A Case of Ventricular Fibrillation in Masked Long-QT Syndrome Coexisting with Coronary Vasospasm

Although long-QT syndrome (LQTS) with a normal range QT interval at rest leads to fatal ventricular arrhythmias, it is difficult to diagnose. In this article, we present a rare case of a patient who suffered a cardiac arrest and was recently diagnosed with LQTS and coronary vasospasm. A 62-year-old man with no syncopal episodes had a cardiopulmonary arrest while running. During coronary angiography, vasospasm was induced and we prescribed coronary vasodilators, including calcium channel blockers. An exercise stress test was performed to evaluate the effect of medications and accidentally unveiled exercise-induced QT prolongation. He was diagnosed with LQTS based on diagnostic criteria. Pharmacotherapy and an implantable cardioverter defibrillator were used for his medical management. It is extremely rare for LQTS and coronary vasospasm to coexist. In cases of exercise-induced arrhythmic events, the exercise stress test might be helpful to diagnose underlying disease.

Risk of Atrial Fibrillation and Adverse Outcomes in Patients With Cardiac Implantable Electronic Devices

BACKGROUND AND OBJECTIVES

Comprehensive epidemiological data are lacking on the incident atrial fibrillation (AF) in patients with cardiac implantable electronic devices (CIEDs). This study aimed to examine the incidence, risk factors, and AF-related adverse outcomes of patients with CIEDs.

METHODS

This was an observational cohort study that analyzed patients without prevalent AF who underwent CIED implantation in 2009-2018 using a Korean nationwide claims database. The subjects were divided into three groups by CIED type and indication: pacemaker (n=21,438), implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy (CRT) with heart failure (HF) (n=3,450), and ICD for secondary prevention without HF (n=2,146). The incidence of AF, AF-associated predictors, and adverse outcomes were evaluated.

RESULTS

During follow-up, the incidence of AF was 4.3, 7.3, and 5.1 per 100 person-years in the pacemaker, ICD/CRT with HF, and ICD without HF cohorts, respectively. Across the three cohorts, older age and valvular heart disease were commonly associated with incident AF. Incident AF was consistently associated with an increased risk of ischemic stroke (3.8-11.4-fold), admission for HF (2.6-10.5-fold), hospitalization for any cause (2.4-2.7-fold), all-cause death (4.1-5.0-fold), and composite outcomes (3.4-5.7-fold). Oral anticoagulation rates were suboptimal in patients with incident AF (pacemaker, 51.3%; ICD/CRT with HF, 51.7%; and ICD without HF, 33.8%, respectively).

CONCLUSIONS

A substantial proportion of patients implanted CIED developed newly diagnosed AF. Incident AF was associated with a higher risk of adverse events. The importance of awareness, early detection, and appropriate management of AF in patients with CIED should be emphasized.

Cost effectiveness of implantable cardioverter defibrillators for 1.5 primary prevention of sudden cardiac arrest in China: an analysis from the Improve SCA study

OBJECTIVES

Implantable cardioverter defibrillator (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) is underutilized in developing countries. The Improve SCA study has identified a subset of 1.5 primary prevention (1.5PP) patients with a higher risk of SCA and a significant mortality benefit from ICD therapy. From the perspective of China's healthcare system, we evaluated the cost-effectiveness of ICD therapy vs. no ICD therapy among 1.5PP patients with a view to informing clinical and policy decisions.

METHODS

A published Markov model was adjusted and verified to simulate the course of the disease and describe different health states of 1.5PP patients. The patient characteristics, mortality, utility and complication estimates were obtained from the Improve SCA study and other literature. Cost inputs were sourced from government tender prices, medical service prices and clinical experts' surveys in 9 Chinese public hospitals. For both ICD and no ICD therapy, the total medical costs and quality-adjusted life-years (QALYs) were modelled over a lifetime horizon and the incremental cost-effectiveness ratio (ICER) was calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters. We used the willingness-to-pay (WTP) threshold recommended by China Guidelines for Pharmacoeconomic Evaluations, one to three times China's GDP per capita (CNY85,698-CNY257,094) in 2022 Chinese Yuan.

RESULTS

The incremental cost effectiveness ratio (ICER) of ICD therapy compared to no ICD therapy is 139,652 CNY/QALY, which is about 1-2 times China's GDP per capita. The probability that ICD therapy is cost effective was 92.1%. Results from sensitivity analysis supported the findings of the base case.

CONCLUSIONS

ICD therapy compared to no ICD therapy is cost-effective for the 1.5PP patients in China.

Machine learning-derived cycle length variability metrics predict spontaneously terminating ventricular tachycardia in implantable cardioverter defibrillator recipients

Aims

Implantable cardioverter defibrillator (ICD) therapies have been associated with increased mortality and should be minimized when safe to do so. We hypothesized that machine learning-derived ventricular tachycardia (VT) cycle length (CL) variability metrics could be used to discriminate between sustained and spontaneously terminating VT.

Methods and results

In this single-centre retrospective study, we analysed data from 69 VT episodes stored on ICDs from 27 patients (36 spontaneously terminating VT, 33 sustained VT). Several VT CL parameters including heart rate variability metrics were calculated. Additionally, a first order auto-regression model was fitted using the first 10 CLs. Using features derived from the first 10 CLs, a random forest classifier was used to predict VT termination. Sustained VT episodes had more stable CLs. Using data from the first 10 CLs only, there was greater CL variability in the spontaneously terminating episodes (mean of standard deviation of first 10 CLs: 20.1 ± 8.9 vs. 11.5 ± 7.8 ms, P < 0.0001). The auto-regression coefficient was significantly greater in spontaneously terminating episodes (mean auto-regression coefficient 0.39 ± 0.32 vs. 0.14 ± 0.39, P < 0.005). A random forest classifier with six features yielded an accuracy of 0.77 (95% confidence interval 0.67 to 0.87) for prediction of VT termination.

Conclusion

Ventricular tachycardia CL variability and instability are associated with spontaneously terminating VT and can be used to predict spontaneous VT termination. Given the harmful effects of unnecessary ICD shocks, this machine learning model could be incorporated into ICD algorithms to defer therapies for episodes of VT that are likely to self-terminate.

Outcomes of catheter ablation in high-risk patients with Brugada syndrome refusing an implantable cardioverter defibrillator implantation

AIMS

The aim of this study was to investigate the outcomes of catheter ablation (CA) in preventing arrhythmic events among patients with symptomatic Brugada syndrome (BrS) who declined implantable cardioverter defibrillator (ICD) implantation.

METHODS AND RESULTS

A total of 40 patients with symptomatic BrS were included in the study, of which 18 refused ICD implantation and underwent CA, while 22 patients received ICD implantation. The study employed substrate modification (including endocardial and epicardial approaches) and ventricular fibrillation (VF)-triggering pre-mature ventricular contraction (PVC) ablation strategies. The primary outcomes were a composite endpoint consisting of episodes of VF and sudden cardiac death during the follow-up period. The study population had a mean age of 43.8 ± 9.6 years, with 36 (90.0%) of them being male. All patients exhibited the typical Type 1 BrS electrocardiogram pattern, and 16 (40.0%) were carriers of an SCN5A mutation. The Shanghai risk scores were comparable between the CA and the ICD groups (7.05 ± 0.80 vs. 6.71 ± 0.86, P = 0.351). Ventricular fibrillation-triggering PVCs were ablated in 3 patients (16.7%), while VF substrates were ablated in 15 patients (83.3%). Epicardial ablation was performed in 12 patients (66.7%). During a median follow-up of 46.2 (17.5-73.7) months, the primary outcomes occurred more frequently in the ICD group than in the CA group (5.6 vs. 54.5%, Log-rank P = 0.012).

CONCLUSION

Catheter ablation is an effective alternative therapy for improving arrhythmic outcomes in patients with symptomatic BrS who decline ICD implantation. Our findings support the consideration of CA as an alternative treatment option in this population.

Efficacy of a web-based healthcare innovation to advance the quality of life and care of patients with an implantable cardioverter defibrillator (ACQUIRE-ICD): a randomized controlled trial

AIMS

Modern clinical management of patients with an implantable cardioverter defibrillator (ICD) largely consists of remote device monitoring, although a subset is at risk of mental health issues post-implantation. We compared a 12-month web-based intervention consisting of goal setting, monitoring of patients' mental health-with a psychological intervention if needed-psychoeducational support from a nurse, and an online patient forum, with usual care on participants' device acceptance 12 months after implantation.

METHODS AND RESULTS

This national, multi-site, two-arm, non-blinded, randomized, controlled, superiority trial enrolled 478 first-time ICD recipients from all 6 implantation centres in Denmark. The primary endpoint was patient device acceptance measured by the Florida Patient Acceptance Survey (FPAS; general score range = 0-100, with higher scores indicating higher device acceptance) 12 months after implantation. Secondary endpoints included symptoms of depression and anxiety. The primary endpoint of device acceptance was not different between groups at 12 months [B = -2.67, 95% confidence interval (CI) (-5.62, 0.29), P = 0.08]. Furthermore, the secondary endpoint analyses showed no significant treatment effect on either depressive [B = -0.49, 95% CI (-1.19; 0.21), P = 0.17] or anxiety symptoms [B = -0.39, 95% CI (-0.96; 0.18), P = 0.18].

CONCLUSION

The web-based intervention as supplement to usual care did not improve patient device acceptance nor symptoms of anxiety and depression compared with usual care. This specific web-based intervention thus cannot be recommended as a standardized intervention in ICD patients.

Epicardial Devices in Pediatrics and Congenital Heart Disease

Epicardial cardiac implantable electronic device implant remains a common option in pediatric patients and certain patients with congenital heart disease due to patient size, complex anatomy, residual intracardiac shunts, and prior surgery precluding transvenous implant. Advantages include the lack of thromboembolic and vascular risks and ability to implant during concomitant surgery. Significant disadvantages include the occurrence of lead dysfunction that can result in bradycardia events in pacemaker patients, inappropriate shocks in implantable cardiac defibrillator patients, and overall a more invasive procedure.

Translation of Tools and Techniques from the Adult Electrophysiology World to Pediatric Cardiac Implantable Electronic Devices

This article reviews various opportunities to translate established and novel tools and techniques used in adult electrophysiology to pediatrics and the adult congenital heart disease population. There is a specific focus on preoperative management of special population, implantation techniques, and postoperative programming of devices.

Emerging Technologies for the Smallest Patients

Pediatric and congenital heart disease patients may require cardiac implantable electronic device implantation, inclusive of pacemaker, ICD, and implantable cardiac monitor, for a variety of etiologies. While leads, generators, and monitors have decreased in size over the years, they remain less ideal for the smallest patients. The potential for a miniature pacemaker, fetal micropacemaker, improving leadless technology, and rechargeable devices creates hope that the development of pediatric-focused devices will increase. Further, alternative approaches that avoid the need for a transvenous or surgical approach may add more options to the toolbox for the pediatric and congenital electrophysiologist.

A web-based intervention for patients with an implantable cardioverter defibrillator - A qualitative study of nurses' experiences (Data from the ACQUIRE-ICD study)

Objective

The aim of this study was to explore cardiac nurses' experiences with a comprehensive web-based intervention for patients with an implantable cardioverter defibrillator.

Methods

We conducted an explorative qualitative study based on individual semi-structured interviews with 9 cardiac nurses from 5 Danish university hospitals.

Results

We found one overall theme: "Between traditional nursing and modern eHealth". This theme was derived from the following six categories: (1) comprehensive content in the intervention, (2) patient-related differences in engagement, (3) following the protocol is a balancing act, (4) online communication challenges patient contact, (5) professional collaboration varies, and (6) an intervention with potential. Cardiac nurses were positive towards the web-based intervention and believe it holds a large potential. However, they felt challenged by not having in-person and face-to-face contact with patients, which they found valuable for assessing patients' wellbeing and psychological distress.

Conclusion

Specific training in eHealth communication seems necessary as web-based care entails a shift in the nursing role and requires a different way of communication.InnovationFocusing on the user experience in web-based care from the perspective of cardiac nurses is innovative, and by applying implementation science this leads to new knowledge to consider when developing and implementing web-based care.

Percutaneous left atrial appendage occlusion in patients with a cardiac implantable electronic device

BACKGROUND

Left atrial appendage occlusion (LAAO) may be a viable option for stroke prevention in patients with non-valvular atrial fibrillation and a contraindication for oral anticoagulation. No evidence evaluating the safety of this procedure in patients with a cardiac implantable electronic device (CIED) exists. The aim of this study was to evaluate whether CIED function is affected by LAAO and to explore LAAO procedural characteristics and complications in patients with a CIED.

METHODS

This single-center cohort study included consecutive patients scheduled for percutaneous LAAO. Patients with a CIED prior to LAAO were selected and compared to the patients without CIED, concerning procedural characteristics and peri-procedural complications. In the group of patients with CIEDs, essential pacemaker integrity parameters were compared before and after the procedure to detect possible micro and macro lead displacements.

RESULTS

Thirty-one patients with CIED were scheduled for LAAO (age 73.7 ± 5.4 years, 65% males, CHA2DS2-VASc 4.3 ± 1.5, and HAS-BLED 3.3 ± 1.0). The 245 patients without CIED were younger, and HAS-BLED-score was slightly lower (69.4 ± 8.2 years, p < 0.001; 2.8 ± 1.0, p = 0.022). Patients without CIED more frequently underwent LAAO combined with catheter ablation (p = 0.002). All other procedural characteristics were comparable between both groups. No visible lead displacement was observed on chest X-ray after LAAO. Additionally, no differences in impedance, threshold, or intracardiac sensing in various CIED lead locations were found prior versus post LAAO.

CONCLUSION

This study supports the feasibility and safety of LAAO in patients with a CIED.

An intuitive method to reduce the defibrillation threshold: a case report

Background

Defibrillation threshold (DFT) testing is done to assess whether proper sensing of ventricular fibrillation and adequate safety margin for defibrillation are present in an implantable cardioverter defibrillator (ICD). This case report presents an intuitive method for lowering the DFT. It may be used on a larger scale in other patients with high DFTs when other methods for lowering the DFT (changing medications, adjusting the device, and adding coils) are not feasible or preferable to use.

Case summary

A 64-year-old male presented to the emergency room with failed appropriate shocks from his ICD. Device interrogation revealed that he failed his first maximum output shock before subsequent shock at the same polarity and output succeeded, suggesting a high DFT. Therefore, the DFT needs to be lowered in our patient. After considering the potential efficacy and risk of a number of traditional options, we used an intuitive method whereby the right ventricular (RV) coils of two separate leads were combined via a y-adapter. This method successfully lowered the patient's DFT, and he received successful shocks from his ICD over the next 9 months before reaching end-stage heart failure. He received a transplant, and the device and transvenous leads, except for the superior vena cava coil, were successfully removed.

Discussion

Combining two RV coils from different locations may lower the DFT. This method may be considered in the larger population in cases where using traditional methods are not safe or possible for certain patients. This method may work by lowering shock impedance and increasing the shock tissue surface area.

Tachycardia Therapy Outcomes of Ischemic Versus Nonischemic Cardiomyopathy on Cardiac Resynchronization Therapy: A Propensity Score-matched Analysis

Objective

This investigation aimed to investigate differences between dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) patients treated with cardiac resynchronization therapy with defibrillator (CRT-D) for tachycardia therapy-related outcomes as well as mortality during follow-up of at least 1 year.

Methods

Seventy-eight patients with DCM (n = 42) and ICM (n = 36) with implantation or upgradation to CRT-D were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), non-sustained ventricular fibrillation (NSVF), defibrillator therapies, anti-tachycardia pacing (ATP), and mortality.

Results

DCM was the underlying etiology in 42 (53.84%) and ICM in 36 (46.15%). Time to first therapy was numerically longer in DCM than in ICM (9.5 ± 2.4 vs. 7.1 ± 3.2; P-value = 0.088). DCM patients had significantly higher therapy-free survival and mortality compared with ICM patients (OR (95%CI): 0.238 (0.155-0.424); log-rank P = 0.017) and (OR (95% CI): 0.612 (0.254-0.924); log-rank P = 0.029). ICM (HR (95%CI): 0.529 (0.243-0.925); P-value = 0.014) CAD (HR (95%CI): 0.326 (0.122-0.691): P-value = 0.003), and NSVT (HR (95%CI): 0.703 (0.513-0.849): P-value = 0.005) were demonstrated as independent predictors of the primary endpoint of appropriate therapy in CRT-D and ICM (HR (95%CI): 0.421 (0.321-0.524); P-value = 0.037), chronic kidney disease (CKD; HR (95%CI): 0.289 (0.198-0.380); P-value = 0.013), and CAD (HR (95%CI): 0.786 (0.531-0.967); P-value = 0.003) were predictors of mortality.

Conclusion

The clinical course of ICM and DCM cohorts who were treated with CRT-D differs significantly during follow-up, with increased tachycardia therapy and increased incidence of mortality in ICM patients.

[Electrical storm in patients with Automatic Implantable Defibrillator : A single Center study]

BACKGROUND

Electrical storms (ES) are serious cardiac emergencies associated with increased short-term mortality. The true incidence of ES in patients with an implantable cardioverter defibrillator (ICD) is still difficult to estimate because of the heterogeneous definition. The clinical presentation is variable and its management is multidisciplinary.

OBJECTIVE

The aim of the study was to analyze the epidemiological profile and evolution of a group of patients implanted with an ICD who had electrical storms detected by a home monitoring system.

METHODS

This is a single-center retrospective observational study, which included 14 patients who were implanted with ICDs, for primary or secondary prevention between 2008 and 2021. All of them were followed by home monitoring. All these patients had an ES detected by home monitoring and authenticated by ECG.

RESULTS

The mean age of the patients at the time of onset of the electrical storm was 75.4 ± 14.5 years, with extremes ranging from 49 to 101 years. Most of patients (n = 11) were male. The majority of them had underlying ischaemic cardiomyopathy (n = 12). In a third of cases (n = 5) patients were implanted for secondary prevention. The electrical storm was related to recurrent episodes of VT. No cases of VF were detected. Syncope was the most frequent clinical presentation (four patients). Nine patients received internal shocks, with an average of four shocks per patient. The triggering factor was myocardial ischaemia in four cases. Majority of patients were managed in the cardiac intensive care unit. Two patients were admitted to the intensive care unit. In addition to anti-arrhythmic treatment with amiodarone and beta blockers. Nine patients underwent ablation of ventricular tachycardia focus. Mortality was high (in half of the cases) mainly due to a cardiogenic shock.

CONCLUSION

This study shows that OR remain rare, but are still associated with high mortality. Home monitoring makes it possible to manage them earlier.

Left ventricular lead implantation failure in an unselected nationwide cohort

BACKGROUND

Left ventricular (LV) lead implantation is often the most challenging aspect of cardiac resynchronization therapy (CRT) procedures; early studies reported implant failure rates in ∼10% of cases.

OBJECTIVE

The purpose of this study was to define rates, reasons for, and factors independently associated with LV lead implant failure.

METHODS

We studied patients with left bundle branch block and ejection fraction ≤ 35% who underwent planned de novo transvenous CRT implantation (2010-2016) and were reported to the National Cardiovascular Data Registry ICD Registry. Independent predictors of LV lead implant failure were determined using logistic regression; age, sex, and variables with a univariable P value of <.15 were considered for inclusion in the model.

RESULTS

Of the 111,802 patients who underwent a planned CRT procedure, 3.6% of patients (n = 3979) had LV lead implant failure. Reasons for implant failure included venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%), and diaphragmatic stimulation (1.7%). Significant independent predictors of LV lead implant failure included younger age (odds ratio [OR] 1.01; 95% confidence interval [CI] 0.1.01-1.02), female sex (OR 1.38; 95% CI 1.29-1.47), black race (vs white, OR 1.44; 95% CI 1.32-1.57), Hispanic ethnicity (OR 1.23; 95% CI 1.08-1.40), QRS duration (OR 1.055 per 10 ms; 95% CI 1.038-1.072 per 10 ms), obstructive sleep apnea (OR 1.14; 95% CI 1.04-1.24), and implantation by a physician without specialized training (vs electrophysiology trained, OR 1.53; 95% CI 1.34-1.76).

CONCLUSION

LV lead implant failure is uncommon in the current era and is most commonly due to coronary sinus access failure. Predictors of LV lead implant failure included younger age, female sex, black race, Hispanic ethnicity, increased QRS duration, sleep apnea, and absence of electrophysiology training.

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.

[Venous access routes for cardiac implantable electronic devices]

Various venous access routes in the region of the clavicle are available for cardiac device treatment. After many years of choosing access via the subclavian vein, current data explicitly show that lateral approaches such as preparation of the cephalic vein or puncture of the axillary vein are clearly superior in terms of probe durability and risk of complications. This article describes the preparation and performance of the various access techniques and is intended to provide a practical guide for the work in cardiac pacemaker operations. This work continues a series of articles designed for advanced training in specialized rhythmology.

A wobble tachycardia… supraventricular, ventricular or both?

We present the case of a 77-year-old man with ischemic heart disease and baseline right bundle branch block having a well-tolerated and regular wide complex tachycardia with right bundle branch block morphology. A wide complex tachycardia (WCT) could be of supraventricular or ventricular origin. In this setting, we discuss the differential diagnosis of WCT, the usefulness and limitations of the diagnostic criteria for ventricular tachycardia.

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.

Efficiency of MVP ECG Risk Score for Prediction of Long-Term Atrial Fibrillation in Patients With ICD for Heart Failure With Reduced Ejection Fraction

BACKGROUND AND OBJECTIVES

The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up.

METHODS

The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups.

RESULTS

The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group.

CONCLUSIONS

The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

Transvenous Lead Extraction: Outcomes From a Single Centre Providing a National Service for New Zealand

BACKGROUND

With increasing demand for cardiac implantable electronic devices there is a parallel increase in the need for transvenous lead extraction (TLE). Due to its small population, all TLE procedures in New Zealand are currently performed in a single centre, Auckland City Hospital. We analysed the clinical characteristics and outcomes of those undergoing TLE since this service was established.

METHODS

We performed a retrospective, single-centre cohort study of all TLE procedures between October 2015 and December 2021. Definitions from the European Lead Extraction Controlled study, Heart Rhythm Society, European Heart Rhythm Association consensus documents were used.

RESULTS

A total of 247 patients had 480 leads extracted, averaging 40 TLE procedures annually. Patients had a median lead dwell time of 6 (interquartile range [IQR] 3-11) years, 60 (13%) of leads had been in-situ >15 years, median age 61 (IQR 48-70) years, 73 (30%) female, 28 (11%) Māori, 23 (9%) Pasifika. Lead dysfunction (115 patients, 47%) and infection (90 patients, 37%) were the most common indications for TLE. Complete clinical and radiological success was achieved for 96% and 95%, respectively. Procedure-related complications occurred in 16 (7%) patients. Major intra-procedure complications occurred in 5 patients (2%), including 2 (1%) deaths. Death within one year of TLE occurred in 13 (26%) with systemic infection, 5 (3%) with local infection, and 5 (3%) with non-infection indications for TLE, p <0.01.

CONCLUSIONS

TLE is associated with high radiographic and clinical success, low complication, and low mortality rate. At our single centre providing a national service, TLE outcomes are comparable with those achieved internationally.

Prevention of Sudden Death and Management of Ventricular Arrhythmias in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is an umbrella term for a group of inherited diseases of the cardiac muscle characterized by progressive fibro-fatty replacement of the myocardium. As suggested by the name, the disease confers electrical instability to the heart and increases the risk of the development of life-threatening arrhythmias, representing one of the leading causes of sudden cardiac death (SCD), especially in young athletes. In this review, the authors review the current knowledge of the disease, highlighting the state-of-the-art approaches to the prevention of the occurrence of SCD.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction

BACKGROUND

Our main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given.

METHODS

An expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review.

RESULTS

Numerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices.

CONCLUSIONS

In some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

Case report: successful termination of ventricular tachycardia by intrinsic anti-tachycardia pacing beyond conventional anti-tachycardia pacing

Background

Anti-tachycardia pacing (ATP) is a pain-free alternative to defibrillation shock for monomorphic ventricular tachycardia (VT). Intrinsic ATP (iATP) is a novel algorithm of auto-programmed ATP. However, the advantage of iATP over conventional ATP in clinical cases is still unknown.

Case summary

A 49-year-old man with no significant past medical history was transferred to our institution with sudden-onset fatigue from working on a farm. A 12-lead electrocardiogram showed monomorphic sustained wide QRS tachycardia with a right bundle branch block pattern and superior axis deviation with a cycle length (CL) of 300 ms. Sustained monomorphic VT originating from the left ventricle due to underlying vasospastic angina was diagnosed by contrast-enhanced cardiac magnetic resonance imaging, coronary angiography, and the acetylcholine stress test, and implantable cardioverter defibrillator implantation was performed. Nine months later, a clinical VT episode with a CL of 300 ms was observed, which could not be terminated by three sequences of conventional burst pacing. Ventricular tachycardia was finally terminated by a third iATP sequence without any acceleration.

Discussion

Although standard burst pacing by conventional ATP reached the VT circuit, it failed to terminate the VT. Using the post-pacing interval, iATP automatically calculated the appropriate number of S1 pulses required to reach the VT circuit. In iATP, the S2 pulses are delivered with a calculated coupling interval based on the estimated effective refractory period during tachycardia. In this case, iATP might have led to less aggressive S1 stimulation, followed by aggressive S2 stimulation, which probably helped terminate the VT without any acceleration.