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 syndromeAtrioventricular (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 fibrillationCatheter 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 syndromePostcardiac 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 contractionIdiopathic 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 syndromeShort 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 electrophysiologyCatheter 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 3Catecholaminergic 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 syndromePainful 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 reportCatheter 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 arteriesMustard 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 thrombusAtrioventricular 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 reportChagas 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 reportCardioneuroablation (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.
Improved symptoms, exercise capacity, and homogeneity of cardiac deformation through conduction system pacing in a patient with symptomatic left bundle branch blockPainful 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 childhoodEbstein’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 syndromeBrugada 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 cardiomyopathyHigh-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 blockLyme 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 totalisThe 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 tachycardiaAccessory 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 tachycardiaAlthough 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.5,6
A case of long QT syndrome type 2 that developed torsades de pointes two days after the initiation of oral β-blocker therapyCongenital 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 syndromeLife-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 fetusLong 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 1:2000.4
Progressive atrial myocardial fibrosis in a 4-year-old girl with atrial standstill associated with an SCN5A gene mutationAtrial 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.