. During isometric exercises, myopotentials with subsequent oversensing were revealed in the selected secondary vector. What was the mechanism of the shock and why the SP was deactivated?

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Why is it important?

This case suggests that the operators should not solely rely on the initial automatic vector set-up performed post implant. A manual set-up along with isometric tests should be carried out in order to confirm that there is no myopotential oversensing at the automatically preselected vector.


It is important to add experience from the use of new technologies that overall contribute to the optimization of treatment.

University Hospital of Patras

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This page is a summary of: A potentially avertable cause of inappropriate shock in a patient with subcutaneous implantable cardioverter defibrillator, Pacing and Clinical Electrophysiology, June 2022, Wiley, DOI: 10.1111/pace.14533.
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