Inappropriate defibrillator shock due to EMI despite noise reversion and SecureSense - What is the mechanism?

Implantable cardioverter defibrillator (ICD) shocks are always a matter of anxiety and concern for both patient and clinician. We report a case of ischemic cardiomyopathy who reported to us after receiving two shocks within 48 hours. The therapy was inappropriate as noted from device logs. EMI was identified as the incriminating cause. We discuss the reasons why he received the therapy despite active 'Noise reversion' and 'SecureSense' algorithms to avoid noise /EMI related oversensing.