Effectiveness of implantation of a subcutaneous implantable cardioverter-defibrillator in a patient with complete heart block and a pacemaker

Severe Tricuspid Regurgitation in a Patient with a Transvenous Dual-chamber Pacemaker: Considerations for Diagnosis and Management

Cardiac implantable electronic device leads can contribute to tricuspid regurgitation and also complicate surgical and transcatheter interventions to manage tricuspid regurgitation. Here we present a case of a patient with sinus node dysfunction and complete heart block who underwent extraction of a right ventricular pacing lead before tricuspid valve surgery. We review the data regarding the contribution of leads to tricuspid regurgitation and the benefits of lead extraction, risks of jailing leads during tricuspid interventions, and pacing considerations around tricuspid valve procedures.

Inappropriate shock incidence in patients with subcutaneous implantable cardioverter-defibrillators with concomitant cardiac implantable electronic devices: A single-center cohort study

BACKGROUND

Subcutaneous implantable cardioverter defibrillators (S-ICDs) are occasionally used in combination with other cardiac implantable electronic devices (CIEDs). However, whether the incidence of inappropriate shock increases in patients with S-ICDs and concomitant CIEDs remains unclear. This study aimed to investigate the association between the concomitant use of CIEDs and the incidence of inappropriate shock in patients with current-generation S-ICDs.

METHODS

A total of 127 consecutive patients received an S-ICD. Patients were assigned to two groups depending on concomitant use of CIEDs at the time of S-ICD implantation: patients without other CIEDs (non-combined group, 106 patients) and patients with other CIEDs (combined group, 21 patients). CIEDs included pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy pacemakers, and cardiac resynchronization therapy defibrillators. The primary outcome was inappropriate shock, defined as a shock other than ventricular arrhythmia. Hazard ratios and 95% confidence intervals were calculated using a time-varying Cox proportional hazards model which was adjusted for age because age differed between the groups and could be a confounder.

RESULTS

During a median follow-up period of 2.2 years (interquartile range, 1.0-3.4 years), inappropriate shock events occurred in 17 (16%) and five (19%) patients of the non-combined and combined groups, respectively. While the age-adjusted hazard ratio for inappropriate shock was 24% higher in the combined than in the non-combined group (hazard ratio = 1.24, 95% confidence interval, 0.39-3.97), this difference was insignificant (p = .71).

CONCLUSION

The incidence of inappropriate shock did not differ between patients with and without concomitant use of CIEDs, suggesting that S-ICDs could potentially be combined with other CIEDs without increasing the number of inappropriate shocks. Further studies are warranted to confirm the safety and feasibility of concomitant use of S-ICDs and CIEDs.

Simultaneous subcutaneous implantable cardioverter-defibrillator and leadless pacemaker implantation for patients at high risk of infection: a retrospective case series report

BACKGROUND

The subcutaneous implantable cardioverter defibrillator (S-ICD) and leadless pacemaker (LP) are alternative options for patients at high risk of infection requiring ICD and pacing therapy. In this analysis, we described the simultaneous implantation of S-ICD and LP in patients with high infectious risk.

METHODS

The study cohort comprised patients referred to our institution for ICD implantation due to high-risk factors of infection.

RESULTS

Between 2018 and 2022, 13 patients were referred, including 11 with infected ICD and 2 for first ICD implantation in the presence of high-risk factors. In cases of infected ICD, successful extraction was performed using a mechanical dilatation technique. Reimplantation was delayed until resolution of infection with antibiotic therapy. The devices were implanted during a single procedure, with S-ICD implantation following LP placement for verification of sensing adequacy through surface ECG screening. Suitable vectors for sensing during inhibited and ventricular pacing were identified in all patients. Defibrillation testing was effective, and no issues with double counting or undersensing were observed. The postoperative period was uneventful, and during a median follow-up of 35 months, no complications or infections were reported. The median ventricular pacing percentage was 5%, and a single inappropriate shock episode due to myopotential interference was reported and resolved by reprogramming the sensing vector.

CONCLUSION

Simultaneous implantation of S-ICD and LP is feasible and safe in patients at high risk of infection requiring both ICD and pacing therapy. This combined approach provides an effective solution for these patients.

Combined subcutaneous implantable cardioverter defibrillator and pacemaker devices in complex congenital heart disease: a single-center experienced based study

BACKGROUND

Subcutaneous implantable cardioverter defibrillators (S-ICD) are widely accepted therapy in congenital heart disease (CHD) patients at risk of life-threatening ventricular arrhythmias or sudden cardiac death (SCD) when pacing is not required. Occasionally, pacemaker (PM)-dependent CHD patients will subsequently develop an indication for a cardioverter defibrillator. The use of S-ICD in complex CHD patients who have had already PM devices implanted implies some specific considerations, as the safety for these patients in unknown and recommendations among physicians may vary widely.

METHODS

We review the data and studied the indications for S-ICD in complex CHD with previous PM and discuss its usefulness in clinical practice.

RESULTS

From a large cohort of 345 patients enrolled in the S-ICD Monaldi care registry, which encompass all the patients implanted in the Monaldi Hospital of Naples, we considered 11 consecutive complex CHD patients (10M/1F aged 40.4 ±18.4 years) who underwent S-ICD implant after a previous PM implant, from February 2015 to October 2022. Mean follow-up was 25.5 ± 22 months. All the patients showed a good compliance to the device system with no complications (infections or skin erosions).

CONCLUSIONS

In complex CHD with already implanted PM devices, S-ICD implant appears to be a safe alternative to PM upgrading to transvenous ICD system, avoiding abandoned leads or life-threatening lead extraction. However, there are important issues with regard to testing and programming that need to be addressed at the time of implantation.

The Role of Subcutaneous ICDs in the Prevention of Sudden Cardiac Death

The ICD is an important therapy in the prevention of sudden cardiac death. The transvenous-ICD (TV-ICD) has been the primary device used for this purpose. However, mechanical and infectious complications occur with traditional TV-ICDs increasing morbidity and mortality. The subcutaneous-ICD (S-ICD) system was developed to circumvent some of these complications, but S-ICDs have their inherent set of limitations as well. These include inappropriate shock delivery, lack of bradycardia, antitachycardia or CRT pacing therapy and shorter device longevity. The S-ICD is now included in guidelines as an acceptable alternative to TV-ICDs among patients without pacing indications. This review discusses the rationale for S-ICDs by reviewing studies including the PRAETORIAN, PAS and UNTOUCHED trials.

Adverse device-device interaction between pacemaker and subcutaneous implantable cardiac defibrillator

A 26-year-old patient with prior surgery for Ebstein's anomaly and a pacemaker (placed for post-surgical heart block and poor underlying rhythm) underwent SICD was placement. During defibrillation testing, device-device interaction led to undersensing of ventricular fibrillation with failure to shock. Increasing the pacemaker sensitivity resolved the problem but post shock pacing was unable to capture the heart after both shocks. The patient underwent removal of both the pacemaker and the SICD and placement of a transvenous ICD. Complex device-device interactions can occur in patients who are pacemaker dependent and undergo placement of a SICD.

His bundle pacing for newly acquired pacing needs in patients implanted with a subcutaneous implantable cardioverter defibrillator: A feasibility study based on the automated screening score and clinical cases

INTRODUCTION

Management of subcutaneous implantable cardioverter defibrillator (S-ICD) patients with newly acquired pacing needs remains problematic. His bundle pacing (HBP) allows for cardiac pacing without significant changes in the QRS morphology. We hypothesized that HBP does not alter S-ICD sensing and functions.

METHODS

Twenty consecutive patients were implanted with a HB pacemaker. Among them, 17 demonstrated successful His recruitment and were prospectively screened with the automated screening tool (AST). Results of screenings performed immediately after implant and during follow-up, during intrinsic rhythm and while pacing from all available pacing configurations, were compared using the AST score. Positive-screening tests were defined by greater than or equal to 1 positive vector.

RESULTS

Among the 17 patients successfully implanted (male: 41%; mean age: 73), 13 presented an indication of ventricular pacing and four of cardiac resynchronization. Absolute AST scores during both HBP (all configurations) and intrinsic rhythm were similar (p: NS). Due to left bundle branch block correction, HBP resulted in higher number of positive vectors (AST ≥ 100). AST scores were higher during HBP when compared with right ventricular pacing (RVP) (primary vector: 272 [16; 648] vs 4.6 [0.8; 16.2]; P = .003; secondary vector: 569 [183; 1186] vs 1.5 [0.7; 8.3]; P < .0001; alternate vector: 44 [2;125] vs 4.8 [0.9; 9.3]; P = .02) and resulted in a much higher number of positive vectors. Up to 90% of the patients had a positive-screening test during HBP. This passing rate was higher when compared RVP (17%; P < .0001).

CONCLUSION

HBP restores normal intrinsic conduction and minimally modifies the surface electrocardiograph and subcutaneous electrograms. When ventricular pacing is needed, HBP might represent an ideal pacing option for patients implanted with a S-ICD.

Pilsicainide Administration Unmasks a Phenotype of Brugada Syndrome in a Patient with Overlap Syndrome due to the E1784K SCN5A Mutation

Mutations in the cardiac sodium channel SCN5A can cause phenotypic overlap syndrome of long QT syndrome and Brugada syndrome. However, Brugada-type ST elevations in patients with overlap syndrome are often concealed, which creates a diagnostic challenge. A 38-year-old man was admitted due to ventricular fibrillation (VF). The 12-lead electrocardiogram showed a prolonged QT interval and saddleback-type ST elevation. Pilsicainide administration induced coved-type ST elevation and VF triggered by a single premature ventricular contraction. A genetic analysis showed an SCN5A c.5350G>A p.E1784K mutation. The present case suggests the importance of a drug administration test being performed in the clinical management of overlap syndrome.

Subcutaneous Implantable Cardioverter Defibrillators: An Overview of Implantation Techniques and Clinical Outcomes

Sudden Cardiac Death (SCD) is a significant health problem worldwide. Multiple randomized controlled trials have shown that Implantable Cardioverter Defibrillators (ICDs) are effective life-saving management option for individuals at risk of SCD in both primary and secondary prevention. Although the conventional transvenous ICDs (TV-ICDs) are safe and effective, there are potential complications associated with its use, including localized pocket or wound infection or systematic infection, a vascular access related complication such as pneumothorax, and venous thrombosis, and lead related complications such as dislodgement, malfunction, and perforation. Furthermore, transvenous leads placement may not be feasible in certain patients like those with venous anomaly or occlusion, or with the presence of intracardiac shunts. Transvenous leads extraction, when needed, is associated with considerable morbidity & mortality and requires significant skills and costs. Totally subcutaneous ICD (S-ICD) is designed to afford the same life-saving benefit of the conventional TV-ICDs while avoiding the shortcomings of the TV-leads and to simplify the implant techniques and hence expand the use of ICDs in clinical practice. It becomes commercially available after receiving CE mark in 2009, and its use increased significantly after its FDA approval in 2012. This review aims to give an overview of the S-ICD system components, implantation procedure, clinical indications, safety, efficacy, and future directions.

Candidacy for a Subcutaneous Implantable Cardioverter Defibrillator in Patients with Cardiac Resynchronization Therapy

In patients requiring an implantable cardioverter defibrillator (ICD), the combined use of a prior pacemaker and a subcutaneous ICD (S-ICD) could be an alternative treatment option to implantation of new leads or upgrading of pacemakers to an ICD if vascular access is limited. Here, we assessed the prevalence of S-ICD's eligibility according to surface electrogram screening in those receiving cardiac resynchronization therapy (CRT). S-ICD's eligibility was assessed in patients with a CRT pacemaker or a CRT defibrillator using the S-ICD template screening tool. Eligibility was defined as fulfillment of the template in both supine and upright positions in one or more leads during biventricular pacing. Among 44 patients (34 men, age: 67 ± 12), 36 (82%) were found to be eligible. The T/QRS amplitude ratio in lead II was significantly lower in those who were eligible (0.31 ± 0.16 versus 0.44 ± 0.18 in the ineligible group, P = 0.04). The lead position, underlying disease, and other electrocardiographic findings were not different between those who were eligible and those who were not. The majority of patients with biventricular pacing were eligible for S-ICD based on current screening tests and may benefit from this treatment. Further study is required.

Eligibility of Pacemaker Patients for Subcutaneous Implantable Cardioverter Defibrillators

INTRODUCTION

The subcutaneous implantable cardioverter defibrillator (ICD) has emerged as a viable therapeutic option for patients who are deemed high risk for sudden cardiac death. Previous studies have shown that 7-15% of patients are not candidates for the S-ICD based on their intrinsic QRS/T-wave morphology. Presently, it is not known if the S-ICD can be considered as supplementary therapy in patients who are ventricularly paced. We sought to determine the proportion of ventricularly paced patients who would qualify for an S-ICD.

METHODS AND RESULTS

We evaluated 100 patients with transvenous pacemakers/ICDs, including 25 biventricular devices to determine S-ICD candidacy during right ventricular (RV) pacing and biventricular pacing based on the recommended QRS:T-wave ratio screening template. Fifty-eight percent of patients qualified for an S-ICD based on their QRS morphology during ventricular pacing. More patients during biventricular pacing met criteria compared to during RV pacing alone (80% vs. 46%, P <0.01). Patients that were paced from the RV septum were more likely to qualify compared to those paced from the RV apex (67% vs. 37%, respectively, P <0.01).

CONCLUSION

While S-ICD implantation may be considered as supplemental therapy in select patients with preexisting transvenous devices, relatively fewer candidates who are paced from the RV apex qualify. QRS morphologies generated from biventricular pacing as well as from septal RV pacing are more likely to screen in based on the recommended S-ICD template.