HRCR Rare Diseases Article Collection
Demonstration of presence of a sling between anterior and posterior bundle branch during tachycardia using twin atrioventricular nodes: A case of asplenia syndrome
Atrioventricular (AV) reciprocating tachycardia via twin AV nodes and corresponding AV bundles with a connecting sling has been reported in patients with asplenia and right isomerism.1,2 Although the presence of the sling has been reported histologically,3 its connection form and electrophysiological properties remain to be elucidated.Very delayed pericarditis associated with ethanol ablation of the vein of Marshall for treatment of atrial fibrillation
Catheter ablation of persistent atrial fibrillation has limited success. Procedural strategies beyond pulmonary vein isolation have failed to consistently improve results.Multiple recurrent episodes of pacemaker-associated postcardiac injury syndrome
Postcardiac injury syndrome (PCIS) is an autoimmune disease that causes damage to the pericardium, myocardium, and pleura after myocardial infarction, cardiac surgery, or trauma. Although most cases are benign, anti-inflammatory agents may be used to treat PCIS. Rarely, PCIS may become refractory or recur after anti-inflammatory treatment.1 In such cases, long-term oral corticosteroids are usually prescribed2; however, the optimal duration of administration remains unclear. We report a patient who experienced multiple recurrent episodes of pacemaker lead–related PCIS that were treated with oral prednisone and pericardial drainage.Idiopathic premature ventricular contraction–triggered ventricular fibrillation: Subcutaneous implantable cardioverter-defibrillator (S-ICD) template matched ablation in the absence of inducible clinical premature ventricular contraction
Idiopathic ventricular fibrillation is diagnosed in patients who have survived sudden cardiac arrest from ventricular fibrillation (VF) without identifiable structural heart disease.1 It is the main cause of unexplained sudden cardiac death, particularly in young patients under the age of 35.2 An implantable cardioverter-defibrillator (ICD) is usually recommended for the secondary prevention of sudden cardiac death. VF ablation is recommended for clinical VF recurrence and for reducing the number of ICD shocks.An unexpected finding by epicardial mapping: Atrial fibrillation in a 14-month-old patient with short QT syndrome
Short QT syndrome (SQTS) is a very rare channelopathy accompanied by familial clustering and sudden cardiac death.1 It has an estimated prevalence ranging from 0.02% up to 2% in the adult population, but only 0.05% among pediatric patients.2–6 To date, 9 mutations in 6 different genes have been identified, including KCNH2, KCNQ1, KCNJ1, CACNA1C, CACNB2, and CACNA2D1. In pediatric patients, SQTS is characterized by shortening of the corrected QT interval (QTcB <316 ms, J-Tpeak cB <181 ms, and the presence of early repolarization) on the surface electrocardiogram (ECG).Right ventricular outflow tract ablation close to an anomalous right coronary artery: When imaging meets electrophysiology
Catheter ablation is a commonly undertaken and highly effective treatment for symptomatic right ventricular outflow tract (RVOT) ventricular ectopy / ventricular tachycardia (VT).1 Despite the high chance of cure with ablation, caution is required to avoid collateral injury to coronary arteries in certain well-described locations. Anomalous coronary arteries are rare2 and may have an unfamiliar path involving the outflow tracts, posing a significantly increased risk with ablation. The approach to outflow tract ablation in a patient with an anomalous coronary artery has not been previously reported.Novel trans-2,3-enoyl-CoA reductase–like variant associated with catecholaminergic polymorphic ventricular tachycardia type 3
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by polymorphic ventricular tachycardia, usually provoked by emotional stress or exercise, in the absence of any structural cardiac abnormality, and in the presence of often normal resting electrocardiogram (ECG).1 It is a highly lethal disease with an overall mortality of 30%–40% if left untreated.2 Studies have shown that almost 35% of affected individuals become symptomatic before the age of 10 and 75% before the age of 20 years.Left bundle branch area pacing for the treatment of painful left bundle branch block syndrome
Painful left bundle branch block (LBBB) syndrome causes intermittent or chronic chest pain and/or shortness of breath in the absence of myocardial ischemia.1 Given its low prevalence and association with coronary artery disease, it is frequently not recognized, making its true prevalence unknown. The mechanistic nature of the associated chest pain has not been completely elucidated but is thought to be related to ventricular dyssynchrony2 and interoceptive hypersensitivity.3 Treatment options include the use of beta-blockers to reduce heart rate and cardiac pacing therapy aimed at reestablishing normal ventricular activation, through biventricular or His bundle pacing (HBP).Groin lymphorrhea after catheter ablation of atrial fibrillation: A case report
Catheter ablation is a well-established therapeutic option for the treatment of atrial fibrillation (AF).1,2 Although nowadays performed on a routine basis, catheter ablation of atrial fibrillation (AFCA) is associated with a non-negligible complication rate of up to 16% with significant discrepancies in incidence and type, with vascular access site complications being the most common (groin hematoma, femoral arterial pseudoaneurysms, and femoral arteriovenous fistula).1–4 We report a case of a 75-year-old White male patient with right groin lymphorrhea as an access site–related complication after second catheter ablation of recurrent atrial fibrillation.A case of successful catheter ablation for biatrial reentrant tachycardia after a Mustard operation for dextro-transposition of the great arteries
Mustard and Senning operations are atrial switch techniques for dextro-transposition of the great arteries (d-TGA) that have been mainly performed during a period from the 1960s to the mid-1980s.Incessant atrioventricular nodal reentrant tachycardia resulting in tachycardia-induced cardiomyopathy and catastrophic embolization of left ventricular thrombus
Atrioventricular nodal reentrant tachycardia (AVNRT) is a common paroxysmal supraventricular tachycardia (SVT) featuring repetitive salvos with spontaneous termination. Few reports exist demonstrating incessant AVNRT with chronically uncontrolled ventricular rates and tachycardia-induced cardiomyopathy (TIC).1,2 Persistent cases of incessant AVNRT resulting in TIC and intracavitary thrombus are exceedingly rare.2 We report a case of incessant slow/fast AVNRT associated with TIC and catastrophic embolization of left ventricular (LV) thrombus treated with acute radiofrequency slow pathway modification.Successful ablation of ventricular tachycardia in a patient with Chagas disease using ethanol ablation in the coronary venous system: A case report
Chagas disease is a parasitic zoonosis that constitutes a severe public health problem and is endemic in 21 Latin American countries.1 It is estimated that between 6 and 8 million people are infected with Trypanosoma cruzi (T cruzi), with an additional 65 million at risk of acquiring the disease by vector-borne transmission, blood or congenital transmission, or food-borne transmission.2,3 Chagas disease has an acute, indeterminate, and chronic phase. If untreated, the acute phase may transition to an indeterminate phase characterized by seropositivity for T cruzi in the absence of clinical symptoms.Carotid sinus syndrome treated by cardioneuroablation: Is sinus node denervation enough? Insights from a syncope recurrence report
Cardioneuroablation (CNA) has been proposed as an alternative treatment for patients with refractory vasovagal syncope (VVS), functional atrioventricular block (AVB), or functional bradyarrhythmia instead of classical treatment or pacemaker.1 Vagal denervation is achieved by endocardial catheter ablation targeting atrial fibrillation nests (AFN)2 and ganglionic plexus (GP)-related areas. We describe a clinical case of cardioinhibitory carotid sinus syndrome (CSS) treated with CNA, where partial vagal denervation was achieved over sinus node.To the Editor—Concealed His or Purkinje extrasystoles?
I read with interest the case report by Ho and colleagues.1 I would like to present arguments suggesting alternative diagnoses.Improved symptoms, exercise capacity, and homogeneity of cardiac deformation through conduction system pacing in a patient with symptomatic left bundle branch block
Painful left bundle branch syndrome is a clinical entity consisting of exertional angina and rate-dependent left bundle branch block (LBBB), affecting patients of all age and sex.1 Because of potentially coexisting other cardiac diseases (ie, cardiomyopathy, coronary artery disease) that may mimic both LBBB and symptoms, the true prevalence is unknown, but fewer than 60 cases have been reported so far.1 Diagnostic criteria do not officially exist, but simultaneous onset of LBBB and angina during exercise test support the diagnosis.Electrophysiology and surgery intertwined in complex treatment of Ebstein’s anomaly in childhood
Ebstein’s anomaly, a rare and highly variable congenital heart defect,1 still presents a treatment challenge. The currently used cone repair of the tricuspid valve has carried favorable results in suitable patients.2 Arrhythmogenic substrates including accessory pathways3,4 and right bundle branch block5 associated with electromechanical ventricular dyssynchrony present additional therapeutic targets. We present a patient with Ebstein’s anomaly of tricuspid valve and Wolff-Parkinson-White syndrome in whom joint electrophysiological and surgical interventions were used to address all major disease components.Epicardial multisite conduction blocks detected by equispaced electrode array and omnipolar technology in Brugada syndrome
Brugada syndrome (BrS) is an inherited channelopathy linked to an increased risk of developing malignant ventricular arrhythmias and sudden cardiac death in otherwise healthy individuals.1 Currently, implantable cardioverter-defibrillator (ICD) is still the mainstay of treatment for BrS,1 but for patients experiencing recurrent ICD shocks despite optimal medical therapy, radiofrequency (RF) transcatheter ablation of the arrhythmogenic substrate is an available option with promising results.2–5 Although there is a generalized consensus in considering the right ventricular outflow tract (RVOT) epicardium as the locus harboring the pathologic substrate, the exact pathogenesis of BrS is still a matter of debate.Localized intramural reentry confined within the ventricular septum in lamin cardiomyopathy
High-resolution electroanatomic mapping systems have greatly improved the ability to characterize the size and dimensions of the reentrant circuit responsible for human ventricular tachycardia (VT). The minimal dimension of critical isthmus regions may be less than 1 cm in more than 25% of circuits mapped.1 Despite advanced, detailed simultaneous epicardial and endocardial mapping, detection of intramural circuit components remains challenging. Epicardial mapping through coronary venous branches has gained popularity owing to refinement of mapping catheters and novel use of transcoronary venous ethanol.Lyme carditis presenting with an incessant atrioventricular nodal reentrant tachycardia masking a variable atrioventricular block
Lyme disease is a common tick-borne illness with a high prevalence in the Northeast region of the United States.1 It is an infection caused by Borrelia burgdorferi, a gram-negative spirochetal bacterium carried by infected ticks such as Ixodes scapularis. They are found outdoors, latched onto blades of grass until they can attach to a host. If not treated early, serious complications can develop. Since Lyme antibodies can take several weeks to develop, false-negatives can arise in about 50% of cases when testing is done too early.The man in the mirror: Biventricular device implantation in a patient with dextrocardia with situs inversus totalis
The population of individuals with adult congenital heart disease is expanding as advances in surgical and medical management allow patients to live into adulthood. Consequently, these patients are developing other cardiovascular diseases, such as arrhythmias and heart failure, later in life. Procedures involving congenital anatomic variations are becoming more commonplace, and operators must become familiar with them. One such congenital abnormality, dextrocardia, involves the reversal of the base–apex axis of the heart caudally and to the right.Open-window mapping of atriofascicular tachycardia
Accessory atrioventricular pathway (AP) conduction is found in 33% of patients with Ebstein anomaly, including atriofascicular (AF) pathways in 5%–8%.1 AF pathways typically conduct anterograde only, with decremental conduction properties analogous to the atrioventricular node (AVN), and participate almost exclusively in antidromic atrioventricular reciprocating tachycardia (AVRT).1,2 Ablation of AF APs may be challenging in such patients due to the deviation from normal anatomic structure, potential for multiple APs, difficulty obtaining catheter stability, hemodynamic instability in tachycardia, and concerns for catheter-induced mechanical conduction block.Masquerade: An unusual accessory pathway with ventricular insertion at the right–left sinus of Valsalva mimicking outflow tract ventricular tachycardia
Although rare, an accessory pathway (AP) can have a ventricular insertion in the region of the aortic sinuses of Valsalva.1–4 This can be difficult to diagnose and may resemble outflow tract ventricular tachycardia (VT).4 Despite the existence of various algorithms that can differentiate wide-complex supraventricular tachycardia (SVT) from VT, these conditions may be impossible to differentiate based on surface QRS morphology alone.5,6A case of long QT syndrome type 2 that developed torsades de pointes two days after the initiation of oral β-blocker therapy
Congenital long QT syndrome (LQT) is a potentially lethal hereditary arrhythmic disorder that can cause syncope and sudden cardiac death owing to polymorphic ventricular tachycardias in association with prolonged QT intervals in electrocardiograms (ECGs), termed as “torsades de pointes” (TdP). The prevalence of LQT is reported to be 1 in 2000, and genetic testing reveals mutations in cardiac ion channel–related genes in about 70% of the cases. Variants in the 3 genes, KCNQ1, KCNH2, and SCN5A, account for approximately 90% of LQT cases, referred to as LQT type 1, 2, and 3 (LQT1, LQT2, and LQT3), respectively.One family’s clinical odyssey from evolving phenotypic and genotypic knowledge of catecholaminergic polymorphic ventricular tachycardia and long QT syndrome
Life-threatening arrhythmias in apparently healthy individuals can be due to diverse heritable cardiac channelopathies.1 Ongoing advances revealing the underlying pathophysiology and genotype-phenotype associations are constantly evolving our approaches to diagnosis and management of these clinical entities.1–3 In some cases, initial diagnoses prove inaccurate over time, so routine reevaluation of each patient and family member remains an important element of care, with potentially life-altering ramifications.Presentation and genetic confirmation of long QT syndrome in the fetus
Long QT syndrome (LQTS) is an ion channelopathy that may cause life-threatening ventricular arrhythmias resulting in intrauterine death, cardiac arrest, or sudden death at any age.1–3 LQTS is often an inherited condition but may present as a de novo mutation, and its prevalence has been reported as high as 1:2000.4Exercise-induced arrhythmogenic right ventricular cardiomyopathy: A clinical syndrome in motion
Exercise-induced arrhythmogenic right ventricular cardiomyopathy (ARVC), a theoretical disease entity, has an unusual history. Lacking a diagnostic gold standard, it is a diagnosis of exclusion built upon a foundation of research compiled for ARVC.Progressive atrial myocardial fibrosis in a 4-year-old girl with atrial standstill associated with an SCN5A gene mutation
Atrial standstill (AS) is a rare cardiac syndrome characterized by the absence of electrical and mechanical activity in the atria. Mutations in the sodium channel α-subunit SCN5A gene have been identified as the cause of arrhythmia syndromes, such as long QT syndrome, Brugada syndrome (BrS), progressive cardiac conduction disease, sinus node dysfunction, atrial fibrillation, and AS.1 Historically, these cardiac sodium channelopathies were considered to be purely electrical disorders. However, with the accumulation of cases, SCN5A mutations also came to be associated with structural disorders involving myocardial fibrosis.Catheter ablation for persistent atrial fibrillation in an elderly patient with cor triatriatum sinister
Cor triatriatum sinister (CTS) accounts for <0.1% of all congenital heart diseases. It is a condition in which the fibromuscular membrane divides the left atrium (LA) into 2 chambers.1 The superior and posterior chambers receive the pulmonary veins, and the inferior and anterior chambers are connected to the left atrial appendage and mitral orifice.2 Pathophysiologically, CTS is similar to mitral stenosis,3 and the symptoms are correlated with pulmonary venous congestion and pressure loading at the right side of the heart.Exercise-induced arrhythmogenic right ventricular cardiomyopathy: Reverse remodeling with detraining
Long-term exercise training leads to structural cardiac adaptations, collectively referred to as the “athlete’s heart.” While the ventricles both undergo dilation and eccentric hypertrophy, it has been shown that the right ventricle (RV) experiences disproportionate remodeling under intense sports activity.1 Occasionally, the remodeling that occurs in the athlete’s heart may resemble arrhythmogenic right ventricular cardiomyopathy (ARVC), a pathologic cardiomyopathy associated with sudden death.Hybrid minithoracotomy approach for zero-fluoroscopy epicardial ablation of the arrhythmogenic substrate in Brugada syndrome
Since its first description in 1992,1 Brugada syndrome (BrS) has claimed global attention as a remarkable cause of sudden cardiac death in young and otherwise healthy adults because of malignant ventricular tachyarrhythmias (mVT).1,2Cardiac arrhythmias in primary hypokalemic periodic paralysis: Case report and literature review
Hypokalemic periodic paralysis (HPP) is a rare neuromuscular disorder characterized by episodes of muscle weakness and paralysis accompanied by hypokalemia. Several studies have reported the presence of cardiac arrhythmias, the majority being secondary to hypokalemia-induced changes. However, other studies have described cardiac arrhythmias that cannot be explained by hypokalemia or the diagnosis of HPP. Herein, we describe the case of a pediatric male patient with HPP and recurrent episodes of monomorphic ventricular tachycardia (VT), followed by a systematic literature review on primary HPP and cardiac arrhythmias.Idiopathic ventricular fibrillation triggered by premature ventricular complexes originating from the false tendon of the left ventricle
Idiopathic ventricular fibrillation (VF) is a diagnosis of exclusion when no evidence of a structural or metabolic cause is found. It is a rare cause of sudden cardiac death reported in 6.8% of patients who survive an out-of-hospital cardiac arrest and is more frequently seen in young adults.1 Premature ventricular contractions (PVCs) originating from the Purkinje network can induce polymorphic ventricular tachycardia (PMVT) or VF in rare cases. The electrophysiologic mechanisms, although not completely clear, have been thought to be related to abnormal automaticity and triggered activity.Successful ablation of an outlet septum ventricular tachycardia in a double-outlet right ventricle patient who underwent an extracardiac Fontan operation
Arrhythmias are one of the most common causes of death in the late period post Fontan operation1 and are associated with a 3.5% incidence of ventricular tachycardia (VT).2 The extracardiac Fontan (EC-Fontan) has recently become the most commonly used approach in the Fontan operation. In such patients, catheter ablation (CA) is difficult to perform because the venous access to the heart is limited. A transcaval cardiac puncture (TCP) technique for gaining access to the heart chamber has previously been suggested for EC-Fontan patients.First reported implantation of a VDD leadless pacemaker and a subcutaneous defibrillator in a patient with congenitally corrected transposition of the great arteries
Entirely subcutaneous implantable cardioverter-defibrillators (S-ICD™ system; Boston Scientific Corp, Marlborough, MA) provide effective defibrillation and reduce the risk of infection or lead-related problems.1–3 S-ICD systems may be a valid alternative to transvenous implantable cardioverter-defibrillator (ICD) in patients in whom bradycardia pacing or cardiac resynchronization therapy (CRT) is not required.4,5 The Micra™ AV Transcatheter Pacing System (Medtronic Inc, Minneapolis, MN) is a recently approved leadless pacemaker enabling atrioventricular (AV) synchronized pacing, which may, in theory, compensate the S-ICD’s inability to pace.Cardiac lymphoma presenting as bradyarrhythmia
Cardiac tumors have been a point of interest and controversy since the earliest attempt to categorize them in 1931 by Yater.1,2 Secondary cardiac tumors are 30 times more common than primary cardiac tumors, with an incidence of 1.7%–14% vs 0.001%–0.03% on autopsy.3 Primary cardiac tumors are most commonly benign (70%–80%).3,4 However, of the primary malignant cardiac tumors, lymphoma has been shown to account for 1%–1.6%.5,6 Up to 20% of patients with noncardiac primary lymphoma will exhibit cardiac metastases.Normalization of ventricular function after cardiac contractility modulation in noncompaction cardiomyopathy heterozygous positive for a pathologic TTN gene variant
Cardiac contractility modulation (CCM) may be used as an adjunct for the treatment of medically refractory class III chronic systolic congestive heart failure (CHF) with ejection fraction (EF) 25%–45% not indicated for biventricular pacing.1–3 CCM treats CHF through effecting improvement in myocardial cellular calcium handling and with reversal of adverse gene dysregulations.4,5 Enhanced phosphorylation of the giant myocardial protein titin also occurs with CCM, which can improve myocardial relaxation.Progressive giant cell myocarditis presenting with inappropriate shocks from a subcutaneous defibrillator
Giant cell myocarditis (GCM) is a rare form of myocarditis predominantly affecting young, healthy adults. It is usually characterized by progressive cardiac failure, and ventricular arrhythmias are common.1 Despite treatment with immunosuppression and guideline-directed heart failure therapy, implantable cardioverter-defibrillators (ICDs) are commonly inserted.2 The currently available subcutaneous ICD (S-ICD; Emblem; Boston Scientific, Marlborough, MA) has a high efficacy rate for conversion of ventricular arrhythmias2 and, when compared to transvenous ICDs, has a numerically lower infection rate at the expense of a higher rate of inappropriate shocks.Takotsubo cardiomyopathy and Brugada syndrome in a patient with a novel loss-of-function variant in the cardiac sodium channel Nav1.5
Takotsubo cardiomyopathy (TTC) is a stress cardiomyopathy characterized by transient left ventricular dysfunction.1 TTC typically presents in postmenopausal women and is triggered by physical or emotional stress, most likely owing to an increased sympathetic activity.1 Symptoms resemble those of an acute myocardial infarction and the patients often present with various electrocardiogram (ECG) changes proposing an alteration in cardiac repolarization.2 Previously, familial clustering of TTC has been described, suggesting a genetic predisposition to TTC.Exercise-induced Brugada syndrome type 1 pattern
Brugada syndrome (BrS) is an inherited disorder usually afflicting patients with otherwise structurally normal hearts. Many triggers have been identified that can result in the phenotypic expression of the higher-risk BrS type 1 pattern. These triggers include but are not limited to fever, heightened vagal tone, and sodium (Na) channel blocking agents. Conversion to the type 1 pattern during exercise is unusual and in fact isoproterenol is a treatment for ventricular tachycardia (VT) storm in Brugada syndrome.Unmasked type 1 Brugada ECG pattern without a fever after a COVID-19 vaccination
Brugada syndrome (BrS) patients are regarded as a high-risk population under the COVID-19 pandemic because infection-induced fevers may unmask a type 1 Brugada electrocardiogram (ECG) pattern potentially leading to lethal ventricular arrhythmias.1 Vaccinations seem to be crucial in BrS patients; however, careful observation and antipyretic drugs are necessary for vaccine-induced fevers.2 Among the enormous number of COVID-19 vaccinations around the world, although the incidence is rare, death events, including sudden cardiac death, after a vaccination have been reported.Ventricular tachycardia ablation in a patient with Ehlers-Danlos syndrome
Ventricular tachycardia (VT) is a well-recognized complication of postinfarct-related scar. Catheter ablation is a guideline-recommended therapy in patients with frequent VT episodes. Ablation aims to target regions of slow conduction within ventricular scar that support reentry.1Late-onset Fabry disease revealed by ventricular tachycardia: A case report
Fabry disease (FD) is an X-linked lysosomal storage disorder due to mutations in the GLA gene leading to deficiency of lysosomal α-galactosidase A (α-Gal A). Classic FD causes multiorgan failure, whereas the later-onset phenotype is characterized by predominantly cardiac manifestations. Ventricular arrhythmias are among the complications.1,2Cardiac sarcoidosis involving the papillary muscle: A case report
Sarcoidosis is a granulomatous multisystem disease that is thought to arise from a dysregulated immunological response. A total of 25% of those suffering from sarcoidosis have cardiac involvement on postmortem analysis, but it is clinically apparent in only 5%.1 Isolated cardiac sarcoidosis (CS) has also been described.2 It may manifest as conduction system dysfunction, ventricular arrhythmias, congestive cardiac failure, or sudden cardiac death.3 CS has a predilection for the ventricular myocardium and its clinical presentation may vary from no symptoms to sudden cardiac death.Malignancies masquerading as device pocket infections
Infectious complications following cardiac implantable electronic device (CIED) implantation are associated with significant mortality. Establishing the correct diagnosis is important and not all presumed CIED pocket infections turn out to be infections. Rare cases of malignancy mimicking a pocket infection have been described. We present 2 cases of malignancy, initially thought to be a primary CIED pocket infection.A diagnostic dilemma upon discovery of a left atrial mass using an intracardiac echocardiogram
It is important to discern the nature of any mass that may appear on the left atrial (LA) ridge, or “coumadin ridge,” which is situated between the LA appendage and the left superior pulmonary vein prior to any procedures involving the left atrium. Despite the rarity of the appearance of LA ridge mass, the shape and location are important in distinguishing a cardiac tumor or thrombus.1 In this case report, a mass on the LA ridge was discovered during an intracardiac echocardiogram prior to transseptal puncture for ablation of atrial fibrillation, posing a diagnostic dilemma and leading to a cascade of imaging studies.Ventricular fibrillation due to a likely pathogenic SOS1 variant: An unrecognized etiology of infantile sudden death?
We present the case of a female infant presenting after a ventricular fibrillation arrest found to have ectopic atrial tachycardia (EAT). Evaluation revealed a likely pathogenic variant in SOS1 not previously reported in affected individuals. SOS1 variants are associated with Noonan syndrome, which belongs to a family of related genetic syndromes affecting the RAS/MAPK signaling pathway. To date, this is the first case reported of a ventricular fibrillation arrest in a patient with a RASopathy-related variant prior to development of the typically associated structural cardiac phenotype and may represent a previously unrecognized etiology of sudden death during infancy.Increased device thresholds with subsequent improvement status post–systemic therapy in a patient with multiple myeloma
The pacemaker device stimulation threshold by definition is the minimal amount of electrical energy required to induce consistent capture outside the refractory period of the heart. The difference between the threshold and the programmed device output reflects the reserve or pacing safety factor.1 It is affected by a multitude of factors, including physiologic variants, use of certain pharmacologic agents, and pathologies such as hypoxia, hypothermia, poorly controlled diabetes, and myocardial ischemia.Leadless atrioventricular synchronous pacing in Eisenmenger syndrome
Eisenmenger syndrome is at the extreme end of the phenotypic spectrum of pulmonary arterial hypertension associated with congenital heart disease. Over time, a large nonrestrictive left-to-right shunt provokes progressive pulmonary vascular disease that results in the shunt becoming bidirectional or reversing direction (ie, right-to-left). When the need for pacing arises, transvenous leads are generally considered contraindicated owing to a prohibitively high risk of paradoxical thromboembolism.A case of cardiac sarcoidosis with concurrent myocardial ischemia
Sarcoidosis is a rare multisystem disease of unknown etiology affecting 10–40 in 100,000 population, characterized by granulomatous inflammation.1 It has a diverse set of presentations ranging from diffuse to localized disease and can have either acute or chronic clinical course with multiple organ involvement.1 Classically, lungs are the most commonly affected organ, but systemic, dermatologic, and cardiac involvement also occur. Specifically, 20%–30% of sarcoidosis patients have been observed to have cardiac involvement in an autopsy1; however, only about 5% have a symptomatic presentation with cardiac disease.Ventricular tachycardia as the initial presentation of missed Kawasaki disease in a teenager
Ventricular tachycardia (VT) has been reported in acute cases of Kawasaki disease. VT secondary to ischemic sequelae is also a known long-term complication of Kawasaki disease, typically seen 2 decades after initial disease onset.1,2 We report the first case, to our knowledge, of an otherwise healthy teenager with sustained VT as the presenting symptom for missed Kawasaki disease and describe the management approach by our team that had not considered Kawasaki disease in the differential. This case broadens our understanding of Kawasaki disease presentations in the young and timing of long-term sequelae.
