The Subcutaneous Implantable Cardioverter-Defi brillator:A Practical Review and Real-World Use and Application

The subcutaneous implantable cardioverter-defi brillator(ICD)is a novel technology using a subcutaneous(extrathoracic)system for treatment of potential lethal ventricular arrhythmias.It avoids many of the risks of transvenous ICD implantation.It may be considered in patients having an ICD indication who do not have a pacing and/or cardiac resynchronization therapy indication,and who are unlikely to benefi t from antitachycardia pacing therapy.We review patient selection,system components,the implantation technique,and screening considerations for subcutaneous ICD implantation.Its uses in specific patient populations,including children,patients with congenital heart disease,hypertrophic cardiomyopathy,or end-stage renal disease,and patients with preexisting pacemakers,are highlighted.Areas of future investigation are reviewed,including potential use with leadless pacing and magnetic resonance imaging.

Better Than You Think—Appropriate Use of Implantable Cardioverter-Defi brillators at a Single Academic Center:A Retrospective Review

Background:Implantable cardioverter-defi brillators(ICDs)can be life-saving devices,although they are expensive and may cause complications.In 2013,several professional societies published joint appropriate use criteria(AUC)assessing indications for ICD implantation.Data evaluating the clinical application of AUC are limited.Previous registry-based studies estimated that 22.5%of primary prevention ICD implantations were“non-evidence-based”implantations.On the basis of AUC,we aimed to determine the prevalence of“rarely appropriate”ICD implantation at our institution for comparison with previous estimates.Methods:We reviewed 286 patients who underwent ICD implantation between 2013 and 2016.Appropriateness of each ICD implantation was assessed by independent review and rated on the basis of AUC.Results:Of 286 ICD implantations,two independent reviewers found that 89.5%and 89.2%,respectively,were appropriate,5.6%and 7.3%may be appropriate,and 1.8%and 2.1%were rarely appropriate.No AUC indication was found for 3.5%and 3.4%of ICD implantations,respectively.Secondary prevention ICD implantations were more likely rarely appropriate(2.6%vs.1.2%and 3.6%vs.1.1%)or unrated(6.0%vs.1.2%and 2.7%vs.0.6%).The reviewers found 3.5%and 3.4%of ICD implantations,respectively,were non-evidence-based implantations.The difference in rates between reviewers was not statistically signifi cant.Conclusion:Compared with prior reports,our prevalence of rarely appropriate ICD implantation was very low.The high appropriate use rate could be explained by the fact that AUC are based on current clinical practice.The AUC could benefi t from additional secondary prevention indications.Most importantly,clinical judgement and individualized care should determine which patients receive ICDs irrespective of guidelines or criteria.

Implantation of an S-ICD in a Patient with a DDD Pacemaker and Congenitally Corrected Transposition of the Great Arteries

Subcutaneous implantable cardioverter-defi brillator(S-ICD)therapy has become a viable alternative to conventional transvenous ICD implantation.Patients with congenitally corrected transposition of the great arteries(ccTGA)have a high risk of sudden cardiac death due to malignant arrhythmia.The interaction between the S-ICD system and the transvenous pacemaker system is not fully understood.We report a case of S-ICD implantation in a patient with ccTGA and a DDD pacemaker.The patient was a 30-year-old man with a previously placed pacemaker with diagnoses of congenital heart disease,ccTGA(SLL),left atrioventricular valve insuffi ciency,and third-degree atrioventricular block.He presented with an out-of-hospital cardiac arrest,and an S-ICD was implanted to prevent sudden cardiac death.Defi brillation checks were performed successfully.We tested the compatibility of the DDD pacemaker with the S-ICD and found that there was no interference between them.In conclusion,an S-ICD system is a reasonable and safe option in patients with ccTGA.