Jean-Benoit le Polain de Waroux1, Sylvain Ploux2, Pierre Mondoly3, Romain Eschalier4, Marc Strik5, Laura Houard6, Bertrand Pierre7, Samuel Buliard2, Nicolas Klotz2, Philippe Ritter2, Michel Haissaguerre2, Karim Mahfouz2, Pierre Bordachar2. 1. Department of Cardiovascular Disease, Cliniques Universitaires Saint-Luc, Bruxelles, Belgium. Electronic address: JBLPDW@hotmail.com. 2. Hospital Haut-Leveque, IHU LIRYC, Pessac, France. 3. Cardiovascular and Metabolic Department, Rangueil Hospital, Toulouse, France. 4. Department of Cardiology, Clermont-Ferrand University Hospital, Clermont-Ferrand, France. 5. Department of Cardiology, University of Maastricht, Maastricht, The Netherlands. 6. Department of Cardiovascular Disease, Cliniques Universitaires Saint-Luc, Bruxelles, Belgium. 7. Department of Cardiology, Hospital Trousseau, Tours, France.
Abstract
BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) remains a new technology requiring accurate assessment of the various aspects of its functioning. Isolated cases of delayed sensing of ventricular arrhythmia have been described. OBJECTIVE: The purpose of this multicenter study was to assess the quality of sensing during induced ventricular fibrillation (VF). METHODS: One hundred thirty-seven patients underwent induction of VF at the end of the S-ICD implantation. RESULTS: VF induction was successful in 133 patients (97%). Mean time to first therapy was 16.2 ± 3.1 seconds, with a substantial range from 12.5 to 27.0 seconds. Four different detection profiles were arbitrarily defined: (1) optimal detection (n = 39 [29%]); (2) undersensing with moderate prolongation of time to therapy (<18 seconds; n = 68 [51%]); (3) undersensing with significant prolongation of the time to therapy (>18 seconds; n = 19 [14%]); and (4) absence of therapy or prolonged time to therapy related to noise oversensing (n = 7 [6%]). In some of the patients in the last group, despite induction of VF the initial counter was never filled, the device did not charge the capacitors, and the shock was not delivered because of a sustained diagnosis of noise (n = 5). A manual shock by the device or an external shock had to be delivered to restore the sinus rhythm. CONCLUSION: Our study demonstrated a marked sensing delay leading to prolonged time to therapy in a large number of S-ICD patients. A few worrisome cases of noise oversensing inhibiting the therapies were detected. These results support the need for systematic intraoperative defibrillation testing.
BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) remains a new technology requiring accurate assessment of the various aspects of its functioning. Isolated cases of delayed sensing of ventricular arrhythmia have been described. OBJECTIVE: The purpose of this multicenter study was to assess the quality of sensing during induced ventricular fibrillation (VF). METHODS: One hundred thirty-seven patients underwent induction of VF at the end of the S-ICD implantation. RESULTS: VF induction was successful in 133 patients (97%). Mean time to first therapy was 16.2 ± 3.1 seconds, with a substantial range from 12.5 to 27.0 seconds. Four different detection profiles were arbitrarily defined: (1) optimal detection (n = 39 [29%]); (2) undersensing with moderate prolongation of time to therapy (<18 seconds; n = 68 [51%]); (3) undersensing with significant prolongation of the time to therapy (>18 seconds; n = 19 [14%]); and (4) absence of therapy or prolonged time to therapy related to noise oversensing (n = 7 [6%]). In some of the patients in the last group, despite induction of VF the initial counter was never filled, the device did not charge the capacitors, and the shock was not delivered because of a sustained diagnosis of noise (n = 5). A manual shock by the device or an external shock had to be delivered to restore the sinus rhythm. CONCLUSION: Our study demonstrated a marked sensing delay leading to prolonged time to therapy in a large number of S-ICDpatients. A few worrisome cases of noise oversensing inhibiting the therapies were detected. These results support the need for systematic intraoperative defibrillation testing.