Non-invasive Management of High Defibrillation Threshold in Patient with Implantable Cardioverter-Defibrillator

We report a case of 81 year-old man with implantable cardioverterdefibrillator (ICD) admitted to our institution after repetitive DC-shocks of the device. The patient was followed by our Heart Failure Center because he had non-ischemic dilated cardiomyopathy (ejection fraction of the left ventricle was 30%, end diastolic volume was 176 ml). 13 months before, he was admitted to the Cardiology Department because he developed a complete atrioventricular block and he received in primary prevention a dual chamber ICD system (Medtronic Protecta DR; dual coil lead 6944 Sprint 4 Medtronic for right ventricle and 5076 Capsure fix Medtronic for the atrium). Defibrillation threshold (DFT) was tested at the implant session and the ICD successfully terminated induced ventricular fibrillation with a 21-Joules shock in 2 consecutive tests. The vector configuration of shock was distal coil (RV) as cathode vs. device can and proximal coil (SVC) as anode.