Predictors of appropriate shock after generator replacement in patients with an implantable cardioverter defibrillator

Abstract

Background Implantable cardioverter defibrillators (ICDs) are indicated for the primary prevention of sudden cardiac death in patients with reduced left ventricular ejection fraction (LVEF). The ongoing risk/benefit profile of an ICD at generator replacement is unknown. This study aimed to identify predictors of appropriate ICD shocks and therapies after first ICD generator replacement, and its procedure‐related complications. Methods We conducted a multicenter, retrospective cohort study including patients with primary prevention ICDs who underwent generator replacement between April 2005 and July 2015 at three Canadian centers. The primary and secondary outcomes were appropriate ICD shock and any appropriate ICD therapy, respectively. Procedure‐related complication rates were also reported. Results Of the 219 patients in the cohort, 61 (28%) experienced an appropriate shock while 40 (18%) experienced appropriate antitachycardia pacing over a median follow up of 2.2 years. Independent predictors of appropriate ICD shocks included: LVEF at time of replacement (adjusted odds ratio [OR] 0.4 per 10% increase in LVEF, P < .001), a history of appropriate ICD shocks prior to replacement (OR 4.9, P < .001), and a history of inappropriate ICD shocks (OR 4.2, 95%, P < .002). Similar predictors were identified for the secondary outcome of any appropriate ICD therapy. Device‐related complications were reported in 25 (11%) patients, with 1 (0.5%) resulting in death, 14 (6.3%) requiring site re‐operation, and 6 (2.7%) requiring cardiac surgical management. Conclusion Not all primary prevention ICD patients undergoing generator replacement will require appropriate device therapies afterwards. Generator replacement is associated with several risks that should be weighed against its anticipated benefit. A comprehensive assessment of the risk‐benefit profile of patients undergoing generator replacement is warranted.

Incidence and Predictors of Implantable Cardioverter-defibrillator Therapies After Generator Replacement—A Pooled Analysis of 31,640 Patients’ Data

“…A total of 31,640 patients from 20 studies (14 retrospective and 6 prospective registries) were included in our meta-analysis (Figure 1) with a mean ± standard deviation age of 65.6 ± 4.7 years (mean age range, 57-76 years) and follow-up period of 3.1 ± 1.5 years. 2,6,10,11,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] The critical appraisal performed using the Newcastle-Ottawa scale revealed that the quality of studies was good (Table S1).…”

“…Our meta-analysis revealed that ICD shocks in the first life of the generator predict overall ICD therapies following GR, which resonated with the findings from Arcinas et al's study. 11 In our meta-analysis, patients with appropriate shocks were associated with the use of β-blockers probably because β-blockers are more likely to be used in patients with previous shocks or those at high risk for shock and primary prevention patients with HF with reduced ejection fraction. The Optimal Pharmacological Therapy in Cardioverter-defibrillator Patients (OPTIC) trial evaluated the effect of amiodarone, β-blockers, sotalol, and the combination of amiodarone and β-blockers on ICD shocks and showed that shocks were lower in the combination amiodarone-β-blocker and sotalol arms than in the β-blockers arm.…”

“…Our meta-analysis revealed that ICD shocks in the first life of the generator predict overall ICD therapies following GR, which resonated with the findings from Arcinas et al’s study. 11 …”

“…However, only Arcinas et al reported 1.4% lead infections in their ICD cohorts. 11 It is also known from the Multicenter Electrophysiologic Device Infection Cohort (MEDIC) trial that the infection risk for ICD replacement increases exponentially with each pocket re-entry. 40 In our meta-analysis, inappropriate shocks were found to be more common in CKD patients, which reflected the finding by Bansal et al, which showed that patients with CKD have a higher probability of having inappropriate shocks, probably owing to a higher incidence of hyperkalemia and AF in this population.…”

“…8 Complication rates after ICD GR range from 5%-10% and tend to be higher in concert with lead upgrades, multiple replacements, and patient frailty. [9][10][11] Of note, experiencing a major complication during ICD implantation is associated with a significantly higher risk of mortality for up to 6 months after the procedure. 12 Moreover, although ICDs reduce arrhythmic death, 25% of patients die after their first ICD generator replacement without ever experiencing an appropriate ICD therapy, and improvement in EF has not been proven as a predictor of all-cause mortality, thus reiterating that ICDs may not reduce non-arrhythmic death.…”