Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications

Comparison of efficacy of pharmacological cardioversion with antazoline and propafenone versus electrical cardioversion in atrial fibrillation during cryoablation

Introduction

Antazoline with propafenone may be an alternative to electrical cardioversion (ECV) in restoring sinus rhythm in patients with atrial fibrillation (AF), including during balloon cryoablation.

Aim

To compare the efficacy of antazoline with propafenone and ECV in restoring and maintaining sinus rhythm at discharge in patients with AF during cryoablation with special regard to type of AF.

Material and methods

The study retrospectively analyzed 196 patients who underwent elective cryoablation. Eighty-nine patients who developed AF in the perioperative period were selected as the study group (32 women and 57 men). The study group was divided into two groups - 46 (51.7%) patients were given pharmacological cardioversion with 70 mg of propafenone and 100 or 200 mg of antazoline, whereas the other 43 (48.3%) patients underwent ECV.

Results

There were no statistically significant differences between the groups regarding: left atrial area, left atrium diameter, right atrial area and right atrium diameter. In the overall population, ECV was more effective than antazoline with propafenone therapy (31 [72.1%] vs. 20 [43.5%]; p = 0.01). A similar relationship was demonstrated in patients with persistent AF (13 [59.1%] vs. 3 [12.5%]; p = 0.002). There was no significant difference in the group of patients with paroxysmal AF (18 (85.6%) vs. 17 (77.3%); p = 0.7).

Conclusions

In AF during the cryoablation procedure ECV appears to be more effective in restoring and maintaining sinus rhythm at discharge than antazoline with propafenone in the general AF patient population, especially in patients with persistent AF.

The application and mechanism of Chinese medicine in the upstream treatment of atrial fibrillation

Upstream treatment of atrial fibrillation (AF, for short) is a new approach to the prevention and treatment of AF with non-antiarrhythmic drugs, which is essentially primary and secondary prevention of AF. The former refers to the prevention of AF by controlling risk factors such as diabetes, hypertension, and heart failure before AF occurs, and the latter mainly refers to targeting ion channels, inflammation, oxidative stress, and other pathways to reduce or reverse atrial electrical and structural remodeling, reduction of AF load, and reduction of the chance of AF occurrence or progression. More and more studies have shown that many traditional Chinese medicines, active ingredients of Chinese medicines, and Chinese herbal formulas have definite effects on the upstream treatment of AF, but their mechanisms of action are different. Therefore, we summarized the relevant literature on the application and mechanisms of Chinese medicine on the upstream treatment of AF in recent years, hoping to be helpful for subsequent studies.

Rule-based definition of muscle bundles in patient-specific models of the left atrium

Atrial fibrillation (AF) is the most common arrhythmia encountered clinically, and as the population ages, its prevalence is increasing. Although the CHA2DS2−VASc score is the most used risk-stratification system for stroke risk in AF, it lacks personalization. Patient-specific computer models of the atria can facilitate personalized risk assessment and treatment planning. However, a challenge faced in creating such models is the complexity of the atrial muscle arrangement and its influence on the atrial fiber architecture. This work proposes a semi-automated rule-based algorithm to generate the local fiber orientation in the left atrium (LA). We use the solutions of several harmonic equations to decompose the LA anatomy into subregions. Solution gradients define a two-layer fiber field in each subregion. The robustness of our approach is demonstrated by recreating the fiber orientation on nine models of the LA obtained from AF patients who underwent WATCHMAN device implantation. This cohort of patients encompasses a variety of morphology variants of the left atrium, both in terms of the left atrial appendages (LAAs) and the number of pulmonary veins (PVs). We test the fiber construction algorithm by performing electrophysiology (EP) simulations. Furthermore, this study is the first to compare its results with other rule-based algorithms for the LA fiber architecture definition available in the literature. This analysis suggests that a multi-layer fiber architecture is important to capture complex electrical activation patterns. A notable advantage of our approach is the ability to reconstruct the main LA fiber bundles in a variety of morphologies while solving for a small number of harmonic fields, leading to a comparatively straightforward and reproducible approach.

The Inverse Correlation Between the Duration of Lifetime Occupational Radiation Exposure and the Prevalence of Atrial Arrhythmia

Objective

Advancements in fluoroscopy-assisted procedures have increased radiation exposure among cardiologists. Radiation has been linked to cardiovascular complications but its effect on cardiac rhythm, specifically, is underexplored.

Methods

Demographic, social, occupational, and medical history information was collected from board-certified cardiologists via an electronic survey. Bivariate and multivariable logistic regression analyses were performed to assess the risk of atrial arrhythmias (AA).

Results

We received 1,478 responses (8.8% response rate) from cardiologists, of whom 85.4% were male, and 66.1% were ≤65 years of age. Approximately 36% were interventional cardiologists and 16% were electrophysiologists. Cardiologists > 50 years of age, with > 10,000 hours (h) of radiation exposure, had a significantly lower prevalence of AA vs. those with ≤10,000 h (11.1% vs. 16.7%, p = 0.019). A multivariable logistic regression was performed and among cardiologists > 50 years of age, exposure to > 10,000 radiation hours was significantly associated with a lower likelihood of AA, after adjusting for age, sex, diabetes mellitus, hypertension, and obstructive sleep apnea (adjusted OR 0.57; 95% CI 0.38-0.85, p = 0.007). The traditional risk factors for AA (age, sex, hypertension, diabetes mellitus, and obstructive sleep apnea) correlated positively with AA in our data set. Cataracts, a well-established complication of radiation exposure, were more prevalent in those exposed to > 10,000 h of radiation vs. those exposed to ≤10,000 h of radiation, validating the dependent (AA) and independent variables (radiation exposure), respectively.

Conclusion

AA prevalence may be inversely associated with radiation exposure in Cardiologists based on self-reported data on diagnosis and radiation hours. Large-scale prospective studies are needed to validate these findings.

Extent of Left Atrial Fibrosis Correlates with Descending Aorta Proximity at 3D Late Gadolinium Enhancement Cardiac MRI in Patients with Atrial Fibrillation

PURPOSE

To determine whether the distance between the descending aorta and left atrial (LA) wall correlates with the amount of fibrosis quantified in the posterior left inferior pulmonary vein (LIPV) area of the LA in patients with atrial fibrillation (AF).

MATERIALS AND METHODS

In this retrospective study, patients with AF underwent cardiac MRI in sinus rhythm prior to a pulmonary vein isolation procedure (July 2018 to February 2020). The mean distance (distance_mean) and shortest distance (distance_short) between the descending aorta and the LA wall were measured on three-dimensional (3D) contrast-enhanced MR angiograms; distance_mean was defined as the average of five measurements at different levels between the descending aorta and the LA wall. The extent of LA fibrosis, both global fibrosis and regional fibrosis within the LIPV area, was derived from postprocessed, 3D, late gadolinium-enhanced images. Associations between the extent of fibrosis and the proximity of the descending aorta were analyzed by using correlative and multivariable analyses.

RESULTS

A total of 47 (mean age, 60 years ± 8 [standard deviation]; 31 men) patients were included for analysis. The extent of fibrosis in the posterior LIPV area was correlated with the distance_mean (r _s = -0.48; P < .01) and distance_short (r _s = -0.49; P < .01). Patients with a short distance between the descending aorta and LA wall (defined as a distance_short < 2 mm) had a higher percentage of fibrosis in the posterior LIPV area than patients with a distance_short greater than 2 mm (38.7% ± 22.7 vs 21.2% ± 17.8; P < .01).

CONCLUSION

The distance between the descending aorta and LA was correlated with the extent of quantified fibrosis within the posterior LIPV area.Keywords: MRI, Cardiac, Left Atrium Supplemental material is available for this article. © RSNA, 2022.

Impaired left atrial reservoir and conduit strain in patients with atrial fibrillation and extensive left atrial fibrosis

BACKGROUND

Atrial fibrillation (AF) is associated with profound structural and functional changes in the atria. In the present study, we investigated the association between left atrial (LA) phasic function and the extent of LA fibrosis using advanced cardiovascular magnetic resonance (CMR) imaging techniques, including 3-dimensional (3D) late gadolinium enhancement (LGE) and feature tracking.

METHODS

Patients with paroxysmal and persistent AF (n = 105) underwent CMR in sinus rhythm. LA global reservoir strain, conduit strain and contractile strain were derived from cine CMR images using CMR feature tracking. The extent of LA fibrosis was assessed from 3D LGE images. Healthy subjects underwent CMR and served as controls (n = 19).

RESULTS

Significantly lower LA reservoir strain, conduit strain and contractile strain were found in AF patients, as compared to healthy controls (- 15.9 ± 3.8% vs. - 21.1 ± 3.6% P < 0.001, - 8.7 ± 2.7% vs. - 12.6 ± 2.5% P < 0.001 and - 7.2 ± 2.3% vs. - 8.6 ± 2.2% P = 0.02, respectively). Patients with a high degree of LA fibrosis (dichotomized by the median value) had lower reservoir strain and conduit strain compared to patients with a low degree of LA fibrosis (- 15.0 ± 3.9% vs. - 16.9 ± 3.3%, P = 0.02 and - 7.9 ± 2.7% vs. - 9.5 ± 2.6%, P = 0.01, respectively). In contrast, no difference was found for LA contractile strain (- 7.1 ± 2.4% vs. - 7.4 ± 2.3%, P = 0.55).

CONCLUSIONS

Impaired LA reservoir and conduit strain are present in AF patients with extensive atrial fibrosis. Future studies are needed to examine the biologic nature of this association and possible therapeutic implications.

Post Procedural Peak Left Atrial Contraction Strain Predicts Recurrence of Arrhythmia after Catheter Ablation of Atrial Fibrillation

Background

Left atrial (LA) function can be impaired by the atrial fibrillation (AF) ablation and might be associated with the risk of recurrence. We sought to determine whether the post-procedural changes in LA function impact the risk of recurrence following AF ablation.

Methods

We retrospectively reviewed patients who underwent AF ablation between 2009 and 2011 and underwent transthoracic echocardiography before ablation, 1-day and 3-month after ablation. Peak left atrial contraction strain (PACS) and left atrial emptying fraction (LAEF) were evaluated during sinus rhythm and compared across the three time points. The primary endpoint was atrial tachyarrhythmia recurrence after ablation.

Results

A total of 144 patients were enrolled (mean age 61 ± 11 years, 77% male, 46% persistent AF). PACS and LAEF initially decreased 1-day following ablation but partially recovered within 3 months in PAF patients, with a similar trend in the PerAF patients. After median 24 months follow-up, 68 (47%) patients had recurrence. Patients with recurrence had higher PACS_1-day than that in non-recurrence subjects (-10.9 ± 5.0% vs. -13.4 ± 4.7%, p = 0.003). PACS_1-day -12% distinguished recurrence cases with a sensitivity of 67.7% and specificity of 60.5%. The Kaplan–Meier curves showed significant difference in 5-year cumulative probability of recurrence between those with PACS ≥ -12% and PACS < -12% (log rank p < 0.0001). Multivariate regression showed that PACS_1-day was an independent risk factor of arrhythmia recurrence.

Conclusions

Left atrial function deteriorates immediately following AF ablation and partially recovers in 3 months but remains abnormal in the majority of patients. PACS_1-day post procedure predicts arrhythmia recurrence at long-term follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12947-021-00250-5.

Tricuspid regurgitation after transcatheter mitral valve repair: Clinical course and impact on outcome

Objectives

The aim of this study was to determine the course of tricuspid regurgitation (TR) after transcatheter mitral valve repair (TMVR), identify predictors for severe TR after TMVR and determine the association of severe TR after TMVR with outcome.

Background

TR is often present in patients with symptomatic mitral regurgitation (MR) and is associated with increased morbidity and mortality. The clinical course of TR after TMVR has not been clearly determined.

Methods

Patients that underwent TMVR between 2009 and 2017 were included. Clinical data were compared between patients with and without severe TR at 6 months after TMVR. Multivariate logistic regression analysis was performed to identify predictors for severe TR after TMVR. Survival analysis was done for both groups, using the Kaplan–Meier method.

Results

A total of 146 patients were included (mean age 76 years, 51% male, 79% New York Heart Association class ≥3 and 29% severe TR at baseline).

Advanced age, atrial fibrillation (AF), right ventricular (RV) dysfunction, and limited procedural MR reduction were revealed as independent predictors for severe TR after TMVR. Survival of patients with severe TR after TMVR was 58% after 2 years compared to 82% for those with non, mild or moderate TR.

Conclusions

Severe TR after TMVR is common in patients at advanced age, those with AF, RV dysfunction and limited MR reduction during TMVR and is associated with impaired survival. As the associated parameters are indicators of longstanding MR, research investigating the benefits of earlier intervention in MR should be initiated.