{Reference Type}: Journal Article
{Title}: A manual synchronous low energy shock impedance as a predictor of successful defibrillation testing during subcutaneous ICD implantation.
{Author}: Calvo N;López-Perales CR;Olóriz T;Díaz-Cortegana F;Jáuregui B;Soto N;Rodríguez P;Santamaría E;Ortas MR;Asso A;
{Journal}: Pacing Clin Electrophysiol
{Volume}: 0
{Issue}: 0
{Year}: 2024 Aug 5
{Factor}: 1.912
{DOI}: 10.1111/pace.15055
{Abstract}: <B>BACKGROUND: </B>Guidelines recommend defibrillation testing (DFT) during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Implant position, patient characteristics and device factors, such as shock impedance, influence defibrillation success. To evaluate the shock impedance, a manual synchronous 10J shock (low energy synchronous shock [LESS]) can be delivered, without the need to induce ventricular fibrillation (VF).<BR><B>OBJECTIVE: </B>To compare LESS and DFT impedance values and to evaluate the diagnostic accuracy of LESS impedance for predicting a successful DFT during S-ICD implantation.<BR><B>METHODS: </B>Consecutive S-ICD implantations were included. Shock impedances were compared by paired t-tests. Univariate analysis was performed to investigate factors associated with successful DFT. A prediction model of successful DFT based on LESS impedance was assessed by logistic regression. Receiver operating characteristic (ROC) curve, area under the ROC curve and the Hosmer-Lemeshow tests were used to evaluate the accuracy of LESS impedance.<BR><B>RESULTS: </B>Sixty patients were included (52 ± 14 years; 69% male). LESS and DFT impedance values were highly correlated (r2 = 0.97, p < .01). Patients with a failed first shock had higher body mass index (BMI) (30 ± 3 vs. 25.7 ± 4.3, p = .014), higher mean LESS (120 ± 35Ω vs. 86. ± 23Ω, p = .0013) and DFT impedance (122 ± 33Ω vs. 87 ± 24Ω, p = .0013). ROC analysis showed that LESS impedance had a good diagnostic performance in predicting a successful conversion test (AUC 84% [95% CI: 0.72-0.92]) with a cutoff value of <94Ω to identify a successful DFT (sensitivity 71%, specificity 73%).<BR><B>CONCLUSIONS: </B>LESS impedance values without the need to induce VF can intraoperatively predict a successful DFT.