Quality of life in the antiarrhythmics versus implantable defibrillators trial: impact of therapy and influence of adverse symptoms and defibrillator shocks

A Systematic Review and Meta-Analysis of Catheter Ablation Versus Anti-arrhythmic Drugs for Treatment of Ventricular Arrhythmia

Catheter ablation (CA) and anti-arrhythmic drugs (AADs) minimize implanted cardioverter-defibrillator (ICD) shocks in individuals with ischemic cardiomyopathy and an ICD, while the best strategy is still unknown. CA has been proposed as a potentially effective means of reducing the occurrence of ICD events in a number of studies; however, there were insufficient relevant dates from randomized controlled trials. A meta-analysis and systematic review of randomized controlled trials were carried out to evaluate the efficacy of CA for the prevention of VA in patients with ischemic heart disease. Cardiovascular mortality, an unscheduled hospitalization due to increasing heart failure, appropriate ICD shock, or serious treatment-related consequences comprised the composite primary outcome. AADs were examined in six trials (n = 1564; follow-up = 15 ± 8 months), while CA was evaluated in four trials (n = 682; follow-up = 12 ± 6 months). Both CA (odds ratio (OR) 0.65, 95% confidence interval (CI) 0.47-0.82, p = 0.001) and AADs (OR 0.76, 95% CI 0.32-0.84, p = 0.034) significantly reduced the number of suitable ICD interventions, with no discernible difference between the two treatment approaches. AADs were observed to reduce incorrect ICD interventions (OR 0.38, p = 0.001), but CA did not. During follow-up, there was no correlation seen between reduced mortality and either CA or AAD. When compared to AAD, CA decreased the composite endpoint of cardiovascular death, adequate ICD shock, heart failure-related hospitalization, or severe treatment-related consequences in ICD patients with ischemic cardiomyopathy and symptomatic VT.

Assessing the impact of omega-3 fatty acids on ventricular tachyarrhythmia and survival in patients with ICDs: A systematic review and meta-analysis

Background

Recent studies investigating the effects of fish oil on shocks administered by ICDs in patients with ventricular tachycardias produced inconclusive results. This systematic review aims to evaluate the effectiveness of omega-3 polyunsaturated fatty acids in lowering the risk of life-threatening VTs among individuals with implantable cardioverter-defibrillators.

Methods

We searched five databases, including Central, PubMed, EMBASE, Web of Science, and Scopus, for studies evaluating the efficacy of omega-3 polyunsaturated fatty acids (PUFAs) for the prevention of ICD events for VT or VF, published up to December 1, 2023.

Results

Four trials were finally included in the study. The pooled risk ratios for mortality and ICD events were 0.87 (95% CI:0.58-1.32) and 0.75 (95% CI:0.48-1.18), respectively.

Conclusion

No significant effect was discovered to support the antiarrhythmic properties or survival advantages of n-3 polyunsaturated fatty acids (PUFA) in individuals with implanted implantable cardioverter-defibrillators (ICD).

A Modular Communicative Leadless Pacing-Defibrillator System

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown.

METHODS

We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%).

RESULTS

We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure.

CONCLUSIONS

The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.).

Evaluation of patients with implantable cardioverter-defibrillator in a Latin American tertiary center

INTRODUCTION

Despite advancements in implantable cardioverter-defibrillator (ICD) technology, sudden cardiac death (SCD) remains a persistent public health concern. Chagas disease (ChD), prevalent in Brazil, is associated with increased ventricular tachycardia (VT) and ventricular fibrillation (VF) events and SCD compared to other cardiomyopathies.

METHODS

This retrospective observational study included patients who received ICDs between October 2007 and December 2018. The study aims to assess whether mortality and VT/VF events decreased in patients who received ICDs during different time periods (2007-2010, 2011-2014, and 2015-2018). Additionally, it seeks to compare the prognosis of ChD patients with non-ChD patients. Time periods were chosen based on the establishment of the Arrhythmia Service in 2011. The primary outcome was overall mortality, assessed across the entire sample and the three periods. Secondary outcomes included VT/VF events and the combined outcome of death or VT/VF.

RESULTS

Of the 885 patients included, 31% had ChD. Among them, 28% died, 14% had VT/VF events, and 37% experienced death and/or VT/VF. Analysis revealed that period 3 (2015-2018) was associated with better death-free survival (p = .007). ChD was the only variable associated with a higher rate of VT/VF events (p < .001) and the combined outcome (p = .009).

CONCLUSION

Mortality and combined outcome rates decreased gradually for ICD patients during the periods 2011-2014 and 2015-2018 compared to the initial period (2007-2010). ChD was associated with higher VT/VF events in ICD patients, only in the first two periods.

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.

Cardiac stereotactic radiation therapy for refractory ventricular arrhythmias in patients with left ventricular assist devices

Left ventricular assist device (LVAD) implantation is an established treatment for patients with advanced heart failure refractory to medical therapy. However, the incidence of ventricular arrhythmias (VAs) is high in this population, both in the acute and delayed phases after implantation. About one-third of patients implanted with an LVAD will experience sustained VAs, predisposing these patients to worse outcomes and complicating patient management. The combination of pre-existing myocardial substrate and complex electrical remodeling after LVAD implantation account for the high incidence of VAs observed in this population. LVAD patients presenting VAs refractory to antiarrhythmic therapy and catheter ablation procedures are not rare. In such patients, treatment options are extremely limited. Stereotactic body radiation therapy (SBRT) is a technique that delivers precise and high doses of radiation to highly defined targets, reducing exposure to adjacent normal tissue. Cardiac SBRT has recently emerged as a promising alternative with a growing number of case series reporting the effectiveness of the technique in reducing the VA burden in patients with arrhythmias refractory to conventional therapies. The safety profile of cardiac SBRT also appears favorable, even though the current clinical experience remains limited. The use of cardiac SBRT for the treatment of refractory VAs in patients implanted with an LVAD are even more scarce. This review summarizes the clinical experience of cardiac SBRT in LVAD patients and describes technical considerations related to the implementation of the SBRT procedure in the presence of an LVAD.

Mechanical Support Strategies for High-Risk Procedures in the Invasive Cardiac Catheterization Laboratory: A State-of-the-Art Review

Thanks to advancements in percutaneous cardiac interventions, an expanding patient population now qualifies for treatment through percutaneous endovascular procedures. High-risk interventions far exceed coronary interventions and include transcatheter aortic valve replacement, endovascular management of acute pulmonary embolism and ventricular tachycardia ablation. Given the frequent impairment of ventricular function in these patients, frequently deteriorating during percutaneous interventions, it is hypothesized that mechanical ventricular support may improve periprocedural survival and subsequently patient outcome. In this narrative review, we aimed to provide the relevant evidence found for the clinical use of percutaneous mechanical circulatory support (pMCS). We searched the Pubmed database for articles related to pMCS and to pMCS and invasive cath lab procedures. The articles and their references were evaluated for relevance. We provide an overview of the clinically relevant evidence for intra-aortic balloon pump, Impella, TandemHeart and ECMO and their role as pMCS in high-risk percutaneous coronary intervention, transcatheter valvular procedures, ablations and high-risk pulmonary embolism. We found that the right choice of periprocedural pMCS could provide a solution for the hemodynamic challenges during these procedures. However, to enhance the understanding of the safety and effectiveness of pMCS devices in an often high-risk population, more randomized research is needed.

Information provision and follow-up of French patients with implantable cardioverter-defibrillators: The APODEC survey

BACKGROUND

Implantable cardioverter-defibrillators reduce mortality, but the electric shocks delivered can impact the patient's quality of life. Patient education is an efficient way to reduce the stress related to both the device and the disease.

AIMS

We assessed the evolution of knowledge and satisfaction of implantable cardioverter-defibrillator recipients regarding their cardiac disease, implantable cardioverter-defibrillator implantation, follow-up complications, remote monitoring and daily life recommendations. Quality of life, implantable cardioverter-defibrillator-related stress levels and remote monitoring benefits were also evaluated.

METHODS

A self-administered questionnaire of 43 items was published on the French Association of Cardiac Electrical Device Wearers (APODEC) website and sent to registered patients.

RESULTS

Overall, 330 patients completed the survey. Physicians were the patients' principal information source regarding their cardiac disease (86.7%) and implantable cardioverter-defibrillator (93.3%), and 90% looked for further information after the procedure, mainly on websites (78.8%). More than half of the patients were not sufficiently informed about implantable cardioverter-defibrillators before implantation (61.2%). In the patients' opinion, the best sources of further information were their physician (81.8%), patient associations (63.6%) and the Internet (45.8%). Although patient knowledge increased during follow-up, their knowledge could be improved regarding daily life with an implantable cardioverter-defibrillator (52.1%), remote monitoring (34.2%) and their cardiac disease (32.1%). Remote monitoring follow-up was used by 92.1% of patients and mostly improved their peace of mind (67.8%). Implantable cardioverter-defibrillator shocks were associated with major stress for patients receiving them (46.6%).

CONCLUSION

These findings highlight the lack of information provided to implantable cardioverter-defibrillator recipients before implantation, a concerning issue to be addressed in the near future.

Recurrences of ventricular tachycardia after stereotactic arrhythmia radioablation arise outside the treated volume: analysis of the Swiss cohort

AIMS

Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of therapy-refractory ventricular tachycardia (VT). VT recurrences have been reported after STAR but the mechanisms remain largely unknown. We analysed recurrences in our patients after STAR.

METHODS AND RESULTS

From 09.2017 to 01.2020, 20 patients (68 ± 8 y, LVEF 37 ± 15%) suffering from refractory VT were enrolled, 16/20 with a history of at least one electrical storm. Before STAR, an invasive electroanatomical mapping (Carto3) of the VT substrate was performed. A mean dose of 23 ± 2 Gy was delivered to the planning target volume (PTV). The median ablation volume was 26 mL (range 14-115) and involved the interventricular septum in 75% of patients. During the first 6 months after STAR, VT burden decreased by 92% (median value, from 108 to 10 VT/semester). After a median follow-up of 25 months, 12/20 (60%) developed a recurrence and underwent a redo ablation. VT recurrence was located in the proximity of the treated substrate in nine cases, remote from the PTV in three cases and involved a larger substrate over ≥3 LV segments in two cases. No recurrences occurred inside the PTV. Voltage measurements showed a significant decrease in both bipolar and unipolar signal amplitude after STAR.

CONCLUSION

STAR is a new tool available for the treatment of VT, allowing for a significant reduction of VT burden. VT recurrences are common during follow-up, but no recurrences were observed inside the PTV. Local efficacy was supported by a significant decrease in both bipolar and unipolar signal amplitude.

From organ at risk to target organ: Dosimetric comparison of myocardial stereotactic ablative body radiotherapy between helical tomotherapy and volumetric arc therapy for refractory ventricular tachycardia

Ventricular tachycardia (VT) is an important type of arrhythmia with a risk of sudden death. Although implanted cardiac defibrillation and radiofrequency ablation are used together with medical treatments for VT, the treatment options are limited in cases that do not respond to them. Stereotactic ablative body radiotherapy (SABR) applied to VT substrates in resistant cases is an emerging treatment with positive results. Such clinical results have increased the interest in this subject. However, the ideal treatment device and method have not yet been described for this therapy, which is generally applied at a single fraction using various devices and methods. Herein, treatment planning was conducted for a total of 8 patients (11 VT substrates) using the Varian TrueBeam EDGE and TomoTherapy Radixact devices at a single center, and the results were compared dosimetrically. The Wilcoxon-signed rank test was used for the statistical analysis, and mean values were expressed as medians and interquartile ranges (IQRs). In the volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) plans, the plan coverages and conformity indexes were similar; meanwhile, the homogeneity indexes were 0.10 (IQR = 0.05) and 0.07 (IQR = 0.05), respectively, and were significantly better in the HT plan (p = 0.02). The gradient indexes were 3.18 (IQR = 0.8) and 5.33 (IQR = 3.68) in the VMAT and HT plans, respectively, and were significantly better in the VMAT plan. For the organs at risk, similar doses were observed. The maximum doses for the stomach and esophagus and the mean doses for the left lung and both lungs were significantly lower in the VMAT plan. Similarly, the maximum and mean doses for the cardiac substructures and great vessels were significantly lower in the VMAT plan. More homogeneous plans were obtained in HT, while a faster dose reduction and lower critical organ dose were observed in VMAT. Reasonable myocardial SABR plans could be obtained with both techniques. The effects of the dosimetric differences on the clinical outcomes should be evaluated in prospective clinical studies.

Design and rationale of the MODULAR ATP global clinical trial: A novel intercommunicative leadless pacing system and the subcutaneous implantable cardioverter-defibrillator

Background

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has demonstrated safety and efficacy for the treatment of malignant ventricular arrhythmias. However, a limitation of the S-ICD lies in the inability to either pace-terminate ventricular tachycardia or provide prolonged bradycardia pacing support.

Objective

The rationale and design of a prospective, single-arm, multinational trial of an intercommunicative leadless pacing system integrated with the S-ICD will be presented.

Methods

A technical description of the modular cardiac rhythm management (mCRM) system (EMPOWER leadless pacemaker and EMBLEM S-ICD) and the implantation procedure is provided. MODULAR ATP (Effectiveness of the EMPOWER™ Modular Pacing System and EMBLEM™ Subcutaneous ICD to Communicate Antitachycardia Pacing) is a multicenter, international trial enrolling up to 300 patients at risk of sudden cardiac death at up to 60 centers trial design. The safety endpoint of freedom from major complications related to the mCRM system or implantation procedure at 6 months and 2 years are significantly higher than 86% and 81%, respectively, and all-cause survival is significantly >85% at 2 years.

Results

Efficacy endpoints are that at 6 months mCRM communication success is significantly higher than 88% and the percentage of subjects with low and stable thresholds is significantly higher than 80%. Substudies to evaluate rate-responsive features and performance of the pacing module are also described.

Conclusion

The MODULAR ATP global clinical trial will prospectively test the safety and efficacy of the first intercommunicating leadless pacing system with the S-ICD. This trial will allow for robust validation of device-device communication, pacing performance, rate responsiveness, and system safety.

Assessing the Cost and Resource Use Impact of Implantable Cardiac Defibrillator Shocks in the UK CareLink Population

Objective

High voltage devices (implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillators referred to jointly as ICDs) reduce rates of sudden cardiac death in patients with cardiovascular disease. However, shocks from ICDs may be associated with healthcare resource use (HCRU) and costs. The aim of this study was to estimate the costs associated with both appropriate and inappropriate shocks from ICDs.

Methods

Patients with appropriate and inappropriate shocks from ICDs were identified via CareLink data from Liverpool Heart and Chest Hospital between March 2017 and March 2019. The devices were SmartShock activated, with anti-tachycardia pacing. Costs were estimated according to the dominant episode of healthcare, from an NHS payer perspective.

Results

There were 2445 patients on the CareLink system with ICDs. Over the two-year period, HCRU data from 143 shock episodes among 112 patients were reported. The total cost for all shocks was £252,552 with mean costs of £1608 and £2795 for appropriate and inappropriate shocks respectively. There was substantial variation in HCRU between shock episodes.

Conclusion

While there was a low rate of inappropriate shocks from ICDs, there were still substantial HCRU and costs incurred. In this study, the specific HCRU was not costed independently, meaning the costs reported are likely to be a conservative estimate. Whilst every attempt to reduce shocks should be made, appropriate shocks cannot be avoided. Strategies to reduce the incidence of inappropriate and unnecessary shocks should be implemented to reduce overall health care costs associated with ICDs.

Overview of Cardiac Arrhythmias and Treatment Strategies

Maintenance of normal cardiac rhythm requires coordinated activity of ion channels and transporters that allow well-ordered propagation of electrical impulses across the myocardium. Disruptions in this orderly process provoke cardiac arrhythmias that may be lethal in some patients. Risk of common acquired arrhythmias is increased markedly when structural heart disease caused by myocardial infarction (due to fibrotic scar formation) or left ventricular dysfunction is present. Genetic polymorphisms influence structure or excitability of the myocardial substrate, which increases vulnerability or risk of arrhythmias in patients. Similarly, genetic polymorphisms of drug-metabolizing enzymes give rise to distinct subgroups within the population that affect specific drug biotransformation reactions. Nonetheless, identification of triggers involved in initiation or maintenance of cardiac arrhythmias remains a major challenge. Herein, we provide an overview of knowledge regarding physiopathology of inherited and acquired cardiac arrhythmias along with a summary of treatments (pharmacologic or non-pharmacologic) used to limit their effect on morbidity and potential mortality. Improved understanding of molecular and cellular aspects of arrhythmogenesis and more epidemiologic studies (for a more accurate portrait of incidence and prevalence) are crucial for development of novel treatments and for management of cardiac arrhythmias and their consequences in patients, as their incidence is increasing worldwide.

Antitachycardia pacing at the His bundle is safer than conventional right ventricular antitachycardia pacing in a canine myocardial ischemic injury model

INTRODUCTION

Antitachycardia pacing (ATP) is used to terminate ventricular tachycardia (VT) by delivering rapid, low energy pacing to the right ventricle (RV). Unfortunately, ATP is not effective against all VT episodes and can result in adverse outcomes, such as VT acceleration and degeneration into ventricular fibrillation (VF). Improving ATP is therefore desirable. Our objective was to compare the efficacy and safety of ATP delivered at the His bundle to traditional ATP.

METHODS

Six dogs were anesthetized and pacing leads were implanted in the RV and His bundle. The left anterior descending artery was occluded for 2 h to create an ischemic injury. In a study 4-7 days later, a 128-electrode sock was placed snugly around the ventricles and VT was induced using rapid pacing. ATP was delivered from either the His bundle or RV lead, then attempted at the other location if unsuccessful. Success rates and instances of VT acceleration and degeneration into VF were calculated.

RESULTS

We induced 83 runs of VT and attempted ATP 128 times. RV ATP was successful in 36% of attempts; His ATP was successful in 38% of attempts. RV ATP resulted in significantly more adverse outcomes. RV and His ATP induced VT acceleration in 9% and 3% of trains, respectively, and induced degeneration into VF in 5% and 1% of trains, respectively.

CONCLUSION

His bundle ATP is safer, but not significantly more effective, than RV ATP.

Long-Term Results of the First Clinical Application of Stereotactic Radioablation Using a Linear Electron Accelerator for the Treatment of Ventricular Tachycardia

We present the first clinical application of non-invasive stereotaxic radioablation of ventricular tachycardia (VT) refractory to medical and surgical treatment. Based on the results of invasive navigational activation mapping, a pericicatrical zone in the interventricular septum associated with VT was verified. Radiosurgical irradiation of the target in the region of the interventricular septum and the posterior apical segment of the left ventricle was performed on a TrueBeam linear electron accelerator (Varian) in accordance with the segmental scheme of the left ventricle. Irradiation doses for 95% of the internal target volume (ITV, 17 cm³) and planned target volume (PTV, 46 cm³) (31.2 and 25 Gy, respectively) were delivered by two full coplanar arches in 1 session. Irradiation was performed during expiration using a respiratory control system. The loading dose to critical structures was within tolerance. The planned follow-up period is 6 months. According to remote monitoring, the intensity of VT paroxysms over 48 days after treatment was from daily to 2-3 per day. Then, the incidence of VT paroxysms decreased (1-3 per week), and from the 64th to the 185th day (the end of the observation period), no VT paroxysms were recorded, which suggests that the impact was highly precise, conformal, and involved the total wall thickness. No undesirable effects and damage to adjacent organs were observed.

Safety and efficacy of catheter ablation for ventricular tachycardia in elderly patients with structural heart disease: a systematic review and meta-analysis

PURPOSE

Data regarding the age-specific outcomes of VT ablation in patients with structural heart disease (SHD) are scarce. We performed a systematic review and meta-analysis to evaluate the outcomes of VT ablation in elderly vs. younger patients with SHD.

METHODS

MEDLINE/PubMed, Cochrane, and Google Scholar and references comparing VT ablation in elderly vs. younger patients were screened and studies included if matching inclusion and exclusion criteria.

RESULTS

Five retrospective studies enrolling 2778 SHD patients (868 elderly vs. 1910 younger) were included. Compared to younger subjects, the elderly showed similar results in terms of acute ablation success (OR 0.78, 95% CI 0.54-1.13, p = 0.189) and minor complications (OR 1.74, 95% CI 0.74-4.09, p = 0.205), a trend toward a higher risk of major complications (OR 2.30, 95% CI 0.83-6.40, p = 0.110) and significantly higher rates of all complications (OR 2.67, 95% CI 1.51-4.71, p = 0.001) and periprocedural mortality (OR 1.93, 95% CI 1.24-3.01, p = 0.004). At a mean follow-up of 18 months, elderly patients showed similar long-term VT recurrence rate (OR 1.02, 95% CI 0.85-1.22, p = 0.861) and higher all-cause mortality (OR 2.00, 95% CI 1.40-2.86, p < 0.001). In elderly patients, urgent VT ablation is associated with higher risk of major complications (beta = 0.06, p < 0.001) and periprocedural mortality (beta = 0.03, p = 0.029), while advanced age is associated with higher risk of major complications (beta = 0.29 with p = 0.009) and all complications + periprocedural mortality (beta = 0.17 with p = 0.037).

CONCLUSIONS

Compared to younger patients, VT ablation in elderly showed similar results in terms of acute ablation success and long-term VT recurrence rate with a significantly higher risk of all complications, periprocedural mortality, and long-term mortality, especially when the procedure is performed urgently and in the most aged patients. Large prospective multicenter randomized trials are required to confirm these findings.

The Use of Cardiac Stereotactic Radiation Therapy (SBRT) to Manage Ventricular Tachycardia: A Case Report, Review of the Literature and Technical Notes

BACKGROUND

among cardiac arrhythmias, ventricular tachycardia (VT) is one that can lead to cardiac death, although significant progress has been made in its treatment, including the use of implantable cardioverter-defibrillators (ICD) and radiofrequency catheter ablation. Nevertheless, long-term recurrence rates remain in about half of patients and drastically impact the patient's quality of life. Moreover, recurrent ICD shocks are painful and are associated with higher mortality and worsening of heart failure. Recently, more and more experiences are demonstrating potential efficacy in the use of stereotactic body radiotherapy (SBRT) (also called cardiac radio-ablation) to treat this condition. In this paper, we report our experience in the use of cardiac radio-ablation for the treatment of refractory ventricular tachycardia with a focus on the technique used, along with a review of the literature and technical notes.

CASE PRESENTATION

an 81-year-old male patient with a long history of non-ischemic dilated cardiomyopathy and mechanical mitral prosthesis underwent a biventricular cardioverter defibrillator implant after atrial ventricular node ablation. At the end of 2021, the number of tachycardias increased significantly to about 10 episodes per day. After failure of medical treatment and conventional RT catheter ablation, the patient was treated with SBRT for a total dose of 25 Gy in a single session at the site of the ectopic focus. No acute toxicity was recorded. After SBRT (follow-up 7 months) no other VT episodes were recorded.

CONCLUSION

SBRT appears to be safe and leads to a rapid reduction in arrhythmic storms as treatment for VT without acute toxicity, representing one of the most promising methods for treating VT storms.

Patient-Reported Outcomes in a Multidisciplinary Electrophysiology-Psychology Ventricular Arrhythmia Clinic

Background Ventricular arrhythmias (VAs) and their treatment have been associated with psychological distress and diminished quality of life (QOL). We administered a battery of patient-reported outcome measures (PROMs) to patients seeing an electrophysiologist and psychologist in a multidisciplinary VA clinic for patients referred for consideration of catheter ablation for sustained VAs or implantable cardioverter-defibrillator therapies. Methods and Results In this retrospective study of the initial VA clinic visit, we analyzed PROMs of: anxiety and depression symptoms, visual analog scales for physical health status and quality of life, cardiac anxiety, implantable cardioverter-defibrillator acceptance, and implantable cardioverter-defibrillator shock anxiety. We quantitated baseline PROM score means and performed correlation analysis with clinical makers of cardiac and VA disease severity. We also performed an item-level analysis of each PROM question to quantify most frequent patient concerns. A total of 66 patients (56±15 years; 77% men) were included; 70% had prior implantable cardioverter-defibrillator shock, and 44% with prior VA ablation. Elevated symptoms of anxiety (53%) and depression (20%) were common. Younger patients had greater symptom burden of general health anxiety, cardiac anxiety, and shock anxiety, and lower device acceptance, but indices of VA burden such as number of ICD shocks and time since last ICD shock did not predict anxiety or depression. Item-level review of cardiac-specific PROMs revealed that >40% of patients expressed concern regarding resumption of physical activity, sex and employment. Conclusions Clinicians can expect elevated symptoms of depression, and cardiac and device-related anxiety among patients with VAs. Routine use of PROMs may elicit these symptoms, which were otherwise not predicted by arrhythmia burden.  Review of individual PROM items can facilitate targeting specific patient concerns, which commonly involved physical activity.

Stereotactic Radiotherapy: An Alternative Option for Refractory Ventricular Tachycardia to Drug and Ablation Therapy

Refractory ventricular tachycardia (VT) often occurs in the context of organic heart disease. It is associated with significantly high mortality and morbidity rates. Antiarrhythmic drugs and catheter ablation represent the two main treatment options for refractory VT, but their use can be associated with inadequate therapeutic responses and procedure-related complications. Stereotactic body radiotherapy (SBRT) is extensively applied in the precision treatment of solid tumors, with excellent therapeutic responses. Recently, this highly precise technology has been applied for radioablation of VT, and its early results demonstrate a favorable safety profile. This review presents the potential value of SBRT in refractory VT.

Reduction in Ventricular Tachyarrhythmia Burden in Patients Enrolled in the RAID Trial

BACKGROUND

The RAID (Ranolazine Implantable Cardioverter-Defibrillator) randomized placebo-controlled trial showed that ranolazine treatment was associated with reduction in recurrent ventricular tachycardia (VT) requiring appropriate implantable cardioverter-defibrillator (ICD) therapy.

OBJECTIVES

This study aimed to identify groups of patients in whom ranolazine treatment would result in the highest reduction of ventricular tachyarrhythmia (VTA) burden.

METHODS

Andersen-Gill analyses were performed to identify variables associated with risk for VTA burden among 1,012 patients enrolled in RAID. The primary endpoint was VTA burden defined as VTA episodes requiring appropriate treatment.

RESULTS

Multivariate analysis identified 7 factors associated with increased VTA burden: history of VTA, age ≥65 years, New York Heart Association functional class ≥III, QRS complex (≥130 ms), low ejection fraction (<30%), atrial fibrillation (AF), and concomitant antiarrhythmic drug (AAD) therapy. The effect of ranolazine on VTA burden was seen among patients without concomitant AAD therapy (HR [HR]: 0.68; 95% CI: 0.55-0.84; P < 0.001), whereas no effect was seen among those who are concomitantly treated with other AADs (HR: 1.33; 95% CI: 0.90-1.96; P = 0.16); P = 0.003 for interaction. In patients with cardiac resynchronization therapy (CRT) ICDs, ranolazine treatment was associated with a 36% risk reduction for VTA recurrence (HR: 0.64; 95% CI: 0.47-0.86; P < 0.001), whereas among patients with ICDs without CRT no significant effect was noted (HR: 0.94; 95% CI: 0.74-1.18; P = 0.57); P = 0.047 for interaction.

CONCLUSIONS

In patients with high risk for VTA, ranolazine is effective in reducing VTA burden, with significantly greater effect in CRT-treated patients, those without AF, and those not treated with concomitant AADs. In patients already on AADs or those with AF, the addition of ranolazine did not affect VTA burden. (Ranolazine Implantable Cardioverter-Defibrillator Trial [RAID]; NCT01215253).

Stereotactic ablative radiotherapy in patients with refractory ventricular tachyarrhythmia

Stereotactic ablative body radiotherapy (SABR) is an innovative therapeutic approach in patients (pts) with a diagnosis of refractory ventricular tachyarrhythmia (VT) after the use of drugs, radiofrequency catheter ablation, and/or defibrillator (ICD) implant. The current efficacy data of SABR are limited and several prospective clinical studies are ongoing to support the use of ablative radiation dose to control VT. The aim of the current prospective pilot study is to report the efficacy and tolerability of SABR in ICD implanted pts with refractory VT in our centre. Non-invasive electroanatomical mapping (EAM), cardiac computed tomography (CT), and 18F-fluorodeoxyglucose positron emission (FDG-PET)-CT scan were used and combined with a radiation CT scan. A dose prescription of 25 Gy in a single dose was delivered by volumetric modulated arc therapy (VMAT) Linac-based. The primary endpoint was efficacy, defined as a reduction in ICD shocks after SABR treatment, while the secondary endpoint was safety. Six consecutive pts (five males and one female) implanted with an ICD and with three or more VT were enrolled. One pts died after 1 month, due to end-stage heart failure. Two pts experienced ICD shocks in VT 2 and 5 months after treatment. Three pts experienced no more ICD shocks on VT after therapy. Our data suggest the efficacy and safety of SABR treatment in pts with VT. Larger dataset of pts and longer follow-up are otherwise required to validate the impact of SABR as a standardized treatment in these pts.

Epicardial ablation of ventricular tachycardia in patients with structural heart disease: a single-centre experience over 12 years

AIMS

Epicardial ablation has risen to an essential part of the treatment of ventricular tachycardias (VTs). In this study, we report the efficacy, risks, and current trends of epicardial ablation in structural heart disease as reported in a tertiary single centre over a 12-year period.

METHODS AND RESULTS

Two hundred and thirty-six patients referred for VT ablation underwent a successful epicardial access and were included in the analysis (89% non-ischaemic cardiomyopathy, 90% males, mean age 60 years, mean left ventricular ejection fraction 38.4%). After performing epicardial ablation the clinical VTs were eliminated in 87% of the patients and 71% of the cohort achieved freedom from VT during 22-month follow-up. Twelve patients (5%) suffered major procedure-related complications. Until the end of follow-up 47 (20%) patients died, 9 (4%) underwent a left ventricular assist device implantation and 10 (4%) patients received a heart transplantation. Antiarrhythmic drugs at baseline and during follow-up were independent predictors of VT recurrence. Atrial fibrillation, renal dysfunction, worse New York Heart Association class, and antiarrhythmic drugs at follow-up were associated with worse survival in our cohort.

CONCLUSION

In this large tertiary single-centre experience, percutaneous epicardial access was feasible in the large majority of the cohort with acceptably low complications rates. A combined endo-/epicardial approach resulted in 87% acute and 71% long-term success. Further studies are needed to clarify the role of routine combined endo-/epicardial ablation in these complex cardiomyopathies.

Psychosocial symptoms of ventricular arrhythmias: Integrating patient-reported outcomes into clinical care

Patient-reported outcome measures (PROMs) are a valuable metric for assessing the quality of life and overall well-being in patients with ventricular arrhythmias (VAs) and/or implantable cardioverter-defibrillators (ICDs). The incorporation of PROMs into the workflow of a VA clinic not only allows for more patient-centered care but also may improve detection and treatment of clinically relevant anxiety or depression symptoms. Awareness of the factors known to correlate with adverse PROM scores may guide PROM administration and subsequent referral to mental health services. Further, change or stability in PROM scores can be used as a gauge to guide the effectiveness of cardiac and psychological treatment in certain populations that are the focus of this manuscript: patients with ICDs (with and without shocks), cardiac arrest survivors, and those with inherited arrhythmia syndromes.

CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia (CERTAINTY)

Better models to identify individuals at low risk of ventricular arrhythmia (VA) are needed for implantable cardioverter-defibrillator (ICD) candidates to mitigate the risk of ICD-related complications. We designed the CERTAINTY study (CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia) with deep learning for VA risk prediction from cine cardiac magnetic resonance (CMR). Using a training cohort of primary prevention ICD recipients (n = 350, 97 women, median age 59 years, 178 ischemic cardiomyopathy) who underwent CMR immediately prior to ICD implantation, we developed two neural networks: Cine Fingerprint Extractor and Risk Predictor. The former extracts cardiac structure and function features from cine CMR in a form of cine fingerprint in a fully unsupervised fashion, and the latter takes in the cine fingerprint and outputs disease outcomes as a cine risk score. Patients with VA (n = 96) had a significantly higher cine risk score than those without VA. Multivariate analysis showed that the cine risk score was significantly associated with VA after adjusting for clinical characteristics, cardiac structure and function including CMR-derived scar extent. These findings indicate that non-contrast, cine CMR inherently contains features to improve VA risk prediction in primary prevention ICD candidates. We solicit participation from multiple centers for external validation.

Depressive symptoms in patients after primary and secondary prophylactic ICD implantation

OBJECTIVE

Implantable cardioverter defibrillators (ICD) are successfully used to treat life-threatening arrhythmias and prevent sudden cardiac death. However, they are also known to have a major psychological impact leading to higher prevalence of depression and anxiety in a substantial proportion of patients. The aim of this study was to assess the prevalence of depressive symptoms in a large cohort of ICD carriers with a different clinical background and to compare prevalence and risk factors between patients with primary and secondary prophylactic indication for ICD implantation.

METHODS

315 out of 622 patients (50.6%), who regularly attended ICD assessments at the University Hospital Zurich completed the Beck Depression Inventory (BDI I-II) to estimate current depressive symptoms.

RESULTS

Overall, depressive symptoms were common in ICD patients, with 20.3% of the patients showing clinically relevant depression (12.4% mild depressive symptoms, 6.0% moderate, 1.9% severe). Moderate to severe depressive symptoms seem to be more likely in patients with secondary prophylactic indication of the ICD as compared to a group of patients with primary prophylactic implantation. Patients that received more than 5 ICD shocks since implantation reveal more depressive symptoms than those with less events. Mean BDI Score in total (n = 315) was at 8.44 ± 7.56 without a statistically significant difference between the primary (M = 8.04 ± 7.10, n = 153) and secondary (M = 8.81 ± 7.98, n = 162) preventive group (p value = 0.362), even after adjustment for various clinical characteristics. ICD patients should therefore be well supported and advised concerning the psychological impact of their device and particular aspects of daily life concerns (e.g. physical activity), with a special focus on patients, who have received multiple shocks.

Health-Related Quality of Life in the Spironolactone to Reduce ICD Therapy (SPIRIT) Trial

To describe health related quality of life (HRQOL) and symptoms in the SPIRIT trial and determine effects of implantable cardioverter defibrillator (ICD) shocks on HRQOL over 24 months. Ninety participants aged 66 ± 10 years, 96% men, 75% with NYHA class II, with an ICD were randomized to spironolactone 25 mg (N = 44) or placebo (N = 46). HRQOL was measured every 6 months for 24 months using: Patient Concerns Assessment (PCA), Short Form Health Survey-Veterans Version (SF-36V), and Kansas City Cardiomyopathy Questionnaire (KCCQ). Linear mixed modeling compared changes in HRQOL over-time and ANCOVA compared HRQOL between those getting an ICD shock or not. Over 24-months, there were no differences in HRQOL between the spironolactone versus placebo groups. Those with at least one ICD shock reported significantly lower HRQOL and more symptoms at 6- and 24-months. Patients receiving one or more ICD shocks reported significant reductions in HRQOL and higher symptoms.

ICD therapy in the elderly: a retrospective single-center analysis of mortality

BACKGROUND

Current implantable cardioverter-defibrillator (ICD) guidelines do not impose age limitations for ICD implantation (IMPL) and generator exchange (GE); however, patients (pts) should be expected to survive for 1 year. With higher age, comorbidity and mortality due to non-sudden cardiac death increase. Thus, the benefit of ICD therapy in elderly pts remains unclear. Mortality after ICD IMPL or GE in pts ≥ 75 years was assessed.

METHODS

Consecutive pts aged ≥ 75 years with ICD IMPL or GE at the University Hospital Cologne, Germany, between 01/2013 and 12/2017 were included in this retrospective analysis.

RESULTS

Of 418 pts, 82 (20%) fulfilled the inclusion criteria; in 70 (55 = IMPL, 79%, 15 = GE, 21%) follow-up (FU) was available. The median FU was 3.1 years. During FU, 40 pts (57%) died (29/55 [53%] IMPL; 11/15 [73%] GE). Mean survival after surgery was 561 ± 462 days. The 1‑year mortality rate was 19/70 (27%) overall, 9/52 (17%) in pts ≥ 75 and 10/18 (56%) in pts ≥ 80 years. Deceased pts were more likely to suffer from chronic renal failure (85% vs. 53%, p = 0.004) and peripheral artery disease (18% vs. 0%, p = 0.02). During FU, seven pts experienced ICD shocks (four appropriate, three inappropriate). In primary prevention (n = 35) mortality was 46% and four pts experienced ICD therapies (two adequate); in secondary prevention (n = 35) mortality was 69% (p = 0.053) with three ICD therapies (two adequate).

CONCLUSION

Mortality in ICD pts aged ≥ 80 years was 56% at 1 and 72% at 2 years in this retrospective analysis. The decision to implant an ICD in elderly pts should be made carefully and individually.

Comparative Study between Subcutaneous and Endovascular Defibrillator Recipients Regarding Tolerance to the Implant Procedure and Perception of Quality of Life

BACKGROUND

The totally subcutaneous implantable cardioverter-defibrillator (S-ICD) is a safe alternative to the conventional transvenous ICD (TV-ICD) system to prevent sudden death.

OBJECTIVE

To compare the impact of the type of ICD system and surgical technique on patients' quality of life, as well as the severity of discomfort and pain, between S-ICD and TV-ICD recipients.

METHODS

Consecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system. In addition, patients undergoing S-ICD implantation after removal of a TV-ICD due to complications were included. Quality of life (measured with the 12-item short-form health survey) and severity of pain and discomfort were evaluated. Statistical significance was defined as p < 0.05.

RESULTS

A total of 64 patients implanted with S-ICD or TV-ICD under local anesthesia and conscious sedation were analyzed. Patients with S-ICD and TV-ICD systems did not differ significantly in quality of life scores. S-ICD patients had a higher level of perioperative pain; no differences were found regarding severity of intraoperative pain. The magnitude of aesthetic discomfort and sleep disturbances did not differ between groups. An S-ICD was implanted in 7 additional patients after removal of a TV-ICD. All but one of these patients recommended the S-ICD system.

CONCLUSIONS

The type of ICD system and the surgical technique have negligible impact on patients' quality of life. These results suggest that conscious sedation, provided by an experienced electrophysiology team, could be considered as an alternative to general anesthesia to manage patients undergoing S-ICD implantation.

Hospitalization for Heart Failure and Subsequent Ventricular Tachyarrhythmias in Patients With Left Ventricular Dysfunction

OBJECTIVES

This study aimed to evaluate the risk of sustained life-threatening ventricular tachyarrhythmias (VTAs) after hospitalization for heart failure (HHF).

BACKGROUND

HHF is common among patients with an implantable cardioverter-defibrillator (ICD).

METHODS

We analyzed all 5,511 ICD patients enrolled in the landmark MADIT and RAID trials. Multivariate Cox regression was used to evaluate the association of in-trial HHF occurrence with the risk of subsequent VTA and the composite end point of VTA or cardiac death.

RESULTS

Mean age was 64 ± 11 years, 23% were women, 62% were ischemic, and 40% had cardiac resynchronization therapy with defibrillators. The 3-year cumulative rate of VTA subsequent to HHF was significantly higher than the corresponding rate without HHF (44% vs. 24%, respectively; p < 0.001). After multivariable adjustment, time-dependent HHF was shown to be associated with a 79% increased risk for VTA and a 2.9-fold increased risk for VTA/cardiac death (p < 0.001 for both). In-trial development of atrial tachyarrhythmia (ATA) was also identified as an independent risk factor for the VTA and VTA/cardiac death end points (hazard ratios [HRs]: 1.59 and 1.43, respectively; p ≤ 0.001 for both) but did not affect the association of HHF with VTA. Subgroup analysis demonstrated that the association of HHF with the risk of subsequent VTA was maintained among risk subsets categorized by age, sex, history of ATA, and implantation indication, but was significantly more pronounced among patients with nonischemic versus ischemic cardiomyopathy (HRs: 2.54 and 1.43, respectively; p value for interaction: 0.017).

CONCLUSIONS

HHF is a powerful risk factor for subsequent VTA in patients implanted with an ICD. These data may be used for improved risk stratification in this population.

The efficacy of catheter ablation versus ICD for prevention of ventricular tachycardia in patients with ischemic heart disease: a systematic review and meta-analysis

Purpose

Although implantable cardioverter defibrillator (ICD) could prevent the sudden death of ventricular tachycardia (VT) in patients with ischemic heart disease, it could not effectively prevent the recurrence of ventricular tachycardia. Several studies have suggested that catheter ablation may effectively decrease the incidence of ICD events, but relevant dates from randomized controlled trials were limited.

Methods

A systematic review and meta-analysis of randomized controlled trials were performed to evaluate the effect of catheter ablation for the prevention of VT in patients with ischemic heart disease. Random-effects model with inverse-variance weighting method was used to pool odds ratios. Egger method was performed to evaluate whether there was public bias in each outcome.

Results

Four studies enrolling a total of 605 patients were included in the present meta-analysis. Compared with the control group (ICD ± AAD), catheter ablation could significantly reduce the incidence of ICD therapy (OR, 0.49; 95% CI, 0.28 ~ 0.87), ICD shock (OR, 0.50; 95% CI, 0.28 ~ 0.87), VT storm (OR, 0.60; 95% CI, 0.40 ~ 0.90), and cardiovascular-related hospitalization (OR, 0.66; 95% CI, 0.45 ~ 0.9). But there was no significant difference among the risk of all-cause mortality (OR, 0.89; 95% CI, 0.59 ~ 1.34), cardiovascular mortality (OR, 0.76; 95% CI, 0.44 ~ 1.30), and complication (OR, 0.89; 95% CI, 0.30 ~ 2.67).

Conclusion

These results showed that catheter ablation combined with ICD could reduce ICD therapy, ICD shock, and VT storm in patients with ischemic heart disease, but there was no improvement in all-cause mortality. Meanwhile, it also provided a basic guidance for the design of larger clinical randomized trials with longer follow-up in the future.

Electronic supplementary material

The online version of this article (10.1007/s10840-020-00848-1) contains supplementary material, which is available to authorized users.

The impact of transvenous cardioverter-defibrillator implantation on quality of life, depression and optimism in dialysis patients: report on the secondary outcome of QOL in the randomized controlled ICD2 trial

RATIONALE

The impact of prophylactic implantable cardioverter-defibrillator (ICD) implantation on the psychological well-being of patients on dialysis is unknown.

OBJECTIVE

We aimed to identify the effect of primary ICD implantation on quality of life (QoL), mood and dispositional optimism in patients undergoing dialysis.

METHODS AND RESULTS

We performed a prespecified subanalysis of the randomized controlled ICD2 trial. In total, 177 patients on chronic dialysis, with an age of 55-81 years, and a left ventricular ejection fraction of ≥ 35%, were included in the per-protocol analysis. Eighty patients received an ICD for primary prevention, and 91 patients received standard care. The Short Form-36 (SF-36), Geriatric Depression Scale-15 (GDS-15), Revised Life Orientation Test (LOT-R) questionnaires were administered prior to ICD implantation (T0), and at 1-year follow-up (T1) to assess QoL, depression and optimism, respectively. The patients were predominantly male (76.0%), with a median age of 67 years. Hemodialysis was the predominant mode of dialysis (70.2%). The GDS-15 score difference (T1 - T0) was 0.5 (2.1) in the ICD group compared with 0.3 (2.2) in the control group (mean difference - 0.3; 95% CI - 1.1 to 0.6; P = 0.58). The LOT-R score difference was - 0.2 (4.1) in the ICD group compared with - 1.5 (4.0) in the control group (mean difference - 1.1 (0.8); 95% CI - 2.6 to 0.4; P = 0.17). The mean difference scores of all subscales of the SF-36 were not significantly different between randomization groups.

CONCLUSIONS

In our population of patients on dialysis, ICD implantation did not affect QoL, mood or dispositional optimism significantly during 1-year follow-up.

CLINICAL TRIAL REGISTRATION

Unique identifier: ISRCTN20479861. http://www.controlled-trials.com .

Updates in Ventricular Tachycardia Ablation

Sudden cardiac death (SCD) due to recurrent ventricular tachycardia is an important clinical sequela in patients with structural heart disease. As a result, ventricular tachycardia (VT) has emerged as a major clinical and public health problem. The mechanism of VT is predominantly mediated by re-entry in the presence of arrhythmogenic substrate (scar), though focal mechanisms are also important. Catheter ablation for VT, when compared to standard medical therapy, has been shown to improve VT-free survival and burden of device therapies. Approaches to VT ablation are dependent on the underlying disease process, broadly classified into idiopathic (no structural heart disease) or structural heart disease (ischemic or non-ischemic heart disease). This update aims to review recent advances made for the treatment of VT ablation, with respect to current clinical trials, peri-procedure risk assessments, pre-procedural cardiac imaging, electro-anatomic mapping and advances in catheter and non-catheter based ablation techniques.

Reassessing the role of antitachycardia pacing in fast ventricular arrhythmias in primary prevention implantable cardioverter-defibrillator recipients: Results from MADIT-RIT

BACKGROUND

In Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy (MADIT-RIT), high-rate cutoff (arm B) and delayed therapy (arm C) reduced the risk of inappropriate implantable cardioverter-defibrillator (ICD) interventions when compared with conventional programming (arm A); however, appropriate but unnecessary therapies were not evaluated.

OBJECTIVE

The purpose of this study was to assess the value of antitachycardia pacing (ATP) for fast ventricular arrhythmias (VAs) ≥ 200 beats/min in patients with primary prevention ICD.

METHODS

We compared ATP only, ATP and shock, and shock only rates in patients in MADIT-RIT treated for VAs ≥ 200 beats/min. The only difference between these randomized groups was the time delay between ventricular tachycardia detection and therapy (3.4 seconds vs 4.9 seconds vs 14.4 seconds).

RESULTS

In arm A, 11.5% patients had events, the initial therapy was ATP in 10.5% and shock in 1%, and the final therapy was ATP in 8% and shock in 3.5%. In arm B, 6.6% had events, 4.2% were initially treated with ATP and 2.4% with shock, and the final therapy was ATP in 2.8% and shock in 3.8%. In arm C, 4.7% had events, 2.5% were initially treated with ATP and 2.3% with shock, and the final therapy was ATP in 1.4% and shock in 3.3%. The final shock rate was similar in arm A vs arm B (3.5% vs 3.8%; P = .800) and in arm A vs arm C (3.5% vs 3.3%; P = .855) despite the marked discrepancy in initial ATP therapy utilization.

CONCLUSION

In MADIT-RIT, there was a significant reduction in ATP interventions with therapy delays due to spontaneous termination, with no difference in shock therapies, suggesting that earlier interventions for VAs ≥ 200 beats/min are likely unnecessary, leading to an overestimation of the value of ATP in primary prevention ICD recipients.

Shock to the Heart: Psychosocial Implications and Applications of Sudden Cardiac Death in the Young

PURPOSE OF REVIEW

Although rare, sudden cardiac death (SCD) in the young is a tragic event, having a dramatic impact upon all involved. The psychosocial burden associated with SCD can leave friends, families, and entire communities bereft. With only limited evidence to describe the volatile emotional reactions associated with a young SCD, there is an urgent need for care providers to better understand the psychological complexities and impacts faced by both at-risk individuals and those directly affected by these tragic events.

RECENT FINDINGS

Current knowledge of the psychosocial implications associated with SCD in the young has recently generated interest in the cardiovascular community, with the goal of addressing prevention strategies (screening), family bereavement, and the psychological impact of at-risk or surviving individuals. With the emergence of novel strategies aimed at reducing the public health impact of SCD in the young, further discussion regarding the psychosocial impact of SCD, encompassing prevention, survivorship, and the downstream communal effects of a young death is required. Support systems and intervention could assist in the management of the associated psychosocial burden, yet there is a lack of clinical guidelines to direct this form of care. There is an important need for multidisciplinary collaboration across subspecialties to provide support to grieving individuals and manage patient well-being throughout the screening process for SCD. This collaborative approach requires the integration of cardiovascular and psychological expertise where relevant.

The impact of implantable cardioverter-defibrillator implantation on health-related quality of life in the DANISH trial

AIM

The Danish Study to Assess the Efficacy of Implantable Cardioverter-Defibrillators (ICD) in Patients with Non-ischaemic Systolic Heart Failure (HF) on Mortality (DANISH) found no overall effect on all-cause mortality. The effect of ICD implantation on health-related quality of life (HRQoL) remains to be established as previous trials have demonstrated conflicting results. We investigated the impact of ICD implantation on HRQoL in patients with non-ischaemic systolic HF, a prespecified secondary endpoint in DANISH.

METHODS AND RESULTS

In DANISH, a total of 1116 patients with non-ischaemic systolic HF were randomly assigned (1:1) to ICD implantation or usual clinical care (control). Patients completed disease-specific HRQoL as assessed by Minnesota Living with Heart Failure Questionnaire (MLHFQ; 0-105, high indicating worse). Changes in HRQoL 8 months after randomization were assessed with a mixed-effects model. At randomization, MLHFQ was completed by 935 (84%) patients (n = 472 in the ICD group and n = 463 in the control group) and was reassessed in 274 (58%) and 292 (63%) patients, respectively after 8 months for the primary analysis. Patients in the ICD group vs. the control group had similar improvements in MLHFQ after 8 months [least square mean -7.0 vs. -4.2 (P = 0.13)]. A clinically relevant improvement (decrease ≥5) in the MLHFQ overall score at 8 months was observed in 151 patients in the ICD group and 148 patients in the control group [55% vs. 51%, respectively (P = 0.25)].

CONCLUSION

Implantable cardioverter-defibrillator implantation in patients with non-ischaemic systolic HF did not significantly alter HRQoL compared with patients randomized to usual clinical care.

Renal Denervation for the Management of Refractory Ventricular Arrhythmias: A Systematic Review

OBJECTIVES

The authors performed a systematic review and meta-analysis to determine the efficacy of renal denervation (RDN) in patients with refractory ventricular arrhythmias (VA) or electrical storm (ES).

BACKGROUND

Although catheter ablation is efficacious for the treatment of structural heart disease ventricular tachycardia (VT), there are proportion of patients who have refractory VT despite multiple procedures. In this setting, novel adjunctive therapies such as renal denervation have been performed.

METHODS

A systematic review of published data was performed. Studies that evaluated patients undergoing RDN for VA or ES were included. Outcome measures of VA, sudden cardiac death, ES, or device therapy were required. Case reports, editorials, and conference presentations were excluded. Random effects meta-analysis was conducted to explore change or final mean values in the study outcomes.

RESULTS

A total of 328 articles were identified by the literature search. Seven studies met the eligibility criteria and were included in the systematic review, with a total of 121 pooled patients. The weighted mean age was 63.8 ± 13.1 years, ejection fraction 30.5 ± 10.3%, 76% were men, 99% were on a beta blocker, 79% were on amiodarone, 46% had previously undergone catheter ablation, and 8.3% had previously undergone cardiac sympathetic denervation. Meta-analysis demonstrated a significant effect of RDN in reducing implantable cardiac defibrillator therapies, with a standardized mean difference (SMD) of -3.11 (p < 0.001). RDN also reduced the number of VA episodes (SMD -2.13; p < 0.001), antitachycardia pacing episodes (SMD -2.82; p = 0.002), and shocks (SMD -2.82; p = 0.002).

CONCLUSIONS

RDN is an effective treatment for refractory VAs and ES, although randomized data are lacking.

Evaluation of a Fully Automatic Measurement of Short-Term Variability of Repolarization on Intracardiac Electrograms in the Chronic Atrioventricular Block Dog

Background: Short-term variability (STV) of repolarization of the monophasic action potential duration (MAPD) or activation recovery interval (ARI) on the intracardiac electrogram (EGM) increases abruptly prior to the occurrence of ventricular arrhythmias in the chronic AV-block (CAVB) dog model. Therefore, this parameter might be suitable for continuous monitoring of imminent arrhythmias using the EGM stored on an implanted device. However, 24/7 monitoring would require automatic STV_ARI measurement by the device.

Objective: To evaluate a newly developed automatic measurement of STV_ARI for prediction of dofetilide-induced torsade de pointes (TdP) arrhythmias in the CAVB-dog.

Methods: Two retrospective analyses were done on data from recently performed dog experiments. (1) In seven anesthetized CAVB-dogs, the new automatic STV_ARI method was compared with the gold standard STV_MAPD at baseline and after dofetilide administration (0.025 mg/kg in 5 min). (2) The predictive value of the automatic method was compared to currently used STV_ARI methods, i.e., slope method and fiducial segment averaging (FSA) method, in 11 inducible (≥3 TdP arrhythmias) and 10 non-inducible CAVB-dogs.

Results: (1) The automatic measurement of STV_ARI had good correlation with STV_MAPD (r² = 0.89; p < 0.001). Bland-Altman analysis showed a small bias of 0.06 ms with limits of agreement between −0.63 and 0.76 ms. (2) STV_ARI of all three methods was significantly different between inducible and non-inducible dogs after dofetilide. The automatic method showed the highest predictive performance with an area under the ROC-curve of 0.93, compared to 0.85 and 0.87 of the slope and FSA methods, respectively. With a threshold of STV set at 1.69 ms, STV_ARI measured with the automatic method had a sensitivity of 0.91 and specificity of 0.90 in differentiating inducible from non-inducible subjects.

Conclusion: We developed a fully-automatic method for measurement of STV_ARI on the intracardiac EGM that can accurately predict the occurrence of ventricular arrhythmias in the CAVB-dog. Future integration of this method into implantable devices could provide the opportunity for 24/7 monitoring of arrhythmic risk.

Radiofrequency catheter ablation of ventricular tachycardia in ischemic heart disease in light of current practice: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Ventricular tachycardia (VT) is a frequent cause of mortality and morbidity in patients with ischemic heart disease (IHD). We aim to perform a systematic review and meta-analysis of randomized controlled trials (RCT) of radiofrequency catheter ablation (RCA) of VT in patients with IHD and to discuss its appropriate timing and limitations.

METHODS

Literature searches of MEDLINE, CENTRAL, the Cochrane Database of Systematic Reviews, Health Technology Assessment, and PsycINFO were performed in February 2020. RCTs comparing RCA vs conventional management for VT in patients with IHD and previous or planned implantable cardioverter defibrillator (ICD) were identified. Clinical outcomes included all-cause mortality, cardiovascular mortality, cardiovascular hospitalization, VT storm, recurrent VT/ventricular fibrillation (VF), appropriate ICD therapies, and appropriate ICD shocks. Using a random-effects model, relative risk (RR) and 95% confidence intervals (CI) were calculated for each outcome.

RESULTS

A total of 6 RCTs (N = 791) met inclusion criteria. RCA was associated with significantly lower VT storm (RR 0.70; CI_95% 0.51 to 0.94, p = 0.02) and appropriate ICD therapies (RR 0.69; CI_95% 0.54 to 0.88, p = 0.003), including appropriate ICD shocks (RR 0.66; CI_95% 0.47 to 0.92, p = 0.02). There was no significant difference in all-cause or cardiovascular mortality, cardiovascular hospitalization, and recurrent VT/VF.

CONCLUSIONS

Radiofrequency catheter ablation for VT in patients with IHD was associated with a reduced risk of VT storm, ICD therapies, and ICD shocks. There is a need for future carefully designed RCTs that incorporate improved RCA procedural aspects.

Secondary prevention of sudden cardiac death

The prevention and treatment of sudden cardiac death (SCD) remains a significant public health challenge. For patients with a history of sudden death attributable to ventricular arrhythmia, implantable cardioverter-defibrillator (ICD) therapy is a mainstay of treatment, although these patients remain at high risk for recurrent ventricular arrhythmia and defibrillator therapies. In this review, we summarize landmark clinical trials evaluating the efficacy of ICD therapy in secondary prevention patients, review clinical outcomes including mode of death in survivors of SCD, and highlight the role for systematic diagnostic evaluation. We additionally discuss the invasive electrophysiological management of these patients, including ICD selection and programming as well as the role and timing of antiarrhythmic drug therapy and catheter ablation. Finally, we frame future challenges and needs to advance the care for secondary prevention patients.