Aim . To assess the long-term risk of life-threatening ventricular arrhythmias and recurrent systolic dysfunction in patients with chronic heart failure (CHF) and improved left ventricular ejection fraction (LVEF) following implantation of implantable cardioverter-defibrillators (ICD) or cardiac resynchronization therapy defibrillators (CRT-D) for primary prevention of sudden cardiac death (SCD), and to identify factors associated with these outcomes. Methods . The study represents a continuation of the analysis of a previously described single-center retrospective cohort of patients with CHF and improved LVEF who had undergone ICD or CRT-D implantation for primary prevention of SCD. The study included 87 patients: 34 with ICDs and 53 with CRT-D. In contrast to the previously published work, which focused on survival, inappropriate electrical therapy, and complications related to implanted devices, the primary endpoint of the present study was the development of sustained ventricular arrhythmia terminated by ICD/CRT-D therapy (arrhythmic composite endpoint - ACE), while the secondary endpoint was relapse to an LVEF ≤35%. Results . Duration follow-up after study inclusion was 5.2±2.8 years, and the total duration after device implantation was 8.3 ± 3.6 years. ACE was observed in 7.1% (n=6) of patients, and in 4.8% of those with persistently improved LVEF. Recurrent reduction in LVEF to ≤35% occurred in 24.4% (n=20) of patients and was associated with higher all-cause mortality (35.0% vs. 5.0%), presence of atrial fibrillation, more pronounced baseline left ventricular remodeling. Conclusion . While a significantly reduced risk of life-threatening arrhythmias is observed upon improvement in LVEF, a certain risk of recurrent progression of systolic dysfunction persists. Despite the retrospective design and limited sample size, these results underscore the need for an individualized management approach for this patient category and provide a basis for planning further prospective studies in this field.
This review summarizes the anatomical and physiological characteristics of the sinoatrial node as a model for bio pacemakers and analyzes current approaches to their development, including sinoatrial node cell transplantation, the use of pluripotent stem cells, gene therapy (HCN overexpression, IK1 suppression, TBX18 transduction, and others), as well as combined and reprogramming strategies Special attention is given to the authors’ own experience and achievements in tissue engineering. Key obstacles to clinical translation are outlined, including safety concerns, stability of therapeutic effects, adequacy of experimental models, and control of biological pacemaker activity. Despite existing limitations, pro gress in gene engineering, stem cell technologies, and biomaterials offers promising opportunities for the development of fully physiological alternatives to electronic pacemakers.
Aim . To evaluate the efficacy of the class IC antiarrhythmic drug flecainide in combination with an atrioventricular nodal slowing agent (metoprolol succinate or diltiazem) for the suppression of refractory to other antiarrhythmic medication atrial fibrillation (AF) in patients with symptomatic paroxysmal AF without significant structural heart disease, as well as to assess the incidence of adverse events associated with this therapy. Material and Methods . This multicenter observational study enrolled patients aged 18-75 years with documented symptomatic (EHRA class ≥2a) paroxysmal AF and frequent episodes (≥2 per month). All patients received flecainide combined with either metoprolol succinate or diltiazem. The primary endpoint was a documented episode of AF within 3 months of therapy. Secondary endpoints included time to AF recurrence and treatment-related adverse events. Rhythm monitoring was performed using a portable device for self-recording of lead I electrocardiograms: daily during the first week, twice weekly during weeks 2-4, and additionally on an ad hoc basis when symptoms occurred. Quality of life was assessed using the EQ-5D questionnaire at baseline and at study completion. Results . The study included 59 patients (57.6% female; mean age 63.5±9.9 years). The combination of flecainide with metoprolol succinate was prescribed to 93.2% (n=55) of patients, and flecainide with diltiazem to 6.8% (n=4). The primary endpoint was reached in 33.9% of patients (n=20). The majority of AF recurrences (85% of all events, n=17) occurred during the first month of follow-up. Adverse events were reported in 10.2% of cases (n=7). Conclusion . In patients with paroxysmal AF refractory to other antiarrhythmic drugs (including prior ineffective catheter ablation in half of the study patients), a combination of flecainide with metoprolol or diltiazem demonstrated a recurrence-free rate of 66% over 3 months, with an acceptable safety profile. Combination therapy is associated with a significant improvement in quality of life. Single-lead remote ECG monitoring is useful for detecting arrhythmia recurrences but is insufficient for a comprehensive assessment of the safety of intraventricular conduction disturbances.
Aim . To evaluate the impact of the extent of left atrial (LA) low-voltage areas on the risk of atrial arrhythmia recurrence after radiofrequency ablation (RFA) in patients with atrial fibrillation (AF). Methods . The study included 159 patients (mean age 65.36±9.33 years; 61.6% male) undergoing first-time RFA for AF (68.6% paroxysmal, 31.4% persistent). High-density LA voltage mapping was performed using a multielectrode catheter and CARTO 3 system. Areas with bipolar amplitude <0.5 mV were classified as low-voltage areas (LVA), and <0.1 mV as very low-voltage areas (vLVA). The percentage of LVA (LVA%) and vLVA% were calculated. The primary endpoint was recurrence of any atrial arrhythmia during 12-month follow-up. Kaplan-Meier survival analysis, Cox regression models, and ROC analysis were performed. Results . Arrhythmia recurrence occurred in 40% of patients with persistent AF and 18.3% with paroxysmal AF. LVA% was significantly higher in patients with recurrence (40.40% vs. 4.80%; p < 0.001). In the Cox model, each 1% increase in LVA% was associated with a 3.6% higher recurrence risk (HR 1.036; p < 0.001). After adjustment for AF type and LA volume, LVA% remained an independent predictor (adjusted HR 1.034; p < 0.001). ROC analysis identified an optimal threshold of 22.4% (AUC=0.746). Patients with LVA% ≥22,4% had more than six-fold higher recurrence risk (adjusted HR 6.478; p < 0.001). LVA% measured during AF showed even stronger discrimination (AUC=0.786 for any arrhythmia; AUC=0.790 for atypical flutter/atrial tachycardia recurrence). Conclusions . The extent of low-voltage substrate in the left atrium is a strong and independent predictor of arrhythmia recurrence after RFA. Thresholds of ≥22,4% (or ≥24,7% for mapping during atrial fibrillation) allow reliable risk stratification and may guide individualized ablation strategies.
