HRCR Rare Diseases Article Collection
- I read with interest the case report by Ho and colleagues.1 I would like to present arguments suggesting alternative diagnoses.
- 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.
- 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.
- 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.
- 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 over 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 due to refinement of mapping catheters and novel use of transcoronary venous ethanol.
- 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 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.
- 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.