Variation in prenatal surveillance and management of anti-SSA/Ro autoantibody positive pregnancies

OBJECTIVE

To describe international surveillance and treatment strategies for managing anti-SSA/Ro autoantibody positive pregnancies.

STUDY DESIGN

An electronic REDCap questionnaire was distributed to Fetal Heart Society and North American Fetal Therapy Network members which queried institution-based risk stratification, surveillance methods/frequency, conduction abnormality treatments, and postnatal anti-SSA/Ro pregnancy assessment.

RESULTS

101 responses from 59 centers (59% US, 17% international) were collected. Most (79%) do not risk stratify pregnancies by anti-SSA/Ro titer; those that do use varied cutoff values. Many pregnant rheumatology patients are monitored for cardiac abnormalities regardless of maternal anti-SSA/Ro status. Surveillance strategies were based on maternal factors (anti-SSA/Ro status 85%, titer 25%, prior affected child 79%) and monitoring durations varied. Most respondents treat 2° and 3° fetal atrioventricular block, commonly with dexamethasone and/or IVIG.

CONCLUSIONS

Wide variation exists in current fetal cardiac surveillance and treatment for anti-SSA/Ro autoantibody positive pregnancies, highlighting the need for evidence-based protocols to optimize care.

Successful prediction of left bundle branch block-induced cardiomyopathy and treatment effect by artificial intelligence-enabled electrocardiogram

BACKGROUND

Left bundle branch block (LBBB) induced cardiomyopathy is an increasingly recognized disease entity.  However, no clinical testing has been shown to be able to predict such an occurrence.

CASE REPORT

A 70-year-old male with a prior history of LBBB with preserved ejection fraction (EF) and no other known cardiovascular conditions presented with presyncope, high-grade AV block, and heart failure with reduced EF (36%). His coronary angiogram was negative for any obstructive disease. No other known etiologies for cardiomyopathy were identified. Artificial intelligence-enabled ECGs performed 6 years prior to clinical presentation consistently predicted a high probability (up to 91%) of low EF. The patient successfully underwent left bundle branch area (LBBA) pacing with correction of the underlying LBBB. Subsequent AI ECGs showed a large drop in the probability of low EF immediately after LBBA pacing to 47% and then to 3% 2 months post procedure. His heart failure symptoms markedly improved and EF normalized to 54% at the same time.

CONCLUSIONS

Artificial intelligence-enabled ECGS may help identify patients who are at risk of developing LBBB-induced cardiomyopathy and predict the response to LBBA pacing.

Transvenous Pacemaker Placement: A Review for Emergency Clinicians

BACKGROUND

Transvenous pacemaker placement is an integral component of therapy for severe dysrhythmias and a core skill in emergency medicine.

OBJECTIVE

This narrative review provides a focused evaluation of transvenous pacemaker placement in the emergency department setting.

DISCUSSION

Temporary cardiac pacing can be a life-saving procedure. Indications for pacemaker placement include hemodynamic instability with symptomatic bradycardia secondary to atrioventricular block and sinus node dysfunction; overdrive pacing in unstable tachydysrhythmias, such as torsades de pointes; and failure of transcutaneous pacing. Optimal placement sites include the right internal jugular vein and left subclavian vein. Insertion first includes placement of a central venous catheter. The pacing wire with balloon is then advanced until electromechanical capture is obtained with the pacer in the right ventricle. Ultrasound can be used to guide and confirm lead placement using the subxiphoid or modified subxiphoid approach. The QRS segment will demonstrate ST segment elevation once the pacing wire tip contacts the endocardial wall. If mechanical capture is not achieved with initial placement of the transvenous pacer, the clinician must consider several potential issues and use an approach to evaluating the equipment and correcting any malfunction. Although life-saving in the appropriate patient, complications may occur from central venous access, right heart catheterization, and the pacing wire.

CONCLUSIONS

An understanding of transvenous pacemaker placement is essential for emergency clinicians.

Pharmacological Management of Cardiac Arrhythmias in the Fetal and Neonatal Periods: A Scientific Statement From the American Heart Association: Endorsed by the Pediatric & Congenital Electrophysiology Society (PACES)

Disorders of the cardiac rhythm may occur in both the fetus and neonate. Because of the immature myocardium, the hemodynamic consequences of either bradyarrhythmias or tachyarrhythmias may be far more significant than in mature physiological states. Treatment options are limited in the fetus and neonate because of limited vascular access, patient size, and the significant risk/benefit ratio of any intervention. In addition, exposure of the fetus or neonate to either persistent arrhythmias or antiarrhythmic medications may have yet-to-be-determined long-term developmental consequences. This scientific statement discusses the mechanism of arrhythmias, pharmacological treatment options, and distinct aspects of pharmacokinetics for the fetus and neonate. From the available current data, subjects of apparent consistency/consensus are presented, as well as future directions for research in terms of aspects of care for which evidence has not been established.

An Unusual Presentation of Adult Intussusception

Intussusception is a condition characterized by the invagination of a proximal segment of the intestine into a distal segment. In adults, intussusception is commonly associated with a lead point. The most alarming lead point is an obstructing malignancy. Here, we present the case of a 57-year-old woman with ileocolic intussusception secondary to colonic adenocarcinoma. The patient presented to the emergency department following an incidental finding of bradycardia, with a heart rate of around 40 beats per minute. She presented with several weeks of cramping, right lower quadrant abdominal pain, lightheadedness, fatigue, and palpitations. A computed tomography scan revealed ileocolic intussusception. After the placement of a semi-permanent right subclavian pacer, the patient underwent a right hemicolectomy. Surgical findings were consistent with ileocolic intussusception suspicious of being initiated by a mass in the right cecum involving the appendiceal orifice and ileocecal valve that invaded through the muscularis propria into subserosal tissue. The mass was resected and sent to pathology, where it was classified as stage II colonic adenocarcinoma. This case highlights a nonspecific presentation of intussusception that was only identified due to incidental bradycardia.

Bradycardia, Renal Failure, Atrioventricular Block, Shock, and Hyperkalemia (BRASH) Syndrome Emergence in a Unique Intersection of COVID-19 and End-Stage Renal Disease: A Case Report

Bradycardia, renal failure, atrioventricular (AV) block, shock, and hyperkalemia (BRASH) syndrome is a rare clinical entity that poses challenges for healthcare practitioners. It is characterized by bradycardia, renal failure, atrioventricular (AV) obstruction, shock, and hyperkalemia. This case is an interesting instance of BRASH syndrome in the setting of COVID-19 infection and end-stage renal disease (ESRD). Initial laboratory results revealed macrocytic anemia, renal dysfunction, acidosis, and mild hyponatremia, along with hyperkalemia. An electrocardiogram (EKG) and telemonitoring showed dopamine-resistant persistent bradycardia until transvenous temporary pacemaker placement was done, which resolved the bradycardia. Anti-hyperkalemic therapy, avoiding AV nodal-blocking medication, and temporary pacemaker placement were all part of the management. After receiving hemodialysis, the patient gradually recovered. Bradycardia improved and potassium normalized. The intricate interaction between hyperkalemia and AV nodal obstruction that causes BRASH syndrome results in severe bradycardia and shock. To the best of our knowledge, this is the first case of BRASH syndrome in a patient with an active COVID-19 infection in a previously vaccinated patient. Even though case reports make up the majority of the material currently in publication, to fully comprehend the mechanisms underlying this illness, more research is required, as early detection of this syndrome is crucial for better patient outcomes.

Atrioventricular block in patients with hyperthyroidism: a narrative review

Atrioventricular block (AVB) is a rare cardiac manifestation of hyperthyroidism (HTH). The scientific literature contains multiple reports of AVB in patients with HTH, ranging from subclinical to overt HTH and even thyroid storm. However, much remains unknown about the true prevalence, clinical course, optimal management, and outcomes of AVB in patients with HTH. Such patients are possibly overtreated with pacemakers because of a lack of understanding that AVB might be secondary to the hyperthyroid state and thus reversible. This narrative review discusses the pathophysiology of AVB in patients with HTH in the context of the available evidence.

A suicide attempt by ingestion of oleander leaves and treatment with digoxin-specific Fab antibody fragments

Natural cardiac glycosides have positive inotropic heart effects but at high, toxic doses they can cause life-threatening cardiac arrhythmias. Here we present the first Croatian case of a 16-year-old girl who attempted suicide by eating dried oleander leaves, which contain natural cardiac glycosides, and her treatment with a specific antidote. The girl presented with an oedema of the uvula indicating local toxicity, severe bradycardia, first-degree atrioventricular block, drowsiness, and vomiting. Having taken her medical history, we started treatment with atropine, intravenous infusion of dextrose-saline solution and gastroprotection, but it was not successful. Then we introduced digoxin-specific Fab antibody fragments and within two hours, the patient's sinus rhythm returned to normal. Cases of self-poisoning with this oleander are common in South-East Asia, because it is often used as a medicinal herb, and digoxin-specific Fab fragments have already been reported as effective antidote against oleander poisoning there. Our case has taught us that it is important to have this drug in the hospital pharmacy both for digitalis and oleander poisoning.

Emergency transvenous temporary pacing during rotational atherectomy

Background

Rotational atherectomy (RA) during percutaneous coronary intervention may cause transient bradycardia or a higher-degree heart block. Traditionally, some operators use prophylactic transvenous pacing wire (TPW) to avoid haemodynamic complications associated with bradycardia.

Objective

We sought to establish the frequency of bail-out need for emergency TPW insertion in patients undergoing RA that have received no upfront TPW insertion.

Methods

We performed a single-centre retrospective study of all patients undergoing RA between October 2009 and October 2022. Patient characteristics, procedural variables, and in-hospital complications were registered.

Results

A total of 331 patients who underwent RA procedure were analysed. No patients underwent prophylactic TPW insertion. The mean age was 73.3 ± 9.1 years, 71.6% (n = 237) were male, while nearly half of the patients were diabetic [N = 158 (47.7%)]. The right coronary artery was the most common target for RA (40.8%), followed by the left anterior descending (34.1%), left circumflex (14.8%), and left main stem artery (10.3%). Altogether 20 (6%) patients required intraprocedural atropine therapy. Emergency TPW insertion was needed in one (0.3%) patient only. Eight (2.4%) patients died, although only one (0.3%) was adjudicated as being possibly related to RA-induced bradycardia. Five patients (1.5%) had ventricular fibrillation arrest, while nine (2.7%) required cardiopulmonary resuscitation. Six (1.8%) procedures were complicated by coronary perforation, two (0.6%) were complicated by tamponade, while 17 (5.1%) patients experienced vascular access complications.

Conclusions

Bail-out transvenous temporary pacing is very rarely required during RA. A standby temporary pacing strategy seems reasonable and may avoid unnecessary TPW complications compared with routine use.

Permanent Complete Heart Block: A Rare Complication of Influenza Infection

The cardiovascular complications of viral illnesses are often underestimated in clinical practice. The influenza virus, one of the most prevalent viral infections, has been associated with a wide spectrum of arrhythmias that are typically transient and self-resolving. We present the case of a 60-year-old female with no prior cardiac comorbidities who developed a complete heart block after an influenza infection. She presented to the clinic with flu-like symptoms and was found to have a complete heart block with a junctional escape rhythm. Polymerase chain reaction testing subsequently confirmed an influenza A infection. She was initially placed on a temporary pacemaker. However, a permanent dual-chamber pacemaker was implanted as bradycardia persisted. Later follow-ups in the cardiology clinic showed that the patient remained dependent on the pacemaker. While there are a few descriptions of influenza-induced transient atrioventricular block, cases of influenza-induced permanent complete heart block are extremely rare, particularly in the absence of severe myocardial inflammation.

Utility of rapid atrial pacing before and after TAVR with balloon-expandable valve in predicting permanent pacemaker implantation

BACKGROUND

High-grade or complete atrioventricular block (AVB) requiring permanent pacemaker (PPM) implantation is a known complication of transcatheter aortic valve replacement (TAVR). Wenckebach AVB induced by rapid atrial pacing (RAP) after TAVR was previously demonstrated in an observational analysis to be an independent predictor for PPM. We sought to investigate the utility of both pre- and post-TAVR RAP in predicting PPM implantation.

METHODS

In a single-center, prospective study, 421 patients underwent TAVR with balloon-expandable valves (BEV) between April 2020 and August 2021. Intraprocedural RAP was performed in patients without a pre-existing pacemaker, atrial fibrillation/flutter, or intraprocedural complete AVB to assess for RAP-induced Wenckebach AVB. The primary outcome was PPM within 30 days after TAVR.

RESULTS

RAP was performed in 253 patients, of whom 91.3% underwent post-TAVR RAP and 61.2% underwent pre-TAVR RAP. The overall PPM implantation rate at 30 days was 9.9%. Although there was a numerically higher rate of PPM at 30 days in patients with RAP-induced Wenckebach AVB, it did not reach statistical significance (13.3% vs. 8.4%, p = 0.23). In a multivariable analysis, RAP-induced Wenckebach was not an independent predictor for PPM implantation at 30 days after TAVR. PPM rates at 30 days were comparable in patients with or without pre-TAVR pacing-induced Wenckebach AVB (11.8% vs. 8.2%, p = 0.51) and post-TAVR pacing-induced Wenckebach AVB (10.2% vs. 5.8%, p = 0.25).

CONCLUSION

In patients who underwent TAVR with BEV, there were no statistically significant differences in PPM implantation rates at 30 days regardless of the presence or absence of RAP-induced Wenckebach AVB. Due to conflicting results between the present study and the prior observational analysis, future studies with larger sample sizes are warranted to determine the role of RAP during TAVR as a risk-stratification tool for significant AVB requiring PPM after TAVR.

Prospective validation of a risk score to predict pacemaker implantation after transcatheter aortic valve replacement

INTRODUCTION

The need for pacemaker is a common complication after transcatheter aortic valve replacement (TAVR). We previously described the Emory Risk Score (ERS) to predict the need for new pacemaker implant (PPM) after TAVR. Metrics included in the score are a history of syncope, pre-existing RBBB, QRS duration ≥140 ms, and prosthesis oversizing ≥16%. To prospectively validate the previously described risk score.

METHODS

We prospectively evaluated all patients without pre-existing pacemakers, ICD, or pre-existing indications for pacing undergoing TAVR with the Edwards SAPIEN 3 prosthesis at our institution from March 2019 to December 2020 (n = 661). Patients were scored prospectively; however, results were blinded from clinical decision-making. The primary endpoint was PPM at 30 days after TAVR. Performance of the ERS was evaluated using logistic regression, a calibration curve to prior performance, and receiver operating characteristic (ROC) analysis.

RESULTS

A total of 48 patients (7.3%) had PPM after TAVR. A higher ERS predicted an increased likelihood of PPM (OR 2.61, 95% CI: 2.05-3.25 per point, p < 0.001). There was good correlation between observed and expected values on the calibration curve (slope = 1.04, calibration at large = 0.001). The area under the ROC curve was 0.81 (95% CI [0.74-0.88], p < 0.001).

CONCLUSIONS

The ERS prospectively predicted the need for PPM in a serial, real-world cohort of patients undergoing TAVR with a balloon-expandable prosthesis, confirming findings previously described in retrospective cohorts. Notably, the prospective performance of the score was comparable with that of the initial cohorts. The risk score could serve as a framework for preprocedural risk stratification for PPM after TAVR.

Pseudo 2:1 AV Block From Acquired Long QT Syndrome From Eating Clay

Age-related degeneration of the cardiac conduction system is an important cause of heart block and a leading indication for permanent pacemaker implantations. However, variations in the myocardial refractory periods from QT interval prolongation or concealed atrioventricular node penetration from premature ventricular complexes can lead to unusual forms of conduction block not requiring permanent pacemaker implantation. (Level of Difficulty: Advanced.).

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.

Anti-U1RNP-70kD-positive case of neonatal lupus presenting with seizure and incomplete heart block: a case report and literature review

Neonatal lupus erythematosus (NLE) is an autoimmune disease caused by the transplacental passage of anti-Ro/SS-A and anti-La/SS-B. This can be less commonly seen with U1-ribonucleoprotein (U1RNP). Our patient is a 7-day-old male, who first presented with seizures. In addition, during an electroencephalogram, he was found to have an irregular heart rhythm. Looking further into the history, we found that the mother was aware that she had systemic lupus erythematosus (SLE). However, she had not been followed up with a rheumatologist. The workup for NLE found a negative anti-Ro/SS-A and anti-La/SS-B, with a positive U1RNP-70kD. U1RNP-70kD is a diagnostic test for mixed connective tissue disease in adults, but no research has been done on its significance in NLE. Despite having SLE, the infant's mother did not receive surveillance during her pregnancy, as the current guidelines are tailored for mothers with anti-Ro/SS-A and anti-La/SS-B. As a result, this calls for the extension of these guidelines to include the U1RNP-70kD antibody. In this case, the 70kD subtype of U1RNP was positive, which may have had a role to play in this unusual presentation. However, further research is needed to improve the care of mothers and babies with U1RNP-70kD.

Dengue beyond fever-fatal dengue myocarditis and complete heart block: A case report and brief overview of cardiac manifestations of dengue fever

Dengue is an endemic viral fever transmitted by mosquitoes that may be asymptomatic or cause a nonspecific flu-like illness. The disease's most severe manifestations are dengue hemorrhagic fever and dengue shock syndrome. Various atypical manifestations have been observed that constitute the expanded dengue syndrome. Although uncommon, it is now known to cause cardiac complications that can be life-threatening and difficult to diagnose. We illustrate a case of a 16-year-old boy infected with dengue who experienced syncope, dizziness, and lethargy. His electrocardiogram showed third degree atrioventricular block which did not resolve with atropine and fluid resuscitation. After excluding all possible causes of complete heart block, transvenous pacing was done. A detailed workup was carried out that favored a diagnosis of subclinical myocarditis leading to complete heart block. The patient did not regain a normal rhythm and was considered for permanent pacemaker implantation. Myocarditis, pericarditis, rhythm disturbances, first- and second-degree atrioventricular blocks, and rarely third-degree heart blocks have been seen in dengue patients. However, a case of dengue illness associated complete heart blocks that is irreversible and necessitates a permanent pacemaker has never been described in the literature, and this is the first such case being reported. This article intends to increase clinicians' awareness, particularly those in dengue-endemic regions, about better recognition and comprehension of cardiac problems associated with dengue fever.

Neonatal lupus erythematosus manifested as a complete heart block: A case report

Key Clinical Message

Fetal bradycardia and congenital complete heart block could be the presentation of neonatal lupus. A high index of suspicion of this condition helps to identify an asymptomatic mother.

Abstract

Neonatal lupus erythematosus (NLE) is a rare acquired autoimmune disease of newborns due to placental transfer of Ro/SSA or La/SSB autoantibodies. Though cardiac, cutaneous, hematological, and hepatobiliary abnormalities are detected, cardiac defects cause significant morbidity and mortality. We report a case of complete congenital heart block due to NLE.

Automatic algorithmic driven monitoring of atrioventricular nodal re-entrant tachycardia ablation to improve procedural safety

Background

During slow pathway modification for atrioventricular nodal reentrant tachycardia, heart block may occur if ablation cannot be stopped in time in response to high risk electrogram features (HREF).

Objectives

To develop an automatic algorithm to monitor HREF and terminate ablation earlier than human reaction.

Methods

Digital electrogram data from 332 ablation runs from February 2020 to June 2022 were included. They were divided into training and validation sets which contained 126 and 206 ablation runs respectively. HREF in training set was measured. Then a program was developed with cutoff values decided from training set to capture all these HREF. Simulation ablation videos were rendered using validation set electrogram data. The videos were played to three independent electrophysiologists who each determined when to stop ablation. Timing of ablation termination, sensitivity, and specificity were compared between human and program.

Results

Reasons for ablation termination in the training set include short AA time, short VV time, AV block and VA block. Cutoffs for the program were set to maximize program sensitivity. Sensitivity and specificity for the program in the validation set were 95.2% and 91.1% respectively, which were comparable to that of human performance at 93.5% and 95.4%. If HREF were recognized by both human and program, ablations were terminated earlier by the program 90.2% of times, by a median of 574 ms (interquartile range 412-807 ms, p < 0.001).

Conclusion

Algorithmic-driven monitoring of slow pathway modification can supplement human judgement to improve ablation safety.

Rocky Mountain Spotted Fever Associated With Cardiac Arrhythmias

Rickettsial infection, known as Rocky Mountain spotted fever, is a challenging diagnosis as early clinical manifestations are difficult to distinguish from viral illnesses. Symptoms at presentation depend on the organs involved, ranging from a skin rash as evidence of vascular damage to prerenal azotemia, respiratory failure, hepatic injury, or encephalitis. We report an unusual case of an otherwise healthy 83-year-old female whose serologies tested positive for Rickettsia rickettsii, which led to cardiac dysrhythmia, i.e., the new onset of atrial fibrillation associated with conversion pauses. The patient was treated with antibiotics and ultimately underwent permanent pacemaker placement with resolution. This case highlights cardiac dysrhythmia as a late and severe manifestation in patients diagnosed with rickettsial illness.

A Case of Chagas Cardiomyopathy in Western Virginia: Worlds Away?

Chagas cardiomyopathy, caused by the parasite Trypanosoma cruzi, is a significant cause of cardiac pathology worldwide. Though most frequently observed in Latin America, Chagas disease is present in the United States and should be considered in patients with heart block or other cardiac abnormalities and previous travel to or residence in endemic areas. Here we describe a new diagnosis of Chagas cardiomyopathy in a patient residing in Virginia with a previous residence in Mexico.

Risk Factors, Management, and Avoidance of Conduction System Disease after Transcatheter Aortic Valve Replacement

Transcatheter valve replacement (TAVR) is a rapidly developing modality to treat patients with aortic stenosis (AS). Conduction disease post TAVR is one of the most frequent and serious complications experienced by patients. Multiple factors contribute to the risk of conduction disease, including AS and the severity of valve calcification, patients' pre-existing conditions (i.e., conduction disease, anatomical variations, and short septum) in addition to procedure-related factors (e.g., self-expanding valves, implantation depth, valve-to-annulus ratio, and procedure technique). Detailed evaluation of risk profiles could allow us to better prevent, recognize, and treat this entity. Available evidence on management of conduction disease post TAVR is based on expert opinion and varies widely. Currently, conduction disease in TAVR patients is managed depending on patient risk, with minimal-to-no inpatient/outpatient observation, inpatient monitoring (24-48 h) followed by ambulatory monitoring, or either prolonged inpatient and outpatient monitoring or permanent pacemaker implantation. Herein, we review the incidence and risk factors of TAVR-associated conduction disease and discuss its management.

Diphtheritic myocarditis: a case report, with toxinmediated complications and multi-organ involvement

The re-emergence of diphtheria in South Africa in recent years warns of incomplete vaccination coverage. Recent outbreaks have been associated with a high mortality rate, due to late presentation, limited access to antitoxin and the occurrence of serious systemic complications. Death due to diphtheria is most commonly associated with diphtheritic myocarditis, which presents with heart failure, cardiogenic shock and conduction abnormalities. This case highlights the key clinical features and systemic complications, and examines the reasons for the return of diphtheria in our community.

COVID-19-Induced Complete Heart Block: Case Series and Literature Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to the emergence of a wide range of complications, including those affecting the cardiovascular system. In this case series, we present four patients who developed complete atrioventricular block, a serious and potentially life-threatening heart rhythm disorder, during the course of their coronavirus disease 2019 (COVID-19) illness. The mechanisms by which SARS-CoV-2 may lead to arrhythmias are not fully understood but may involve direct infection and damage to heart tissue, as well as inflammation and cytokine storms. The extent and duration of complete heart block varied among these cases, highlighting the need for further research to understand the spectrum of disease and to improve mortality and morbidity in future waves of SARS-CoV-2 infections. We hope that this case series will draw attention to this serious complication of COVID-19 and inspire further research to improve management and outcomes for affected patients.

Acute Onset of Heart Failure and Renal Failure Due to Pacemaker Syndrome

Here, we report the outcome of an 87-year-old man with permanent non-valvular atrial fibrillation who initially presented with complete heart block and received a single right ventricle lead pacemaker programmed to ventricular demand pacing (VVIR). Over the next 10 months, the patient was readmitted to the hospital four times with recurrent edema, pleural effusions, and ascites. He was diagnosed with new onset systolic heart failure with mid-range (40-49%) ejection fraction and cardiorenal syndrome requiring dialysis. The underlying cause of his presentation was determined to be pacemaker syndrome mediated by new onset severe tricuspid regurgitation. He was treated with reimplantation of a pacemaker with His bundle pacing with subsequent improvement in his cardiac status and renal function. Implantation of dual-chamber pacing (DDDR) or His bundle pacing to achieve a narrow QRS complex over ventricular demand pacemaker is recommended whenever possible to reduce the incidence of pacemaker syndrome and improve patient outcomes.

Is It Possible to Place a Pacemaker Lead Through a Bileaflet Mechanical Prosthesis?

We present a 64-year-old woman who underwent mitral, aortic, and tricuspid valve (TV) replacement with mechanical prostheses. Two months after TV surgery, she presented third-degree atrioventricular block. After attempting to place a pacemaker lead through the coronary sinus, it was placed through the mechanical valve in the tricuspid position as the last option. At 1 year of follow-up, the device shows no signs of dysfunction, and the prosthesis has moderate regurgitation.

Vulnerability of the ventricular conduction axis during transcatheter aortic valvar implantation: A translational pathologic study

The ventricular components of the conduction axis remain vulnerable following transcatheter aortic valvar replacement. We aimed to describe features which may be used accurately by interventionalists to predict the precise location of the conduction axis, hoping better to avoid conduction disturbances. We scanned eight normal adult heart specimens by 3T magnetic resonance, using the images to simulate histological sections in order accurately to place the conduction axis back within the heart. We then used histology, tested in two pediatric hearts, to prepare sections, validated by the magnetic resonance images, to reveal the key relationships between the conduction axis and the aortic root. The axis was shown to have a close relationship to the nadir of the right coronary leaflet, in particular when the aortic root was rotated in counterclockwise fashion. The axis was more vulnerable in the setting of a narrow inferoseptal recess, when the inferior margin of the membranous septum was above the plane of the virtual basal ring, and when minimal myocardium was supporting the right coronary sinus. The features identified in our study are in keeping with the original description provided by Tawara, but at variance with more recent accounts. They suggest that the vulnerability of the axis during transcatheter valvar replacement can potentially be inferred on the basis of knowledge of the position of the aortic root within the ventricular base. If validated by clinical studies, our findings may better permit avoidance of new-onset left bundle branch block following transcatheter aortic valvar replacement.

Successful treatment with bortezomib for POEMS syndrome, overcoming complicated severe heart block

Cardiac bradyarrhythmia and conduction disorder may be rare, but recurrent adverse events caused by bortezomib. Here we report a case with POEMS syndrome presenting severe heart block after bortezomib plus dexamethasone therapy. After permanent pacemaker implantation, bortezomib was restarted and maintained, resulting in sustained complete response for POEMS syndrome.

Discordant expression of maternal SLE in twin pregnancy with a single fetal AV block: A case report

There are multiple manifestations in the neonatal period for infants born to mothers with systematic lupus erythematosus (SLE), ranging from cardiac, hematologic and dermatologic abnormalities. Cardiac complications may arise in utero in the form of heart block with a resulting increase in fetal mortality. The fetal conduction system is suspected to be affected by transplacental maternal antibodies, however additional environmental and fetal factors appear to play a role. We describe a rare case of a dichorionic-diamniotic twin pregnancy in which only one twin developed a complete heart block progressing to hydrops fetalis and fetal demise.

Conduction mapping during complex congenital heart surgery: Creating a predictive model of conduction anatomy

OBJECTIVES

The study objectives were to report on a growing experience of conduction system mapping during complex congenital heart surgery and create a predictive model of conduction anatomy.

METHODS

Patients undergoing complex cardiac repair with conduction mapping were studied. Intraoperative mapping used a multielectrode catheter to collect His bundle electrograms in the open, decompressed, beating heart. Patient anatomy, operative details, His bundle location, and postoperative conduction status were analyzed. By using classification and regression tree analysis, a predictive model of conduction location was created.

RESULTS

A total of 109 patients underwent mapping. Median age and weight were 1.8 years (range, 0.2-14.9) and 10.8 kg (range, 3.5-50.4), respectively. Conduction was identified in 96% (105/109). Median mapping time was 6 minutes (range, 2-33). Anatomy included atrioventricular canal defect, double outlet right ventricle, complex transposition of the great arteries, and multiple ventricular septal defects. By classification and regression tree analysis, ventricular looping and visceroatrial situs were the greatest discriminators of conduction location. A total of 94 of 105 patients (89.5%) were free of complete heart block. Only 1 patient (2.9%) with heterotaxy syndrome developed complete heart block.

CONCLUSIONS

The precise anatomic location of the conduction system in patients with complex congenital heart defects can be difficult for the surgeon to accurately predict. Intraoperative conduction mapping enables localization of the His bundle and adds to our understanding of the anatomic factors associated with conduction location. Predictive modeling of conduction anatomy may build on what is already known about the conduction system and help surgeons to better anticipate conduction location preoperatively and intraoperatively.

Fetal heart block: Vaginal delivery an option

BACKGROUND

Fetal heart block (FHB) occurs in approximately 1:20 000 births and is associated with significant morbidity and mortality. Vaginal delivery with intrapartum fetal scalp lactate monitoring is offered as an option at our centre for selected cases, in contrast with the published literature advocating caesarean birth.

AIMS

To review perinatal outcomes at delivery for FHB at a tertiary referral hospital.

MATERIALS AND METHODS

Ours was a retrospective cohort study from 1 January, 2007 to 30 June, 2020. The infant outcomes are summarised in three delivery groups: vaginal delivery, planned caesarean section (CS) and unplanned CS.

RESULTS

There were 23 newborns in the study period, with a median gestation at birth of 37.2 weeks and there was one antepartum fetal death in this cohort. Vaginal delivery was planned in 12 women: eight had normal births, three of these women progressed to an intrapartum (unplanned) CS and one woman had a planned CS. All live babies in the vaginal delivery cohort had an Apgar score greater than seven at five minutes. Of the 22 newborns, six required intubation, of which five had been delivered by a planned CS.

CONCLUSION

Our data suggest that planned vaginal delivery is a safe option for selected women carrying a fetus with FHB. Managing labour with serial fetal scalp lactates, and the involvement of senior clinicians are important factors in achieving a successful outcome.

Randomized Pragmatic Trial of Pacemaker Versus Implantable Cardiac Monitor in Syncope and Bifascicular Block

OBJECTIVES

In this study, the authors tested whether a strategy of empiric permanent pacing reduces major composite events more effectively than acting on the results of an implantable cardiac monitor (ICM).

BACKGROUND

Syncope may be caused by intermittent complete heart block in patients with bifascicular heart block, but competing diagnoses coexist. Whether empiric permanent pacing or acting on investigative results provides best care is unknown.

METHODS

This was a multinational, randomized, pragmatic clinical trial of patients ≥50 years of age with bifascicular block, preserved left ventricular function, and ≥1 syncope in the preceding year. The primary composite outcome measure comprised cardiovascular death, syncope, bradycardia resulting in pacemaker insertion, and device complications.

RESULTS

There were 57 and 58 subjects randomized to receive a pacemaker or ICM. A total of 41 patients had left bundle branch block and 74 had right bundle branch block and a left fascicular block. Patients were followed for a median 33 months. There were fewer composite primary outcomes in patients randomized to pacemaker compared with ICM, respectively (20 [35%] vs 44 [76%]; chi square P < 0.0001), with lower actuarial probabilities of a primary outcome (0.45 and 1.00; P < 0.001). Syncope was as likely in the groups randomized to receive a pacemaker or ICM (29% vs 26%, chi-square P = 0.95).

CONCLUSIONS

Empiric permanent pacing compared with ICM reduced major adverse events but not syncope in older patients with bifascicular block and recent syncope. There remains a substantial likelihood of syncope recurrence in patients who receive a permanent pacemaker likely caused by vasodepressor syncope. (Syncope: Pacing or Recording in the Later Years [SPRITELY]; NCT01423994).

Outcome of Antibody-Mediated Fetal Heart Disease With Standardized Anti-Inflammatory Transplacental Treatment

Background Transplacental fetal treatment of immune-mediated fetal heart disease, including third-degree atrioventricular block (AVB III) and endocardial fibroelastosis, is controversial. Methods and Results To study the impact of routine transplacental fetal treatment, we reviewed 130 consecutive cases, including 108 with AVB III and 22 with other diagnoses (first-degree/second-degree atrioventricular block [n=10]; isolated endocardial fibroelastosis [n=9]; atrial bradycardia [n=3]). Dexamethasone was started at a median of 22.4 gestational weeks. Additional treatment for AVB III included the use of a β-agonist (n=47) and intravenous immune globulin (n=34). Fetal, neonatal, and 1-year survival rates with AVB III were 95%, 93%, and 89%, respectively. Variables present at diagnosis that were associated with perinatal death included an atrial rate <90 beats per minute (odds ratio [OR], 258.4; 95% CI, 11.5-5798.9; P<0.001), endocardial fibroelastosis (OR, 28.9; 95% CI, 1.6-521.7; P<0.001), fetal hydrops (OR, 25.5; 95% CI, 4.4-145.3; P<0.001), ventricular dysfunction (OR, 7.6; 95% CI, 1.5-39.4; P=0.03), and a ventricular rate <45 beats per minute (OR, 12.9; 95% CI, 1.75-95.8; P=0.034). At a median follow-up of 5.9 years, 85 of 100 neonatal survivors were paced, and 1 required a heart transplant for dilated cardiomyopathy. Cotreatment with intravenous immune globulin was used in 16 of 22 fetuses with diagnoses other than AVB III. Neonatal and 1-year survival rates of this cohort were 100% and 95%, respectively. At a median age of 3.1 years, 5 of 21 children were paced, and all had normal ventricular function. Conclusions Our findings reveal a low risk of perinatal mortality and postnatal cardiomyopathy in fetuses that received transplacental dexamethasone±other treatment from the time of a new diagnosis of immune-mediated heart disease.

Lacosamide-Related Arrhythmias: A Systematic Analysis and Review of the Literature

Lacosamide (LCM) is a new antiepileptic drug used as an adjunctive treatment for partial seizures with and without secondary generalization. One of the modes of action is the enhancement of slow inactivation of voltage-gated sodium channels. Experimental studies and clinical trials suggest that LCM acts upon both neurons and the heart and may increase the risk of cardiac arrhythmias. A systematic review was conducted to investigate characteristics of arrhythmias related to the use of LCM for the treatment of seizures. The search terms “lacosamide”, “arrhythmias”, “AV block”, “atrial fibrillations/flutter”, “cardiac conductions defects”, “ventricular tachycardia”, “ventricular fibrillation were used. Case reports and retrospective studies were gathered by searching Medline/PubMed, Google Scholar, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane CENTRAL (Cochrane Central Register of Controlled Trials), and Web of Science databases. Seventeen articles were selected for review. Ventricular tachycardia was the most reported LCM related arrhythmia (29.4%), followed by new-onset atrial fibrillation (17.6%), complete heart block (17.6%), Mobitz type 1 Atrio-ventricular block (11.8%), sinus pauses (11.8%), pulseless electrical activity (5.9%) and widening QRS complex (5.9%). Further research and clinical trials are needed to explore the etiopathogenesis and causative relationship between the use of LCM and arrhythmias.

Tricuspid insufficiency after cardiac-implantable electronic device placement

Objective

Device-related estimates of incidence and significance of tricuspid regurgitation (TR) is mainly based on case reports and small observational studies. We sought to determine whether right-heart device implantation increased the risk of TR in this interventional study.

Methods

All patients who underwent permanent pacemaker (PPM) or other device implantation were assessed for degree of TR at one year. The data collected was analyzed on IBM SPSS version 26. Descriptive statistics were applied for qualitative variables. Mean and standard deviation were applied for quantitative variables. Regression analysis and paired t-tests were applied for the degree of change and predictors of TR.

Results

Out of 165 participants, 73.94% were male. The mean age of the participants was 59.86 ± 12.03 years. Dual-chamber pacemaker (DDDR) was the most common device implanted (78.18%) causing significant TR and drop in left ventricular ejection fraction as compared to other devices (p-value < 0.05). The paired t-test for changes in ejection fraction (LVEF) and TR were also significant (p-value < 0.05). A regression model predicted significant TR to depend on baseline LVEF (p-value < 0.05).

Conclusion

Device-related worsening of TR is related to mechanical mechanisms. It is significantly associated with DDDR pacemakers after a 1-year follow-up.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Relationship between non-alcoholic fatty liver disease and cardiac arrhythmia: a systematic review and meta-analysis

Objective

We performed a meta-analysis to create a quantitative estimate of the association between non-alcoholic fatty liver disease (NAFLD) and the risk of cardiac arrhythmia (including atrial fibrillation (AF), prolonged QT interval, premature atrial/ventricular contraction [PAC/PVC] and heart block).

Methods

A literature review was conducted using PubMed, Embase, Web of Science and the Cochrane Library database to identify observational studies of the link between NAFLD and cardiac arrhythmia. Effect sizes were expressed as odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs). The method of analysis of AF was also analysed separately, according to the effect estimate (OR or HR).

Results

Nineteen studies of 7,012,960 individuals were included. NAFLD was independently associated with higher risks of AF (OR 1.71, 95% CI: 1.14–2.57; HR 1.12, 95% CI: 1.11–1.13), prolonged QT interval (OR 2.86, 95% CI: 1.64–4.99), PAC/PVC (OR 2.53, 95% CI: 1.70–3.78) and heart block (OR 2.65, 95% CI: 1.88–3.72). The heterogeneity of the data with respect to AF and prolonged QT was moderate on sensitivity analysis.

Conclusions

We found a significantly higher risk of cardiac arrhythmia in patients with NAFLD, but the observational design of the studies does not permit conclusions regarding causality.

Exercise Stress Test-Induced Atrioventricular Dissociation With Syncope

Background: The exercise stress test is widely used as a diagnostic test for evaluating coronary artery disease in symptomatic patients or those with underlying cardiovascular disorders. Although exercise stress test risk is minimal with a <1% chance of causing heart block, physician awareness of potential complications is paramount for prompt recognition and treatment. Case Report: A 65-year-old-female with angina-like chest pain underwent an exercise stress test for ischemic heart disease evaluation. She performed the exercise stress test up to stage 2 (exercise Bruce protocol) with an exercise duration of 5 minutes and maximum metabolic equivalents of 7. During her recovery phase, the patient developed atrioventricular dissociation with junctional rhythm followed by syncope. Immediate treatment was administered, including intravenous normal saline, and she recovered without any complications. Conclusion: This case reminds clinicians to be aware of the unpredictable effects of the exercise stress test even though atrioventricular dissociation after an exercise stress test is rare. Providing immediate treatment to prevent any untoward effects is essential.

Brain and heart-specific death in cancer patients: Population-based study

BACKGROUND

The occurrence of cardiovascular events is a major cause of death in patients with cancer. Small studies have documented a connection between specific brain alterations and autonomic cardiac dysfunctions, possibly resulting in a worse prognosis. We aimed to refine the knowledge of fatal cardiac events in patients with brain metastasis (BM).

METHODS

We performed a Surveillance, Epidemiology, and End Results SEER registry-based investigation (timeline: 2010-2016) and extracted all the advanced patients who had experienced fatal cardiac outcomes. Populations were compared according to the presence or not BM. Kaplan-Meier (KM) methodology was used for survival analysis and a multivariate model was developed by adjusting for multiple possible confounders.

RESULTS

Most related BM and cardiac death were observed at the site of lung cancer (81.4%). We extracted 3187 patients with lung cancer site, including 417 patients who had experienced fatal heart-specific with a history of BM, which is considered a BM group. The second group of heart-specific death included 2770 patients was stated as a non-BM group. Patients who had experienced heart-specific death in the BM group were predominately male, right side, upper site, and non-small type (62.11%, 54.92%, 51.56%, 69.78%), respectively. The survival outcomes between BM and the non- BM was significantly prominent (p = 0.003; median: 2 months vs. 3 months).The negative prognostic independent significance of heart-fatal events was confirmed after adjusting for multiple variables (HR = 0.76, CI = 0.68-84, p < 0.0001). The metastatic liver site was significantly associated with poorer survival rates (HR = 0.68; CI = 0.52-0.88, p = 0.005). We revealed a possible connection between the brain and heart functions.

CONCLUSIONS

The prognosis of heart-specific death patients in BM is unfavorable compared to non-BM settings in lung cancer. We may be at the gates of a new field of neurocardiooncology.

Adrenal crisis and acute exacerbation of interstitial lung disease after thymoma needle biopsy: a case report and literature review

Thymoma is the most common paraneoplastic syndrome–associated tumor. It is related to a variety of autoimmune diseases including myasthenia gravis, systemic lupus erythematosus, and hypogammaglobulinemia. Only a few reports of thymoma associated with Addison’s disease have been reported to date. Herein, we report a novel case of thymoma complicated with autoimmune Addison’s disease and interstitial lung disease. The patient developed adrenal crisis with persistent hypotensive shock and heart block after needle biopsy. Acute exacerbation of the interstitial lung disease was also observed, accompanied by severe respiratory failure. After treatment with glucocorticoids, somatostatin, and temporary pacemaker implantation, the patient’s condition improved, and the thymoma had shrunk in size. Finally, he underwent transsternal extended thymectomy and lymph node dissection. Hydrocortisone was given intravenously before surgery, on the operation day and after the surgery. The operation was uneventful, and no hypotension or fever occurred. Cortisol and ACTH were still obviously abnormal at 1 month post-surgery. The clinical manifestations of Addison’s disease and interstitial lung disease are hidden and can be easily overlooked. However, in the postoperative period, Addison’s disease can lead to adrenal crisis developing, which can progress to life-threatening shock, arrhythmia, and acute respiratory failure. Therefore, clinicians should be aware of this phenomenon and consider a regimen combining proactive glucocorticoid replacement therapy with somatostatin to preserve the life of such patients.

Evaluation and Management of Heart Block After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has developed substantially since its inception. Improvements in valve design, valve deployment technologies, preprocedural imaging and increased operator experience have led to a gradual decline in length of hospitalisation after TAVR. Despite these advances, the need for permanent pacemaker implantation for post-TAVR high-degree atrioventricular block (HAVB) has persisted and has well-established risk factors which can be used to identify patients who are at high risk and advise them accordingly. While most HAVB occurs within 48 hours of the procedure, there is a growing number of patients developing HAVB after initial hospitalisation for TAVR due to the trend for early discharge from hospital. Several observation and management strategies have been proposed. This article reviews major known risk factors for HAVB after TAVR, discusses trends in the timing of HAVB after TAVR and reviews some management strategies for observing transient HAVB after TAVR.

Epistatic interaction of PDE4DIP and DES mutations in familial atrial fibrillation with slow conduction

The genetic causes of atrial fibrillation (AF) with slow conduction are unknown. Eight kindreds with familial AF and slow conduction, including a family affected by early-onset AF, heart block, and incompletely penetrant nonischemic dilated cardiomyopathy (DCM) underwent whole exome sequencing. A known pathogenic mutation in the desmin (DES) gene resulting in p.S13F substitution (NM_001927.3:c.38C>T) at a PKC phosphorylation site was identified in all four members of the kindred with early-onset AF and heart block, while only two developed DCM. Higher penetrance for AF and heart block prompted a genetic screening for DES modifier(s). A deleterious mutation in the phosphodiesterase-4D-interacting-protein (PDE4DIP) gene resulting in p.A123T substitution (NM_001002811:c.367G>A) was identified that segregated with early-onset AF, heart block, and the DES mutation. Three additional novel deleterious PDE4DIP mutations were identified in four other unrelated kindreds. Characterization of PDE4DIP^A123T in vitro suggested impaired compartmentalization of PKA and PDE4D characterized by reduced colocalization with PDE4D, increased cAMP activation leading to higher PKA phosphorylation of the β2-adrenergic-receptor, and decreased PKA phosphorylation of desmin after isoproterenol stimulation. Our findings identify PDE4DIP as a novel gene for slow AF and unravel its epistatic interaction with DES mutations in development of conduction disease and arrhythmia.

Atypical presentation of complete heart block in children with pediatric inflammatory multisystem syndrome: A case series of two patients

In the midst of the COVID-19 pandemic, we report two cases of children presenting with typical diagnosis of pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) who suffered from complete heart block requiring pacemaker placement which is an unusual presentation of PIMS-TS. We also compared it with the already existing data with similar manifestations. PIMS-TS is reported to occur in children with predominantly gastrointestinal symptoms, hemodynamic instability, and myocardial dysfunction. The implications of development of atrioventricular block during critical illness in PIMS-TS are yet unknown. Both patients had an otherwise normal cardiac structure and had no gastrointestinal symptoms but suffered complete heart block without any other identifiable etiology, both requiring temporary pacemaker placement. While one child recovered completely with medical management, the other child required permanent pacemaker placement. While we cannot be certain that COVID-19 was the cause, complete heart block appeared to be temporally related to COVID-19 infection in both patients, and hence, it is important for pediatricians to be aware of the potential manifestation of this disease.

Risk of sudden cardiac death in EXOSC5-related disease

The RNA exosome is a multi-subunit complex involved in the processing, degradation, and regulated turnover of RNA. Several subunits are linked to Mendelian disorders, including pontocerebellar hypoplasia (EXOSC3, MIM #614678; EXOSC8, MIM #616081: and EXOSC9, MIM #618065) and short stature, hearing loss, retinitis pigmentosa, and distinctive facies (EXOSC2, MIM #617763). More recently, EXOSC5 (MIM *606492) was found to underlie an autosomal recessive neurodevelopmental disorder characterized by developmental delay, hypotonia, cerebellar abnormalities, and dysmorphic facies. An unusual feature of EXOSC5-related disease is the occurrence of complete heart block requiring a pacemaker in a subset of affected individuals. Here, we provide a detailed clinical and molecular characterization of two siblings with microcephaly, developmental delay, cerebellar volume loss, hypomyelination, with cardiac conduction and rhythm abnormalities including sinus node dysfunction, intraventricular conduction delay, atrioventricular block, and ventricular tachycardia (VT) due to compound heterozygous variants in EXOSC5: (1) NM_020158.4:c.341C > T (p.Thr114Ile; pathogenic, previously reported) and (2) NM_020158.4:c.302C > A (p.Thr101Lys; novel variant). A review of the literature revealed an additional family with biallelic EXOSC5 variants and cardiac conduction abnormalities. These clinical and molecular data provide compelling evidence that cardiac conduction abnormalities and arrhythmias are part of the EXOSC5-related disease spectrum and argue for proactive screening due to potential risk of sudden cardiac death.