Septal vs apical defibrillator electrode placement a systematic review

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background The optimal right ventricular defibrillator lead placement is still a debatable matter. We attempt to performed a systemic review to evaluate whether septal and apical placement had significant differences in the follow-up with an indication for implantation of these devices. Objective Review the evidence regarding the efficacy and safety of right ventricular apical and septal defibrillator lead placement. Methods A systemic research on MEDLINE and PUBMED with the term "septal pacing", "apical pacing" "septal defibrillation" or "apical defibrillation". 309 results were identified, however, after a serious analysis, several articles were excluded. Comparisons between apical and septal placement were performed regarding R wave amplitude, pacing threshold at 0.5 ms, lead impedance, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD) and lead complication that produced lead re-placement. Mean differences (MD) and confidence interval (CI) was used as a measurement of treatment. Results Six studies were selected, including a total of 2180 patients. The studies were performed with different techniques, analyses and goals. The studies presented heterogeneous and diverse results, with a varied follow-up period, that resulted in the exclusion of one of the studies. Mean age 64.51 years old, 76.86% male, a median ejection fraction of 27.84%, NYHA class of 2.65, ischemic etiologic in 51.10% and a follow-up period of 26.49 months. Septal defibrillator lead placement was established in 772 patients, while the apical defibrillator lead placement was performed in 1399 patients. No differences regarding the lead performance on apical and septal placement were detected regarding the R-wave (MD -0.36, CI -0.75 - +0.03, p = 0.68, I2 = 0%) (reported in 3 studies) and lead impedance (MD -23.83, CI -51.36 - +3.69, p = 0.003, I2 = 82%) (reported in 3 studies). Pacing threshold seems to be favor a septal defibrillator lead implantation (MD -0.05, CI -0.09 - -0.02, p = 0.12, I2 = 53%) (reported in 3 studies). Concerning echocardiography parameters during the follow up period, LVEF (MD -0.83, CI -3.05 - +1.38, p = 0.10, I2 = 57%) (reported in 3 studies) and LVEDD (MD -0.51, CI -2.13 - +1.10, p = 0.20, I2 = 38%) (reported in 3 studies) were not significant influenced for the defibrillator lead placement. Lead complications that provoke a lead replacement was not significant between the lead placement (MD 1.25, CI 0.53 – 2.94, p = 0.71, I2 = 0%) (reported in 3 studies). Conclusions Just pacing threshold proved to improve the septal defibrillator lead placement. Neither the other lead parameters or the echocardiography results during the follow-up were influenced by the lead placement. For a definitive conclusion is important to further investigation.