Implantable cardioverter-defibrillator lead failure and revision following transcutaneous bicaval valve (TricValve®) implantation

INTRODUCTION

Tricuspid regurgitation is associated with significant morbidity and mortality, and occurs at a higher rate in patients with cardiovascular implantable electronic devices. Percutaneous strategies for managing tricuspid regurgitation are evolving, including the development of bicaval valve implantation which has been successfully used in patients with pacing leads.

METHODS AND RESULTS

We present the first documented case of lead failure following TricValve® implantation, a dedicated self-expanding system for bicaval valve implantation, and the first successful lead revision procedure in this setting.

CONCLUSION

The case illustrates important considerations in undertaking percutaneous intervention in patients with cardiovascular implantable electronic devices, and their ongoing management.

Differences in underlying cardiac substrate among S-ICD recipients and its impact on long-term device-related outcomes: Real-world insights from the iSUSI registry

BACKGROUND

Outcome comparisons among subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with nonischemic cardiomyopathies are scarce.

OBJECTIVE

The aim of this study was to evaluate differences in device-related outcomes among S-ICD recipients with different structural substrates.

METHODS

Patients enrolled in the i-SUSI (International SUbcutaneouS Implantable cardioverter defibrillator registry) project were grouped according to the underlying substrate (ischemic vs nonischemic) and subgrouped into dilated cardiomyopathy, hypertrophic cardiomyopathy, Brugada syndrome (BrS), arrhythmogenic right ventricular cardiomyopathy (ARVC). The main outcome of our study was to compare the rates of appropriate and inappropriate shocks and device-related complications.

RESULTS

Among 1698 patients, the most common underlying substrate was ischemic (31.7%), followed by dilated cardiomyopathy (20.5%), BrS (10.8%), hypertrophic cardiomyopathy (8.5%), and ARVC (4.4%). S-ICD for primary prevention was more common in the nonischemic cohort (70.9% vs 65.4%; P = .037). Over a median (interquartile range) follow-up of 26.5 (12.6-42.8) months, no differences were observed in appropriate shocks between ischemic and nonischemic patients (4.8%/y vs 3.9%/y; log-rank, P = .282). ARVC (9.0%/y; hazard ratio [HR] 2.492; P = .001) and BrS (1.8%/y; HR 0.396; P = .008) constituted the groups with the highest and lowest rates of appropriate shocks, respectively. Device-related complications did not differ between groups (ischemic: 6.4%/y vs nonischemic: 6.1%/y; log-rank, P = .666), nor among underlying substrates (log-rank, P = .089). Nonischemic patients experienced higher rates of inappropriate shocks than did ischemic S-ICD recipients (4.4%/y vs 3.0%/y; log-rank, P = .043), with patients with ARVC (9.9%/y; P = .001) having the highest risk, even after controlling for confounders (adjusted HR 2.243; confidence interval 1.338-4.267; P = .002).

CONCLUSION

Most S-ICD recipients were primary prevention nonischemic cardiomyopathy patients. Among those, patients with ARVC tend to receive the most frequent appropriate and inappropriate shocks and patients with BrS the least frequent appropriate shocks.

Modified Haller Index is inversely associated with asymptomatic status in atrial fibrillation patients undergoing electrical cardioversion: a preliminary observation

BACKGROUND

No previous study evaluated the possible influence of chest wall conformation on symptoms perception in atrial fibrillation (AF) patients candidates for electrical cardioversion (ECV). We aimed at evaluating the anthropometric and clinical characteristics of patients with persistent AF undergoing ECV, categorized according to the presence or absence of symptoms.

METHODS

This study retrospectively analyzed a series of persistent AF patients scheduled for early ECV who underwent pre-procedural clinical evaluation, MHI (the ratio of chest transverse diameter over the distance between sternum and spine) assessment, transthoracic and transesophageal echocardiography implemented with strain analysis of both left atrium and left atrial appendage. Thromboembolic risk and burden of comorbidities were assessed by CHA2DS2-VASc Score and Charlson Comorbidity Index (CCI), respectively. The independent predictors of "asymptomatic AF" were assessed.

RESULTS

A total of 25 asymptomatic and 90 symptomatic AF patients were retrospectively examined. Compared to symptomatic AF patients, those asymptomatic were significantly older (78.4±3.8 vs. 71.0±7.7 years, P<0.001), predominantly males (84 vs. 44.4%, P<0.001), with significantly lower MHI (2.0±0.1 vs. 2.4±0.1, P<0.001), higher CHA2DS2-VASc Score (5.8±1.1 vs. 3.6±1.1, P<0.001) and CCI (6.8±1.4 vs. 2.3±0.9, P<0.001), and greater impairment in biventricular systolic function and atrio-auricolar myocardial strain indices. On multivariate logistic regression analysis, CHA2DS2-VASc Score (OR=2.65, 95% CI: 1.53-4.60) and CCI (OR=2.36, 95% CI: 1.16-4.66) were linearly associated with the endpoint "asymptomatic AF," whereas MHI (OR 0.76, 95% CI 0.59-0.97) was inversely associated with the asymptomatic status. A MHI <2.2 was the best cut-off for detecting asymptomatic AF patients.

CONCLUSIONS

MHI is inversely associated with asymptomatic status in persistent AF patients undergoing ECV. MHI assessment might represent an innovative practical approach to AF patients.

Left ventricular assist device in the presence of subcutaneous implantable cardioverter defibrillator: Data from a multicenter experience

BACKGROUND

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure (HF). Subcutaneous implantable cardioverter defibrillator (S-ICD) might be a viable alternative to conventional ICDs with a lower risk of short- and long-term of device-related complications and infections.The aim of this multicenter study was to evaluate the outcomes and management of S-ICD recipients who underwent LVAD implantation.

METHODS

The study population included patients with a preexisting S-ICD who underwent LVAD implantation for advanced HF despite optimal medical therapy.

RESULTS

The study population included 30 patients (25 male; median age 45 [38-52] years).The HeartMate III was the most common LVAD type. Median follow-up in the setting of concomitant use of S-ICDs and LVADs was 7 months (1-20).There were no reports of inability to interrogate S-ICD systems in this population. Electromagnetic interference (EMI) occurred in 21 (70%) patients. The primary sensing vector was the one most significantly involved in determining EMI. Twenty-seven patients (90%) remained eligible for S-ICD implantation with at least one optimal sensing vector. The remaining 3 patients (10%) were ineligible for S-ICD after attempts of reprogramming of sensing vectors. Six patients (20%) experienced inappropriate shocks (IS) due to EMI. Six patients (20%) experienced appropriate shocks. No S-ICD extraction because of need for antitachycardia pacing, ineffective therapy or infection was reported.

CONCLUSIONS

Concomitant use of LVAD and S-ICD is feasible in most patients. However, the potential risk of EMI oversensing, IS and undersensing in the post-operative period following LVAD implantation should be considered. Careful screening for EMI should be performed in all sensing vectors after LVAD implantation.

Prior history of atrial fibrillation and arrhythmic outcomes: Data from the WEARIT-II prospective registry

INTRODUCTION

Wearable cardioverter defibrillator (WCD) is utilized in patients with assumed but not yet confirmed risk for sudden cardiac death (SCD). Many of these patients also present with atrial fibrillation (AF). However, the rate of WCD-detected ventricular or atrial arrhythmia events in this specific high-risk cohort is not well understood.

METHODS

In WEARIT-II, the cumulative probability of any sustained or nonsustained VT/VF (WCD-treated and nontreated), and atrial/supraventricular arrhythmias during WCD use was assessed using the Kaplan-Meier method by prior AF, with comparisons by the log-rank test. The incidence of ventricular and atrial arrhythmia events were expressed as events per 100 patient-years, and were analyzed by prior AF using negative binomial regression.

RESULTS

WEARIT-II enrolled 2000 patients, 557 (28%) of whom had AF before enrollment. Cumulative probability of any sustained or nonsustained WCD-detected VT/VF during WCD use was significantly higher among patients with a history of AF than without AF (6% vs. 3%, p = .001). Similarly, the recurrent rate of any sustained or nonsustained VT/VF was significantly higher in patients with prior AF versus no prior AF (131.5 events per 100 patient-years vs. 22.7 events per 100 patient-years, p = .001). Patients with prior AF also had a significantly higher burden of any WCD-detected atrial arrhythmias/SVT/inappropriate arrhythmias therapy (183.2 events per 100 patient-years vs. 74.8 events per 100 patient-years, p < .001).

CONCLUSION

Our results demonstrate that patients with a history of AF wearing the WCD for risk assessment have a higher incidence of ventricular arrhythmias that may facilitate the decision making for ICD implantation.

Incorporation of Drone Technology Into the Chain of Survival for OHCA: Estimation of Time Needed for Bystander Treatment of OHCA and CPR Performance

BACKGROUND

Drone-delivered automated external defibrillators (AEDs) hold promises in the treatment of out-of-hospital cardiac arrest. Our objective was to estimate the time needed to perform resuscitation with a drone-delivered AED and to measure cardiopulmonary resuscitation (CPR) quality.

METHODS

Mock out-of-hospital cardiac arrest simulations that included a 9-1-1 call, CPR, and drone-delivered AED were conducted. Each simulation was timed and video-recorded. CPR performance metrics were recorded by a Laerdal Resusci Anne Quality Feedback System. Multivariable regression modeling examined factors associated with time from 9-1-1 call to AED shock and CPR quality metrics (compression rate, depth, recoil, and chest compression fraction). Comparisons were made among those with recent CPR training (≤2 years) versus no recent (>2 years) or prior CPR training.

RESULTS

We recruited 51 research participants between September 2019 and March 2020. The median age was 34 (Q1-Q3, 23-54) years, 56.9% were female, and 41.2% had recent CPR training. The median time from 9-1-1 call to initiation of CPR was 1:19 (Q1-Q3, 1:06-1:26) minutes. A median time of 1:59 (Q1-Q3, 01:50-02:20) minutes was needed to retrieve a drone-delivered AED and deliver a shock. The median CPR compression rate was 115 (Q1-Q3, 109-124) beats per minute, the correct compression depth percentage was 92% (Q1-Q3, 25-98), and the chest compression fraction was 46.7% (Q1-Q3, 39.9%-50.6%). Recent CPR training was not associated with CPR quality or time from 9-1-1 call to AED shock. Younger age (per 10-year increase; β, 9.97 [95% CI, 4.63-15.31] s; P<0.001) and prior experience with AED (β, -30.0 [95% CI, -50.1 to -10.0] s; P=0.004) were associated with more rapid time from 9-1-1 call to AED shock. Prior AED use (β, 6.71 [95% CI, 1.62-11.79]; P=0.011) was associated with improved chest compression fraction percentage.

CONCLUSION

Research participants were able to rapidly retrieve an AED from a drone while largely maintaining CPR quality according to American Heart Association guidelines. Chest compression fraction was lower than expected.

The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming

INTRODUCTION

Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines.

METHODS

Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2) GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4) NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality.

RESULTS

Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030).

CONCLUSION

Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project

AIMS

Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers.

METHODS AND RESULTS

International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006].

CONCLUSION

In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up.

CLINICALTRIALS.GOV IDENTIFIER

NCT0473876.

Expanded application of wearable cardioverter defibrillators beyond current guidelines: proposal for a European register explained through single clinical scenarios

The wearable cardioverter defibrillator (WCD) is becoming a more and more widely used instrument for the prevention of sudden cardiac death of patients either with a secondary prevention implantable cardioverter defibrillator indication or with a transient high risk of sudden cardiac death. Although clinical practice has demonstrated a benefit of protecting patients for a period as long as 3-6 months with such devices, the current European guidelines concerning ventricular arrhythmias and sudden cardiac death are still extremely restrictive in the patient selection in part because of the costs derived from such a prevention device, in part because of the lack of robust randomised trials.To illustrate expanded use cases for the WCD, four real-life clinical cases are presented where patients received the device slightly outside the established guidelines. These cases demonstrate the broader utility of WCDs in situations involving acute myocarditis, thyrotoxicosis, pre-excited atrial fibrillation and awaiting staging/prognosis of a lung tumour. The findings prompt expansion of the existing guidelines for WCD use to efficiently protect more patients whose risk of arrhythmic cardiac death is transient or uncertain. This could be achieved by establishing a European register of the patients who receive a WCD for further analysis.

Detecting deceased patients on cardiac device remote monitoring: A case series and management guide for cardiac device services

BACKGROUND

Remote monitoring (RM) of implantable cardiac devices provides substantial and complex information, presenting new challenges such as detection of a patient's death.

OBJECTIVE

This study aims to describe RM transmissions indicating death and propose a management strategy for services.

METHODS

The study included consecutive ambulatory outpatients whose deaths were detected via RM. Clinical and device data were collected from electronic records, and ethical approval was obtained from the service's institutional review board.

RESULTS

Over a 9-year period (2014-2023), 28 patients were detected. The deceased patients had implantable cardioverter-defibrillators, pacemakers, and implantable loop recorders. In 54% of the cases, the patient's death had already been recognized. Alert transmissions indicating death were commonly related to ventricular arrhythmia events, but also due to lead measurements, and implantable loop recorder battery status. Several diagnostic features may indicate a patient's death. The most reliable was the presenting electrogram, demonstrating base rate pacing with no capture. Device diagnostics, lead parameters, and arrhythmia recordings may indicate death; however, not all cases present with recordings and diagnosis may not be conclusive. A majority (82%) had ventricular arrhythmia at the time of death. In cases where defibrillator shocks were delivered, the arrhythmia reinitiated shortly after successful cardioversion. Delayed therapy was observed, and some patients did not receive defibrillator shocks because of discriminators or because the arrhythmia rate fell below the shock zone.

CONCLUSION

Detecting a patient death via RM presents unique challenges and considerations for services. Standard operational policies and legal consultation should be established to address the implications.

Defibrillation threshold in elective subcutaneous implantable defibrillator generator replacements: Time to reduce the size of the pulse generator?

INTRODUCTION

The first step-down defibrillation studies in the subcutaneous implantable cardioverter-defibrillator (S-ICD) described a defibrillation threshold (DFT) of 32.5 ± 17.0 J and 36.6 ± 19.8 J. Therefore, the default shock output of the S-ICD was set at 80 J. In de novo implants, the DFT is lower in optimally positioned S-ICDs. However, a retrospective analysis raised concerns about a high DFT in S-ICD replacements, possibly related to fibrosis.

OBJECTIVE

We aimed to find the DFT in patients undergoing S-ICD generator replacement.

METHODS

This prospective study enrolled patients who underwent S-ICD generator replacement with subsequent defibrillation testing. A pre-specified defibrillation testing protocol was used to determine the DFT, defined as the lowest shock output that effectively terminated the induced ventricular arrhythmia.

RESULTS

A total of 45 patients were enrolled, 6.0 ± 2.1 years after initial implant. Mean DFT during replacement in the total cohort was 27.4 ± 14.3 J. In patients with a body mass index (BMI) 18.5-25 kg/m2 (N = 22, BMI 22.5 ± 1.6), median DFT was 20 J (IQR 17.5-30). In 18/22 patients, the DFT was ≤30 J and 5/22 patients were successfully defibrillated at 10 J. One patient with hypertrophic cardiomyopathy had a DFT of 65 J. In patients with a BMI >25 kg/m2 (N = 23, BMI 29.5 ± 4.2), median DFT was 30 J (IQR 20-40). In 15/23 patients, the DFT was ≤30 J and 4/23 patients had a successful defibrillation test at 10 J.

CONCLUSIONS

This study eases concerns about a high DFT after S-ICD generator replacement. The majority of patients had a DFT ≤30 J, regardless of BMI, suggesting that the shock output of the S-ICD could be safely reduced.

Hypotension and respiratory events related to electrical cardioversion for atrial fibrillation or atrial flutter in the emergency department

INTRODUCTION

Electrical cardioversion for atrial fibrillation/atrial flutter (AF/AFL) is common in the ED. Our previous work showed that hypotension and respiratory events were important adverse events that occurred in patients undergoing electrical cardioversion for AF/AFL. The purpose of this study was to examine if (1) beta-blockers or calcium channel blocker use prior to ECV were associated with hypotension and (2) medications used for procedural sedation were associated with respiratory events.

METHODS

This was a secondary analysis of pooled study data from four previous multicentred studies on AF/AFL. We conducted a multivariable logistic regression to examine predictors of hypotension and respiratory adverse events.

RESULTS

There were 1736 patients who received ECV. A hypotensive event occurred in 62 (3.6%) patients. There was no significant difference in the odds of a hypotensive event in patients who received a beta-blocker or calcium channel blocker in the ED compared to no rate control. Procedural sedation with fentanyl (OR 2.01 95% CI 1.15-3.51) and home beta-blocker use (OR 1.92, 95% CI 1.14-3.21) were significantly associated with hypotensive events. A respiratory event occurred in 179 (10.3%) patients. Older age (OR 2.02, 95% CI 1.30- 3.15) and receiving midazolam for procedural sedation were found to be significantly associated with respiratory events (OR 1.99, 95% CI 1.02-3.88).

CONCLUSION

Beta-blocker or calcium channel blocker use prior to ECV for AF/AFL was not associated with hypotension. However, sedation with fentanyl and home beta-blocker use was associated with hypotension. The use of midazolam for procedural sedation was significantly associated with respiratory events.

The clinical and economic impact of extended battery longevity of a substernal extravascular implantable cardioverter defibrillator

INTRODUCTION

The extravascular implantable cardioverter defibrillator (EV ICD) has extended projected battery longevity compared to the subcutaneous implantable cardioverter defibrillator (S-ICD). This study used modeling to characterize the need for generator changes, long-term complications, and overall costs for both the EV ICD and S-ICD in healthcare systems of various countries.

METHODS

Battery longevity data were modeled using a Markov model from averages reported in device labeling for the S-ICD and with engineering estimates based on real life usage from EV ICD Pivotal Study patient data to introduce variability. Clinical demographic data were derived from published literature. The primary outcomes were defined as the number of generator replacement surgeries, complications, and total healthcare system costs due to battery depletion over the expected lifetime of patients receiving EV ICD or S-ICD therapy.

RESULTS

Average modeled battery longevity was determined to be 7.3 years for the S-ICD versus 11.8 years for the EV ICD. The probability of a complication after a replacement procedure was 1.4%, with an operative mortality rate of 0.02%. The use of EV ICD was associated with 1.4-1.6 fewer replacements on average over an expected patient lifetime as compared to S-ICD and a 24.3%-26.0% reduction in cost. A one-way sensitivity analysis of the model for the US healthcare system found that use of an EV ICD resulted in a reduction in replacement surgeries of greater than 1 (1.1-1.6) along with five-figure cost savings in all scenarios ($18 602-$40 948).

CONCLUSION

The longer projected battery life of the EV ICD has the potential to meaningfully reduce long-term morbidity and healthcare resources related to generator changes from the perspective of multiple diverse healthcare systems.

Artificial Intelligence Model Predicts Sudden Cardiac Arrest Manifesting With Pulseless Electric Activity Versus Ventricular Fibrillation

BACKGROUND

There is no specific treatment for sudden cardiac arrest (SCA) manifesting as pulseless electric activity (PEA) and survival rates are low; unlike ventricular fibrillation (VF), which is treatable by defibrillation. Development of novel treatments requires fundamental clinical studies, but access to the true initial rhythm has been a limiting factor.

METHODS

Using demographics and detailed clinical variables, we trained and tested an AI model (extreme gradient boosting) to differentiate PEA-SCA versus VF-SCA in a novel setting that provided the true initial rhythm. A subgroup of SCAs are witnessed by emergency medical services personnel, and because the response time is zero, the true SCA initial rhythm is recorded. The internal cohort consisted of 421 emergency medical services-witnessed out-of-hospital SCAs with PEA or VF as the initial rhythm in the Portland, Oregon metropolitan area. External validation was performed in 220 emergency medical services-witnessed SCAs from Ventura, CA.

RESULTS

In the internal cohort, the artificial intelligence model achieved an area under the receiver operating characteristic curve of 0.68 (95% CI, 0.61-0.76). Model performance was similar in the external cohort, achieving an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.59-0.84). Anemia, older age, increased weight, and dyspnea as a warning symptom were the most important features of PEA-SCA; younger age, chest pain as a warning symptom and established coronary artery disease were important features associated with VF.

CONCLUSIONS

The artificial intelligence model identified novel features of PEA-SCA, differentiated from VF-SCA and was successfully replicated in an external cohort. These findings enhance the mechanistic understanding of PEA-SCA with potential implications for developing novel management strategies.

ICD outcome in pediatric arrhythmogenic cardiomyopathy

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is a very rare condition among pediatric patients. Sudden cardiac death (SCD) is the main complication and often requires ICD implantation. Aim of the study is the evaluation of the outcomes of ICD implanted ACM pediatric patients in terms of safety, efficacy and complications.

METHODS

All pediatric patients (<18 y.o.) diagnosed with ACM and who were implanted with ICD since 2009 in Our Institution were collected. Implantation was decided according to current recommendations/ guidelines, and outcome was recorded during follow-up.

RESULTS

Nineteen consecutive ACM patients were implanted with ICD. Subcutaneous ICDs (S-ICD) were implanted in 15 patients (79%) while transvenous ICDs (TV-ICD) in 4 patients (21%). Mean age at implantation was 14.3 ± 2.1 y.o. ICDs were implanted for secondary prevention in 4 (21%) patients, and for primary prevention in 15 (79%). During the follow-up (5.59 ± 3.4 years), appropriate ICD interventions were delivered in 4 (21%) patients for sustained VTs, [2 implanted in primary prevention (13%) and 2 in secondary prevention (50%)]. No defibrillation failures occurred. Inappropriate shocks occurred in 2 cases (10.5%). Device-related complications requiring device revision occurred in 3 (16%): lead dislodgement, surgical skin erosion and sensing defect.

CONCLUSIONS

In a pediatric ACM cohort, appropriate ICD therapies occurred in a minority of primary prevention patients and frequently in secondary prevention patients. The rate of inappropriate shocks and device-related complications were even more rare and mostly wound related. Therefore, ICD therapy in pediatric ACM is effective and safe.

Electric Cardioversion in Older Adults. Is Sedation Using Propofol Safe in the Absence of the Direct Anesthetist's Assistance?

Aims: This study aimed to assess the safety of electric cardioversion in the absence of anesthetists assistance. We also evaluated the efficacy and safety of this procedure in older adults (≥80 years) compared to younger populations. Methods: We retrospectively analyzed the data of patients who underwent electric cardioversion at our cardiology department. Patients were divided into 2 groups according to age: ≥ 80 years and <80 years old. Results: The study included 218 participants, 73 were aged 80 years or more (mean age: 84.8 years), and 145 were younger than 80 years (mean age: 66.7 years). Electric cardioversion was effective in 97.3% of older patients and 96.5% of younger patients (P = 1.00). No thromboembolic complications were observed in either of the groups. Asystole >5 s occurred immediately after shock in 4.1% of older and 2.1% of younger patients (P = .405). Propofol was used as a sedative, with a mean dose of 0.83 mg/kg versus 0.93 mg/kg, in older and younger patients, respectively. Intubation, medical intervention, or other advanced resuscitation techniques were not required. During hospitalization, arrhythmia recurred in 9.6% and 12.4% of the older and younger patients, respectively (P = .537). Conclusions: Electrical cardioversion is an effective and safe procedure regardless of patient age. Sedation with propofol administered by cardiologists was safe. Adverse events were not considered serious or reversible.

Medical cardioversion of atrial fibrillation and flutter with class IC antiarrhythmic drugs in young patients with and without congenital heart disease

INTRODUCTION

The use of flecainide and propafenone for medical cardioversion of atrial fibrillation (AF) and atrial flutter/intra-atrial reentrant tachycardia (IART) is well-described in adults without congenital heart disease (CHD). Data are sparse regarding their use for the same purpose in adults with CHD and in adolescent patients with anatomically normal hearts and we sought to describe the use of class IC drugs in this population and identify factors associated with decreased likelihood of success.

METHODS

Single center retrospective cohort study of patients who received oral flecainide or propafenone for medical cardioversion of AF or IART from 2000 to 2022. The unit of analysis was each episode of AF/IART. We performed a time-to-sinus rhythm analysis using a Cox proportional hazards model clustering on the patient to identify factors associated with increased likelihood of success.

RESULTS

We identified 45 episodes involving 41 patients. As only episodes of AF were successfully cardioverted with medical therapy, episodes of IART were excluded from our analyses. Use of flecainide was the only factor associated with increased likelihood of success. There was a statistically insignificant trend toward decreased likelihood of success in patients with CHD.

CONCLUSIONS

Flecainide was more effective than propafenone. We did not detect a difference in rate of conversion to sinus rhythm between patients with and without CHD and were likely underpowered to do so, however, there was a trend toward decreased likelihood of success in patients with CHD. That said, medical therapy was effective in >50% of patients with CHD with AF.

Acute human defibrillation performance of a subcutaneous implantable cardioverter-defibrillator with an additional coil electrode

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (S-ICD) delivers 80 J shocks from an 8 cm left-parasternal coil to a 59 cm3 left lateral pulse generator (PG). A system that defibrillates with lower energy could significantly reduce PG size. Computer modeling and animal studies suggested that a second shock coil either parallel to the left-parasternal coil or transverse from the xiphoid to the PG pocket would significantly reduce the defibrillation threshold.

OBJECTIVE

The purpose of this study was to acutely assess the defibrillation efficacy of parallel and transverse configurations in patients receiving an S-ICD.

METHODS

Testing was performed in patients receiving a conventional S-ICD system. Success at 65 J was required before investigational testing. A second electrode was temporarily inserted from the xiphoid incision connected to the PG with an investigational Y-adapter. Phase 1 (n = 11) tested the parallel configuration. Phase 2 (n = 21) tested both parallel and transverse configurations in random order.

RESULTS

This study enrolled 35 patients (28 males (80%); mean age 51 ± 17 years; left ventricular ejection fraction 40% ± 15%; body mass index 26 ± 4 kg/m2; prior myocardial infarction 46%; congestive heart failure 49%; cardiomyopathy 63%). Compared to the conventional S-ICD system, mean shock impedance decreased for both parallel (69 ± 15 Ω vs 86 ± 20 Ω; n = 33; P < .001) and transverse (56 ± 14 Ω vs 81 ± 21 Ω; n = 20; P < .001) configurations. Shock success rates at 20, 30, and 40 J were 55%, 79%, 97%, and 25%, 70%, 90% for parallel and transverse configurations, respectively. Defibrillation threshold testing was well tolerated with no serious adverse events.

CONCLUSION

Adding a second shock coil, particularly in the parallel configuration, significantly reduced the impedance and had a high likelihood of defibrillation success at energies ≤40 J. This may enable the development of a smaller S-ICD.

Changes in cardiac output, rhythm regularity, and symptom severity after electrical cardioversion of atrial fibrillation

OBJECTIVES

Symptoms in atrial fibrillation (AF) range from none to disabling. The physiological correlates of AF symptoms are not well characterized. This study investigated the association between physiological parameters and symptom severity before and after electrical cardioversion (EC) of AF.

DESIGN

We studied 44 patients with persistent AF (age 66.2 ± 7.9 years, 16% females) 4 ± 2 days before and 5 ± 2 days after EC. Physiological parameters included cardiac output (CO; non-invasive inert gas rebreathing), heart rate (HR), RR variability and resting and ambulatory blood pressure (BP). Symptoms and quality of life (QoL) were assessed by the modified European Heart Rhythm Association score (mEHRA), the Atrial Fibrillation Effect on Quality of Life (AFEQT) and the Symptom Checklist for frequency and severity of symptoms (SCL).

RESULTS

28 of 44 patients were still in sinus rhythm (SR) at post EC evaluation. Those in SR had a decreased HR (-15.4 ± 13.1 bpm, p < 0.001), and an increased CO (+0.8 ± 0.7 L/min, p < 0.001) as compared to those with recurrent AF. Changes in CO after EC correlated with symptom improvement as scored by AFEQT (r = 0.36; p < 0.05), AFEQT symptoms subscore (r = 0.46; p < 0.01), SCL for frequency (r = 0.62; p < 0.01) and severity (r = 0.33; p < 0.05) of symptoms, and the mEHRA score (r = 0.50; p < 0.01). A decrease in RR variability showed similar correlations with these measures of symptom improvement.

CONCLUSIONS

Improvements in symptoms and quality of life experienced by patients after electrical conversion of atrial fibrillation are correlated with an increase in CO and a decreased RR variability.

How likely is the sense-B-noise to affect patients with subcutaneous implantable cardioverter-defibrillators and can we solve that problem in every case?

BACKGROUND

Sense-B-noise is a newly reported possible cause of inappropriate shocks in patients with subcutaneous implantable cardioverter-defibrillators (S-ICDs). The nature of that noise is unknown, it is not related to mechanical failure of the S-ICD system. Reprogramming to the secondary sensing vector is suggested by the producer as a possible solution.

METHODS

We analyzed the medical records of S-ICD recipients from two university clinical centers (Gdansk and Szczecin, Poland). Our aim was to determine the rate of sense-B-noise, and whether the secondary sensing vector would be available for reprogramming if such a problem occurred in our patients.

RESULTS

The sense-B-noise issue affected three patients in our cohort (3%), which corresponds to the incidence of 0.012 events per patient-year of follow-up. The primary vector was permanently used in 47 patients (52%), secondary in 28 (31%), and alternate in 16 (17%), respectively. Therefore, the total number of patients potentially vulnerable to sense-B noise (with the primary or alternate vector programmed permanently) was 63 (69%). Among those 63 patients, 51 individuals (81%) had also the secondary vector available for permanent use.

CONCLUSION

The sense-B-noise affected 3% of patients in our cohort, with an incidence of 0.012 per patient-year of follow-up. Most patients potentially vulnerable to sense-B noise could be reprogrammed to the secondary sensing vector, if necessary. Further investigation of the sense-B-noise issue is needed.

Real-world evidence for the use of subcutaneous implantable cardioverter-defibrillators in China: A single-center experience

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have been shown to be non-inferior to transvenous ICDs in the prevention of sudden cardiac death (SCD), but there is still a lack of evidence from clinical trials in China. We investigated whether S‑ICD implantation in the Chinese population is safe and feasible and should be promoted in the future.

METHODS

Consecutive patients undergoing S‑ICD implantation at our center were enrolled in this retrospective study. Data were collected within the median follow-up period of 554 days. Data concerning patient selection, implantation procedures, complications, and episodes of shock were analyzed.

RESULTS

In total, 70.2% of all 47 patients (median age = 39 years) were included for secondary prevention of SCD with different etiologies. Vector screening showed that 98% of patients were with > 1 appropriate vector in all postures. An intraoperative defibrillation test was not performed on six patients because of the high risk of disease deterioration, while all episodes of ventricular fibrillation induced post implantation were terminated by one shock. As expected, no severe complications (e.g., infection and device-related complications) were observed, except for one case of delayed healing of the incision. Overall, 15 patients (31.9%) experienced appropriate shocks (AS) with all episodes terminated by one shock. Two patients (4.3%) experienced inappropriate shocks (IAS) due to noise oversensing, resulting in a high Kaplan-Meier IAS-free rate of 95.7%.

CONCLUSION

Based on appropriate patient selection and standardized implantation procedures, this real-world study confirmed the safety and efficacy of S‑ICD in Chinese patients, indicating that it may help to promote the prevention of SCD in China.

Is there a reduced confidence towards direct oral anticoagulants compared to vitamin K antagonists in patients scheduled for an elective electrical cardioversion? The results of the BLITZ-AF study

OBJECTIVE

To study the confidence of cardiologists in performing an electrical cardioversion in patients on oral anticoagulation (OA) with or without transoesophageal echocardiography (TOE).

METHODS

Data about atrial fibrillation (AF) patients admitted to cardiology wards for elective cardioversion (ECV) were extrapolated from the BLITZ-AF study. Percentage of vitamin K antagonists (VKAs), direct oral anticoagulants (DOAC) and heparin prescription were analysed in relation to the use of TOE before ECV.

RESULTS

Overall rate of TOE was 33.7% (240/713); it was used before ECV in 124/313 (39.6%) of DOACs patients and in 96/372 (25.8%) of the patients on VKAs, showing a significant reduced resort to TOE in VKAs patients (p = 0.0001). Among non-valvular patients TOE was more frequently performed in males, at younger ages and in patients on heparin when compared to patients treated with OA. TOE was also more frequently performed in tertiary hospitals and in hospitals with cardiology wards and electrophysiology labs, when compared to hospital provided only with cardiology wards. At multivariable analysis there was a significant less recourse to TOE in patients on VKAs (OR 0.47; 95% CI: 0.33-0.67) and higher recourse in the heparin group (OR: 3.85; 95% CI:1.59-9.28) with respect to patients on DOACs; a higher recourse to TOE was observed also in tertiary hospitals (OR 4.25; 95% CI 2.69-6.69) and in hospitals with cardiology wards and electrophysiology (EP) labs (OR 1.87; 95% CI 1.23-2.82).

CONCLUSION

our study shows the reluctance in cardioverting patients on DOACs respect to VKAs without a previous TOE, despite adequate anticoagulant treatment.

Risk prediction of inappropriate implantable cardioverter-defibrillator therapy using machine learning

We aimed to develop machine learning-based predictive models for identifying inappropriate implantable cardioverter-defibrillator (ICD) therapy. Our study included 182 consecutive cases (average age 62.2 ± 4.5 years, 169 men) and employed 14 non-deep learning models for prediction (hold-out method). These models utilized selected electrocardiogram parameters and clinical features collected after ICD implantation. From the feature importance analysis of the best ML model, we established easily calculable scores. Among the patients, 25 (13.7%) experienced inappropriate therapy, and we identified 16 significant predictors. Using recursive feature elimination with cross-validation, we reduced the features to six with high feature importance: history of atrial arrhythmia (Atr-arrhythm), ischemic cardiomyopathy (ICM), absence of diabetes mellitus (DM), lack of cardiac resynchronization therapy (CRT), V3 ST level at J point (V3 STJ), and V5 R-wave amplitudes (V5R amp). The extra-trees classifier yielded the highest area under receiver operating characteristics curve (AUROC; 0.869 on test data). Thus, the Cardi35 score was defined as [+ 5.5*Atr-arrhythm - 1.5*CRT + 1.0*V3STJ + 1.0*V5R - 1.0*ICM - 0.5*DM], which demonstrated a hazard ratio of 1.62 (P < 0.001). A cut-off value of the score + 5.5 showed high AUROC (0.826). The ML approach can yield a robust prediction model, and the Cardi35 score was a convenient predictor for inappropriate therapy.

Electrical energy by electrode placement for cardioversion of atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE

Electrode patch position may not be critical for success when cardioverting atrial fibrillation (AF), but the relevance of applied electrical energy is unclarified. Our objective was to perform a meta-analysis of randomised trials to examine the dose-response relation between energy level and cardioversion success by electrode position in elective cardioversion.

METHODS

We searched PubMed, Embase, The Cochrane Library, Google Scholar and Scopus Citations. Inclusion criteria were randomised controlled trials using biphasic shock waves and self-adhesive patches, and publication date from 2000 to 2023. We used random-effects dose-response models to meta-analyse the relation between energy level and cardioversion success by anterolateral and anteroposterior position. Random-effects models estimated pooled risk ratios (RR) for cardioversion success after the first and the final shocks between the two electrode positions.

RESULTS

We included five randomised controlled trials (N=1078). After the first low-energy shock, the electrode position was not significantly associated with the likelihood of successful cardioversion (pooled RR anterolateral vs anteroposterior placement 1.28, 95% CI 0.93 to 1.76, with considerable heterogeneity). After a high-energy final shock, there was no evidence of an association between the electrode position and the cumulative chance of cardioversion success (pooled RR anterolateral vs anteroposterior 1.05, 95% CI 0.97 to 1.14). Regardless of electrode position, cardioversion success was significantly less likely with shock energy levels < 200J compared with 200J.

CONCLUSION

Evidence from contemporary randomised trials suggests that higher level of electrical energy is associated with higher conversion rate when cardioverting AF with a biphasic shockwave. Positioning of electrodes can be based on convenience.

Follow-up ICD generator explantation in tuberculous myocarditis induced ventricular tachycardia patient

A rare case of ventricular tachycardia caused by extrapulmonary tuberculosis has been followed up. Automatic implantable cardioverter defibrillator implantation was done at the time of presentation. Following this, the patient is clinically well without any episodes of ventricular tachycardia and is considered for an implantable cardioverter defibrillator explantation.

Impact of Age on Subcutaneous Implantable Cardioverter-Defibrillator in a Large Patient Cohort: Mid-Term Follow-Up

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an accepted alternative to transvenous (TV) ICD to provide defibrillation therapy to treat life-threatening ventricular tachyarrhythmias in high-risk patients. S-ICD outcomes by age group have not been reported.

OBJECTIVES

In this study, the authors sought to report S-ICD outcomes in different age groups in a multicenter S-ICD post-approval study (PAS) involving the largest cohort of patients ever reported.

METHODS

Patients were prospectively enrolled in the S-ICD PAS and stratified based on age: young, aged 15-34 years; adult, aged 35-69 years; and elderly, aged ≥70 years. Patient characteristics and clinical outcomes through 3 years of follow up after implantation were compared.

RESULTS

The S-ICD PAS enrolled 1,637 patients. Elderly patients were more likely to receive an S-ICD as a replacement of a TV-ICD (15.1% elderly vs 12.3% adult vs 7.4% young). Secondary prevention indication decreased with age (32.7% young vs 22.2% adult vs 20.5% elderly). Mortality rate was significantly higher in the elderly group (24.0% elderly vs 13.0% adult vs 7.4% young; P < 0.0001), whereas the complication rate did not differ significantly (12.3% young vs 11.3% adult vs 8.1% elderly). Rates of appropriate shock (12.7% young vs 13.0% adult vs 13.8% elderly) and inappropriate shock (7.8% young vs 9.1% adult vs 8.8% elderly) rates did not differ between groups (P = 0.96 and P = 0.98, respectively).

CONCLUSIONS

Implant complications and appropriate and inappropriate shock rates were similar among age groups. S-ICD for secondary prevention was more common in the young group. Replacing a TV-ICD for an S-ICD increases with age. (S-ICD System Post-Approval Study; NCT01736618).

Ventricular arrhythmia detection for contemporary Biotronik and Abbott implantable cardioverter defibrillators with markedly prolonged detection in Biotronik devices

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are typically programed with both ventricular tachycardia (VT) and ventricular fibrillation (VF) treatment zones. Biotronik and Abbott ICDs do not increment the VT counter when the tachycardia accelerates to the VF zone, which could result in a prolonged delay in tachycardia detection.

METHODS

Patients with Biotronik and Abbott ICDs receiving care at Veterans Affairs facilities in Northern California were identified. Patient information and device tracings for patients with any ICD therapies were examined to assess for possible delayed tachycardia detection.

RESULTS

Among 52 patients with Biotronik ICDs, 8 (15%) experienced appropriate ICD therapy over a median follow-up of 29 months. Among 68 patients with Abbott ICDs, 26 (38%) experienced appropriate ICD therapy over a median follow-up of 83 months. Three of the patients with Biotronik ICDs who received appropriate therapy experienced a delay in VT/VF detection due to the tachycardia rate oscillating between the VT and VF treatment zones (longest 31.2 s on detection), compared with four of the patients with Abbott ICDs (longest 4.1 s on the detection and 8 s on redetect). One of the patients with a Biotronik ICD experienced recurrent syncope associated with delayed detection and another died on the day of delayed detection. One of the patients with an Abbott ICD experienced syncope.

CONCLUSIONS

Because contemporary Biotronik and Abbott ICDs freeze the VT counters when tachycardia is in the VF zone, ICD therapies can be markedly delayed when the tachycardia oscillates between the VT and VF zone.

Efficacy and safety of catheter ablation as first-line therapy for the management of ventricular tachycardia

BACKGROUND

Ventricular tachycardia (VT) is associated with significantly increased morbidity and mortality. Catheter ablation (CA) in line with an implantable cardioverter-defibrillator (ICD) is highly effective in VT management; however, it is unknown if CA should be considered as first-line therapy. The aim of this study is to verify the efficacy and safety of CA as first-line therapy for the first VT presentation (as adjunctive to ICD insertion), compared to initial ICD insertion and anti-arrhythmic drug (AAD) therapy.

METHODS

Data from patients with the first presentation for VT from January 2017 to January 2021 was reviewed. Patients were classified as "ablation first" vs "ICD first" groups and compared the clinical outcomes between groups.

RESULTS

One hundred and eighty-four consecutive patients presented with VT; 34 underwent CA as first-line therapy prior to ICD insertion, and 150 had ICD insertion/AAD therapy as first-line. During the median follow-up of 625 days, patients who underwent CA as first-line therapy had significantly higher ventricular arrhythmia (VA)-free survival (91% vs 59%, log-rank P = 0.002) and composite of VA recurrence, cardiovascular hospitalization, transplant, and death (84% vs 54%, log-rank P = 0.01) compared to those who did not undergo CA. Multivariate analysis revealed that first-line CA was the only protective predictor of VA recurrence (hazard ratio (HR) 0.20, P = 0.003). There were 3 (9%) peri-procedural complications with no peri-procedural deaths.

CONCLUSION

Real-world data supports the efficacy and safety of CA as first-line therapy at the time of the first VT hospitalization, compared to the initial ICD implant and AAD therapy.

Programming of implantable cardioverter defibrillators for primary prevention: outcomes at centers with high vs. low concordance with guidelines

BACKGROUND

While ICD therapy reduction programming strategies are recommended in current multi-society guidelines, concerns remain about a possible trade-off between the benefits of ICD therapy reduction and failure to treat episodes of ventricular arrhythmias. The study is to evaluate the outcomes of primary prevention patients followed in centers with high and low concordance with the 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines.

METHODS

Consecutive patients with primary prevention ICD implantation from two centers between 2014 and 2016 were included. One center was classified as high guideline concordance center (HGC) with 47% (146/310) of patients with initial ICD concordant with the guidelines, and the other center was classified as low guideline concordance center (LGC) with only 1% (2/178) of patients with guideline-concordant initial ICD programming. Cox proportional hazard models were used to assess risk of first ICD therapy (ATP or shock), first ICD shock, and mortality.

RESULTS

A total of 488 patients were included (mean age, 66 ± 13 years). During a mean follow-up of 1.9 ± 0.9 years, patients followed at HGC were 63% less likely to receive any ICD therapy (adjusted HR [aHR] 0.37, 95% CI 0.42-0.99). There were no significant differences in the rate of first ICD shock (aHR 0.72, 95% CI 0.34-1.52) or mortality (aHR 1.19, 95% CI, 0.47-3.05).

CONCLUSIONS

Compared to primary prevention patients followed at LGC, primary prevention ICD patients followed at HGC received a significantly lower rate of ICD therapy, mainly from ATP reduction, without a difference in mortality during follow-up.

Long-term risk of cardiovascular implantable electronic device reinterventions following external cardioversion of atrial fibrillation and flutter: A nationwide cohort study

BACKGROUND

External cardioversion (ECV) is an essential part of rhythm control of atrial fibrillation and flutter in patients with and without cardiovascular implantable electronic devices (CIEDs). Long-term follow-up data on ECV-related CIED dysfunctions are limited.

OBJECTIVE

The purpose of this study was to investigate the risk of CIED reintervention following ECV in a nationwide cohort.

METHODS

We identified CIED implants and surgical reinterventions from 2005 to 2021 in the Danish Pacemaker and ICD Register. We included CIED patients undergoing ECV from 2010 to 2019 from the Danish National Patient Registry. For each ECV-exposed generator, 5 matched generators without ECV were identified, and for each ECV-exposed lead, 3 matched leads were identified. The primary endpoints were generator replacement and lead reintervention.

RESULTS

We compared 2582 ECV-exposed patients with 12,910 matched patients with a pacemaker (47%), implantable cardioverter-defibrillator (ICD) (29%), cardiac resynchronization therapy-pacemaker (6%), or cardiac resynchronization therapy-defibrillator (18%). During 2 years of follow-up, 210 ECV-exposed generators (8.1%) vs 670 matched generators (5.2%) underwent replacements, and 247 ECV-exposed leads (5.6%) vs 306 matched leads (2.3%) underwent reintervention. Unadjusted hazard ratios were 1.61 (95% confidence interval [CI] 1.37-1.91; P <.001) for generator replacement and 2.39 (95% CI 2.01-2.85; P <.001) for lead reintervention. One-year relative risks were 1.73 (95% CI 1.41-2.12; P <.001) for generator replacement and 2.85 (95% CI 2.32-3.51; P <.001) for lead reintervention, and 2-year relative risks were 1.39 (95% CI 1.19-1.63; P <.001) and 2.18 (95% CI 1.84-2.57; P <.001), respectively.

CONCLUSION

ECV in patients with a CIED is associated with a higher risk of generator replacement and lead reintervention. The risks of reinterventions were more pronounced within the first year after cardioversion.

Flecainide for conversion and maintenance of sinus rhythm after mitral valve replacement in rheumatic atrial fibrillation

BACKGROUND

Despite successful mitral valve replacement (MVR), many patients remain in AF. Flecainide can be useful in these patients but has not been used because of underlying structural heart disease.

METHODS

We assessed oral flecainide for conversion and maintenance of SR in 25 patients of chronic rheumatic AF following MVR (age 34.4 yrs, mean AF duration: 3.6 yrs). Non-converters underwent DC cardioversion at 24 h and 4 weeks. Patients received flecainide and bb/diltiazem at discharge.

RESULTS

Single oral dose of Flecainide achieved SR in 6/25 (24%) while 19/25 achieved SR after DCC; at24 h 21/25 (84%) were in SR. With mean flecainide dose (93.10 ± 9.40 mg), successful maintenance of SR at 6 months was seen in 16/23 (69.5%). No significant changes in PR interval, QRS duration or QTc were noted; flecainide was well tolerated. Patients in SR had significantly better functional status, QOL scores and higher LA strain at 6 months (25.25 vs 17.43%, p < .0001). Baseline LA diameter ≤ 61 mm predicted SR at 6 months (sensitivity/specificity 93.7% and 85.71%) while the values for AF duration ≤ 4 years and LA strain > 21% for predicting SR were 87.5/71.43% and 100/85.71% respectively.

CONCLUSION

Oral flecainide was safe and effective in post MVR rheumatic AF patients; maintenance of SR was achieved in 76% of initial converters and 64% of overall population, with better LA strain values. More studies are needed to validate these results.

One-year quality-of-life outcomes of cardiac arrest survivors by initial defibrillation provider

OBJECTIVE

To assess the long-term functional and health-related quality-of-life (HRQoL) outcomes for out-of-hospital cardiac arrest (OHCA) survivors stratified by initial defibrillation provider.

METHODS

This retrospective study included adult non-traumatic OHCA with initial shockable rhythms between 2010 and 2019. Survivors at 12 months after arrest were invited to participate in structured telephone interviews. Outcomes were identified using the Glasgow Outcome Scale-Extended (GOS-E), EuroQol-5 Dimension (EQ-5D), 12-Item Short Form Health Survey and living and work status-related questions.

RESULTS

6050 patients had initial shockable rhythms, 3211 (53.1%) had a pulse on hospital arrival, while 1879 (31.1%) were discharged alive. Bystander defibrillation using the closest automated external defibrillator had the highest survival rate (52.8%), followed by dispatched first responders (36.7%) and paramedics (27.9%). 1802 (29.8%) patients survived to 12-month postarrest; of these 1520 (84.4%) were interviewed. 1088 (71.6%) were initially shocked by paramedics, 271 (17.8%) by first responders and 161 (10.6%) by bystanders. Bystander-shocked survivors reported higher rates of living at home without care (87.5%, 75.2%, 77.0%, p<0.001), upper good recovery (GOS-E=8) (41.7%, 30.4%, 30.6%, p=0.002) and EQ-5D visual analogue scale (VAS) ≥80 (64.9%, 55.9%, 52.9%, p=0.003) compared with first responder and paramedics, respectively. After adjustment, initial bystander defibrillation was associated with higher odds of EQ-5D VAS ≥80 (adjusted OR (AOR) 1.56, 95% CI 1.15-2.10; p=0.004), good functional recovery (GOS-E ≥7) (AOR 1.53, 95% CI 1.12-2.11; p=0.009), living at home without care (AOR 1.77, 95% CI 1.16-2.71; p=0.009) and returning to work (AOR 1.72, 95% CI 1.05-2.81; p=0.031) compared with paramedic defibrillation.

CONCLUSION

Survivors receiving initial bystander defibrillation reported better functional and HRQoL outcomes at 12 months after arrest compared with those initially defibrillated by paramedics.

Sex differences in clinical characteristics and prognosis of patients with cardiac sarcoidosis

OBJECTIVE

Owing to the paucity of data, this study aimed to investigate sex differences in clinical features and prognosis of patients with cardiac sarcoidosis (CS).

METHODS

This study was a secondary analysis of the ILLUstration of the Management and prognosIs of JapaNese PATiEnts with Cardiac Sarcoidosis registry-a retrospective multicentre registry that enrolled patients with CS between 2001 and 2017. The primary outcome was potentially fatal ventricular arrhythmia events (pFVAEs)-a composite of sudden cardiac death, sustained ventricular tachycardia lasting >30 s, ventricular fibrillation or the requirement for implantable cardioverter defibrillator therapy.

RESULTS

Of the 512 participants (mean age±SD 61.6±11.4 years), 329 (64.2%) were females. Both sexes had peak ages of 60-64 years at diagnosis. Male patients were younger and had a higher prevalence of coronary artery disease and lower left ventricular ejection fraction than female patients. During a median follow-up of 3 years (IQR 1.6-5.6), pFVAEs were observed in 99 patients, with males having a significantly higher risk than females (p=0.002). This association was retained even after adjustment for other risk factors for pFVAEs, including left ventricular ejection fraction (adjusted HR 1.80; 95% CI 1.08 to 3.01, p=0.025).

CONCLUSION

Approximately two-thirds of patients with CS were females, with a peak age of approximately 60 years at clinical diagnosis in both sexes; male patients were younger than female patients. Male patients had a significantly higher risk of pFVAEs than female patients.

TRIAL REGISTRATION NUMBER

UMIN000034974.

Post-Shock Asystole in Patients Dying Out of Hospital While Wearing a Cardioverter Defibrillator

BACKGROUND

The wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death due to ventricular tachycardia (VT) or ventricular fibrillation (VF) but does not pace for post-shock asystole (PS-A) or bradycardia (PS-B;<50 beats/ min).

OBJECTIVES

The purpose of this study was to assess PS-A and PS-B in patients dying out of hospital (OOH) while wearing a WCD.

METHODS

The database of the U.S. Food and Drug Administration Manufacturers and User Facility Device Experience (MAUDE) was queried for manufacturers' reports of OOH deaths while patients were wearing a WCD. Excluded were patients who did not receive a shock or were initially shocked for asystole or during resuscitation.

RESULTS

From January 2017 to March 2022, 313 patients received an initial WCD shock for VF (n = 150), VT (n = 90), and non-VF/VT rhythms (n = 73). PS-A occurred in 204 patients (65.2%), and PS-B occurred in 111 (35.5%); 85 (41.7%) PS-A patients also had PS-B. Most PS-A patients (n = 185; 90.7%) had an initial shocked rhythm of VF or VT, but 19 patients (9.3%) were initially inappropriately shocked for atrial fibrillation/supraventricular tachycardia (n = 7) and idioventricular (n = 8) or sinus (n = 4) rhythm. PS-A occurred after the first WCD shock in 118 (63.8%) and after the first, second, or third shocks in 159 patients (85.9%). Seven patients had post-shock heart block. Eight patients had permanent pacemakers; 1 became nonfunctional after 1 shock, and 7 showed noncapture and/or asystole after 1 to 4 shocks.

CONCLUSIONS

Post-shock asystole appears to be common in patients who die OOH after being shocked by a WCD for VF or VT. PS-A also occurs after inappropriate WCD shocks for non-VF/VT rhythms. Implanted pacemakers may not prevent PS-A after a WCD shock. WCD backup pacing should be explored.

Direct current cardioversion practices following percutaneous left atrial appendage closure

INTRODUCTION

Among patients with non-valvular atrial fibrillation (AF) and percutaneous left atrial appendage closure (LAAC) undergoing direct current cardioversion (DCCV), the need for and use of LAA imaging and oral anticoagulation (OAC) is unclear.

OBJECTIVE

The purpose of this study is to evaluate the real-world use of transesophageal echocardiography (TEE) or cardiac computed tomography angiography (CCTA) before DCCV and use of OAC pre- and post-DCCV in patients with AF status post percutaneous LAAC.

METHODS

This retrospective single center study included all patients who underwent DCCV after percutaneous LAAC from 2016 to 2022. Key measures were completion of TEE or CCTA pre-DCCV, OAC use pre- and post-DCCV, incidence of left atrial thrombus (LAT) or device-related thrombus (DRT), incidence of peri-device leak (PDL), and DCCV-related complications (stroke, systemic embolism, device embolization, major bleeding, or death) within 30 days.

RESULTS

A total of 76 patients with AF and LAAC underwent 122 cases of DCCV. LAAC consisted of 47 (62%), 28 (37%), and 1 (1%) case of Watchman 2.5, Watchman FLX, and Lariat, respectively. Among the 122 DCCV cases, 31 (25%) cases were identified as "non-guideline based" due to: (1) no OAC for 3 weeks and no LAA imaging within 48 h before DCCV in 12 (10%) cases, (2) no OAC for 4 weeks following DCCV in 16 (13%) cases, or (3) both in 3 (2%) cases. Among the 70 (57%) cases that underwent TEE or CCTA before DCCV, 16 (23%) cases had a PDL with a mean size of 3.0 ± 1.1 mm, and 4 (6%) cases had a LAT/DRT on TEE resulting in cancellation. There were no DCCV-related complications within 30 days.

DISCUSSION

There is a widely varied practice pattern of TEE, CCTA, and OAC use with DCCV after LAAC, with a 6% rate of LAT/DRT. LAA imaging before DCCV appears prudent in all cases, especially within 1 year of LAAC, to assess for device position, PDL, and LAT/DRT.

Prediction of Shock-Refractory Ventricular Fibrillation During Resuscitation of Out-of-Hospital Cardiac Arrest

BACKGROUND

Out-of-hospital cardiac arrest due to shock-refractory ventricular fibrillation (VF) is associated with relatively poor survival. The ability to predict refractory VF (requiring ≥3 shocks) in advance of repeated shock failure could enable preemptive targeted interventions aimed at improving outcome, such as earlier administration of antiarrhythmics, reconsideration of epinephrine use or dosage, changes in shock delivery strategy, or expedited invasive treatments.

METHODS

We conducted a cohort study of VF out-of-hospital cardiac arrest to develop an ECG-based algorithm to predict patients with refractory VF. Patients with available defibrillator recordings were randomized 80%/20% into training/test groups. A random forest classifier applied to 3-s ECG segments immediately before and 1 minute after the initial shock during cardiopulmonary resuscitation was used to predict the need for ≥3 shocks based on singular value decompositions of ECG wavelet transforms. Performance was quantified by area under the receiver operating characteristic curve.

RESULTS

Of 1376 patients with VF out-of-hospital cardiac arrest, 311 (23%) were female, 864 (63%) experienced refractory VF, and 591 (43%) achieved functional neurological survival. Total shock count was associated with decreasing likelihood of functional neurological survival, with a relative risk of 0.95 (95% CI, 0.93-0.97) for each successive shock (P<0.001). In the 275 test patients, the area under the receiver operating characteristic curve for predicting refractory VF was 0.85 (95% CI, 0.79-0.89), with specificity of 91%, sensitivity of 63%, and a positive likelihood ratio of 6.7.

CONCLUSIONS

A machine learning algorithm using ECGs surrounding the initial shock predicts patients likely to experience refractory VF, and could enable rescuers to preemptively target interventions to potentially improve resuscitation outcome.

Successful defibrillation testing in patients undergoing elective subcutaneous implantable cardioverter-defibrillator generator replacement

AIMS

After implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD), a defibrillation test (DFT) is performed to ensure that the device can effectively detect and terminate the induced ventricular arrhythmia. Data on DFT efficacy at generator replacement are scarce with a limited number of patients and conflicting results. This study evaluates conversion efficacy during DFT at elective S-ICD generator replacement in a large cohort from our tertiary centre.

METHODS AND RESULTS

Retrospective data of patients who underwent an S-ICD generator replacement for battery depletion with subsequent DFT between February 2015 and June 2022 were collected. Defibrillation test data were collected from both implant and replacement procedures. PRAETORIAN scores at implant were calculated. Defibrillation test was defined unsuccessful when two conversions at 65 J failed. A total of 121 patients were included. The defibrillation test was successful in 95% after the first and 98% after two consecutive tests. This was comparable with success rates at implant, despite a significant rise in shock impedance (73 ± 23 vs. 83 ± 24 Ω, P < 0.001). Both patients with an unsuccessful DFT at 65 J successfully converted with 80 J.

CONCLUSION

This study shows a high DFT conversion rate at elective S-ICD generator replacement, which is comparable to conversion rates at implant, despite a rise in shock impedance. Evaluating device position before generator replacement may be recommended to optimize defibrillation success at generator replacement.

Identifying Patients at High Risk of Left Atrial Appendage Thrombus Before Cardioversion: The CLOTS-AF Score

Background Transesophageal echocardiography-guided direct cardioversion is recommended in patients who are inadequately anticoagulated due to perceived risk of left atrial appendage thrombus (LAAT); however, LAAT risk factors remain poorly defined. Methods and Results We evaluated clinical and transthoracic echocardiographic parameters to predict LAAT risk in consecutive patients with atrial fibrillation (AF)/atrial flutter undergoing transesophageal echocardiography before cardioversion between 2002 and 2022. Regression analysis identified predictors of LAAT, combined to create the novel CLOTS-AF risk score (comprising clinical and echocardiographic LAAT predictors), which was developed in the derivation cohort (70%) and validated in the remaining 30%. A total of 1001 patients (mean age, 62±13 years; 25% women; left ventricular ejection fraction, 49.8±14%) underwent transesophageal echocardiography, with LAAT identified in 140 of 1001 patients (14%) and dense spontaneous echo contrast precluding cardioversion in a further 75 patients (7.5%). AF duration, AF rhythm, creatinine, stroke, diabetes, and echocardiographic parameters were univariate LAAT predictors; age, female sex, body mass index, anticoagulant type, and duration were not (all P>0.05). CHADS2VASc, though significant on univariate analysis (P<0.001), was not significant after adjustment (P=0.12). The novel CLOTS-AF risk model comprised significant multivariable predictors categorized and weighted according to clinically relevant thresholds (Creatinine >1.5 mg/dL, Left ventricular ejection fraction <50%, Overload (left atrial volume index >34 mL/m2), Tricuspid Annular Plane Systolic Excursion (TAPSE) <17 mm, Stroke, and AF rhythm). The unweighted risk model had excellent predictive performance with an area under the curve of 0.820 (95% CI, 0.752-0.887). The weighted CLOTS-AF risk score maintained good predictive performance (AUC, 0.780) with an accuracy of 72%. Conclusions The incidence of LAAT or dense spontaneous echo contrast precluding cardioversion in patients with AF who are inadequately anticoagulated is 21%. Clinical and noninvasive echocardiographic parameters may identify patients at increased risk of LAAT better managed with a suitable period of anticoagulation before undertaking cardioversion.