Clinical features and antiarrhythmic therapy in patients with catecholaminergic polymorphic ventricular tachycardia

Aims. To evaluate the long-term efficacy of antiarrhythmic therapy in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).Methods. CPVT was diagnosed in 11 patients between the ages of 3-12 years with a minimum follow-up of 10 years. The data analyzed was obtained from existing medical records that included symptoms, family screenings, treadmill tests, electrocardiography, echocardiography, implanted cardioverter-defibrillator data (ICD), and medical treatments.Results. Cardiac events were registered in 75% of patients on beta-blocker therapy. Supraventricular arrhythmias such as atrial and atrioventicular nodal tachycardia, atrial fibrillation and atrial flutter were detected using various ECG diagnostic methods in all patients, which is significantly higher than reported in similar studies. A combination of anti-arrhythmic therapy and beta-blocker treatment reduced the number of cardiac events by 50% as compared to only beta-blocker treatment.Conclusion. Multiple supraventricular arrhythmias have a high prevalence in patients with CPVT and can trigger ventricular arrhythmia. Combined antiarrhythmic therapy is effective because it prevents cardiac events in patients with CPVT. Combined antiarrhythmic therapy improves the prognosis of patients with CPVT and may help to avoid or postpone ICD implantation.

Characteristics and Long-Term Ablation Outcomes of Supraventricular Arrhythmias in Hypertrophic Cardiomyopathy: A 10-Year, Single-Center Experience

Background: A variety of supraventricular arrhythmias (SVAs) may occur in patients with hypertrophic cardiomyopathy (HCM). The characteristics and long-term ablation outcomes of different types of SVAs in HCM have not been comprehensively investigated.Methods: We retrospectively enrolled 101 consecutive patients with HCM who were referred to the electrophysiology and arrhythmia service from May 2010 to October 2020. The clinical features and ablation outcomes were analyzed.Results: Seventy-eight patients had SVAs, which comprised 50 (64.1%) cases of atrial fibrillation (AF), 16 (20.5%) of atrial flutter (AFL), 15 (19.2%) of atrioventricular reentrant tachycardia (AVRT), 11 (14.1%) of atrial arrhythmia (AT), and 3 (3.8%) of atrioventricular nodal reentrant tachycardia (AVNRT). Thirty-four patients underwent catheter ablation and were followed up for a median (interquartile range) of 58.5 (82.9) months. There was no recurrence in patients with non-AF SVAs. In patients with AF, the 1- and 7-year AF-free survival rates were 87.5 and 49.5%, respectively. A receiver operator characteristic analysis showed that a greater left ventricular end-diastolic dimension (LVEDD) was associated with a higher recurrence of AF, with an optimum cutoff value of 47 mm (c-statistic = 0.91, p = 0.011, sensitivity = 1.00, specificity = 0.82). In Kaplan–Meier analysis, patients with a LVEDD ≥ 47 mm had worse AF-free survival than those with a LVEDD <47 mm (log-rank p = 0.014).Conclusions: In this unique population of HCM, AF was the most common SVA, followed in order by AFL, AVRT, AT, and AVNRT. The long-term catheter ablation outcome for non-AF SVAs in HCM is satisfactory. A greater LVEDD predicts AF recurrence after catheter ablation in patients with HCM.

Molecular Remodeling of Cardiac Sinus Node Associated with Acute Chagas Disease Myocarditis

Chagas disease principally affects Latin-American people, but it currently has worldwide distribution due to migration. Death among those with Chagas disease can occur suddenly and without warning, even in those who may not have evidence of clinical or structural cardiac disease and who are younger than 60 years old. HCN4 channels, one of the principal elements responsible for pacemaker currents, are associated with cardiac fetal reprogramming and supraventricular and ventricular arrhythmias, but their role in chagasic arrhythmias is not clear. We found that a single-dose administration of ivabradine, which blocks HCN4, caused QTc and QRS enlargement and an increase in P-wave amplitude and was associated with ventricular and supraventricular arrhythmias in mice challenged with isoproterenol, a chronotropic/ionotropic positive agent. Continuous treatment with ivabradine did not alter the QTc interval, but P-wave morphology was deeply modified, generating supraventricular arrhythmias. In addition, we found that repolarization parameters improved with ivabradine treatment. These effects could have been caused by the high HCN4 expression observed in auricular and ventricular tissue in infected mice. Thus, we suggest, for the first time, that molecular remodeling by overexpression of HCN4 channels may be related to supraventricular arrhythmias in acute Chagas disease, causing ivabradine over-response. Thus, ivabradine treatment should be administered with caution, while HCN4 overexpression may be an indicator of heart failure and/or sudden death risk.

Emery-Dreifuss muscular dystrophy presenting as a heart rhythm disorders in children

Introduction Emery-Dreifuss muscular dystrophy (EDMD) is an inherited muscle dystrophy often accompanied by cardiac abnormalities in the form of supraventricular arrhythmias, conduction defects, sinus node dysfunction. Cardiac phenotype typically arises years after skeletal muscle presentations, though, can be severe and life-threatening. The disease usually manifests during the third decade of life with elbow joint contractions and progressive muscle weakness and atrophy. Objective To present our clinical experience of diagnosis and treatment of arrhythmias in children with Emery-Dreifuss muscular dystrophy Materials and methods We enrolled 5 patients with different forms of EDMD (X-linked and autosomal dominant) linked to the mutations in EMD and LMNA genes, presented with early onset of cardiac abnormalities and no leading skeletal muscle phenotype. The predominant forms of cardiac pathology were atrial flutter, atrial fibrillation and conduction disturbances that progress over time. Clinical examination included physical examination, 12-lead electrocardiography, Holter ECG monitoring (HM), transthoracic echocardiography, neurological examination and biochemical and hormone tests. Also we performed CMR, electrophysiological study (EPS), treadmill test of some patients. One patient underwent an endomyocardial biopsy to exclude inflammatory heart disease. Target sequencing was performed using a panel of 108 or 172 genes Results We observed five patients with EDMD and cardiac debut during first-second decades of life: 3 with 1st subtype (variants in EMD gene) and 2 with 2nd subtype (variants in LMNA gene). All patients were males. The mean age of cardiac manifestation was 13,2±3,11 (from 9 to 16 y.o.). The mean follow-up period was 7,4±2,6 years. All patients presented with sinus node dysfunction and four out of five with AV conduction abnormalities. The leading arrhythmic phenotypes included various types of supraventricular arrhythmias: multifocal atrial tachycardia (AT) (n=4), premature atrial captures (PACs) (n=4), atrial flutter, (AF) (n=3), atrial fibrillation (AFib) (n=3) and AV nodal recurrent tachycardia (AVRNT). Heart rhythm disorders were the first manifestation in all three patients with 1st EDMD subtype. Radiofrequency ablation was performed in 2 patients, one of them received permanent pacemaker implantation. Conclusions In conclusion, while being the rare cases, heart rhythm disorders can represent the first and for a long time, the only clinical symptom of EDMD even in the pediatric group of patients. Therefore, thorough laboratory and neurological screening along with genetic studies, are of importance in each pediatric patient presenting with complex heart rhythm disorders of primary supraventricular origin to exclude EDMD or other neuromuscular disorders. FUNDunding Acknowledgement Type of funding sources: None.

Characteristics and long-term ablation outcomes of supraventricular arrhythmias in hypertrophic cardiomyopathy: a 10-year, single-center experience

Background A variety of supraventricular arrhythmias (SVAs) may occur in patients with hypertrophic cardiomyopathy (HCM). The characteristics and long-term ablation outcomes of different types of SVAs in HCM have not been comprehensively investigated. Methods We retrospectively enrolled 101 consecutive symptomatic HCM patients with suspected arrhythmia from May 2010 to October 2020. The clinical features and ablation outcomes of patients with SVAs were further analyzed. Results Seventy-eight patients had SVAs, consisting of 50 (64.1%) atrial fibrillation (AF), 16 (20.5%) atrial flutter (AFL), 15 (19.2%) atrioventricular reentrant tachycardia (AVRT), 11 (14.1%) atrial arrhythmia (AT), and 3 (3.8%) atrioventricular nodal reentrant tachycardia (AVNRT). Thirty-four patients underwent catheter ablation including 14 for AF, 9 for AVRT, 6 for AFL, 3 for AVNRT, 1 for both AF and AFL, and 1 for both AF and AVRT. They were followed up for a median (interquartile range) of 58.5 (82.9) months. There were no recurrences for patients with non-AF SVAs. For patients with AF, the 1- and 7-year AF-free survival were 87.5% and 49.5%, respectively. A ROC analysis revealed that a greater left ventricular end-diastolic dimension (LVEDD) was associated with higher recurrence of AF with an optimum cutoff value of 47mm (c-statistic = 0.91, p=0.011, sensitivity = 1.00, specificity = 0.82). In Kaplan-Meier analysis, patients with LVEDD ≥47mm had worse AF-free survival (log-rank p=0.014). Conclusions AF is the most common SVA in HCM, with AFL, AVRT, AT, and AVNRT ranking the second to the last according to the prevalence. The long-term catheter ablation outcome for non-AF SVAs in HCM is satisfying. A greater LVEDD predicts AF recurrence after catheter ablation in patients with HCM. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China Figure 1 Figure 2

Brugada Pattern in a Child with Severe SARS-CoV-2 Related Multisystem Inflammatory Syndrome

This report presents the first case of Brugada pattern complicated by a supraventricular arrhythmia in a child with SARS-CoV-2 related Multisystem Inflammatory Syndrome in Children (MIS-C). A 7-year-old boy came to our Emergency Department with 7 days of abdominal pain and fever. MIS-C was diagnosed on the basis of the clinical, laboratory and instrumental tests. On admission, ECG showed type 1 Brugada pattern in the right precordial leads. During hospitalization the onset of supraventricular arrhythmias complicated the clinical picture. This case underlines management complexity of supraventricular arrhythmic events, different from atrial fibrillation, in patients with Brugada pattern in the context of a systemic inflammatory condition with significant cardiac involvement. All potential therapeutic choices should be considered to ensure the best outcomes.

Efficiency of dimephosphonum, cytochrom cand mexidol in the treatment of cardiac rhythm disorders in children

The efficiency of dimephosphonum, cytochrom c and mexidol in the treatment of ventricular, supraventricular arrhythmias in children is shown. Dimephosphonum (100 mg/kg i.v.), mexidol (10 mg/kg p.o.) and cytochrom c (0,5 mg/kg i.v.) were studied in comparison with cordaron, finoptin and also with the standard neurometabolic therapy. It is shown that dimephosphonum was the most effective drug in all kinds of disturbances of cardiac rhythm and conductivity in children. In supraventricular arrithmias and sinus node dysfunction it surpasses traditional drugs. At ventricular arrhythmias dimephosphonum was less effective than cordaron. However, cordaron induced cardiac (20%) and extracardiac (20%) negative effects. The dimephosphonum treatment was safe and was accompanied by favourable influence on the basic heart functions