Radiofrequency ablation impact on the morpho-functional state of the heart in patients with atrial fibrillation and chronic heart failure

Funding Acknowledgements

Type of funding sources: None.

Introduction

Heart failure with preserved left ventricular ejection fraction (HFpLVEF) has become the dominant form of heart failure worldwide, along with an aging population and an increasing prevalence of obesity, diabetes and hypertension. Drug rhythm control has limited efficacy in HFpLVEF and a fairly high risk of side effects.

The aim of the study was to evaluate the radiofrequency ablation impact on the morpho-functional state of the heart in patients with atrial fibrillation and HFpLVEF based on 2-year follow-up.

Materials and methods

The study included 194 patients with an average age of 59.3±8.5 years with atrial fibrillation and concomitant HFpLVEF of I-III functional class of New York Heart Association. Patients were divided into 2 groups: 136 patients who underwent radiofrequency catheter ablation and 58 patients in the control group who did not undergo intervention and continued antiarrhythmic pharmacotherapy. Patients were comparable in terms of basic clinical and demographic indicators. In order to assess the morpho-functional state of the heart, transthoracic echocardiography was performed at the stage of inclusion in the study and 2 years after.

Results and discussion. According to the results of the analysis in the radiofrequency catheter ablation group 2 years after the intervention revealed: a statistically significant decrease in the mean end-systolic diameter of the left ventricle (3.3±0.48 cm versus 3.2±0.41cm, p<0.001); decreased size of the left atrium (4.3±0.71 cm versus 4.2±0.30 cm, p<0.001); LVEF increased significantly (61.9±7.14% versus 63.9±5.65%, p<0.001); the E/e’ ratio decreased statistically significantly (11.9±1.65 versus 9.4±1.48; p<0.001) and the left ventricular myocardial mass index (118.3±25.04 g/m2 versus 116.4±18.04 g/m2; p=0.045). In the pharmacotherapy group there were: a statistically significant increase in the average end-systolic size of the left ventricle (3.61±0.45 cm versus 3.63±0.41, p=0.007); statistically significant increased left atrium (4.3±0.61 cm versus 4.4±0.36; p <0.001) and the right atrium (4.1±0.52 cm versus 4.2±0.26; p<0.001); decreased left ventricular ejection fraction (58.1±6.12% versus 56.6±6.11; p<0.001); increased values of the ratio E/e’ (12.1±1.63 versus 12.7±1.27; p=0.002) and decreased level of the left ventricular myocardial mass index (120.5±24.05 g/m2 versus 118.3±20.13 g/m2; p=0.044).

Conclusion

Radiofrequency ablation of atrial fibrillation in patients with HFpLVEF to control sinus rhythm is associated with improved morpho-functional state of the heart at the 2-year follow-up compared with antiarrhythmic pharmacotherapy strategy: the left ventricular ejection fraction increases, the left ventricular diastolic function improves according to the E/e’ value, the size of the left atrium decreases.

Outcomes of heart failure with preserved ejection fraction after radiofrequency catheter ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction. Recent randomized controlled trials have shown that in heart failure (HF) patients with reduced left ventricle ejection fraction (HFrEF) atrial fibrillation (AF) ablation reduces hospitalization and mortality due to HF compared to medical therapy (MT). However, only few studies have examined outcomes of catheter ablation (CA) for AF in HF patients with preserved left ventricle ejection fraction (HFpEF). 

Purpose. To compare the effect of catheter ablation on the outcomes of atrial fibrillation with chronic heart failure with preserved ejection fraction.

Methods. Our prospective study included the main group (136 patients with the HFpEF who underwent a single procedure of the CA for symptomatic AF) and control group (58 patients with the HFpEF patients with paroxysmal or persistent AF on MT for rhythm and rate control strategy). To be eligible for inclusion for both groups, left ventricular diastolic dysfunction had to be present and/or relevant structural heart disease according to the current guidelines had to be fulfilled within 6 months prior to AF ablation. Outpatient follow-up were performed at 6, 12, 24 months intervals thereafter baseline. 

Results. At the follow-up the composite primary end point (all-cause death or worsening of HF that led to an unplanned hospitalization) appeared in significantly fewer patients in the CA group than in the MT group (18 (13,2%) patients vs. 16 (27,5%) patients; p =0,005). The secondary analyses showed there was 5 deaths in the CA group and 2 deaths in MT group, with rate of 3,7%  and 3,4% respectively that were equal in comparable groups (p = 0,362). The incidences of HF hospitalization and cardiovascular hospitalization were also significantly higher in MT group than in CA group (14 (24,1%) vs. 13 (9,6%), p = 0,005) vs. 21 (15,4%), p = 0,016, respectively). Cardiovascular death and cerebrovascular accident were equal in comparable groups. The Kaplan–Meier curve for primary end-point demonstrated significant higher survival and freedom from hospitalizations due to HF in the CA group compared to MT group (p = 0,005); the freedom from hospitalization for worsening HF and the freedom from the cardiovascular hospitalization were having higher probability in the СA group (p = 0,003 and p= 0,016 ).

Conclusion. Comparing catheter ablation with medical therapy for rhythm or rate control strategy in patients with heart failure with preserved left ventricle ejection fraction and atrial fibrillation, we found that catheter ablation was associated with lower rate of deaths and hospitalization due to worsening of heart failure.

Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

Halide perovskites have undergone remarkable developments as highly efficient optoelectronic materials for a variety of applications. Several studies indicated the critical role of defects on the performance of perovskite devices. However, the parameters of defects and their interplay with free charge carriers remain unclear. In this study, we explored the dynamics of free holes in methylammonium lead tribromide (MAPbBr₃) single crystals using the time-of-flight (ToF) current spectroscopy. By combining ToF spectroscopy and Monte Carlo simulation, three energy states were detected in the bandgap of MAPbBr₃ In addition, we found the trapping and detrapping rates of free holes ranging from a few microseconds to hundreds of microseconds. Contrary to previous studies, we revealed a strong detrapping activity of traps. We showed that these traps substantially affect the transport properties of MAPbBr₃, including mobility and mobility-lifetime product. Our results provide an insight on charge transport properties of perovskite semiconductors.

[FUNCTIONAL PARAMETERS OF BLOOD CIRCULATION IN FIRST THREE MONTHS AFTER RADIOFREQUENCY ABLATION OF ATRIAL FIBRILLATION AND FLUTTER]

The purpose of the study was to evaluate functional parameters of blood circulation in first 3 months after radiofrequency ablation of atrial fibrillation and atrial flutter. The study included 113 patients aged 59.3±10.1 years, after radiofrequency ablation (RFA) with pulmonary veins isolation (PVI) for atrial fibrillation (AF), RFA of cava-tricuspid isthmus (CTI) for atrial flutter (AFl), or combined RFA PVI and CTI. Presence of arrhythmia recurrence episodes, blood pressure (BP) levels, electrocardiographic and echocardiographic indices were assessed before RFA, in acute postoperative period (3-5 days) and 3 months after RFA in the groups of AF, AFl, and AF/AFl combination. In acute postoperative period, arrhythmia recurrence of was most often recorded in the AF/AFl group, less often in groups of isolated AF and AFl, 3 months later - the frequency of recurrence decreased in all groups, but the largest remained in group of combined AF/AFl. In first 3 months after RFA of AF a decreased heart rate (HR), right atrium (RA) and ventricle (RV) size, an increased QTc interval duration and BP; after RFA of AFl - a decreased HR, end-diastolic volume (EDV) and RA; and after RFA of AF/AFl - a decreased ejection fraction (EF), an increased BP, QTc interval duration, and the end-systolic volume (EDV) were recorded. The results showed that effectiveness of RFA of isolated AF and AFl is higher than RFA of combined AF/AFl in the first 3 months after the procedure. Isolated AF and AFl after RFA were associated with BP and QTc interval duration increase, HR, EDV, RA and RV decrease; combined RFA of AF and AFl - with BP, QTc interval duration and ESV increase and left ventricular EF decrease.