ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons

Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation

The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.

Long-term follow-up of patients with Brugada syndrome: Foremost risk factors associated with overall arrhythmic events

Brugada syndrome (BS) is characterized by ST segment elevation in right precordial leads (V1-V3), ventricular tachycardia (VT), ventricular fibrillation (VF), and sudden cardiac death (SCD) in individuals without structural heart disease. The aim of this study is to contribute to the controversial issue of finding the most valuable marker that can predict poor prognosis during follow-up in patients with a diagnosis of BS. A total of 68 patients diagnosed with BS or had Brugada-type ECG change between January 1997 and July 2012 at the Department of Cardiology of Başkent University Faculty of Medicine, Ankara, Turkey, were included in this cohort study. Patients were screened every 6 months for arrhythmia-related syncope, SCD, appropriate and inappropriate defibrillation (shock), AF development and death; collectively defined as "arrhythmic events" and were the primary endpoints. Patients with and without arrhythmic events were compared. The mean age was 34.9 ± 12.2 years (9-71 years), and 52 (76.5%) patients were male. Mean follow-up was 49.6 ± 37.6 months (4-188 months). Univariate analysis showed that male sex (P = .004), type 1 electrocardiographic pattern (P = .008), SCD (P = .036), VT/VF history (P = .046), requirement for electrophysiological studies (P = .034), implantable cardioverter-defibrillator placement (P = .014) were found to demonstrate significant differences in patients with and without arrhythmic events. In multivariable analyzes, spontaneous type 1 ECG presence (HR = 8.54, 95% CI: 0.38-26.37; P = .003) and VT/VF history (HR = 9.21, 95% CI: 0.004-1.88; P = .002) were found to be independently associated with arrhythmic events. We found the presence of spontaneous type 1 ECG and a history of VT/VF to be associated with increased likelihood of overall arrhythmic events in BS. Given the higher risk of poor prognosis, we recommend additional measures in patients with BS who have these features.

Patient informed consent, ethical and legal considerations in the context of digital vulnerability with smart, cardiac implantable electronic devices

Advancements in digitalisation with cardiac implantable electronic devices (CIEDs) allow patients opportunities for improved autonomy, quality of life, and a potential increase in life expectancy. However, with the digital and functional practicalities of CIEDs, there exists also cyber safety issues with transferring wireless information. If a digital network were to be hacked, a CIED patient could experience both the loss of sensitive data and the loss of functional control of the CIED due to an unwelcome party. Moreover, if a CIED patient were to become victim of a cyber attack, which resulted in a serious or lethal event, and if this information were to become public, the trust in healthcare would be impacted and legal consequences could result. A cyber attack therefore poses not only a direct threat to the patient's health but also the confidentiality, integrity, and availability of the CIED, and these cyber threats could be considered "patient-targeted threats." Informed consent is a key component of ethical care, legally concordant practice, and promoting patient-as-partner therapeutic relationships [1]. To date, there are no standardised guidelines for listing cybersecurity risks within the informed consent or for discussing them during the consent process. Providers are responsible for adhering to the ethical principles of autonomy, beneficence, non-maleficence, and justice, both in medical practice generally and the informed consent process specifically. At present, the decision to include cybersecurity risks is mainly left to the provider's discretion, who may also have limited cyber risk information. Without effective and in-depth communication about all possible cybersecurity risks during the consent process, CIED patients can be left unaware of the privacy and physical risks they possess by carrying such a device. Therefore, cyber risk factors should be covered within the patients' informed consent and reviewed on an ongoing basis as new risk information becomes available. By including cyber risk information in the informed consent process, patients are given the autonomy to make the best-informed decision.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry

BACKGROUND AND AIMS

Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed.

METHODS

All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models.

RESULTS

1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001).

CONCLUSIONS

Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

PR prolongation as a predictor of atrial fibrillation onset: A state-of-the-art review

First-degree atrioventricular block (1-AVB), characterized by a PR interval exceeding 200 milliseconds, has traditionally been perceived as a benign cardiac condition. Recently, this perception has been challenged by investigations that indicate a potential association between PR prolongation and an elevated risk of atrial fibrillation (AF). To consolidate these findings, we performed a comprehensive review to assess the available evidence indicating a relationship between these two conditions. We searched MEDLINE and EMBASE databases as well as manually searched references of retrieved articles. We selected 18 cohort studies/meta-analyses involving general and special populations. Consistent findings across expansive cohort studies reveal that incremental increases in the PR interval may serve as an independent risk factor for AF. However, our analyses underscore the need for further research into the association between 1-AVB, defined by a specified PR interval cutoff, and the risk of AF.

First implantable cardiac defibrillator insertions in New South Wales, 2005-2020: an analysis of linked administrative data

OBJECTIVES

To determine the annual numbers of first ICD insertions in New South Wales during 2005-2020; to examine health outcomes for people who first received ICDs during this period.

STUDY DESIGN

Retrospective cohort study; analysis of linked administrative health data.

SETTING, PARTICIPANTS

All first insertions of ICDs in NSW, 2005-2020.

MAIN OUTCOME MEASURES

Annual numbers of first ICD insertions, and of emergency department presentations and hospital re-admissions 30 days, 90 days, 365 days after first ICD insertions; all-cause and disease-specific mortality (to ten years after ICD insertion).

RESULTS

During 2005-2020, ICDs were first inserted into 16 867 people (18.5 per 100 000 population); their mean age was 65.7 years (standard deviation, 13.5 years; 7376 aged 70 years or older, 43.7%), 13 214 were men (78.3%). The annual number of insertions increased from 791 in 2005 to 1256 in 2016; the first ICD insertion rate increased from 15.5 in 2005 to 18.9 per 100 000 population in 2010, after which the rate was stable until 2019 (19.8 per 100 000 population). Of the 16 778 people discharged alive from hospital after first ICD insertions, 54.4% presented to emergency departments within twelve months, including 1236 with cardiac arrhythmias (7.4%) and 434 with device-related problems (2.6%); 56% were re-admitted to hospital, including 1944 with cardiac arrhythmias (11.5%) and 2045 with device-related problems (12.1%). A total of 5624 people who received first ICDs during 2005-2020 (33.3%) died during follow-up (6.7 deaths per 100 person-years); the survival rate was 94.4% at one year, 76.5% at five years, and 54.2% at ten years.

CONCLUSIONS

The annual number of new ICDs inserted in NSW has increased since 2005. A substantial proportion of recipients experience device-related problems that require re-admission to hospital. The potential harms of ICD insertion should be considered when assessing the likelihood of preventing fatal ventricular arrhythmia.

Association between cardiac conduction block and cardiovascular disease and all-cause mortality: The kailuan study

BACKGROUND

Although bundle branch block and atrioventricular block are recognized to be association with cardiovascular disease (CVD) and mortality, the relationship between cardiac conduction block (CCB) and both CVD and all-cause mortality has yet to be explored.

AIMS

To explore the relationship between CCB and CVD and all-cause mortality.

METHODS AND RESULTS

We included 145,805 subjects (mean age 49.7 years, 81.2% males) from the kailuan study. CCB was diagnosed through a 12‑lead electrocardiograph (ECG). Mortality and CVD events were ascertained through multiple sources, including a municipal social insurance institution, hospital records, death certificates, and regular active follow-ups. After a mean follow-up of 12.5 years, 18,301 cases developed all-cause mortality. After excluding 4443 subjects with CVD presence at baseline, 13,208 cases of CVD occurred among the 141,362 study subjects during follow-up. Compared with non-CCB group, the cumulative incidence of CVD and all-cause mortality for CCB group was 18.38% VS 12.14% and 33.45% VS 14.18%, respectively. The multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) with CCB group were 1.25(1.17-1.34) for CVD, and 1.31(1.25-1.38) for all-cause mortality. Additionally, there were generally stronger associations for CCB with all-cause mortality and CVD in younger participants compared with their older counterparts (Ps-interaction <0.001).

CONCLUSION

CCB can increase the risk of CVD and all-cause mortality in the general population. Our findings highlight the importance of strategies for preventing CCB to reduce the risk of CVD and mortality.

Efficacy and safety of novel left ventricular pacing leads: 1-year analysis of the NAVIGATOR trial

OBJECTIVES

Assess safety and performance of novel quadripolar preshaped left ventricular (LV) leads: NAVIGO 4LV 2D ('S shaped') and NAVIGO 4LV ARC ('U shaped').

METHODS

Patients indicated for cardiac resynchronisation therapy were enrolled in a multicentre, prospective, controlled study (NAVIGATOR, NCT03279484). Patients were implanted with either a NAVIGO 4LV 2D or ARC lead, and assessed at 10 weeks, 6, 12 and 24 months post-implant. Co-primary safety and performance endpoints were assessed at 10 weeks. Safety endpoint was the patients' rate free from lead-related complications. Performance endpoint was the rate of patients with successful lead performance, defined as LV pacing threshold ≤2.5 V at 0.5 ms on at least one pacing vector, and the absence of phrenic nerve stimulation at the final programmed configuration. Lead-related complications and electrical parameters were monitored throughout study.

RESULTS

A NAVIGO 4LV lead was successfully implanted in 211 out of 217 patients (97.2%). The safety endpoint was met, with 100% and 96.1% of patients free from complications for NAVIGO 4LV 2D and ARC, respectively. The performance endpoint was met with 98.1% and 98.9% of patients with a successful lead performance for NAVIGO 4LV 2D and ARC, respectively. Over 12 months, the global complication-free rate for both leads was 97.1% (95% CI: 93.71% to 98.70%), with a mean pacing capture threshold of 1.23 V±0.73 V and a mean impedance of 951 Ω±300.1 Ω.

CONCLUSION

A high implantation success rate and low complication rate was reported for the novel NAVIGO 4LV 2D and ARC leads, along with successful performance up to 12 months.

Metabolomics Profiling Predicts Ventricular Arrhythmia in Patients with an Implantable Cardioverter Defibrillator

Implantable cardioverter defibrillators (ICDs) reduce sudden cardiac death (SCD) when patients experience life-threatening ventricular arrhythmias (LTVA). However, current strategies determining ICD patient selection and risk stratification are inefficient. We used metabolomics to assess whether dysregulated metabolites are associated with LTVA and identify potential biomarkers. Baseline plasma samples were collected from 72 patients receiving ICDs. Over a median follow-up of 524.0 days (range 239.0-705.5), LTVA occurred in 23 (31.9%) patients (22 effective ICD treatments and 1 SCD). After confounding risk factors adjustment for age, smoking, secondary prevention, and creatine kinase MB, 23 metabolites were significantly associated with LTVA. Pathway analysis revealed LTVA associations with disrupted metabolism of glycine, serine, threonine, and branched chain amino acids. Pathway enrichment analysis identified a panel of 6 metabolites that potentially predicted LTVA, with an area under the receiver operating characteristic curve of 0.8. Future studies are necessary on biological mechanisms and potential clinical use.

Epicardial Implantation of a Micra™ Pacemaker in a Premature Neonate with Congenital Complete Heart Block

Pacemaker implantation in neonates can be challenging due to their small size. Even pulse generators adapted for pediatric patients, such as the Microny device (Abbott, Chicago, IL, USA), are proportionately large in comparison to the size of the smallest newborns. Due to anatomic considerations, such as small vascular and ventricular sizes, leadless pacemakers and transvenous implantation in the youngest neonatal population remain unsuitable. Even so, the desire for leadless devices has prompted the industry to create the smallest pacemakers available. Adapting the smaller Micra™ transcatheter leadless pacing system (Medtronic, Minneapolis, MN, USA) for an epicardial pacing application may be advantageous to the smallest patients. This case illustrates the use of a Micra™ device modified with a header block to serve as the pulse generator in a ventricular epicardial pacing system for a 1-day-old, 2.68-kg patient with complete heart block.

Modifying the trajectory of epicardial leads can substantially reduce MRI-induced RF heating in pediatric patients with a cardiac implantable electronic device at 1.5T

PURPOSE

After epicardial cardiac implantable electronic devices are implanted in pediatric patients, they become ineligible to receive MRI exams due to an elevated risk of RF heating. We investigated whether simple modifications in the trajectories of epicardial leads could substantially and reliably reduce RF heating during MRI at 1.5 T, with benefits extending to abandoned leads.

METHODS

Electromagnetic simulations were performed to assess RF heating of two common 35-cm epicardial lead trajectories exhibiting different degrees of coupling with MRI incident electric fields. Experiments in anthropomorphic phantoms implanted with commercial cardiac implantable electronic devices confirmed the findings. Both electromagnetic simulations and experimental measurements were performed using head-first and feet-first positioning and various landmarks. Transfer function approach was used to assess the performance of suggested modifications in realistic body models.

RESULTS

Simulations (head-first, chest landmark) of a 35-cm epicardial lead with a trajectory where the excess length of the lead was looped and placed on the inferior surface of the heart showed an 87-fold reduction in the 0.1 g-averaged specific absorption rate compared with the lead where the excess length was looped on the anterior surface. Repeated experiments with a commercial epicardial device confirmed this. For fully implanted systems following low-specific absorption rate trajectories, there was a 16-fold reduction in the average temperature rise and a 28-fold reduction for abandoned leads. The transfer function method predicted a 7-fold reduction in the RF heating in 336 realistic scenarios.

CONCLUSION

Surgical modification of epicardial lead trajectory can substantially reduce RF heating at 1.5 T, with benefits extending to abandoned leads.

Current Device Needs for Patients with Pediatric and Congenital Heart Disease

Pediatric electrophysiologists believe that there is a paucity of pediatric-specific cardiac implantable electronic devices (CIEDs) available for their patients. Specific patient characteristics such as vascular size, intracardiac anatomy, and expected somatic growth limit the types of CIED implants possible for pediatric and congenital heart disease (CHD) patients. These patients demonstrate higher CIED-related complication rates compared with adults. As the number of pediatric and CHD patients who require CIEDs increases, so does the need for advocacy. Fortunately, collaboration among the Food and Drug Administration, industry, and pediatric societies has led to the improvement of regulations and support for clinical trials.

Techniques for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease

Cardiac resynchronization therapy (CRT) for congenital heart disease has shown promising suucess as an adjunct to medical therapy for heart failure. While cardiac conduction defects and need for ventricular pacing are common in congential heart disease, CRT indications, techniques and long term outcomes have not been well establaished. This is a review of the techniques nad short term outcomes of CRT for the following complex congenital heart disease conditions: single ventricle physiology, systemic right ventricle, and the subpulmonic right ventricle.

U-Shaped Association Between Monocyte-Lymphocyte Ratio and Risk of Cardiac Conduction Block

Purpose

Inflammation plays a critical role in the development of cardiac conduction block (CCB), which is associated with an increased risk of morbidity and mortality. The monocyte-lymphocyte ratio (MLR) acts as a novel inflammatory marker; however, its association with CCB has not yet been studied. This study aimed to investigate the association between MLR and CCB risk.

Patients and Methods

In total, 82,472 CCB-free participants were identified from the Kailuan study. MLR was calculated using the monocyte count/lymphocyte count. The participants were stratified based on quartiles of MLR levels. Incident CCB and its subtypes were ascertained from electrocardiograms at biennial follow-up visits. The Cox proportional hazards model and restricted cubic spline analysis were used to investigate the association between MLR with CCB and its subtypes.

Results

During a median follow-up of 10.4 years, 3222 incident CCB cases were observed. A U-shaped association was observed between MLR and CCB risk (Pnonlinearity <0.05). After multivariate adjustment, individuals in the highest MLR quartile had a hazard ratio (HR) of 1.212 (95% CI: 1.097-1.340; Q4 vs Q2), while those in the lowest MLR quartile had an HR of 1.106 (95% CI: 1.000-1.224; Q1 vs Q2). Sensitivity and subgroup analyses yielded consistent results. The U-shaped association persisted for atrioventricular block (AVB) in subtype analyses.

Conclusion

MLR was significantly associated with an increased risk of new-onset CCB. Assessing MLR may have clinical relevance for predicting CCB risk, providing valuable insights for preventive strategies and patient management.

Pre-Registered Clinical Trial Number

The pre-registered clinical trial number is ChiCTR-TNC-11001489.

Concomitant ablation of atrial fibrillation: New pacemakers and early rhythm recovery

OBJECTIVE

New permanent pacemaker (PPM) implantation after concomitant atrial fibrillation (AF) ablation has been associated with surgical ablation (SA). We sought to determine factors for PPM use as well as early rhythm recovery.

METHODS

From 2004 through 2019, 6135 patients underwent valve surgery and were grouped: No AF (n = 4584), AF no SA (n = 346), and AF with SA (n = 1205) to evaluate predischarge PPM and 3-month rhythm recovery (intrinsic heart rate >40 beats per minute).

RESULTS

Overall, 282 (4.6%) patients required a predischarge PPM: atrioventricular node dysfunction in 75.3%, sick sinus syndrome in 19.1%, both (5%), and indeterminate (0.7%). Patients with AF had more PPMs: AF with SA (7.9%) versus AF no SA (6.9%) versus No AF (3.6%) (P < .001). For patients with AF, PPM rates were not significantly higher for ablation patients (7.6% SA vs 6.9% AF no SA; P = .56). There were differences in PPM by SA lesion set (biatrial 12.8%; left atrial only 6.1%; pulmonary vein isolation 3.0%; P < .001). Among patients with AF treated with 3-month PPM follow-up, rhythm recovery was common (35 out of 62 [56.5%]) and did not differ by lesion set. Rhythm recovery was seen in 63 out of 141 (44.7%) in the atrioventricular node dysfunction group versus 24 out of 35 (68.6%) in the sick sinus syndrome group (P = .011). In propensity score-matched groups, late survival was similar (P = .63) for new PPM patients.

CONCLUSIONS

Avoiding conduction system trauma and delaying implantation reduces the need for postoperative PPM. Rhythm recovery within 3 months is frequent, especially for patients with sick sinus syndrome. A conservative approach to the implantation of a new PPMs is warranted.

Predicting arrhythmic event score in Brugada syndrome: Worldwide pooled analysis with internal and external validation

BACKGROUND

Brugada syndrome is an inherited arrhythmic disease associated with major arrhythmic events (MAE). Risk predictive scores were previously developed with various performances.

OBJECTIVE

The purpose of this study was to create a novel score-Predicting Arrhythmic evenT (PAT)-with internal and external validation.

METHODS

A systematic review was performed to identify risk factors for MAE. The odds ratios (ORs) of each factor were pooled across studies. The PAT scoring scheme was developed based on pooled ORs. The PAT score was internally validated with published 105 Asian patients (follow-up 8.0 ± 4.1 [SD] years) and externally validated with unpublished 164 multiracial patients (82.3% White, 14.6% Asian, 3.2% Black; mean follow-up 8.0 ± 6.9 years) with Brugada syndrome. Performances were assessed and compared with previous scores using receiver operating characteristic curve (ROC) analysis.

RESULTS

Sixty-seven studies published between 2002 and 2022 from 26 countries (7358 patients) were included. Pooled ORs were estimated, indicating that 15 of 23 risk factors were significant. The PAT score was then developed accordingly. The PAT score had significantly better discrimination (ROC 0.9671) than the BRUGADA-RISK score (ROC 0.7210; P = .006), Shanghai Score System (ROC 0.7079; P = .003), and Sieira et al score (ROC 0.8174; P = .026) in an external validation cohort. PAT score ≥ 10 predicted the first MAE with 95.5% sensitivity and 89.1% specificity (ROC 0.9460) and the recurrent MAE (ROC 0.7061) with 15.4% sensitivity and 93.3% specificity.

CONCLUSION

The PAT score was shown to be useful in predicting MAE for primary prevention in patients with Brugada syndrome.

Elevated high-sensitivity C-reactive protein levels increase the risk of new-onset cardiac conduction disorders

BACKGROUND

Previous studies have reported that inflammatory responses can promote the onset of cardiovascular diseases; however, its association with cardiac conduction disorders remains unclear. The present community-based cohort study aimed to elucidate the effects of inflammatory responses on the risk of developing cardiac conduction disorders.

METHODS

After the exclusion of participants failing to meet the inclusion criteria, 86,234 eligible participants (mean age: 50.57 ± 11.88 years) were included. The participants were divided into high-sensitivity C-reactive protein (hsCRP)  ≤  3 mg/L, and hsCRP > 3 mg/L groups based on hsCRP values. Multivariate Cox proportional hazard model was used to analyze the relationship between inflammatory responses and various cardiac conduction disorders.

RESULTS

After adjusting for confounding factors, we observed that compared with the hsCRP ≤ 3 mg/L group, the hsCRP > 3 mg/L group exhibited increased risks of atrioventricular block (hazard ratio [HR]:1.64, 95%confidence interval [CI] 1.44-1.87) and left (HR:1.25, 95% CI 1.07-1.45) and right bundle branch block (HR:1.31, 95% CI 1.17-1.47). Moreover, the risk of various cardiac conduction disorders increased for every 1 standard deviation increase in log (hsCRP). The restricted cubic spline function confirmed a linear relationship between log (hsCRP) and the risk of developing cardiac conduction disorders (All nonlinearity P > 0.05).

CONCLUSIONS

High hsCRP levels are an independent risk factor for cardiac conduction disorders, and hsCRP levels are dose-dependently associated with the risk of conduction disorders. Our study results may provide new strategies for preventing cardiac conduction disorders.

A retrospective audit of young adults who received permanent pacemakers at a teaching hospital in the Western Cape, South Africa

Introduction

While most pacemaker implantations occur in older individuals, younger patients also receive pacemakers. In these, degenerative conduction system disease is less likely to be the cause of atrioventricular block (AVB), with other diseases being more common. There is, however, a paucity of data on this group as well as on younger pacemaker recipients that have undergone pacemaker implantation for reasons other than AVB. The aim of this study was to perform an audit of young adult permanent pacemaker recipients.

Method

This was a retrospective record review, conducted in the Division of Cardiology at Tygerberg Hospital, Cape Town, South Africa. We included 169 adult patients between the ages of 18 and 60, who received permanent pacemakers between 2010 and 2020. A subgroup analysis of patients 55 years and younger was also performed.

Results

Third degree AVB was the most common indication for pacemaker implantation (n = 115; 68%), followed by high degree AVB (n = 23; 13.6%) and sick sinus syndrome (SSS; n = 14; 8.3%). A specific underlying cause for conduction system abnormalities was found in only 25.4% of patients (n = 43), with most of them being 55 years or younger (n = 32; 30.8% of patients ≤ 55 years). Specific causes that were identified included prosthetic valve implantation and/or valve repair (n = 14; 8.3%), myocardial infarction (n = 6; 3.6%), cardiac sarcoidosis (n = 5; 3.0%), coronary artery bypass grafting (n = 3; 1.8%), cardiomyopathy (n = 2; 1.2%), muscular dystrophy (n = 2; 1.2%), congenital heart disease (ventricular septal defect; atrioventricular septal defect; Tetralogy of Fallot; bicuspid aortic valve; n = 6; 3.6%), acute myocarditis (n = 1; 0.6%), atrial myxoma removal (n = 1; 0.6%), planned AV node ablation (n = 2; 1.2%), and following a previous stab in the chest (n = 1; 0.6%).

Conclusion

Given that the mean age of our study population was high, the low number of identified underlying causes in the whole cohort (≤60 years) may reflect some AVB due to age related degeneration of the conductions system in the patients 56 to 60 years age, but also raises the possibility that these patients may be less likely to be extensively investigated for an underlying cause than those ≤55 years, where diseases such as sarcoidosis were more readily confirmed. As access to advanced diagnostic tools improves, the percentage of young pacemaker recipients with an underlying cause identified may increase.

Risk of Arrhythmic Death in Patients With Nonischemic Cardiomyopathy: JACC Review Topic of the Week

Nonischemic cardiomyopathy (NICM) is common and patients are at significant risk for early mortality secondary to ventricular arrhythmias. Current guidelines recommend implantable cardioverter-defibrillator (ICD) therapy to decrease sudden cardiac death (SCD) in patients with heart failure and reduced left ventricular ejection fraction. However, in randomized clinical trials comprised solely of patients with NICM, primary prevention ICDs did not confer significant mortality benefit. Moreover, left ventricular ejection fraction has limited sensitivity and specificity for predicting SCD. Therefore, precise risk stratification algorithms are needed to define those at the highest risk of SCD. This review examines mechanisms of sudden arrhythmic death in patients with NICM, discusses the role of ICD therapy and treatment of heart failure for prevention of SCD in patients with NICM, examines the role of cardiac magnetic resonance imaging and computational modeling for SCD risk stratification, and proposes new strategies to guide future clinical trials on SCD risk assessment in patients with NICM.

Cardiac implantable electronic device implantation and device-related infection

AIMS

Cardiac implantable electronic devices (CIED) are important tools for managing arrhythmias, improving hemodynamics, and preventing sudden cardiac death. Device-related infections (DRI) remain a significant complication of CIED and are associated with major adverse outcomes. We aimed to assess the trend in CIED implantations, and the burden and morbidity associated with DRI.

METHODS AND RESULTS

The 2011-2018 National Inpatient Sample database was searched for admissions for CIED implantation and DRI. A total of 1 604 173 admissions for CIED implantations and 71 007 (4.4%) admissions for DRI were reported. There was no significant change in annual admission rates for DRI (3.96-4.59%, P value for trend = 0.98). Those with DRI were more likely to be male (69.3 vs. 57%, P < 0.001) and have a Charlson comorbidity index score ≥3 (46.6 vs. 36.8%, P < 0.001). The prevalence of congestive heart failure (CHF) increased in those admitted with DRI over the observation period. Pulmonary embolism, deep vein thrombosis, and post-procedural hematoma were the most common complications in those with DRI (4.1, 3.6, and 2.90%, respectively). Annual in-hospital mortality for those with DRI ranged from 3.9 to 5.8% (mean 4.4%, P value for trend = 0.07). Multivariate analysis identified CHF [odds ratio (OR) = 1.67; 95% confidence interval (CI) = 1.35-2.07], end-stage renal disease (OR = 1.90; 95% CI = 1.46-2.48), coagulopathy (OR = 2.94; 95% CI = 2.40-3.61), and malnutrition (OR = 2.50; 95% CI = 1.99-3.15) as the predictors of in-hospital mortality for patients admitted with DRI.

CONCLUSION

Device-related infection is relatively common and continues to be associated with high morbidity and mortality. The prevalence of DRI has not changed significantly despite technical and technological advances in cardiac devices and their implantation.

Incidence of atrioventricular block after isolated coronary artery bypass grafting: a systematic review and pooled-analysis

Background and objectives

Atrioventricular block (AVB) is a serious complication following coronary artery bypass grafting (CABG) surgery, and its high-grade form may necessitate the implantation of a permanent pacemaker (PPM). AVB is associated with increased morbidity and mortality rates. This study aims to estimate the incidence of AVB and subsequent PPM implantation after isolated CABG surgery.

Material and methods

We searched electronic databases of PubMed, Embase, and Scopus from inception to 18 November 2022. Clinical trials and observational studies reporting the incidence of post-CABG AVB or subsequent PPM implantation in adult patients were included. The total incidence for all included outcomes was calculated using the inverse variance method, and the I2 statistic was reported to evaluate the heterogeneity of studies.

Results

A total of 28 studies met the inclusion criteria. Four studies [3 cohorts, 1 randomized controlled trial (RCT)] reported AVB without specifying its type; one (cohort) reported different degrees of AVB, 20 (12 cohorts, 8 RCTs) reported complete heart block (CHB) (or AVB requiring temporary pacing), and nine (8 cohorts, 1 RCT) reported the number of PPM inserted due to AVB. The pooled incidence of AVB, CHB (or AVB requiring temporary pacing), and PPM due to AVB was 1.16%, 1.73%, and 0.58%, respectively. Meta-regression analysis revealed that age, gender, diabetes, hypertension, hyperlipidemia, or smoking were not significantly associated with AVB, CHB, or PPM implantation.

Conclusion

This study highlights the incidence of AVB and the need for PPM implantation following CABG surgery. The findings emphasize the importance of postoperative monitoring and surveillance to improve patient outcomes.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022377181, identifier PROSPERO CRD42022377181.

Rationale and Design of the Randomized Bayesian Multicenter COME-TAVI Trial in Patients With a New Onset Left Bundle Branch Block

Patients with new-onset left bundle branch block (LBBB) after transcatheter aortic valve implantation (TAVI) are at risk of developing delayed high-degree atrioventricular block. Management of new-onset LBBB post-TAVI remains controversial. In the Comparison of a Clinical Monitoring Strategy Versus Electrophysiology-Guided Algorithmic Approach in Patients With a New LBBB After TAVI (COME-TAVI) trial, consenting patients with new-onset LBBB that persists on day 2 after TAVI, meeting exclusion/inclusion criteria, are randomized to an electrophysiological study (EPS)-guided approach or 30-day electrocardiographic monitoring. In the EPS-guided approach, patients with a His to ventricle (HV) interval ≥ 65 ms undergo permanent pacemaker implantation. Patients randomized to noninvasive monitoring receive a wearable continuous electrocardiographic recording and transmitting device for 30 days. Follow-up will be performed at 3, 6, and 12 months. The primary endpoint is a composite outcome designed to capture net clinical benefit. The endpoint incorporates major consequences of both strategies in patients with new-onset LBBB after TAVI, as follows: (i) sudden cardiac death; (ii) syncope; (iii) atrioventricular conduction disorder requiring a pacemaker (for a class I or IIa indication); and (iv) complications related to the pacemaker or EPS. The trial incorporates a Bayesian design with a noninformative prior, outcome-adaptive randomization (initially 1:1), and 2 prespecified interim analyses once 25% and 50% of the anticipated number of primary endpoints are reached. The trial is event-driven, with an anticipated upper limit of 452 patients required to reach 77 primary outcome events over 12 months of follow-up. In summary, the aim of this Bayesian multicentre randomized trial is to compare 2 management strategies in patients with new-onset LBBB post-TAVI-an EPS-guided approach vs noninvasive 30-day monitoring. Trial registration number: NCT03303612.

End-Stage/Advanced Heart Failure: Geriatric Palliative Care Considerations

Heart failure remains a condition with high morbidity and mortality affecting 23 million people globally with a cost burden equivalent to 5.4% of the total health care budget in the United States. These costs include repeated hospitalizations as the disease advances and care that may not align with individual wishes and values. The coincidence of comorbid conditions with advanced heart failure poses significant challenges in the geriatric population. Advance care planning, medication education, and minimizing polypharmacy are primary palliative opportunities leading to specialist palliative care such as symptom management at end of life and timing of referral to hospice.

Pathophysiology and pathogenic mechanisms of pulmonary hypertension: role of membrane receptors, ion channels, and Ca2+ signaling

The pulmonary circulation is a low-resistance, low-pressure, and high-compliance system that allows the lungs to receive the entire cardiac output. Pulmonary arterial pressure is a function of cardiac output and pulmonary vascular resistance, and pulmonary vascular resistance is inversely proportional to the fourth power of the intraluminal radius of the pulmonary artery. Therefore, a very small decrease of the pulmonary vascular lumen diameter results in a significant increase in pulmonary vascular resistance and pulmonary arterial pressure. Pulmonary arterial hypertension is a fatal and progressive disease with poor prognosis. Regardless of the initial pathogenic triggers, sustained pulmonary vasoconstriction, concentric vascular remodeling, occlusive intimal lesions, in situ thrombosis, and vascular wall stiffening are the major and direct causes for elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension and other forms of precapillary pulmonary hypertension. In this review, we aim to discuss the basic principles and physiological mechanisms involved in the regulation of lung vascular hemodynamics and pulmonary vascular function, the changes in the pulmonary vasculature that contribute to the increased vascular resistance and arterial pressure, and the pathogenic mechanisms involved in the development and progression of pulmonary hypertension. We focus on reviewing the pathogenic roles of membrane receptors, ion channels, and intracellular Ca2+ signaling in pulmonary vascular smooth muscle cells in the development and progression of pulmonary hypertension.

Initial studies on the implanting sites of high and low ventricular septa using leadless cardiac pacemakers

OBJECTIVE

To study the safety and electrical characteristics of various implanting sites of the Micra pacemaker.

METHOD

A total of 15 patients from Beijing Anzhen Hospital, Capital Medical University, were included, who were implanted with Micra leadless pacemakers and allocated to either the high ventricular septum group (eight patients) or the low ventricular septum group (seven patients) based on their individual patient factors and clinical conditions. The baseline of the patients, the implanting area, the electrocardiogram change after implantation, the implantation data, the threshold, R wave, impedance, and the date of the 1-month follow-up were then analyzed. With all of the data, the characteristics of different implantation sites of the Micra pacemaker were determined.

RESULTS

Overall, the thresholds were low at implantation and remained stable over the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups. On comparing the two groups, there was no difference in QRS duration at pacing (140.00 [40.00] ms vs. 179.00 [50.00] ms), threshold at implantation (0.38 [0.22] mV vs. 0.63 [1.00] mV), R wave at implantation ([10.85 ± 4.71] V vs. [7.26 ± 2.98] V), or impedance at implantation ([906.25 ± 162.39] Ω vs. [750.00 ± 173.40] Ω). While the difference in QRS duration between the two groups was not significant, the QRS duration of the high ventricular septum group exhibited a reduced tendency compared with that of the low ventricular group. The corrected QT interval during pacing exhibited a significant difference (440.00 [80.00] ms vs. 520.00 [100.00] ms; p < .05). For the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups, there was no difference between the threshold of the high ventricular septum group and that of the low ventricular septum group (p > .05).

CONCLUSION

High ventricular septum pacing appears to be a safe site for implantation of the Micra pacemaker. It could entail a shorter QRS duration at pacing and could be more physiological than low ventricular septum pacing.

Association between Severity of Diabetic Retinopathy and Cardiac Function in Patients with Type 2 Diabetes

Background

The purpose of this research was to assess the relationship between the severity of diabetic retinopathy (DR) and indexes of left ventricle (LV) structure and function in type 2 diabetes mellitus (T2DM).

Methods

Retrospective analysis of 790 patients with T2DM and preserved LV ejection fraction. Retinopathy stages were classified as no DR, early nonproliferative DR, moderate to severe nonproliferative DR, or proliferative DR. The electrocardiogram was used to assess myocardial conduction function. Echocardiography was used to evaluate myocardial structure and function.

Results

Patients were divided into three groups based on the DR status: no DR group (NDR, n = 475), nonproliferative DR group (NPDR, n = 247), and proliferative DR group (PDR, n = 68). LV interventricular septal thickness (IVST) increased significantly with more severe retinopathy (NDR: 10.00 ± 1.09; NPDR: 10.42 ± 1.21; and PDR: 10.66 ± 1.58; P < 0.001). Multivariate logistic regression analysis showed that the significant correlation of IVST persisted between subjects with no retinopathy and proliferative DR (odds ratio = 1.35, P = 0.026). Indices of myocardial conduction function were assessed by electrocardiogram differences among groups of retinopathy (all P < 0.001). In multiple-adjusted linear regression analyses, the increasing degree of retinopathy was closely correlated with heart rate (β = 1.593, P = 0.027), PR interval (β = 4.666, P = 0.001), and QTc interval (β = 8.807, P = 0.005).

Conclusion

The proliferative DR was independently associated with worse cardiac structure and function by echocardiography. Furthermore, the severity of retinopathy significantly correlated with abnormalities of the electrocardiogram in patients with T2DM.

His-Purkinje system pacing versus biventricular pacing in clinical efficacy: a systematic review and meta-analysis

BACKGROUND

His-Purkinje system pacing (HPSP), including his-bundle pacing (HBP) and left bundle branch area pacing (LBBaP), imitates the natural conduction of the heart as an alternative to biventricular pacing (BVP) in cardiac resynchronization therapy (CRT). However, the feasibility and efficacy of HPSP were currently only evidenced by studies with a limited sample size, so this study aimed to provide a comprehensive assessment through a systematic review and meta-analysis.

METHODS

In order to compare the clinical outcomes associated with HPSP and BVP in patients for CRT, PubMed, EMBASE, Cochrane Library and Web of Science database were searched from inception to April 10, 2023. Clinical outcomes of interest including QRS duration (QRSd), left ventricular (LV) function and New York Heart Association (NYHA) functional classification, pacing threshold, echocardiographic and clinical response, hospitalization rate of HF and all-cause mortality were also extracted and summarized for meta-analysis.

RESULTS

A total of 13 studies (ten observational studies and three randomized studies) involving 1,121 patients were finally included. The patients were followed up for 6-27 months. Compared with BVP, CRT patients treated by HPSP presented shorter QRSd [mean difference (MD): -26.23 ms, 95% confidence interval (CI): -34.54 to -17.92, P < 0.001, I² = 91%], greater LV functional improvement with increased left ventricular ejection fraction (LVEF) (MD: 6.01, 95% CI: 4.81 to 7.22, P < 0.001, I² = 0%), decreased left ventricular end-diastolic dimension (LVEDD) (MD: -2.91, 95% CI: -4.86 to -0.95, P = 0.004, I² = 35%), and more improved NYHA functional classification (MD: -0.45, 95% CI: -0.67 to -0.23, P < 0.001, I² = 70%). In addition, HPSP was more likely to have higher echocardiographic [odds ratio (OR): 2.76, 95% CI: 1.74 to 4.39, P < 0.001, I² = 0%], clinical (OR: 2.10, 95% CI: 1.16 to 3.80, P = 0.01, I² = 0%) and super clinical (OR: 3.17, 95% CI: 2.09 to 4.79, P < 0.001, I² = 0%) responses than BVP, and a lower hospitalization rate of HF (OR: 0.34, 95% CI: 0.22 to 0.51, P < 0.001, I² = 0%), while presented no difference (OR: 0.68, 95% CI: 0.44 to 1.06, P = 0.09, I² = 0%) in all-cause mortality compared with BVP. With threshold change taking into account, BVP was less stable than LBBaP (MD: -0.12 V, 95% CI: -0.22 to -0.03, P = 0.01, I² = 57%), but had no difference with HBP (MD: 0.11 V, 95% CI: -0.09 to 0.31, P = 0.28, I² = 0%).

CONCLUSION

The present findings suggested that HPSP was associated with greater improvement of cardiac function in patients with indication for CRT and was a potential alternative to BVP to achieve physiological pacing through native his-purkinje system.

Advances in symptomatic therapy for left ventricular non-compaction in children

Left ventricular non-compaction is a complex cardiomyopathy and the third largest childhood cardiomyopathy, for which limited knowledge is available. Both pathogenesis and prognosis are still under investigation. Currently, no effective treatment strategy exists to reduce its incidence or severity, and symptomatic treatment is the only clinical treatment strategy. Treatment strategies are constantly explored in clinical practice, and some progress has been made in coping with the corresponding symptoms because the prognosis of children with left ventricular non-compaction is usually poor if there are complications. In this review, we summarized and discussed the coping methods for different left ventricular non-compaction symptoms.

Challenges of anaesthetising a child with Bow Hunter's syndrome and dilated cardiomyopathy for occipitocervical fusion

Paediatric Bow Hunter's syndrome (BHS), or rotational vertebral artery syndrome, is a rare cause of posterior circulation insufficiency in children. It results from mechanical obstruction of the vertebral artery by the transverse process of cervical vertebrae resulting in vertebrobasilar insufficiency during the neck rotation to the sides. Paediatric dilated cardiomyopathy (DCM) is a rare myocardial disease that presents with ventricular dilatation and cardiac dysfunction. This case report describes the successful anaesthetic management of an boy with BHS due to atlantoaxial dislocation and DCM. The child was anaesthetised by keeping the following anaesthetic goals in mind such as maintenance of the heart rate, rhythm, preload, afterload and contractility close to the baseline for both DCM and BHS. Haemodynamic management with optimal fluids, inotrope and a vasopressor and titrating its volume and doses using multimodal haemodynamic monitoring while keeping both cardio and neuroprotective strategies, and the multimodal analgesia techniques helped the child for faster recovery.

Reduced inferior wall longitudinal strain is associated with malignant arrhythmias in non-ischemic heart failure

BACKGROUND

Reduced systolic myocardial function in the inferior region of the left ventricle has been suggested to be associated with malignant arrhythmias. We tested this hypothesis in patients with non-ischemic heart failure.

METHODS

Patients with non-ischemic heart failure (left ventricular ejection fraction [LVEF] < 35%) were evaluated by 2D-speckle-tracking echocardiography. The regional longitudinal strain was calculated for each of the six left ventricular walls. The reduced regional function was defined as strain below the median. The outcome was a composite of sudden cardiac death, admission with sustained ventricular arrhythmia, resuscitated cardiac arrest, and appropriate therapy from a primary prophylactic implantable cardioverter defibrillator. Time-to-first-event analysis was performed using a Cox model.

RESULTS

From two centers, 401 patients were included (median age: 63 years, 72% male) with a median LVEF of 25% (interquartile range [IQR] 20;30), and a median inferior wall strain of -9.0% (-12.5; -5.4). During a median follow-up of 4.0 years, 52 outcomes occurred. After multivariate adjustment for clinical and electrocardiographic parameters, inferior wall strain was independently associated with the outcome (HR 2.50 [1.35; 4.62], p = .003). No independent association was found between the composite outcome and reduced strain in any of the other left ventricular walls, Global Longitudinal Strain (HR 1.66 [0.93; 2.98], p = .09), or LVEF (HR 1.33 [0.75; 2.33], p = .33).

CONCLUSIONS

Below median strain in the left ventricular inferior region was independently associated with a 2.5-fold increase in the risk of malignant arrhythmias and sudden cardiac death in patients with non-ischemic heart failure.

Bradycardia-Induced Torsades de Pointes in Atrioventricular Block

Bradycardia is known to prolong QT interval. Persistent bradycardia and high-grade atrioventricular (AV) block may lead to persistently prolonged QTc interval with a risk for life-threatening ventricular arrhythmias, which needs addressing the underlying cause. We present the case of a patient with persistent sinus bradycardia with a high-grade AV block leading to persistently prolonged QTc without any reversible etiology that resulted in torsades de pointes. The underlying treatment involved shortening the QTc by increasing the heart rate to prevent any further episodes of polymorphic ventricular tachycardia.

Relationship between Exercise Test Parameters, Device-Delivered Electric Shock and Adverse Clinical Events in Patients with an Implantable Cardioverter Defibrillator for Primary Prevention

(1) Background: Receiving the first internal electric shock is a turning point for patients with an implantable cardioverter defibrillator (ICD) for primary prevention. However, no study has investigated whether patients who receive a first device-delivered electric shock have a poor prognosis even at the time of ICD implantation. (2) Methods: We retrospectively identified 55 patients with ischemic (n = 31) or dilated (n = 24) cardiomyopathy who underwent ICD implantation for primary prevention with exercise test at the time of implantation. We recorded baseline characteristics, exercise test parameters, and clinical events. (3) Results: After a median follow-up of 5 years, we observed an association between an appropriate device-delivered electric shock, the occurrence of death or heart transplant, and the occurrence of the composite endpoint. There was also a significant relation between a VE/VCO2 slope >35 and the occurrence of the composite endpoint. Conversely, there was no significant association between negative outcomes on the exercise test and the occurrence of a device-delivered electric shock. (4) Conclusions: The exercise test performed at the time of ICD implantation do not predict the occurrence of device-delivered electric shock. The exercise test and the first electric shock are two independent markers of poor prognosis.

Cardioverter-defibrillator reduces mortality risk in eligible ischemic and non-ischemic cardiomyopathy patients: Sub-analysis of the multi-center Improve SCA study

BACKGROUND & OBJECTIVE

Despite the burden of sudden cardiac arrest (SCA) worldwide, implantable cardioverter-defibrillators (ICDs) are underutilized, particularly in Asia, Latin America, Eastern Europe, the Middle East, and Africa. The Improve SCA trial demonstrated that primary prevention (PP) patients in these regions benefit from an ICD or a cardiac resynchronization therapy defibrillator (CRT-D). We aimed to compare the rate of device therapy and mortality among ischemic and non-ischemic cardiomyopathy (ICM and NICM) PP patients who met guideline indications for ICD therapy and had an ICD/CRT-D implanted.

METHODS

Improve SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from the above-mentioned regions. All-cause mortality and device therapy were examined by cardiomyopathy (ICM vs NICM) and implantation status. Cox proportional hazards methods were used, adjusting for factors affecting mortality risk.

RESULTS

Of 1848 PP NICM patients, 1007 (54.5%) received ICD/CRT-D, while 303 of 581 (52.1%) PP ICM patients received an ICD/CRT-D. The all-cause mortality rate at 3 years for NICM patients with and without an ICD/CRT-D was 13.1% and 18.3%, respectively (HR 0.51, 95% CI 0.38-0.68, p < 0.001). Similarly, all-cause mortality at 3 years in ICM patients was 13.8% in those with a device and 19.9% in those without an ICD/CRT-D (HR 0.54, 95% CI 0.33-.0.88, p = 0.011). The time to first device therapy, time to first shock, and time to first antitachycardia pacing (ATP) therapy were not significantly different between groups (p ≥ 0.263).

CONCLUSIONS

In this large data set of patients with a guideline-based PP ICD indication, defibrillator device implantation conferred a significant mortality benefit in both NICM and ICM patients. The rate of appropriate device therapy was also similar in both groups.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02099721.

Failure of Guidelines and Consensus Statements to Recommend Follow-up for Chronic Cardiovascular Conditions

BACKGROUND

Many cardiac conditions require long-term clinical follow-up to monitor progression of disease and tolerance and adherence to therapies. Providers are often unsure as to the frequency of clinical follow-up and who should provide the follow-up. In the absence of formal guidance, patients may be seen more frequently than necessary - thereby limiting clinic space for other patients, or not frequently enough, potentially leading to undetected progression of disease.

OBJECTIVES

To determine the extent to which guidelines (GL)/consensus statements (CS) provide guidance about appropriate follow-up for common cardiovascular conditions.

METHODS

We identified 31 chronic cardiovascular disease conditions for which long-term (beyond 1 year) follow-up is indicated and used PubMed and professional society websites to identify all relevant GL/CS (n = 33) regarding these chronic cardiac conditions.

RESULTS

Of the 31 cardiac conditions reviewed, GL/CS contained no recommendation or vague recommendation for long-term follow-up for 7 of the conditions. Of the 24 conditions with recommendations for follow-up, 3 had recommendations for imaging follow-up only without mention of clinical follow-up. Of the 33 GL/CS reviewed, 17 made any recommendations about long-term follow-up. When recommendations were made regarding follow-up, they were often vague, using terminology such as "as needed".

CONCLUSIONS

Half of GL/CS fail to provide recommendations for clinical follow-up of common cardiovascular conditions. Writing groups for GL/CS should adopt a standard of routinely including recommendations for follow-up including specific advice about level of expertise needed (eg, primary care physician, cardiologist), need for imaging or testing, and frequency of follow-up.

A systematic review and meta-analysis comparing radiofrequency catheter ablation with medical therapy for ventricular tachycardia in patients with ischemic and non-ischemic cardiomyopathies

BACKGROUND

In patients with cardiomyopathy, radiofrequency catheter ablation (CA) for ventricular tachycardia (VT) is an adjunctive and alternative treatment option to long-term anti-arrhythmic drug therapy. We sought to compare CA with medical therapy for the management of VT in patients with ischemic and non-ischemic cardiomyopathies.

METHODS

MEDLINE, Cochrane, and ClinicalTrials.gov databases were evaluated for relevant studies.

RESULTS

Eleven studies with 2126 adult patients were included (711 in CA, 1415 in medical therapy). In the randomized controlled trial (RCT) analysis, CA reduced risk of recurrent VT (risk ratio (RR) 0.79 [95% CI 0.67 to 0.93], p = 0.005), ICD shocks (RR 0.64 [95% CI 0.45 to 0.89] p = 0.008), and cardiac hospitalizations (RR 0.76 [95% CI 0.63 to 0.92] p = 0.005). There was no difference in all-cause mortality (RR 0.94, p = 0.71). In combined RCT and observational study analysis, there was a trend for reduction in all-cause mortality (RR 0.75 [95% CI 0.55 to 1.02] p = 0.07). In subgroup analysis of studies with mean left ventricular ejection fraction (LVEF) < 35%, CA demonstrated reduction in mortality (RR 0.71, p = 0.004), ICD shocks (RR 0.63, p = 0.03), VT recurrence (RR 0.76, p = 0.004), and cardiac hospitalizations (RR 0.75, p = 0.02). The subgroup of early CA prior to ICD shocks demonstrated reduction in ICD shocks (RR 0.57, p < 0.001) and VT recurrence (RR 0.74, p = 0.01).

CONCLUSIONS

CA for VT demonstrated a lower risk of VT recurrence, ICD shocks, and hospitalization in comparison to medical therapy. The subgroups of early CA and LVEF < 35% demonstrated better outcomes.

Catheter ablation of ventricular tachycardia associated with structural heart disease: Current status and perspectives

Catheter ablation is an effective and safe treatment for ventricular tachycardia attributable to structural heart disease, reducing the risk of recurrent arrhythmias and defibrillator shock therapy. Advances in medical technology and an accumulation of data have led to the development of detailed guidelines. Successful ablation requires accurate identification of the arrhythmia substrate and effective delivery of radiofrequency energy to the target tissue. Modern practice requires use of traditional electrophysiological mapping processes such as entrainment mapping and three-dimensional activation sequence mapping in combination with newer functional mapping techniques for which there is growing support. Thorough non-invasive preoperative assessment is also necessary before an invasive procedure is undertaken. In this review, we summarize contemporary practice and recent randomized controlled trials underpinning the latest developments in mapping and ablation and discuss potential future developments in this field.

The Aging Heart: A Molecular and Clinical Challenge

Aging is associated with an increasing burden of morbidity, especially for cardiovascular diseases (CVDs). General cardiovascular risk factors, ischemic heart diseases, heart failure, arrhythmias, and cardiomyopathies present a significant prevalence in older people, and are characterized by peculiar clinical manifestations that have distinct features compared with the same conditions in a younger population. Remarkably, the aging heart phenotype in both healthy individuals and patients with CVD reflects modifications at the cellular level. An improvement in the knowledge of the physiological and pathological molecular mechanisms underlying cardiac aging could improve clinical management of older patients and offer new therapeutic targets.

Arrhythmogenic Cardiomyopathy: A Review of a Rare Case of Biventricular Phenotype

Arrhythmogenic cardiomyopathy is a rare hereditary structural heart disease, with various phenotypes, which mostly affects the right ventricle of the heart, resulting in fibrofatty replacement of the heart muscles and a proclivity to create spontaneous malignant cardiac arrhythmias that may lead to sudden death. Most previous reports were noted on young people. We report a case of its biventricular phenotype in a 61-year-old heavy truck driver who has a current medical history of diabetes mellitus and smoking and was incidentally diagnosed based on the Padua criteria after presenting to the hospital with complaints of lightheadedness and syncope. He eventually had an implantable cardioverter defibrillator, hence preventing death. We were able to correctly diagnose the case and prevent sudden cardiac death by instituting the necessary management.

Incidence of Sudden Cardiac Death and Life-Threatening Arrhythmias in Clinically Manifest Cardiac Sarcoidosis With and Without Current Indications for an Implantable Cardioverter Defibrillator

BACKGROUND

Cardiac sarcoidosis (CS) predisposes to sudden cardiac death (SCD). Guidelines for implantable cardioverter defibrillators (ICDs) in CS have been issued by the Heart Rhythm Society in 2014 and the American College of Cardiology/American Heart Association/Heart Rhythm Society consortium in 2017. How well they discriminate high from low risk remains unknown.

METHODS

We analyzed the data of 398 patients with CS detected in Finland from 1988 through 2017. All had clinical cardiac manifestations. Histological diagnosis was myocardial in 193 patients (definite CS) and extracardiac in 205 (probable CS). Patients with and without Class I or IIa ICD indications at presentation were identified, and subsequent occurrences of SCD (fatal or aborted) and sustained ventricular tachycardia were recorded, as were ICD indications emerging first on follow-up.

RESULTS

Over a median of 4.8 years, 41 patients (10.3%) had fatal (n=8) or aborted (n=33) SCD, and 98 (24.6%) experienced SCD or sustained ventricular tachycardia as the first event. By the Heart Rhythm Society guideline, Class I or IIa ICD indications were present in 339 patients (85%) and absent in 59 (15%), of whom 264 (78%) and 30 (51%), respectively, received an ICD. Cumulative 5-year incidence of SCD was 10.7% (95% CI, 7.4%-15.4%) in patients with ICD indications versus 4.8% (95% CI, 1.2%-19.1%) in those without (χ2=1.834, P=0.176). The corresponding rates of SCD were 13.8% (95% CI, 9.1%-21.0%) versus 6.3% (95% CI, 0.7%-54.0%; χ2=0.814, P=0.367) in definite CS and 7.6% (95% CI, 3.8%-15.1%) versus 3.3% (95% CI, 0.5%-22.9%; χ2=0.680, P=0.410) in probable CS. In multivariable regression analysis, SCD was predicted by definite histological diagnosis (P=0.033) but not by Class I or IIa ICD indications (P=0.210). In patients without ICD indications at presentation, 5-year incidence of SCD, sustained ventricular tachycardia, and emerging Class I or IIa indications was 53% (95% CI, 40%-71%). By the American College of Cardiology/American Heart Association/Heart Rhythm Society guideline, all patients with complete data (n=245) had Class I or IIa indications for ICD implantation.

CONCLUSIONS

Current ICD guidelines fail to distinguish a truly low-risk group of patients with clinically manifest CS, the 5-year risk of SCD approaching 5% despite absent ICD indications. Further research is needed on prognostic factors, including the role of diagnostic histology. Meanwhile, all patients with CS presenting with clinical cardiac manifestations should be considered for an ICD implantation.

Interventions in the Diagnosis and Adoption of Pacemaker Therapy in Sinus Node Dysfunction Patients: Results from the IMPROVE Brady study

Aims

IMPROVE Brady assessed whether a process improvement intervention could increase adoption of guideline-based therapy in sinus node dysfunction (SND) patients.

Methods

/Results: IMPROVE Brady was a sequential, prospective, quality improvement initiative conducted in India and Bangladesh. Patients with symptomatic bradycardia were enrolled. In Phase I, physicians assessed and treated patients per standard care. Phase II began after implementing educational materials for physicians and patients. Primary objectives were to evaluate the impact of the intervention on SND diagnosis and pacemaker (PPM) implant. SF-12 quality of life (QoL) and Zarit burden surveys were collected pre- and post-PPM implant.

A total of 978 patients were enrolled (57.7 ± 14.8 years, 75% male), 508 in Phase I and 470 in Phase II. The diagnosis of SND and implantation of PPM increased significantly from Phase I to Phase II (72% vs. 87%, P < 0.001 and 17% vs. 32%, P < 0.001, respectively). Pacemaker implantation was not feasible in 41% of patients due to insurance/cost barriers which was unaltered by the intervention. Both patient QoL and caregiver burden improved at 6-months post-PPM implant (P < 0.001).

Conclusions

A process improvement initiative conducted at centers across India and Bangladesh significantly increased the diagnosis of SND and subsequent treatment with PPM therapy despite the socio-economic constraints.

Cardiac and Pulmonary Management Status of Duchenne Muscular Dystrophy in South Korea Based on Data From the National Health Insurance Database

Background and Purpose

The purpose of this study was to determine the cardiac and pulmonary management status of patients with Duchenne muscular dystrophy (DMD) in South Korea based on the Korean National Health Insurance database.

Methods

This study used data of patients with code G71.0 in the National Health Information database, and also those with the special case of code V012. Cardiac function was assessed based on whether echocardiography and 24-h electrocardiography were performed, as well as the frequency of these investigations. Furthermore, information on the use of angiotensin-converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARB), and beta blockers (BB) in the drug benefit list was checked. Medical charge records were also checked regarding the prescription of respiratory functional assessments and treatments.

Results

The diagnostic criteria were met by 479 patients, with 41% of these patients receiving a cardiac evaluation, 29.8% being prescribed ACEi at 14.4±3.7 years of age, 59.5% undergoing pulmonary function tests, and 42.1% received pulmonary rehabilitation. The age at receiving ventilator support was 19.4±2.7 years. The frequency of cardiac and respiratory function tests increased with age, but the interval between tests was longer than the recent DMD care recommendations. The trend of taking ACEi, ARB, and BB for cardiac management in South Korea did not change during the study analysis period.

Conclusions

The findings of this study will contribute to recognizing the current status and the importance of applying an anticipatory approach to cardiopulmonary function in DMD patients.

Amateur Athlete with Sinus Arrest and Severe Bradycardia Diagnosed through a Heart Rate Monitor: A Six-Year Observation-The Necessity of Shared Decision-Making in Heart Rhythm Therapy Management

Heart rate monitors (HRMs) are used by millions of athletes worldwide to monitor exercise intensity and heart rate (HR) during training. This case report presents a 34-year-old male amateur soccer player with severe bradycardia who accidentally identified numerous pauses of over 4 s (maximum length: 7.3 s) during sleep on his own HRM with a heart rate variability (HRV) function. Simultaneous HRM and Holter ECG recordings were performed in an outpatient clinic, finding consistent 6.3 s sinus arrests (SA) with bradycardia of 33 beats/min. During the patient's hospitalization for a transient ischemic attack, the longest pauses on the Holter ECG were recorded, and he was suggested to undergo pacemaker implantation. He then reduced the volume/intensity of exercise for 4 years. Afterward, he spent 2 years without any regular training due to depression. After these 6 years, another Holter ECG test was performed in our center, not confirming the aforementioned disturbances and showing a tendency to tachycardia. The significant SA was resolved after a period of detraining. The case indicates that considering invasive therapy was unreasonable, and patient-centered care and shared decision-making play a key role in cardiac pacing therapy. In addition, some sports HRM with an HRV function can help diagnose bradyarrhythmia, both in professional and amateur athletes.

Implantable cardioverter-defibrillator placement among patients with left ventricular ejection fraction ≤35 % at least 40 days after acute myocardial infarction

Background

Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death among patients with persistently reduced (≤35 %) left ventricular ejection fraction (LVEF) at least 40 days following acute myocardial infarction (AMI). Few prior studies have used LVEF measured after the 40-day waiting period to examine primary prevention ICD placement.

Methods

We sought to determine factors associated with ICD placement among patients who met LVEF criteria post-MI within a large integrated health care system in the U.S by conducting a retrospective cohort study of Veteran patients hospitalized for AMI from 2004 to 2017 who had documented LVEF ≤35 % from echocardiograms performed between 40 and 455 (90 days +1 year) days post-MI. We used multivariable logistic regression to examine factors associated with ICD placement.

Results

Of 12,893 patients with LVEF ≤35 % at least 40 days post-MI, 2176 (16.9 %) received an ICD between 91- and 455-days post-MI. Younger age, fewer comorbidities, revascularization with PCI, and greater use of GDMT were associated with increased odds of receiving an ICD. However, half of patients treated with a beta-blocker, ACE inhibitor or angiotensin receptor blocker, and mineralocorticoid receptor antagonist prior to LVEF assessment did not receive an ICD. Eligible Black patients were less likely (odds ratio 0.80, 95 % confidence interval 0.69-0.92) to receive an ICD than White patients.

Conclusion

Many factors affect ICD placement among Veteran patients with a confirmed LVEF ≤35 % at least 40 days post-MI. Greater understanding of factors influencing ICD placement would help clinicians ensure guideline-concordant care.

Ventricular Arrhythmias in Patients with Implanted Cardiac Devices at High Risk of Obstructive Sleep Apnea

Background and Objectives: Patients with pre-existing cardiac disease have a higher prevalence of Obstructive Sleep Apnea (OSA). OSA has been associated with an increased risk of supraventricular and ventricular arrhythmia. We screened subjects with implanted pacemakers and automated implantable cardioverter defibrillators (AICD) for OSA with the Berlin Questionnaire and compared the incidence of ventricular arrhythmias and automated implantable cardioverter defibrillator (AICD) firing between high and low OSA risk groups. Materials and Methods: We contacted 648 consecutive patients from our arrhythmia clinic to participate in the study and performed final analyses on 171 subjects who consented and had follow-up data. Data were abstracted from the electronic health record for the incidence of non-sustained ventricular tachycardia (NSVT), ventricular tachycardia (VT), ventricular fibrillation (VF) and AICD firing and then compared between those at high versus low risk of OSA using the Berlin Questionnaire and multivariate negative binomial regression. Results: The average follow-up period was 24.2 ± 4.4 months. After adjusting for age, gender and history of heart failure, those subjects at high risk of OSA had a higher burden of NSVT vs. those with a low risk of OSA (33.4 ± 96.2 vs. 5.82 ± 17.1 episodes, p = 0.003). A predetermined subgroup analysis of AICD recipients also demonstrated a significantly higher burden of NSVT in the high vs. low OSA risk groups (66.2 ± 128.6 vs. 18.9 ± 36.7 episodes, p = 0.033). There were significant differences in the rates of VT, VF or AICD shock burden between the high and low OSA risk groups and in the AICD subgroup analysis. Conclusions: There was increased ventricular ectopy among pacemaker and AICD recipients at high risk of OSA, but the prevalence of VT, VF or AICD shocks was similar to those with low risk of OSA.