Progressive and Simultaneous Right and Left Atrial Remodeling Uncovered by a Comprehensive Magnetic Resonance Assessment in Atrial Fibrillation

Predictive value of left and right atrial strain for the detection of device-detected atrial fibrillation in patients with cryptogenic stroke and implantable cardiac monitor

BACKGROUND AND OBJECTIVE

Device-detected atrial fibrillation (DDAF) is frequently identified using implantable cardiac monitors (ICMs) following cryptogenic stroke (CS). While left atrium (LA) echocardiographic parameters have been linked to DDAF risk, right atrial (RA) parameters remain underexplored. This study aimed to assess the relationship between speckle-tracking echocardiography parameters and the occurrence of DDAF detected via ICM in patients with CS.

METHODS

We retrospectively analyzed consecutive CS patients who received an ICM at our institution. All underwent transthoracic echocardiography to evaluate LA, RA, left and right ventricle (LV, RV) function using standard and strain-derived parameters. The primary endpoint was the first DDAF episode lasting >6 min recorded by ICM.

RESULTS

Between May 2013 and July 2022, 204 patients (82 % males, median age 69 years) received an ICM. Over a median follow-up of 15.3 months [interquartile range: 7.4-23.5], DDAF was detected in 96 patients (47.0 %). LA peak longitudinal strain (adjusted-hazard ratio [HR] 0.87, 95 %CI 0.84-0.89, p < 0.001), peak conduit strain (adjusted-HR 1.17, 95 %CI 1.13-1.22, p < 0.001), and peak contraction strain (adjusted-HR 1.17, 95 % CI 1.11-1.22, p < 0.001) significantly predicted DDAF. RA peak longitudinal strain (adjusted-HR 0.89, 95 % CI 0.83-0.95, p < 0.001) and peak contraction strain (adjusted-HR 1.39, 95 % CI 1.26-1.53, p < 0.001) were also predictive, but peak conduit strain was not (p = 0.103). No significant associations were found for LV or RV parameters.

CONCLUSIONS

LA and RA strain analyses are valuable for predicting DDAF detection following CS and can aid in risk stratification before ICM insertion.

Impact of Tricuspid Regurgitation on Atrial Fibrillation Recurrence After Pulmonary Vein Isolation

BACKGROUND

The impact of tricuspid regurgitation (TR) on the outcomes of pulmonary vein isolation (PVI) for atrial fibrillation (AF) remains unclear. While the effects of mitral regurgitation (MR) on PVI outcomes are well-documented, there are limited data on how moderate or greater TR influences PVI efficacy and recurrence rates.

OBJECTIVES

The aim of this study was to assess the impact of moderate or greater TR on the outcomes of PVI, particularly focusing on AF recurrence rates within the first year post-PVI.

METHODS

We conducted an observational cohort study involving 421 patients undergoing their first PVI. 96 patients with moderate or greater TR were propensity score-matched with 96 controls based on age, sex, body mass index, and MR severity. Procedural parameters, complication rates, and AF recurrence within 1-year post-PVI were analyzed.

RESULTS

Despite comparable procedural parameters and low overall complication rates between the groups, patients with moderate or greater TR experienced significantly higher AF recurrence rates within the first year after PVI. Right atrium (RA) area was notably larger in these patients, suggesting a potential link between RA remodeling and increased AF recurrence.

CONCLUSIONS

Our findings indicate that moderate or greater TR is associated with higher recurrence rates of AF after PVI, potentially due to RA enlargement and remodeling. This highlights the need for tailored ablation strategies that consider the RA substrate and/or TR treatment in patients with significant TR and AF. Further multicenter, prospective studies are required to validate these results and explore long-term outcomes.

Atrial FDG uptake and atrial fibrillation: A systematic review and meta-analysis

Background

Atrial inflammatory and metabolic derangements have been reported in patients with atrial fibrillation (AF).

Objective

We sought to evaluate the association of 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) in the left and right atria and AF.

Methods

We conducted a systematic review and meta-analysis, using the PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, of studies involving patients undergoing FDG-PET scans with reported atrial or ventricular uptake and outcomes of AF. Data were pooled and analyzed, and FDG uptake in AF and non-AF patients was compared using odds ratios (ORs).

Results

Six studies (4 retrospective, 1 prospective, and 1 case-control) were included in the meta-analysis of studies on patients not meeting diagnostic criteria for cardiac sarcoidosis (CS): 832 patients with a mean age of 67 years, 62% male, and 53% with hypertension. AF patients demonstrated higher odds of FDG uptake in the left atrium (pooled OR 14.50, 95% confidence interval 6.78-31.02; P < .0001, I 2 = 0) and right atrium (pooled OR 51.98, 95% confidence interval 22.77-118.63, P < .0001, I 2 = 0). Two studies on patients met diagnostic criteria for CS: one did not report atrial uptake and the other did not demonstrate a statistically significant association between right or left atrial uptake in AF patients.

Conclusion

In patients undergoing FDG-PET without meeting CS diagnostic criteria, FDG uptake in the atria was strongly associated with AF, suggesting altered metabolism or inflammation in AF pathophysiology and risk assessment.

Right atrial reverse remodeling after pulmonary vein isolation: Analyzing changes in volume and function using cardiac magnetic resonance imaging

BACKGROUND

Successful pulmonary vein isolation (PVI) promotes left atrial (LA) reverse remodeling, but its effect on right atrial (RA) remodeling remains unclear.

OBJECTIVE

The purpose of this study was to assess the impact of radiofrequency (RF) PVI on RA volumes and function in patients with atrial fibrillation by using cardiac magnetic resonance imaging.

METHODS

Forty-three patients with atrial fibrillation (32 (74.4%) males; mean age 61±7 years) undergoing first RF PVI, without atrial flutter ablation, underwent 3 cardiac magnetic resonance scans: pre-PVI, early (<72 hours) post-PVI, and 3 months post-PVI. Indexed atrial volumes (RA maximal/minimal volume index and LA maximal/minimal volume index) and function were derived from 2- and 4-chamber cine images, with longitudinal atrial strain analyzed using feature tracking.

RESULTS

Early post-PVI, RA minimal volume index significantly decreased (from 28.7±10.3 to 26.0±9.9 mL/m2; P=.03) while RA emptying fraction significantly increased (from 37.3%±11.5% to 41.7%±10.1%; P=.03). At 3 months, both RA minimal volume index and RA maximal volume index showed further significant reductions compared with baseline (from 28.7±10.3 to 24.8±8.8 mL/m2; P=.002 and from 45.2±11.8 to 40.3±11.9 mL/m2; P<.001, respectively). During this period, RA functional improvement persisted, as evidenced by RA reservoir and contractile strain (from 16.2%±4.1% to 18.9%±3.6%; P=.003 and from 6.6%±2.6% to 8.3%±2.8%; P=.005, respectively). LA volumes remained unchanged early post-PVI, but at 3 months, LA maximal volume index significantly decreased compared with baseline (from 46.1±13.0 to 39.1±11.3 mL/m2; P<.001). LA function, demonstrated by reservoir and contractile strain, was significantly diminished early post-PVI, which persisted at 3 months compared with baseline (from 18.6%±4.0% to 17.0%±3.4%; P=.04 and from 8.5%±3.0% to 6.9%±2.4%; P<.01, respectively).

CONCLUSION

This study demonstrates that RF PVI results in reverse biatrial remodeling, with significant reductions observed in RA and LA volumes. RA function showed a significant improvement post-PVI, while LA function demonstrated persistent impairment at 3 months, possibly because of LA ablation scarring.

Endo-epicardial mapping of human sinus node in vivo: Novel electrophysiologic findings and anatomic correlations

BACKGROUND

The human sinoatrial node (SAN) pacemaker is a complex structure located at the right atrium (RA)-superior vena cava (SVC) junction.

OBJECTIVE

This study aimed to perform in vivo endocardial and epicardial electroanatomic mapping of human SAN in inappropriate sinus node tachycardia (IST) and to correlate electrical findings with anatomic observations from thoracoscopy during hybrid SAN-sparing IST ablation.

METHODS

All consecutive patients with diagnosis of symptomatic IST, refractory to or intolerant of drugs, and endocardial and epicardial mapping of SAN during hybrid ablation were included. Local activation time was defined by steepest -dV/dT on unipolar electrogram (EGM). Exit zone (EZ) was defined as the earliest activation site on endocardial and epicardial maps. Endo-epicardial delay was the time difference between the first endo-epicardial activations. Bipolar EGM morphology and SVC sleeve extension were analyzed.

RESULTS

A total of 61 patients were included. The SAN-EZ area was 1.4 ± 0.6 cm2; it was located in the superior anterior region of the RA in 46 (75.4%) patients and in the mid RA in 15 (24.6%) patients. The earliest activation occurred on epicardial SAN-EZ in all patients. The local activation time of the epicardial vs endocardial SAN-EZ was -30.8 ms vs -12.4 ms (P < .001). Endo-epicardial delay was 19.7 ms. Bipolar EGM reversed polarity at SAN-EZs was observed in 43 (70.5%) patients. SVC sleeve extension was 31.2 mm and inversely correlated with age.

CONCLUSION

The earliest SAN-EZ was found in the epicardium. Bipolar EGM reversed polarity is a novel electrophysiologic marker for SAN-EZs.

Comparative analysis of recurrence predictors and outcomes for atrial tachyarrhythmia following atrial fibrillation ablation: high-power short-duration vs. conventional pulmonary vein isolation

Atrial fibrillation (AF) is a common cardiac arrhythmia, with structural and electrical remodeling being significant risk factors for recurrence post-catheter ablation. The advent of high-power short-duration pulmonary vein isolation (HPSD-PVI) presents a novel approach, potentially enhancing procedural success rates through the creation of transmural lesions without overheating. This study investigates the predictors of atrial tachyarrhythmia (ATA) recurrence and compares outcomes between HPSD-PVI and conventional PVI techniques. A total of 1005 patients undergoing radiofrequency catheter ablation (RFA) for AF were retrospectively analyzed in this study. The cohort was divided based on the ablation strategy: conventional PVI from February 2013 to September 2018, and HPSD-PVI from October 2018 onwards. The primary objective was to compare the predictors of ATA recurrence and the outcome between the two groups. Among 969 patients analyzed after exclusions, independent predictors of recurrence differed between groups; higher CHADS2/CHA2DS2-VASc scores and lower left ventricular ejection fraction (LVEF) were significant in the HPSD-PVI group, while non-paroxysmal AF, larger left atrial volume index (LAVI), and longer AF history were predictors in the conventional PVI group. The HPSD-PVI group showed a trend toward lower ATA recurrence rates compared to the conventional PVI group in the propensity-score-matched (PSM) cohort (log-rank test, p = 0.06). Higher CHADS2/CHA2DS2-VASc scores and lower LVEF were also independent predictors of ATA recurrence in the PSM cohort.

Right atrial volume index and right atrial volume predict atrial fibrillation recurrence: A meta-analysis

BACKGROUND

Atrial volume index and atrial volume have recently been identified as predictors of atrial fibrillation (AF) recurrence following electrical cardioversion or radiofrequency ablation. However, most studies have reported the relationship between LAVI/LAV and AF recurrence, whereas there is little information on the relationship between RAVI/RAV and AF recurrence. Therefore, we performed a meta-analysis to assess the relationship between the risk of AF recurrence and RAVI/RAV in patients with AF who underwent electrical cardioversion or radiofrequency ablation.

METHODS

CNKI, Wanfang Database, Pubmed, Embase, Cochrane Library, and Web of Science were searched up to October 01, 2024. A meta-analysis of relative risk data from prospective and retrospective cohort studies that reported on the relationship between the risk of AF recurrence and RAVI/RAV in patients with AF after electrical cardioversion or radiofrequency ablation was performed.

RESULTS

The results showed that patients with AF recurrence had a higher mean right atrial volume index (RAVI) compared to patients with no recurrence. After electrical cardioversion or radiofrequency ablation, RAVI can independently predict the recurrence of AF (OR = 1.06, 95%CI (1.02, 1.11)). The average right atrial volume (RAV) of patients with AF recurrence was higher than that of patients without AF recurrence. After electrical cardioversion or radiofrequency ablation, RAV can independently predict the recurrence of AF (OR = 1.02, 95%CI (1.00, 1.05)).

CONCLUSION

Patients with AF recurrence after electrical cardioversion or radio frequency ablation had higher mean RAVI and RAV compared to patients with no recurrence. After electrical cardioversion or radiofrequency ablation in patients with AF, higher levels of RAVI and RAV increase the chance of recurrence of AF.

Atrial flutter and sick sinus syndrome

BACKGROUND

Sick sinus syndrome (SSS) is a common condition resulting in reduced quality of life, syncope, and permanent pacemaker (PPM) implantation, but predictors have not been elucidated. Whereas atrial arrhythmias are frequently associated with SSS, we hypothesized that atrial flutter (AFL) would strongly predict SSS, given shared relationships with right atrial and particularly crista terminalis fibrosis.

OBJECTIVE

The study aimed to assess the impact of AFL on the occurrence of SSS and associated syncope and PPM implantation.

METHODS

Health care databases were used to identify adults aged ≥18 years receiving hospital-based care in California in 2005-2019. International Classification of Diseases codes were used to identify diagnoses and procedures. Patients were classified on the basis of the presence of AFL and atrial fibrillation (AF). Cox proportional hazards models adjusting for demographics and comorbidities were employed.

RESULTS

We included 29,357,609 individuals (54% female; mean age, 46 years), 101,243 with AFL alone, 1,674,680 with AF alone, and 284,547 with AF and AFL. After adjustment for age, sex, race and ethnicity, and comorbidities, AF, AFL, and both arrhythmias were each associated with increased risk of SSS and associated syncope and PPM implantation (all P < .001). In the population with AF, an additional AFL diagnosis conferred a higher risk for development of SSS (hazard ratio [HR],1.62; 95% confidence interval, 1.59-1.64), syncope (HR, 1.63; 1.54-1.72), and PPM implantation (HR, 1.74; 1.70-1.79).

CONCLUSION

AFL is associated with an increased risk of incident SSS and its adverse consequences, especially in patients with coexisting AF. AFL may be useful for risk stratification strategies to predict, to prevent, and to treat SSS.

Echocardiographic Assessment of Left Atrial Mechanics in Patients with Atrial Fibrillation Undergoing Electrical Cardioversion: A Systematic Review

Background: To date, only a few studies have evaluated left atrial (LA) mechanics in patients with atrial fibrillation (AF) scheduled for electrical cardioversion (ECV). The present systematic review has been primarily designed to summarize the main findings of these studies and to examine the overall effect of AF on left atrial reservoir strain (LASr) in patients undergoing ECV. Methods: All the echocardiographic studies evaluating the effect of AF on LA mechanics in patients scheduled for ECV, selected from the PubMed and EMBASE databases, were included. There was no limitation of time period. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results: The full texts of 12 studies with 880 AF patients were analyzed. The pooled ECV success rate was 91.5% (range 65.8-100%). Over a median follow-up of 5.4 months (range 0.3-12 months), 35.2% of the patients (range 5-68.8%) experienced AF recurrence. At baseline, the average LASr was 11.4% (range 6.2-17.7%). A reduced LASr before ECV was strongly correlated with reduced left atrial appendage (LAA) flow velocities and/or thrombosis. The main independent predictors of cardioversion failure were impaired LASr and previous AF history. A severe LASr deterioration was independently correlated with AF recurrence after ECV. The other independent predictors of AR relapses were LA asynchrony, reduced difference between post- and pre-ECV LASr, and reduced right atrial reservoir strain. Conclusions: LASr assessment before ECV may provide useful prognostic information about AF relapses and improve the refinement of the thromboembolic risk of AF patients scheduled for ECV.

Relationships between biatrial substrate and recurrence after radiofrequency ablation in patients with persistent atrial fibrillation

BACKGROUND

Global longitudinal strain (GLS) and atrial voltage are acknowledged markers for worse rhythm outcome after ablation of persistent atrial fibrillation (PeAF). The majority of research efforts have been directed towards the left atrium (LA), with relatively fewer studies focusing on the right atrium (RA). The aim of this study was to investigate the effect of the biatrial substrate on the outcome following radiofrequency catheter ablation (RFCA).

METHODS

All patients underwent two-dimensional speckle tracking echocardiography (2D-STE) and high-density mapping (HDM) on LA and RA in preoperative and postoperative stages of RFCA. Atrial substrate was assessed by GLS, average voltage, and low voltage zone (LVZ).

RESULTS

This retrospective study enrolled 48 patients. With a follow-up of 385.98 ± 161.78 days, 22.92% (11/48) of all patients had AF recurrence and 63.64% in low strain group. Left atrial-low voltage zone (LA-LVZ) prior to RFCA was 67.52 ± 15.27% and 54.21 ± 20.07%, respectively, in the recurrence group and non-recurrence group. Multivariate regression analysis showed that preoperative LA-GLS (OR 0.047, 95%CI 0.002-0.941, p = .046) was independent predictors of AF recurrence. Biatrial average voltage in preoperative and postoperative stages were positively correlated (preoperative: r = 0.563 p < .001; postoperative: r = 0.464 p = .002). There was no significant difference in the proportion of RA in the recurrence group except the septum in preoperative and postoperative stages.

CONCLUSIONS

Low LA-GLS and high LA-LVZ may be predictors of RFCA recurrence in PeAF patients. Biatrial average voltage were positively correlated in preoperative and postoperative stages.

Combined Area of Left and Right Atria May Outperform Atrial Volumes as a Predictor of Recurrences after Ablation in Patients with Persistent Atrial Fibrillation-A Pilot Study

Background and Objectives: Left atrial (LA) remodelling and dilatation predicts atrial fibrillation (AF) recurrences after catheter ablation. However, whether right atrial (RA) remodelling and dilatation predicts AF recurrences after ablation has not been fully evaluated. Materials and Methods: This is an observational study of 85 consecutive patients (aged 57 ± 9 years; 70 [82%] men) who underwent cardiac magnetic resonance before first catheter ablation for AF (40 [47.1%] persistent AF). Four-chamber cine-sequence was selected to measure LA and RA area, and ventricular end-systolic image phase to obtain atrial 3D volumes. The effect of different variables on event-free survival was investigated using the Cox proportional hazards model. Results: In patients with persistent AF, combined LA and RA area indexed to body surface area (AILA + RA) predicted AF recurrences (HR = 1.08, 95% CI 1.00-1.17, p = 0.048). An AILA + RA cut-off value of 26.7 cm2/m2 had 72% sensitivity and 73% specificity for predicting recurrences in patients with persistent AF. In this group, 65% of patients with AILA + RA > 26.7 cm2/m2 experienced AF recurrence within 2 years of follow-up (median follow-up 11 months), compared to 25% of patients with AILA + RA ≤ 26.7 cm2/m2 (HR 4.28, 95% CI 1.50-12.22; p = 0.007). Indices of LA and RA dilatation did not predict AF recurrences in patients with paroxysmal AF. Atrial 3D volumes did not predict AF recurrences after ablation. Conclusions: In this pilot study, the simple measurement of AILA + RA may predict recurrences after ablation of persistent AF, and may outperform measurements of atrial volumes. In paroxysmal AF, atrial dilatation did not predict recurrences. Further studies on the role of RA and LA remodelling are needed.

Standardized 2D atrial mapping and its clinical applications

The visualization and comparison of electrophysiological information in the atrium among different patients could be facilitated by a standardized 2D atrial mapping. However, due to the complexity of the atrial anatomy, unfolding the 3D geometry into a 2D atrial mapping is challenging. In this study, we aim to develop a standardized approach to achieve a 2D atrial mapping that connects the left and right atria, while maintaining fixed positions and sizes of atrial segments across individuals. Atrial segmentation is a prerequisite for the process. Segmentation includes 19 different segments with 12 segments from the left atrium, 5 segments from the right atrium, and two segments for the atrial septum. To ensure consistent and physiologically meaningful segment connections, an automated procedure is applied to open up the atrial surfaces and project the 3D information into 2D. The corresponding 2D atrial mapping can then be utilized to visualize different electrophysiological information of a patient, such as activation time patterns or phase maps. This can in turn provide useful information for guiding catheter ablation. The proposed standardized 2D maps can also be used to compare more easily structural information like fibrosis distribution with rotor presence and location. We show several examples of visualization of different electrophysiological properties for both healthy subjects and patients affected by atrial fibrillation. These examples show that the proposed maps provide an easy way to visualize and interpret intra-subject information and perform inter-subject comparison, which may provide a reference framework for the analysis of the atrial fibrillation substrate before treatment, and during a catheter ablation procedure.

Heart Failure, Female Sex, and Atrial Fibrillation Are the Main Drivers of Human Atrial Cardiomyopathy: Results From the CATCH ME Consortium

BACKGROUND

Atrial cardiomyopathy (atCM) is an emerging prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy, and capillary density are hallmarks of atCM. The contribution of etiological factors and atrial fibrillation (AF) to the development of differential atCM phenotypes has not been quantified. This study aimed to evaluate the association between histological features of atCM and the clinical phenotype.

METHODS AND RESULTS

We examined left atrial (LA, n=95) and right atrial (RA, n=76) appendages from a European cohort of patients undergoing cardiac surgery. Quantification of histological atCM features was performed following wheat germ agglutinin/CD31/vimentin staining. The contributions of AF, heart failure, sex, and age to histological characteristics were determined with multiple linear regression models. Persistent AF was associated with increased endomysial fibrosis (LA: +1.13±0.47 μm, P=0.038; RA: +0.94±0.38 μm, P=0.041), whereas total extracellular matrix content was not. Men had larger cardiomyocytes (LA: +1.92±0.72 μm, P<0.001), while women had more endomysial fibrosis (LA: +0.99±0.56 μm, P=0.003). Patients with heart failure showed more endomysial fibrosis (LA: +1.85±0.48 μm, P<0.001) and extracellular matrix content (LA: +3.07±1.29%, P=0.016), and a higher capillary density (LA: +0.13±0.06, P=0.007) and size (LA: +0.46±0.22 μm, P=0.044). Fuzzy k-means clustering of histological features identified 2 subtypes of atCM: 1 characterized by enhanced endomysial fibrosis (LA: +3.17 μm, P<0.001; RA: +2.86 μm, P<0.001), extracellular matrix content (LA: +3.53%, P<0.001; RA: +6.40%, P<0.001) and fibroblast density (LA: +4.38%, P<0.001), and 1 characterized by cardiomyocyte hypertrophy (LA: +1.16 μm, P=0.008; RA: +2.58 μm, P<0.001). Patients with fibrotic atCM were more frequently female (LA: odds ratio [OR], 1.33, P=0.002; RA: OR, 1.54, P=0.004), with persistent AF (LA: OR, 1.22, P=0.036) or heart failure (LA: OR, 1.62, P<0.001). Hypertrophic features were more common in men (LA: OR=1.33, P=0.002; RA: OR, 1.54, P=0.004).

CONCLUSIONS

Fibrotic atCM is associated with female sex, persistent AF, and heart failure, while hypertrophic features are more common in men.

Incremental Value of Right Atrial Strain Analysis to Predict Atrial Fibrillation Recurrence After Electrical Cardioversion

BACKGROUND

Although the assessment of left atrial (LA) mechanics has been reported to refine atrial fibrillation (AF) risk prediction, it doesn't completely predict AF recurrence. The potential added role of right atrial (RA) function in this setting is unknown. Accordingly, this study sought to evaluate the added value of RA longitudinal reservoir strain (RASr) for the prediction of AF recurrence after electrical cardioversion (ECV).

METHODS

We retrospectively studied 132 consecutive patients with persistent AF who underwent elective ECV. Complete two-dimensional and speckle-tracking echocardiography analyses of LA and RA size and function were obtained in all patients before ECV. The end point was AF recurrence.

RESULTS

During a 12-month follow-up, 63 patients (48%) showed AF recurrence. Both LASr and RASr were significantly lower in patients experiencing AF recurrence than in patients with persistent sinus rhythm (LASr, 10% ± 6% vs 13% ± 7%; RASr, 14% ± 10% vs 20% ± 9%, respectively; P < .001 for both). Right atrial longitudinal reservoir strain (area under the curve = 0.77; 95% CI, 0.69-0.84; P < .0001) was more strongly associated with the recurrence of AF after ECV than LASr (area under the curve = 0.69; 95% CI, 0.60-0.77; P < .0001). Kaplan-Meier curves showed that patients with both LASr ≤ 10% and RASr ≤ 15% had a significantly increased risk for AF recurrence (log-rank, P < .001). However, at multivariable Cox regression, RASr (hazard ratio, 3.26; 95% CI, 1.73-6.13; P < .001) was the only parameter independently associated with AF recurrence. Right atrial longitudinal reservoir strain was more strongly associated with the occurrence of AF relapse after ECV than LASr, and LA and RA volumes.

CONCLUSION

Right atrial longitudinal reservoir strain was independently and more strongly associated than LASr with AF recurrence after elective ECV. This study highlights the importance of assessing the functional remodeling of both the RA and LA in patients with persistent AF.

The inter-chamber differences in the contractile function between left and right atrial cardiomyocytes in atrial fibrillation in rats

Introduction

The left and right atria (LA, RA) work under different mechanical and metabolic environments that may cause an intrinsic inter-chamber diversity in structure and functional properties between atrial cardiomyocytes (CM) in norm and provoke their different responsiveness to pathological conditions. In this study, we assessed a LA vs. RA difference in CM contractility in paroxysmal atrial fibrillation (AF) and underlying mechanisms.

Methods

We investigated the contractile function of single isolated CM from LA and RA using a 7-day acetylcholine (ACh)-CaCl2 AF model in rats. We compared auxotonic force, sarcomere length dynamics, cytosolic calcium ([Ca2+]i) transients, intracellular ROS and NO production in LA and RA CM, and analyzed the phosphorylation levels of contractile proteins and actin-myosin interaction using an in vitro motility assay.

Results

AF resulted in more prominent structural and functional changes in LA myocardium, reducing sarcomere shortening amplitude, and velocity of sarcomere relengthening in mechanically non-loaded LA CM, which was associated with the increased ROS production, decreased NO production, reduced myofibrillar content, and decreased phosphorylation of cardiac myosin binding protein C and troponin I. However, in mechanically loaded CM, AF depressed the auxotonic force amplitude and kinetics in RA CM, while force characteristics were preserved in LA CM.

Discussion

Thus, inter-atrial differences are increased in paroxysmal AF and affected by the mechanical load that may contribute to the maintenance and progression of AF.

The Impact of Right Atrial Size to Predict Success of Direct Current Cardioversion in Patients With Persistent Atrial Fibrillation

BACKGROUND AND OBJECTIVES

The prognostic implication of right atrial (RA) and left atrial (LA) size for an immediate success of direct current cardioversion (DCCV) in atrial fibrillation (AF) remains unclear. This study aimed to compare RA and LA size for the prediction of DCCV success.

METHODS

Between 2012 and 2018, 734 consecutive outpatients were screened for our prospective registry. Each eligible patient received a medical history, blood analysis, and transthoracic echocardiography with a focus on indexed RA (iRA) area and LA volume (iLAV) prior to DCCV with up to three biphasic shocks (200-300-360 J) or additional administration of amiodarone or flecainide to restore sinus rhythm.

RESULTS

We enrolled 589 patients, and DCCV was in 89% (n=523) successful. Mean age was 68 ± 10 years, and 40% (n=234) had New York heart association class >II. A prevalence of the male sex (64%, n=376) and of persistent AF (86%, n=505) was observed. Although DCCV success was associated with female sex (odds ratio [OR], 1.88; 95% confidence interval [CI], 1.06-3.65), with absence of coronary heart disease and normal left ventricular function (OR, 2.24; 95% CI, 1.26-4.25), with short AF duration (OR, 1.93; 95% CI, 1.05-4.04) in univariable regression, only iRA area remained a stable and independent predictor of DCCV success (OR, 0.27; 95% CI, 0.12-0.69; area under the curve 0.71), but not iLAV size (OR, 1.16; 95% CI, 1.05-1.56) in multivariable analysis.

CONCLUSIONS

iRA area is superior to iLAV for the prediction of immediate DCCV success in AF.