This editorial refers to a paper Komissarova SM, Chakova NN, Rebeko ES, Dolmatovish TV, Niyazova SS. Clinical characteristics of patients with various genetic types of long QT syndrome. Journal of Arrhythmology. 2022;29(1): 7-16.

The aim of the study is to evaluate clinical characteristics, including adverse events and outcomes, in patients with various genetic types of long QT syndrome (LQTS).

Material and methods. We examined 24 patients with a clinical diagnosis of LQTS, observed in the for 5 years. The clinical and instrumental study included registration of electrocardiography (ECG), Holter monitoring, collection of a genealogical history with an ECG assessment of all family members and identification of cases of sudden cardiac death (SCD) in the family or the presence of a family form of the disease, echocardiography and cardiac magnetic resonance imaging to exclude structural changes in the myocardium. The search for mutations in the coding sequences of genes associated with the development of channelopathy and other hereditary heart rhythm disorders was carried out by next generation sequencing (NGS).

Results. Mutations in 4 genes associated with LQTS (KCNQ1, KCNH2, CACNA1C, ANK2) were detected in 18 out of 24 (75.0%) patients. Mutations in the KCNQ1, KCNH2 and CACNA1C genes were detected in 14 (58.0%) patients. In 4 out of 24 (17%) patients, two or more variants of clinical significance (VUS) were detected in the genes associated with LQTS and hereditary arrhythmias, 6 patients had no genetic changes. The most severe form of the disease with pronounced clinical manifestations and episodes of clinical death with subsequent resuscitation measures, as well as a significant increase in the QTc interval exceeding 500 ms, was observed in patients with LQT2 and multiple mutations. Implantation of a cardioverter-defibrillator (CD) was required in 14 (58.3%) patients, including 11 (78.56%) - for secondary prevention of SCD and 3 (21.4%) - for primary prevention.

Conclusion. A comparative analysis between different genetic types of LQTS (LQT1; LQT2; patients with multiple VUS) showed that in patients with LQT1 syndrome, despite the early manifestation of the disease and the presence of syncopal conditions, life-threatening arrhythmias, SCD and the frequency of CD implantation were significantly less often recorded than in other LQTS. The most severe form of the disease with pronounced clinical manifestations, episodes of clinical death with subsequent resuscitation and CD implantation was observed both in the group of probands with LQT2 and in patients with several nucleotide variants (VUS), one of which was in the CACNA1C or ANK2 genes. 

Aim. Evaluate the overall effectiveness of cardiac contractility modulation (CCM) therapy in patients with chronic heart failure of various etiology.

Methods. The study included 61 patients with chronic heart failure (NYHA class II-III), ejection fraction 20-40% and narrow QRS <130 ms, who were implanted the CCM devices. Depending on the etiology of heart failure, ischemic cardiomyopathy prevailed (41 patients). All patients were performed echocardiography, 6-min walk test and Minnesota Living with Heart Failure questionnaire (MHFLQ). Results. The observation period was 25 months. All 54 patients significantly improved left ventricular ejection fraction from 32.2% to 37.6% (р=0.026) and volume parameters (left ventricle end systolic volume from 150 to 137 ml (р=0.034), left ventricle end diastolic volume from 220 to 201 ml (р=0.044), reduced the heart failure NYHA class >1 in 29 (53.7%) patients (р=0.015), increased 6-min walk test from 265 to 343 m (р=0.029), and the MHFLQ improved from 46.1 to 35.8 (р=0.042). Non-ischemic cardiomyopathy was associated with significant improvement in MHFLQ (from 42.7 to 30.3, р=0.029) and lowering the heart failure NYHA class>1 (83.3%, vs 47.2%, p=0.012) compared to ischemic group. Conclusion. CCM is safe and effective in patients with chronic heart failure NYHA class II-III, ejection fraction 20- 40% and narrow QRS˂130 ms, who were implanted the CCM devices. Depending on the etiology of heart failure, ischemic cardiomyopathy prevailed (41 patients). All patients were performed echocardiography, 6-min walk test and Minnesota Living with Heart Failure questionnaire (MHFLQ).

Results. The observation period was 25 months. All 54 patients significantly improved left ventricular ejection fraction from 32.2% to 37.6% (р=0.026) and volume parameters (left ventricle end systolic volume from 150 to 137 ml (р=0.034), left ventricle end diastolic volume from 220 to 201 ml (р=0.044), reduced the heart failure NYHA class >1 in 29 (53.7%) patients (р=0.015), increased 6-min walk test from 265 to 343 m (р=0.029), and the MHFLQ improved from 46.1 to 35.8 (р=0.042). Non-ischemic cardiomyopathy was associated with significant improvement in MHFLQ (from 42.7 to 30.3, р=0.029) and lowering the heart failure NYHA class>1 (83.3%, vs 47.2%, p=0.012) compared to ischemic group.

Conclusion. CCM is safe and effective in patients with chronic heart failure NYHA class II-III, ejection fraction 20- 40% and narrow QRS˂130 ms. Non-ischemic etiology of cardiomyopathy was associated with significant improvement in MHFLQ and lowering the heart failure class. 

Aim. To assess the antithrombotic therapy after left atrial appendage occlusion (LAAO) with the Watchman device (WD) and Amplarzer Cardiac Plug (ACP) for stroke prevention in patients with nonvalvular atrial fibrillation (AF) with contraindications for long anticoagulation therapy.

Methods. 200 consecutive patients with nonvalvular AF and contraindications to oral anticoagulation therapy with contraindications for long anticoagulation who undergone LAAO implantation using WD (n=108; WD group) and ACP (n=92; ACP group) were enrolled into this study. Antithrombotic therapies were prescribed after successful LAAO implantation according to indications. Patients were followed at 45 days, 3, 6 and 12 months after enrollment. At each follow-up visit the data regarding clinical events and healthcare utilization were collected. Transesophageal echo (TEE) was perfomed at 45 days and 6 months after successful LAAO implantation. The efficacy end point was the composite of transit ischemic attack (TIA)/stroke, device thrombosis and procedure-related death.

Results. During the follow-up TIA/stroke has occurred in 4.8% of patients in the WD group with no such events in ACP group (4.8% vs 0%, p=0.062). These patients had 4 or more points on the CHA2 DS2 -VASc, and they were prescribed various combinations of antithrombotic therapy, except warfarin, while patients from the WD group with 4 or more points on the CHA2 DS2 -VASc score taking warfarin had no thromboembolic events. Device thrombosis during TEE at 45 days after successful LAAO implantation was confirmed in 3 patients (2,9%) with WD with no such events in ACP group (2.9% vs 0%, p=0.251). The efficacy end point events in all groups were 4.6%: 8 events in WD group (7.6%) and 1 case in ACP group (1.1%). One patient in the ACP group died in 6 weeks after LAAO implantation. No autopsy was performed; therefore, the exact cause of death was not determined (p=0.038). Survival rate showed significantly higher rate events in WD group versus ACP group (p=0.027).

Conclusion. Any combinations of antithrombotic therapy could be prescribed to patients with contraindications for anticoagulant therapy and high risk of stroke who undergone successful (LAAO) implantation with Amplatzer Cardiac Plug. It’s possible to cancel oral anticoagulants in this patient. Patients aged 70 and older with a CHA2 DS2 -VASc >4 and a history of stroke are recommended to take warfarin after successful Watchman Device implantation. 

Aim. To present the experience and assess the complications of permanent pacing in children with bradyarrhythmias based on long-term follow-up.

Methods. Data of 145 children with structurally normal heart with implanted pacemakers at the age from 1 month to 18 years were retrospectively assessed. The follow-up was from 1999 to 2020 years. Epicardial pacemaker was implanted in 71 children, endocardial - in 74. The mean age of the primary implantation was 8.67±5.2 years.

Results. The following complications were disclosed: hemodynamic complications (heart chamber enlargement in dynamics and/or development of dyssynchrony, the appearance and increase in the regurgitation degree on the atrioventricular valves), bacterial endocarditis, hemopericardium, subclavian vein occlusion, pericarditis, infection of the pacemaker and its pocket, leads dislocation and fracture. With epicardial pacing various complications were detected in 24 (33.8%) examined patients, with endocardial - in 37 (50%). Hemodynamic complications with epicardial permanent pacing are associated with intraventricular dyssynchrony due to implantation of a ventricular lead on the lateral wall or the right ventricular outflow tract. Hemodynamic complications were not recorded in patients that performed the implantation of an epicardial lead at the left ventricular (LV) apex.

Conclusion. Children with pacemakers require careful follow-up. The most rational is the use of a primary epicardial pacemaker system with lead implantation on the apex of the LV. Such approach allows the veins to be preserved for endocardial stimulation at an older age, and to prevent hemodynamic complications. Neither epicardial nor endocardial pacemaker implantation guarantee the absence of complications. However, compliance with the above conditions will allow achieving high efficiency and safety of cardiac stimulation in children. 

Dabigatran is highly effective oral anticoagulant used in patients with atrial fibrillation, venous thrombosis, pulmonary embolism, orthopedic surgery. The most important role in activation and transport of dabigatran play hepatic carboxylesterase-1 (CES-1) and P-glycoprotein. To date were studied different polymorphisms that affect the pharmacokinetics of dabigatran such as rs2244613 (C > A), rs8192935 (T > C) и rs71647871 (G > A), rs1128503 (1236 C > T), rs2032582 (2677 G > T), rs1045642 (3435 C > T) и rs4148738 (G > A) and others. At the same time, there is no need of dabigatran pharmacogenetics testing in routine care. On the other side, existing literature data is often controversial, that’s why future studies are needed to answer the above-mentioned question. 

We present a case of successful percutaneous epicardial access in patients with non-ischemic cardiomyopathy with limited mapping and ablation of the ventricular tachycardia substrate on the epicardial surface. 

Intraluminal formations of the heart are a heterogeneous group: from blood clots to malignant neoplasms. The nosology of these formations can only be determined by morphological research. Myxofibrosarcoma of the heart is a rare malignant tumor. According to modern concepts, myxofibrosarcoma belongs to the group of intimal sarcomas, subgroup of undifferentiated pleomorphic sarcomas. We describe two cases of myxofibrosarcoma of the heart: in one subject against the background of inflammatory myofibroblastic heart tumor; in another subject - with a history of breast cancer and diffuse large B-cell lymphoma. An attempt was made to identify similar mutations in patients with these tumors according to the literature. 

In this article we have described clinical case of successful balloon catheter for peripheral angioplasty usage for occlusion of subclavian vein which was damaged during transvenous lead extraction of old leads. It helped to prevent life-threatening bleeding. 

We present a case of takotsubo cardiomyopathy characterized as acute transient left ventricular systolic dysfunction in a patient with persistent atrial fibrillation, that occurred after cryoballoon pulmonary vein ablation procedure.

Fragments of Holter monitoring of a 64-year-old patient with paroxysms of supraventricular tachycardia are presented, atrial ectopic activity during tachycardia is recorded, which does not interrupt the tachycardia, but changes the sequence of RR intervals. The possibility of remote analysis of the data of 3-day monitoring of the patient’s electrocardiogram in 12-channel is provided.