Association between left and right atrial remodeling with atrial fibrillation recurrence after pulmonary vein catheter ablation in patients with paroxysmal atrial fibrillation: a pilot study

Deep learning-based workflow for automatic extraction of atria and epicardial adipose tissue on cardiac computed tomography in atrial fibrillation

BACKGROUND

Preoperative estimation of the volume of the left atrium (LA) and epicardial adipose tissue (EAT) on computed tomography (CT) images is associated with an increased risk of atrial fibrillation (AF) recurrence. We aimed to design a deep learning-based workflow to provide reliable automatic segmentation of the atria, pericardium, and EAT for future applications in the management of AF.

METHODS

This study enrolled 157 patients with AF who underwent first-time catheter ablation between January 2015 and December 2017 at Taipei Veterans General Hospital. Three-dimensional (3D) U-Net models of the LA, right atrium (RA), and pericardium were used to develop a pipeline for total, LA-EAT, and RA-EAT automatic segmentation. We defined fat within the pericardium as tissue with attenuation between -190 and -30 HU and quantified the total EAT. Regions between the dilated endocardial boundaries and endocardial walls of the LA or RA within the pericardium were used to detect voxels attributed to fat, thus estimating LA-EAT and RA-EAT.

RESULTS

The LA, RA, and pericardium segmentation models achieved Dice coefficients of 0.960 ± 0.010, 0.945 ± 0.013, and 0.967 ± 0.006, respectively. The 3D segmentation models correlated well with the ground truth for the LA, RA, and pericardium ( r = 0.99 and p < 0.001 for all). The Dice coefficients of our proposed method for EAT, LA-EAT, and RA-EAT were 0.870 ± 0.027, 0.846 ± 0.057, and 0.841 ± 0.071, respectively.

CONCLUSION

Our proposed workflow for automatic LA, RA, and EAT segmentation using 3D U-Nets on CT images is reliable in patients with AF.

Atrial dimension reference values in healthy participants using the biplane/monoplane method for clinical and research use

AIM

To provide reference values of the dimensions of the left and right atrium (RA) obtained using the biplane and monoplane methods, respectively, on two- and four-chamber views, which represent the standard projections acquired in clinical practice, and correlation with body surface area (BSA), age, and gender.

MATERIALS AND METHODS

Healthy volunteers, M:F = 1:1, including five participants per gender and age decile from 20 to 70 years, who underwent cardiovascular magnetic resonance imaging (CMR) were enrolled prospectively. Normal atrial reference values were calculated for male and female subpopulations and stratified by age. Atrial areas and volumes were assessed both as absolute values and indexed to BSA. Differences among genders and correlation with age were assessed. Intra- and interobserver reproducibility were assessed in a subpopulation.

RESULTS

Fifty participants (mean age 43.3 ± 14 years, 25 men) were evaluated. Image analysis took <1 minute for each subject (mean time 30 ± 5 seconds). Intra- and interobserver reproducibility were excellent (ICC >0.85 for all datasets). RA areas were significantly higher in males (p=0.0001). The left atrial (LA) surface did not show significant differences among genders. Atrial areas normalised to BSA did not show significant gender differences. Both right and left absolute atrial volumes turned out to be significantly higher in males (p=0.0001 and p=0.0047, respectively), and normalised to BSA remained significantly different only for the RA (p=0.0006). Neither atrial volume nor areas showed significant correlation with age.

CONCLUSIONS

The monoplane method is a fast and reproducible technique to assess atrial dimensions. Absolute atrial dimensions show significant variations among genders. Gender-specific reference ranges for atrial dimensions are recommended.

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.

Right atrial dysfunction is associated with atrial arrhythmias in adults with repaired tetralogy of fallot

BACKGROUND

Adults with repaired tetralogy of Fallot (TOF) have right atrial (RA) remodeling and dysfunction, and RA function can be measured using speckle tracking echocardiography. There are limited data about the role of RA strain imaging for risk stratification in this population. We hypothesized that RA reservoir strain can identify TOF patients at risk of developing atrial arrhythmia. To test this hypothesis, we assessed the relationship between RA reservoir strain and atrial arrhythmias in adults with repaired TOF.

METHOD

Retrospective cohort study of adults with repaired TOF, and no prior history of atrial arrhythmias. Atrial arrhythmia was defined as atrial fibrillation, atrial flutter/atrial tachycardia, and categorized as new-onset versus recurrent atrial arrhythmias.

RESULTS

We identified 426 patients (age 33 ± 12 years; males 208 (49%)) that met the inclusion criteria. The mean RA reservoir strain, conduit strain, and booster strain were 34 ± 11%, 20 ± 9%, and 15 ± 12%, respectively. Of 426 patients, 73 (17%) developed new-onset atrial arrhythmias (atrial flutter/tachycardia n = 42; atrial fibrillation n = 31); annual incidence 1.9%. RA reservoir strain was associated with new-onset atrial arrhythmias (adjusted HR 0.95, 95% CI 0.93-0.97) after multivariable adjustment. Of 73 patients with new-onset atrial arrhythmia, 41 (56%) had recurrent atrial arrhythmia (atrial flutter/tachycardia n = 18; atrial fibrillation n = 23); annual incidence 11.2%. Similarly, RA reservoir strain was associated with recurrent atrial arrhythmias (adjusted HR 0.92, 95% CI 0.88-0.96) after multivariable adjustment.

CONCLUSIONS

RA strain indices can identify patients at risk for atrial arrhythmias, and this can in turn, be used to guide the type/intensity of therapy in such patients.

Impact of catheter ablation on functional tricuspid regurgitation in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) plays the main role in atrial functional tricuspid regurgitation (TR). However, the effectiveness of catheter ablation (CA) for atrial functional TR together with the mechanisms of improvement of atrial functional TR have not been fully evaluated.

METHODS

We retrospectively investigated consecutive 2685 patients with AF who received CA from February 2004 to December 2019 in Kyoto University Hospital, Kyoto, Japan. The current study population consisted of 2331 patients with available transthoracic echocardiographic (TTE) data before CA (2110 patients without significant TR and 221 patients with significant TR). Among the 221 patients with significant TR, there were 64 patients with functional TR and follow-up TTE at 6-18 months after CA for AF, in whom we compared echocardiographic parameters from baseline to follow-up.

RESULTS

Patients with significant TR were older, and more often women, and had more persistent AF than those without significant TR. Among the 64 patients with functional TR, TR severity and TR jet area significantly improved at follow-up (TR jet area: 5.8 [4.0-7.6] cm2 to 2.1 [1.1-3.1] cm2, P < 0.001). Moreover, mitral regurgitation jet area, left atrial area, mitral valve diameter, right ventricular end-diastolic area, right atrial area, and tricuspid valve diameter decreased at follow-up.

CONCLUSIONS

TR severity and jet area improved after CA in patients with AF and significant TR. The improvement of TR might be associated with reverse remodeling of the right heart.

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.

Left atrial strain is associated with arrhythmia recurrence after atrial fibrillation ablation: Cardiac magnetic resonance rapid strain vs. feature tracking strain

PURPOSE

The present study assesses different left atrial (LA) strain approaches in relation to atrial fibrillation (AF) recurrence after ablation and compares LA feature tracking (FT) strain to novel rapid LA strain approaches in AF patients.

METHODS

This retrospective single-center study comprised of 110 prospectively recruited AF patients who underwent cardiac magnetic resonance (CMR) imaging in sinus rhythm prior to their first pulmonary vein isolation ablation. LA rapid strain (long axis strain and atrioventricular (AV)-junction strain), LA FT strain, and LA volumes were derived from 2-chamber and 4-chamber cine images. AF recurrence was followed up for 12 months using either 12‑lead ECGs or rhythm Holter monitoring.

RESULTS

Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (122-286) days. LA long axis strain, AV-junction strain, and FT strain were all more impaired in patients with AF recurrence compared to patients without AF recurrence (long axis strain: P < 0.01; AV-junction strain: P < 0.001; FT strain: P < 0.01, respectively). Area under the curve (AUC) values for LA remodeling parameters in association with AF recurrence were 0.68 for long axis strain, 0.68 for AV-junction strain, 0.66 for FT strain, 0.66 for LA volume index. Phasic FT LA strain demonstrated that contractile strain had the highest AUC (0.70).

CONCLUSION

Both LA rapid strain and LA FT strain are associated with arrhythmia recurrence after ablation in AF patients. LA rapid strain can be a convenient and reproducible alternative for LA FT strain to assess LA function in clinical practice.

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.

Efficacy of catheter ablation for atrial fibrillation in patients with significant functional mitral regurgitation

BACKGROUND

Catheter ablation has been established to be an effective therapy for paroxysmal atrial fibrillation (AF) and is recommended as the treatment of choice for many patients, including those with clinically significant functional mitral regurgitation (MR). However, there is little information available about the clinical efficacy of catheter ablation for paroxysmal AF in patients with significant functional MR.

METHODS

We performed a retrospective study of 247 patients with paroxysmal AF who underwent AF ablation. The study included 28 (11.3%) patients with significant functional MR and 219 (88.7%) without significant functional MR. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting >30 seconds beyond 3 months after catheter ablation.

RESULTS

During a mean follow-up of 20.1 ± 7.4 months (range, 3-36 months), 45 (18.2%) patients developed recurrence of AF. The recurrence rate of AF was higher in patients with significant functional MR than in those without significant functional MR (42.9% vs 15.1%; P < .001). Univariable Cox proportional hazards regression analysis showed that significant functional MR (hazard ratio [HR], 3.46; 95% confidence interval [CI], 1.78-6.72; P < .001), age (HR, 1.04; 95% CI, 1.01-1.08; P = .009), the CHA2DS2-VASc score (HR, 1.28; 95% CI, 1.05-1.56; P = .017), and heart failure (HR, 4.71; 95% CI, 1.85-11.96; P = .001) were associated with the risk of recurrence. Multivariable analysis showed that significant functional MR (HR, 2.48; 95% CI, 1.21-5.05; P = .013), age (HR, 1.04; 95% CI, 1.00-1.07; P = .031), and heart failure (HR, 3.39; 95% CI, 1.27-9.03; P = .015) were independent predictors of AF recurrence.

CONCLUSION

Patients with significant functional MR have an increased risk of AF recurrence after catheter ablation.

Quantification of right atrial fibrosis by cardiac magnetic resonance: verification of the method to standardize thresholds

INTRODUCTION AND OBJECTIVES

Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) allows noninvasive detection of left atrial fibrosis in patients with atrial fibrillation (AF). However, whether the same methodology can be used in the right atrium (RA) remains unknown. Our aim was to define a standardized threshold to characterize RA fibrosis in LGE-CMR.

METHODS

A 3 Tesla LGE-CMR was performed in 53 individuals; the RA was segmented, and the image intensity ratio (IIR) calculated for the RA wall using 1 557 767 IIR pixels (40 994±10 693 per patient). The upper limit of normality of the IIR (mean IIR+2 standard deviations) was estimated in healthy volunteers (n=9), and patients who had undergone previous typical atrial flutter ablation (n=9) were used to establish the dense scar threshold. Paroxysmal and persistent AF patients (n=10 each) were used for validation. IIR values were correlated with a high-density bipolar voltage map in 15 patients undergoing AF ablation.

RESULTS

The upper normality limit (total fibrosis threshold) in healthy volunteers was set at an IIR = 1.21. In the postablation group, 60% of the maximum IIR pixel (dense fibrosis threshold) was calculated as IIR = 1.29. Endocardial bipolar voltage showed a weak but significant correlation with IIR. The overall accuracy between the electroanatomical map and LGE-CMR to characterize fibrosis was 56%.

CONCLUSIONS

An IIR > 1.21 was determined to be the threshold for the detection of right atrial fibrosis, while an IIR > 1.29 differentiates interstitial fibrosis from dense scar. Despite differences between the left and right atria, fibrosis could be assessed with LGE-CMR using similar thresholds in both chambers.

Echocardiographic evaluation of the right atrial size and function: Relevance for clinical practice

Right atrial (RA) structural and functional evaluations have recently emerged as powerful biomarkers for adverse events in various cardiovascular conditions. Quantitative analysis of the right atrium, usually performed with volume changes or speckle-tracking echocardiography (STE), has markedly changed our understanding of RA function and remodeling. Knowledge of reference echocardiographic values and measurement methods of RA volumes and myocardial function is a prerequisite to introduce RA quantitation in the clinical routine. This review describes the methodology, benefits and pitfalls of measuring RA size and function by echocardiography based on the current understanding of right atrial anatomy and physiological function and provides the current knowledge of right atrial function in related cardiac diseases.

Association of Right Ventricular Afterload With Atrial Fibrillation Risk in Older Adults: The Atherosclerosis Risk in Communities Study

BACKGROUND

Atrial fibrillation (AF) is widely perceived to originate from the left atrium (LA). Whether increases in right ventricular (RV) afterload in older adults play an etiological role in AF genesis independent of LA and left ventricular (LV) remodeling is unknown.

RESEARCH QUESTION

Is higher RV afterload associated with greater AF risk independent of LA and LV remodeling?

STUDY DESIGN AND METHODS

In this observational prospective study, we included 2,246 community-dwelling older adults (mean age, 75 years) without known cardiovascular disease, with LV ejection fraction > 50%, LA volume index < 34 mL/m2, and E/e' ratio < 14 and a measurable functional tricuspid regurgitation jet velocity. From 2D-echocardiograms, we estimated pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR). We ascertained incident AF (through 2018) from hospital discharge codes and death certificates. We estimated hazard ratios (HR) by Cox regression.

RESULTS

During follow-up (median, 6.3 years; interquartile interval, 5.5-6.9 years), 215 participants developed AF. AF risk was significantly higher in the third (vs first) tertile of PASP (HR, 1.65; 95% CI, 1.08-2.54) and PVR (HR, 1.38; 95% CI, 1.00-2.08) independent of LA and LV structure and function, heart rate, BMI, prevalent sleep apnea, systemic BP, antihypertensive medications, and lung, kidney, and thyroid function. These associations persisted after further exclusion of participants with tricuspid regurgitation jet velocity > 2.8 m/s and lateral and septal mitral annular velocity above age- and sex-specific reference limits.

INTERPRETATION

In older adults, higher RV afterload is associated with greater AF risk independent of LA and LV remodeling. Future research should focus on confirming this novel association and elucidate underlying mechanisms.

The Right Atrial Area as a New Factor to Predict Successful Pulmonary Vein Isolation: an Emergent Predictor Variable

Up to now, few factors have been identified to predict successful pulmonary vein isolation, none of which with high predictive values. The objective of our study was to compare different predictive factors of atrial fibrillation recurrence after pulmonary vein isolation,including new parameters of the right atrium (area and index volume). We retrospectively analysed data from 66 patients and included echocardiogram parameters performed within 18 months prior to the ablation procedure. We excluded patients with left ventricular dysfunction (defined as a left ventricular ejection fraction < 50%); previous diagnostic of cardiomyopathy; severe valvular heart disease; severe pulmonary hypertension; or those with poor image quality in the echocardiogram. We considered atrial fibrillation recurrence to be the presence of atrial fibrillation of 30 seconds or longer demonstrated by a standard electrocardiogram or in a 24-hour Holter electrocardiogram within a year after the ablation procedure. We found that the right atrium area (odds ratio = 1.52; 95% confidence interval 0.95–2.43, P = 0.08) and a previous pulmonary vein isolation procedure (odds ratio = 0.21; 95% confidence interval 0.04–1.01, P = 0.05) were nearly statistically significant predictors of successful atrial fibrillation ablation at one year. Although our study was limited because of a low number of patients and because it is a retrospective analysis, we found that a higher right atrial area may be related to the late recurrence of atrial fibrillation. This tendency may be useful in predicting patient outcomes.

Impact of right atrial enlargement on clinical outcome in patients with atrial fibrillation

Background

Left atrial (LA) remodeling is associated with adverse cardiovascular events, including heart failure (HF) and stroke in patients with atrial fibrillation (AF). However, there are limited data on the value of right atrial (RA) remodeling in this population. We investigated the prognostic role of RA enlargement in patients with non-valvular AF.

Methods and results

We analyzed 254 consecutive patients (age = 69 ± 12years, male:female = 165:89, mean left ventricular ejection fraction = 58.0 ± 7.2%) with non-valvular AF who underwent two-dimensional echocardiography from a single center. RA and LA volumes were measured from apical views and indexed to the body surface areas (right atrial volume index [RAVI] and left atrial volume index [LAVI]) and RAVI &gt; 30mL/m2 and LAVI &gt; 34mL/m2 were considered as enlarged. The relationship between RA enlargement and composite clinical outcome of hospitalization for HF (HHF), stroke, systemic embolism, or death from any cause was assessed. Right atrial (RA) enlargement was associated with older age and more frequent prevalence of persistent or permanent AF. During a median follow-up of 47.1 months, 77 patients (30%) had experienced primary composite outcome. In a multivariable model, RA enlargement, but not LA enlargement, was independently associated with adverse clinical outcomes even after adjusting for clinical and echocardiographic factors {adjusted hazard ratio [HR], 1.90 [95% confidence interval (CI), 1.14–3.18], p = 0.014 for primary composite outcome; adjusted HR, 2.70 [95% CI, 1.27–5.67], p = 0.001 for HHF or all cause death}.

Conclusion

RA enlargement was independently associated with an increased risk of HF, stroke, systemic embolization or death in patients with non-valvular AF, suggesting that RA volume can be helpful in assessing future cardiovascular risk in this population.

Effect of Bi-Atrial Size and Function in Patients With Paroxysmal or Permanent Atrial Fibrillation

Atrial fibrillation (AF) remains the most common arrhythmia in clinical practice. The choice between a rate-control and rhythm-control strategy depends on various factors, including the anatomical and functional substrate. This study investigates the anatomical and functional characteristics of both atria in patients with AF and explores the potential therapeutic implications. From an ongoing registry of patients with paroxysmal or permanent AF, those who underwent cardiac computed tomography (CCT) were included. Left atrial (LA) and right atrial (RA) sizes were measured on CCT, whereas bi-atrial function was quantified with speckle tracking strain echocardiography. The mean LA volume index was 41.6 ± 5.6 ml/m², and the mean RA volume index was 71.0 ± 21.6 ml/m². Mean LA reservoir strain was 24.3 ± 15.1%, compared with the mean RA reservoir strain of 21.6 ± 13.2%. Patients with smaller LA volumes had higher LA reservoir strain values than those with larger LA volumes (24.6% [interquartile range (IQR) 15.8 to 35.8] vs 16.5% [IQR 11.2 to 25.0], p <0.001). Patients with permanent AF had larger LA volumes (44.0 [IQR 33.7 to 55.2] ml/m² vs 36.9 [IQR 30.1 to 47.1] ml/m², p = 0.025) compared with paroxysmal AF. Patients with permanent AF had more impaired LA reservoir strain (15.5% [IQR 11.6 to 22.7] vs 26.9% [IQR 17.4 to 35.6], p <0.001) compared with paroxysmal AF. Similar trends were observed in the RA. In conclusion, atrial substrate characterization by CCT and speckle tracking strain echocardiography may have therapeutic implications, especially for choosing between a rate-control and rhythm-control strategy.

Right atrial function and fibrosis in relation to successful atrial fibrillation ablation

AIMS

Bi-atrial remodelling in patients with atrial fibrillation (AF) is rarely assessed and data on the presence of right atrial (RA) fibrosis, the relationship between RA and left atrial (LA) fibrosis, and possible association of RA remodelling with AF recurrence after ablation in patients with AF is limited.

METHODS AND RESULTS

A total of 110 patients with AF undergoing initial pulmonary vein isolation (PVI) were included in the present study. All patients were in sinus rhythm during cardiac magnetic resonance (CMR) imaging performed prior to ablation. LA and RA volumes and function (volumetric and feature tracking strain) were derived from cine CMR images. The extent of LA and RA fibrosis was assessed from 3D late gadolinium enhancement images. AF recurrence was followed up for 12 months after PVI using either 12-lead electrocardiograms or Holter monitoring. Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (interquartile range: 122-286) days. RA remodelling parameters were not significantly different between patients with and without AF recurrence after ablation, whereas LA remodelling parameters were different (volume, emptying fraction, and strain indices). LA fibrosis had a strong correlation with RA fibrosis (r = 0.88, P < 0.001). Both LA and RA fibrosis were not different between patients with and without AF recurrence.

CONCLUSIONS

This study shows that RA remodelling parameters were not predictive of AF recurrence after AF ablation. Bi-atrial fibrotic remodelling is present in patients with AF and moreover, the amount of LA fibrosis had a strong correlation with the amount of RA fibrosis.

Prophylactic Cavotricuspid Isthmus Ablation in Atrial Fibrillation without Documented Typical Atrial Flutter: A Systematic Review and Meta-analysis

Background: The advantage of prophylactic cavotricuspid isthmus (CTI) ablation for AF patients without documented atrial flutter is still unclear. The present study aimed to evaluate the role of prophylactic CTI ablation in this population. Methods: A systematic review and meta-analysis study was conducted. The overall effects estimation was conducted using random effects models. The pooled effects were presented as the risk difference and standardised mean difference for dichotomous and continuous outcomes, respectively. Results: A total of 1,476 patients from four studies were included. The risk of atrial tachyarrhythmias following a successful catheter ablation procedure was greater in the pulmonary vein isolation + CTI ablation group than pulmonary vein isolation alone group (34.8% versus 28.2%; risk difference 0.08; 95% CI [0.00–0.17]; p=0.04). Prophylactic CTI ablation was associated with a higher recurrent AF rate (33.8% versus 27.1%; risk difference 0.07; 95% CI [0.01–0.13]; p=0.02). Additional prophylactic CTI ablation to pulmonary vein isolation significantly increased the radio frequency application time (standardised mean difference 0.52; 95% CI [0.04–1.01]; p=0.03). Conclusion: This study suggested that prophylactic CTI ablation was an ineffective and inefficient approach in AF without documented typical atrial flutter patients.

Association between complete right bundle branch block and atrial fibrillation development

Background

Complete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association between CRBBB and AF development remains unclear.

Methods

We performed a retrospective study of 2639 patients (male, n = 1549; female, n = 1090; mean age, 58 ± 13 years). CRBBB was defined as a late R (R′) wave in lead V₁ or V₂ with a slurred S wave in lead I and/or lead V₆ with a prolonged QRS duration (≥120 ms).

Results

Among the 2639 patients, CRBBB was detected in 40 patients (1.5%), and the prevalence of AF was 7.4% (196/2639). The proportion of patients with AF and CRBBB was higher than the proportion of patients with AF without CRBBB (22.5% vs. 7.2%; p = 0.001). In the forward multivariate logistic analysis, CRBBB (odds ratio [OR], 3.329; 95% confidence interval [CI], 1.350–8.211; p = 0.009), complete left bundle branch block (OR, 2.209; 95% CI, 1.238–3.940; p = 0.007), age (OR, 1.020; 95% CI, 1.005–1.035; p = 0.009), valvular heart disease (OR, 2.332; 95% CI, 1.531–3.552; p < 0.001), left atrial diameter (OR, 1.133; 95% CI, 1.104–1.163; p < 0.001), left ventricular ejection fraction (OR, 1.023; 95% CI, 1.006–1.041; p = 0.007), and class I or III anti‐arrhythmic drug use (OR, 10.534; 95% CI, 7.090–15.651; p < 0.001) were associated with AF.

Conclusion

Complete right bundle branch block was significantly associated with AF development in hospitalized patients with cardiovascular diseases.

Assessment of right atrial dyssynchrony by 2D speckle-tracking in healthy young men following high altitude exposure at 4100 m

Background

High altitude exposure induces overload of right-sided heart and may further predispose to supraventricular arrhythmia. It has been reported that atrial mechanical dyssynchrony is associated with atrial arrhythmia. Whether high altitude exposure causes higher right atrial (RA) dyssynchrony is still unknown. The aim of study was to investigate the effect of high altitude exposure on right atrial mechanical synchrony.

Methods

In this study, 98 healthy young men underwent clinical examination and echocardiography at sea level (400 m) and high altitude (4100 m) after an ascent within 7 days. RA dyssynchrony was defined as inhomogeneous timing to peak strain and strain rate using 2D speckle-tracking echocardiography.

Results

Following high altitude exposure, standard deviation of the time to peak strain (SD-TPS) [36.2 (24.5, 48.6) ms vs. 21.7 (12.9, 32.1) ms, p<0.001] and SD-TPS as percentage of R–R’ interval (4.6 ± 2.1% vs. 2.5 ± 1.8%, p<0.001) significantly increased. Additionally, subjects with higher SD-TPS (%) at high altitude presented decreased right ventricular global longitudinal strain and RA active emptying fraction, but increased RA minimal volume index, which were not observed in lower group. Multivariable analysis showed that mean pulmonary arterial pressure and tricuspid E/A were independently associated with SD-TPS (%) at high altitude.

Conclusion

Our data for the first time demonstrated that high altitude exposure causes RA dyssynchrony in healthy young men, which may be secondary to increased pulmonary arterial pressure. In addition, subjects with higher RA dyssynchrony presented worse RA contractile function and right ventricular performance.

The Value of Voltage Histogram Analysis Derived Right Atrial Scar Burden in the Prediction of Left Atrial Scar Burden

Introduction

Growing evidence suggests that fibrotic changes can be observed in atrial fibrillation (AF) in both atria. Quantification of the scar burden during electroanatomical mapping might have important therapeutic and prognostic consequences. However, as the current invasive treatment of AF is focused on the left atrium (LA), the role of the right atrium (RA) is less well understood. We aimed to characterize the clinical determinates of the RA low-voltage burden and its relation to the LA scaring.

Methods

We have included 36 patients who underwent catheter ablation for AF in a prospective observational study. In addition to LA mapping and ablation, high-density RA bipolar voltage maps (HD-EAM) were also reconstructed. The extent of the diseased RA tissue (≤0.5 mV) was quantified using the voltage histogram analysis tool (CARTO^®3, Biosense Webster).

Results

The percentage of RA diseased tissue burden was significantly higher in patients with a CHA₂DS₂-VASc score ≥ 2 (p = 0.0305), higher indexed LA volume on the CTA scan and on the HD‐EAM (p = 0.0223 and p = 0.0064, respectively), or higher indexed RA volume on the HD‐EAM (p = 0.0026). High RA diseased tissue burden predicted the presence of high LA diseased tissue burden (OR = 7.1, CI (95%): 1.3–38.9, p = 0.0145), and there was a significant correlation of the same (r = 0.6461, p < 0.0001).

Conclusions

Determining the extent of the right atrial low-voltage burden might give useful clinical information. According to our results, the diseased tissue burden correlates well between the two atria: the right atrium mirrors the left atrium.

Association of right atrial structure with incident atrial fibrillation: a longitudinal cohort cardiovascular magnetic resonance study from the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

While studies of the left atrium (LA) have demonstrated associations between volumes and emptying fraction with atrial fibrillation (AF), the contribution of right atrial (RA) abnormalities to incident AF remains poorly understood.

OBJECTIVES

Assess the association between RA structure and function with incident AF using feature-tracking cardiovascular magnetic resonance (CMR).

METHODS

This is a prospective cohort study of all participants in the Multi-Ethnic Study of Atherosclerosis with baseline CMR, sinus rhythm, and free of clinical cardiovascular disease at study initiation. RA volume, strain, and emptying fraction in participants with incident AF (n = 368) were compared against AF-free (n = 2779). Cox proportional-hazards models assessed association between variables.

RESULTS

Participants were aged 60 ± 10 yrs., 55% female, and followed an average 11.2 years. Individuals developing AF had higher baseline RA maximum volume index (mean ± standard deviation [SD]: 24 ± 9 vs 22 ± 8 mL/m2, p = 0.002) and minimum volume index (13 ± 7 vs 12 ± 6 mL/m2, p < 0.001), and lower baseline RA emptying fraction (45 ± 15% vs 47 ± 15%, p = 0.02), peak global strain (34 ± 17% vs 36 ± 19%, p < 0.001), and peak free-wall strain (40 ± 23% vs 42 ± 26%, p = 0.049) compared with the AF-free population. After adjusting for traditional cardiovascular risk factors and LA volume and function, we found RA maximum volume index (hazards ratio [HR]: 1.13 per SD, p = 0.041) and minimum volume index (HR: 1.12 per SD, p = 0.037) were independently associated with incident AF.

CONCLUSIONS

In a large multiethnic population, higher RA volume indices were independently associated with incident AF after adjustment for conventional cardiovascular risk factors and LA parameters. It is unclear if this predictive value persists when additional adjustment is made for ventricular parameters.

Biatrial volume, estimated using magnetic resonance imaging, predicts atrial fibrillation recurrence after ablation

INTRODUCTION

The predictive value of left atrial volume (LAV) in atrial fibrillation (AF) is known, but the relationship of right atrial volume (RAV) and biatrial volume (BAV) with AF recurrence after pulmonary vein isolation (PVI) is not clear. Cardiac magnetic resonance (CMR) imaging allows us to more precisely quantify atrial volume. We investigated LAV, RAV, and BAV as predictors of AF recurrence following PVI in AF patients.

METHODS AND RESULTS

We assessed 100 AF patients (age = 59.8 ± 9.5 years, 74 males, 26 females) who underwent nonenhanced CMR before their first PVI. LAV and RAV were measured using CMR. All patients were in sinus rhythm during CMR. BAV was calculated as the sum of LAV and RAV. During the 8-month follow-up, AF recurrence occurred in 23 patients. LAV, RAV, and BAV were significantly greater in patients with AF recurrence than in those without (LAV, 103.7 ± 25.8 vs 81.8 ± 24.2 mL, P < 0.001; RAV, 109.4 ± 27.0 vs 82.2 ± 19.6 mL, P < 0.001; BAV, 213.1 ± 46.7 vs 164.1 ± 38.7 mL, P < 0.001). Multivariate logistic regression analysis revealed that increased LAV, RAV, and BAV were significantly correlated with AF recurrence. The area under the receiver operation characteristic curve for BAV showed the largest value compared to that of LAV or RAV alone.

CONCLUSIONS

LAV, RAV, and BAV were independent predictors of AF recurrence after PVI. Quantifying BAV may additionally improve prognostic stratification compared with LAV or RAV.

Right atrial function by speckle tracking echocardiography in atrial septal defect: Prediction of atrial fibrillation

BACKGROUND

Most antiarrhythmic interventional therapies for atrial fibrillation (AF) have been provided with special focus on the treatment of left-sided valvular disease and enlarged left atrium but few studies have assessed AF associated with congenital heart disease and dilated right atrium.

HYPOTHESIS

We hypothesized that right atrial (RA) function assessed by two-dimensional (2DSTE) and three-dimensional (3DSTE) speckle-tracking echocardiography in patients with atrial septal defect (ASD) before and after percutaneous trancatheter closure could predict paroxysmal atrial fibrillation (PAF) development.

METHODS

Seventy-three patients with hemodynamically significant secundum ASD were prospectively studied and followed up for 6 months after occluder insertion and compared with a normal age-matched group (n = 73). A subgroup of 17 patients who developed PAF after device implantation was also studied. RA peak global longitudinal strain (PS) was determined using 2DSTE. Standard deviations (SDs) of times to peak strain (TPS) were calculated as indices of dyssynchrony. RA volumes, emptying fraction (EF), and expansion index (EI) were determined using 3DSTE.

RESULTS

RA-PS, EF, and EI (pre-closure values) were reduced in patients with atrial devices compared with controls, and further reductions were observed in patients with PAF. Pre-closure 3D-RA-EI (P = 0.009) and RA-TPS (P = 0.023) were independent predictors of PAF by multivariate analysis after adjustment for age and left atrial dysfunction. The areas under the ROC-curve (AUC) for 3D-RA-EI, RA-PS, RA-TPS (pre-closure values) showed high discriminative values(from 0.76 to 0.85) in predicting PAF. By combining 3D-RA-EI and RA-TPS, the AUC increased to 0.90.

CONCLUSIONS

Two-dimensional and three-dimensional speckle tracking echocardiography was clinically helpful in ASD patients in revealing right atrial dilatation and dysfunction pre-existent to device closure and associated with PAF development. RA parameters had a higher association with PAF compared to both the size of the implanted device and left atrial indices.

Right atrial myocardial deformation by two-dimensional speckle tracking echocardiography predicts recurrence in paroxysmal atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a bi-atrial disease yet little attention has been given to right heart function in AF. We propose that the assessment of right atrial (RA) and right ventricular function (RV) using two-dimensional speckle tracking echocardiography (2D-STE) could be valuable in predicting AF recurrence in patients with paroxysmal AF (PAF).

METHODS

Thirty patients with PAF were prospectively recruited from a dedicated AF clinic. Right atrial size, volume, and area and RV dimensions were analyzed along with RA and RV strain derived from 2D-STE at baseline and at 3 and 12 months.

RESULTS

Higher RA booster strain independently predicted sinus rhythm (SR) maintenance for up to 1 year (P = 0.001). RV strain was impaired in patients with recurrent AF compared to those in SR (P < 0.05) but did not predict AF recurrence. Two-dimensional STE for RA and RV function was simple to perform with excellent reproducibility (adjusted R ² 0.92-0.99).

CONCLUSIONS

Two-dimensional STE is useful and highly reproducible in assessing right heart function in AF patients. RA booster strain function was predictive of sinus rhythm maintenance for up to 1 year.

Prognostic implication of left atrial sphericity in atrial fibrillation patients undergoing radiofrequency catheter ablation

BACKGROUND

Left atrial (LA) sphericity can predict recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). We sought to reconfirm the prognostic role of atrial sphericity after RFCA of atrial fibrillation (AF), assess any relationship between the atrial pressure and sphericity, and determine the characteristics of the patients for whom atrial sphericity was most highly predictive.

METHODS

All 148 nonvalvular AF patients (57 ± 11 years, 121 men, 95 paroxysmal AF [PaAF]) who underwent RFCA were enrolled. The LA volume (LAV) was determined and LA sphericity assessed from three-dimensional computed tomographic images. The preprocedural mean LA pressure (mLAP) was measured.

RESULTS

After a 3-month blanking period, AF/atrial tachycardia (AT) recurrences within 1 year were documented in 38 patients (26%). Patients with recurrence had a greater LAV (124 ± 35 mL vs 151 ± 45 mL, P < 0.001) and LA sphericity (0.669 ± 0.040 vs 0.684 ± 0.038, P = 0.041). In patients with smaller LAs (LAV < 125 mL), LA sphericity predicted AF/AT recurrences (odds ratio [OR]: 1.030 [for each 0.001 increase], 95% confidence interval [CI]: 1.008-1.053, P = 0.007), whereas the LAV did not. In patients with larger LAs (LAV ≥ 125 mL), the LAV could predict recurrence (OR: 1.021, 95% CI: 1.001-1.041, P = 0.036), while the LA sphericity could not. The LA sphericity and mLAP are linearly correlated (r = 0.345, P < 0.022) in persistent AF, but not PaAF.

CONCLUSIONS

LA spherical change precedes severe LA enlargement in AF. It predicts 1-year AF/AT recurrence after RFCA and is more important than the LA size in patients with less severe LA enlargement.

Gender influence on the adaptation of atrial performance to training

BACKGROUND

High-intensity training has been associated with atrial remodelling and arrhythmias in men. Our purpose was to analyse atrial performance in female endurance athletes, compared to male athletes and controls.

METHODS

This was a cross-sectional study. We included four groups: female athletes, females controls, male athletes and male controls. Left (LA) and right atrial (RA) volumes and function were assessed using 2D and speckle-tracking echocardiography to determine peak atrial strain-rate at atrial (SRa) and ventricular contraction (SRs), as surrogates of atrial contractile and reservoir function, respectively. ANOVA and Bonferroni's statistical tests were used to compare variables among groups.

RESULTS

We included 82 subjects, 39 women (19 endurance athletes, 20 controls) and 43 men (22 endurance athletes, 21 controls). Mean age was similar between groups (36.6 ± 5.6 years). Athletes had larger bi-atrial volumes, compared to controls (women, LA 27.1 vs. 15.8 ml/m², p < 0.001; RA 22.31 vs. 14.2 ml/m², p = 0.009; men, LA: 25.0 vs. 18.5 ml/m², p = 0.003; RA 30.8 vs. 21.9 ml/m², p < 0.001) and lower strain-rate (women, LASRa -1.60 vs. -2.18 s^-1, p < 0.001; RASRa -1.89 vs. -2.38 s^-1, p = 0.009; men, LASRa -1.21 vs. -1.44 s^-1, p = 1; RASRa -1.44 vs. -1.60 s^-1, p = 1). However, RA indexed size was lower and bi-atrial deformation greater in female athletes, compared to male athletes.

CONCLUSIONS

The atria of both male and female athletes shows specific remodelling, compared to sedentary subjects, with larger size and less deformation at rest, particularly for the RA. Despite a similar extent of remodelling, the pattern in women had greater bi-atrial myocardial deformation and smaller RA size.

Asymptomatic Intradialytic Supraventricular Arrhythmias and Adverse Outcomes in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

Supraventricular arrhythmias are associated with high morbidity and mortality. Nevertheless, this condition has received little attention in patients on hemodialysis. The objective of this study was to analyze the incidence of intradialysis supraventricular arrhythmia and its long-term prognostic value.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We designed an observational and prospective study in a cohort of patients on hemodialysis with a 10-year follow-up period. All patients were recruited for study participation and were not recruited for clinical indications. The study population comprised 77 patients (42 men and 35 women; mean age =58±15 years old) with sinus rhythm monitored using a Holter electrocardiogram over six consecutive hemodialysis sessions at recruitment.

RESULTS

Hypertension was present in 68.8% of patients, and diabetes was present in 29.9% of patients. Supraventricular arrhythmias were recorded in 38 patients (49.3%); all of these were short, asymptomatic, and self-limiting. Age (hazard ratio, 1.04 per year; 95% confidence interval, 1.00 to 1.08) and right atrial enlargement (hazard ratio, 4.29; 95% confidence interval, 1.30 to 14.09) were associated with supraventricular arrhythmia in the multivariate analysis. During a median follow-up of 40 months, 57 patients died, and cardiovascular disease was the main cause of death (52.6%). The variables associated with all-cause mortality in the Cox model were age (hazard ratio, 1.04 per year; 95% confidence interval, 1.00 to 1.08), C-reactive protein (hazard ratio, 1.04 per 1 mg/L; 95% confidence interval, 1.00 to 1.08), and supraventricular arrhythmia (hazard ratio, 3.21; 95% confidence interval, 1.29 to 7.96). Patients with supraventricular arrhythmia also had a higher risk of nonfatal cardiovascular events (hazard ratio, 4.32; 95% confidence interval, 2.11 to 8.83) and symptomatic atrial fibrillation during follow-up (hazard ratio, 17.19; 95% confidence interval, 2.03 to 145.15).

CONCLUSIONS

The incidence of intradialysis supraventricular arrhythmia was high in our hemodialysis study population. Supraventricular arrhythmias were short, asymptomatic, and self-limiting, and although silent, these arrhythmias were independently associated with mortality and cardiovascular events.

Investigation of the atrial conduction time measured by tissue Doppler imaging at the left atrial appendage and the actual electrical conduction time: consideration of left atrial remodeling in atrial fibrillation patients

PURPOSE

The atrial conduction time measured by echocardiography using tissue Doppler imaging (TDI) has been reported as a predictive factor of left atrial (LA) remodeling. We investigated the P wave to LA appendage (LAA) conduction time defined by transthoracic echocardiography using TDI (P-LAA TDI), and directly compared the actual LA electrical conduction time determined by the electrophysiological data. Additionally, we confirmed the clinical utility of the P-LAA TDI by examining the relationship to the electroanatomical LA remodeling data.

METHODS

Sixty-three AF patients (22 paroxysmal AF, 41 persistent AF) underwent ablation and electroanatomical LA mapping. The P-LAA TDI was measured after the ablation and was compared with the electrophysiological data during sinus rhythm, including the actual electrical conduction time.

RESULTS

A strong linear correlation (r = 0.776, p < 0.001, y = 1.28x + 49) was observed between the P-LAA TDI (161 ± 24 ms) and electrophysiological P-LAA time (87 ± 15 ms). The P-LAA TDI was also strongly correlated with the LA volume (173 ± 52 ml, r = 0.632, p < 0.001) and LA conduction velocity index (1.07 ± 0.19 mm/ms, r = -0.735, p < 0.001), but less to the focal anterior-LVA region surface area (2.2 [0.4-5.0] cm², r = 0.380, p = 0.002). Additionally, a stepwise multiple linear regression demonstrated that both the LA volume and LA conduction velocity index were strongly associated with the value of the P-LAA TDI (p < 0.001).

CONCLUSIONS

The P-LAA TDI was useful for estimating the actual electrophysiological conduction time and represented both electrical and anatomical LA remodeling.

Spectral Analysis of Electrocardiograms in Patients with Inducible Atrial Fibrillation after Catheter Ablation Predicts Sinus Rhythm Maintenance

BACKGROUND

We aimed to develop a novel predictive marker for atrial fibrillation (AF) recurrence in patients with inducible AF after catheter ablation, based on power spectral analysis of baseline and postablation electrocardiograms.

METHODS

Twenty-five patients who had undergone their first AF ablation procedure (pulmonary vein isolation and ganglionated plexi ablation) and had inducible AF after ablation were included. A 30-second interval of AF was chosen for each patient before and after ablation, and a periodogram of the atrial activity was computed. A ratio of the power in the dominant frequency to the power in the remainder of the periodogram (DFR) was calculated.

RESULTS

Eight (32%) patients had recurrent AF at 1 year. The clinical and echocardiographic characteristics of patients with and without recurrence were similar (P > 0.05). After ablation, there was organization of atrial activity, evidenced by an increase in the DFR (0.28 ± 0.22 vs 0.53 ± 0.29; P = 0.001). The percent change in DFR before and after ablation (median [interquartile range]) was significantly higher in patients without AF recurrence (120% [30% to 344%] vs 3% [-27% to 66%]; P = 0.01). Receiver operating curve (ROC) analysis demonstrated that a less than 16% increase in DFR postablation was able to predict recurrence of AF (area under ROC curve = 0.82; P = 0.03) with 75% sensitivity and 94% specificity.

CONCLUSION

AF ablation leads to variable organization of atrial activity. Organization of atrial activity after AF ablation is associated with lower 1-year recurrence rates and may be used intraprocedurally after as a novel end point for AF ablation. Larger prospective studies are warranted.

Advanced interatrial block predicts clinical recurrence of atrial fibrillation after catheter ablation

BACKGROUND

It has been demonstrated that advanced interatrial block (IAB) is associated with an increased risk of atrial fibrillation (AF); however, the impact of advanced IAB on recurrence of paroxysmal AF after catheter ablation is not clear.

METHODS

204 consecutive patients with paroxysmal AF who underwent index circumferential pulmonary vein (PV) isolation were prospectively enrolled. In all patients, a resting electrocardiogram in sinus rhythm was evaluated for the presence of advanced IAB, defined as a P-wave duration >120ms and biphasic (±) morphology in the inferior leads. Advanced IAB was detected in 20.1% of patients. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting more than 30s beyond 3 months after the catheter ablation in the absence of any antiarrhythmic treatment.

RESULTS

During the mean follow-up period of 13.9±6.2 months (range, 3-27 months), 62 patients (30.4%) developed recurrence of AF. The recurrence rate was higher in patients with advanced IAB than those without advanced IAB (46.3% vs. 26.4%, p=0.006). Cox regression analysis with adjustment for age, P-wave duration, CHADS2 score, and PV isolation identified advanced IAB (hazard ratio, 2.111; 95% confidence interval, 1.034-4.308; p=0.040) and left atrial diameter (hazard ratio, 1.051; 95% confidence interval, 1.004-1.100; p=0.034) as two independent predictors of recurrence of AF.

CONCLUSIONS

Patients with advanced IAB were at an increased risk of AF recurrence after catheter ablation.

Prognostic Implications of Right and Left Atrial Enlargement after Radiofrequency Catheter Ablation in Patients with Nonvalvular Atrial Fibrillation

Background and Objectives

The prognostic role of the right atrium (RA) compared with that of the left atrium (LA) is unclear in patients with atrial fibrillation (AF). We assessed structural changes in both atria and determined their association with recurrence of AF after radiofrequency catheter ablation (RFCA).

Subjects and Methods

All 111 patients with nonvalvular AF (87 men; mean age, 57±11 years; 68 with paroxysmal AF) who underwent RFCA were enrolled consecutively. Three-dimensional volumes of both atria measured from computed tomography images were compared between subjects with and without recurrence of AF during the follow-up.

Results

Early (<3 months), 6-month, and 1-year recurrence was documented in 26 (24%), 30 (27%), and 36 (32%) patients, respectively. Significantly larger RA and LA volume indices (RAVI and LAVI) were observed in the early, 6-month, and 1-year recurrence groups (p<0.05 for all). In multivariate analysis, Early recurrence was independently associated with RAVI (for each 10 mL/m2 increase; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.03-1.66, p= 0.03), but not with LAVI. However, both RAVI and LAVI failed to predict 6-month outcomes independently. LAVI was the only independent predictor of 1-year recurrence (for each 10 mL/m2 increase; OR, 1.36; 95% CI, 1.08-1.71, p=0.009).

Conclusion

RA enlargement was more closely related to early recurrence of AF after RFCA than LA size. However, LA size, rather than RA volume, was a determinant of long-term AF prognosis after RFCA. These findings suggest a temporal pattern in the prognostic implication of enlargement in each atrium that switches over time after RFCA for AF.

A low fibrillatory wave amplitude predicts sinus node dysfunction after catheter ablation in patients with persistent atrial fibrillation

BACKGROUND

Concealed sinus node dysfunction (SND) may become manifest after restoration of sinus rhythm by ablation in patients with persistent atrial fibrillation (AF). The purpose of this study was to investigate the predictors of SND after catheter ablation of persistent AF.

METHODS

Two hundred two consecutive patients who underwent ablation for persistent AF were enrolled. Ipsilateral pulmonary vein isolation followed by, if necessary, electrical cardioversion were performed in all patients. SND was defined when temporary and/or permanent pacemakers were needed due to sinus bradycardia after ablation.

RESULTS

SND developed in 12 (5.9 %) patients. There was no difference between the patients with and without SND in terms of the age (with SND, 67 ± 9 and without, 66 ± 10 years old, P = 0.599) and sex (male; 58 vs. 79 %, P = 0.186). However, the patients with SND had a lower amplitude of the fibrillatory waves (0.115 ± 0.086 vs. 0.176 ± 0.077 mV, P = 0.009) and larger left atrial volume index (LAVI; 66 ± 31 vs. 34 ± 13, P = 0.007) than those without. A receiver operating characteristic curve identified a fibrillatory wave amplitude of 0.145 mV (AUC = 0.742; sensitivity = 65 %; specificity = 83 %) and LAVI of 47.5 ml/m(2) (AUC = 0.837; sensitivity = 82 %; specificity = 87 %) as the optimal cutoff values for predicting SND. A multivariate analysis revealed that the amplitude of the fibrillatory waves (odds ratio = 0.84 for 0.010 mV increase, 95 % CI = 0.71-0.98, P = 0.031) and LAVI (odds ratio = 1.08 for 1.0 cm(3)/m(2) increase, 95 % CI = 1.04-1.12, P < 0.001) were independent risk factors for SND.

CONCLUSIONS

A low amplitude of the fibrillatory waves and a large LAVI were predictors of SND after restoration of sinus rhythm by ablation in patients with persistent AF.

Measurements of the left atrium and pulmonary veins for analysis of reverse structural remodeling following cardiac ablation therapy

RATIONALE AND OBJECTIVES

Geometric analysis of the left atrium and pulmonary veins is important for assessing reverse structural remodeling following cardiac ablation therapy. Most volumetric analysis techniques, however, require laborious manual tracing of image cross-sections. Pulmonary vein diameters are typically measured at the junction between the left atrium and pulmonary veins, called the pulmonary vein ostia, with manually drawn lines on volume renderings or in image slices. In this work, we describe a technique for making semi-automatic measurements of left atrial volume and pulmonary vein diameters from high resolution CT scans and demonstrate its use for analyzing reverse structural remodeling following cardiac ablation therapy.

METHODS

The left atrium and pulmonary veins are segmented from high-resolution computed tomography (CT) volumes using a 3D volumetric approach and cut planes are interactively positioned to separate the pulmonary veins from the body of the left atrium. Left atrial volume and pulmonary vein ostial diameters are then automatically computed from the segmented structures. Validation experiments are conducted to evaluate accuracy and repeatability of the measurements. Accuracy is assessed by comparing left atrial volumes computed with the proposed methodology to a manual slice-by-slice tracing approach. Repeatability is assessed by making repeated volume and diameter measurements on duplicated and randomized datasets. The proposed techniques were then utilized in a study of 21 patients from the Catheter Ablation versus Antiarrhythmic Drug Therapy for Atrial Fibrillation Trial (CABANA) pilot study who were scanned both before and approximately 3 months following ablation therapy.

RESULTS

In the high resolution CT scans the left atrial volume measurements show high accuracy with a mean absolute difference of 2.3±1.9 cm(3) between volumes computed with the proposed methodology and a manual slice-by-slice tracing approach. In the intra-rater repeatability study, the mean absolute difference in left atrial volume was 4.7±2.5 cm(3) and 4.4±3.4 cm(3) for the two raters. Intra-rater repeatability for pulmonary vein diameters ranged from 0.9 to 2.3 mm. The inter-rater repeatability for left atrial volume was 5.8±5.1 cm(3) and inter-rater repeatability for pulmonary vein diameter measurements ranged from 1.4 to 2.3 mm. In the patient study, significant (p<.05) decreases in left atrial volume and all four pulmonary vein diameters were observed. The absolute change in LA volume was 20.0 cm(3), 95%CI [12.6, 27.5]. The left inferior pulmonary vein diameter decreased 2.1 mm, 95%CI [0.4, 3.7], the left superior pulmonary vein diameter decreased 3.2 mm, 95%CI [1.0, 5.4], the right inferior pulmonary vein diameter decreased 1.5 mm, 95%CI [0.3, 2.7], and the right superior pulmonary vein diameter decreased 2.8 mm, 95%CI [1.4, 4.3].

CONCLUSIONS

Using the proposed techniques, we demonstrate high accuracy of left atrial volume measurements as well as high repeatability for left atrial volume and pulmonary vein diameter measurements. Following cardiac ablation therapy, a significant decrease was observed for left atrial volume as well as all four pulmonary vein diameters.

Left atrial appendage flow velocity and time from P-wave onset to tissue Doppler-derived A' predict atrial fibrillation recurrence after radiofrequency catheter ablation

BACKGROUND

Atrial fibrillation (AF) is associated with atrial remodeling. We investigate the abilities of preprocedural echocardiographic parameters reflecting atrial remodeling to predict AF recurrence after radiofrequency catheter ablation (RFCA) for paroxysmal AF (PAF).

METHODS

Preprocedural echocardiographic parameters were measured during sinus rhythm in 105 patients with PAF undergoing RFCA. Electrical remodeling was assessed by the time from the onset of the P-wave to the peak A'-wave on the tissue Doppler imaging (PA-TDI), functional remodeling was assessed by the left atrial appendage flow velocity (LAAFV), and structural remodeling was assessed by the left atrial volume index (LAVI). PA-TDI, LAAFV, and LAVI values were divided into tertiles, and their abilities to predict AF recurrence were assessed using Cox regression analysis.

RESULTS

AF recurrence occurred in 39/105 (37.1%) patients. After adjustment for confounders, the rate of AF recurrence was significantly higher in the highest tertile of PA-TDI compared with the lowest tertile (≥151.3 msec vs. <131.0 msec; hazard ratio [HR]: 2.477, 95% confidence interval [CI]: 1.031-5.950; P = 0.042), and in the lowest tertile of LAAFV compared with the highest tertile (<48.5 cm/sec vs. ≥64.9 cm/sec; HR: 2.680, 95% CI: 1.136-6.318; P = 0.024). The risk of AF recurrence was also higher in the highest tertile of LAVI (≥34.2 mL/m(2) ) compared with the lowest tertile, but this difference was not significant (HR: 2.146, 95% CI: 0.834-5.523; P = 0.113).

CONCLUSIONS

LAAFV (reflecting functional remodeling) and PA-TDI (reflecting electrical remodeling) are independent predictors of AF recurrence after RFCA for PAF.

Right atrial volume is superior to left atrial volume for prediction of atrial fibrillation recurrence after direct current cardioversion

BACKGROUND

The value of right atrial volume as a predictor for recurrence of atrial fibrillation (AF) after direct current cardioversion (DCCV) is unknown.

METHODS

We sought to compare the performance of right atrial volume indexed to body surface area (RAVI), left atrial diameter, left atrial volume indexed to body surface area (LAVI), and biatrial volume index (BAVI) for the prediction of AF recurrence at 6 months after DCCV. This study included the first 95 consecutive patients from the AF Clinic at a large tertiary care hospital who underwent DCCV and who had an echocardiogram available within 6 months before DCCV. Maximal LAVI, RAVI, and BAVI were determined from the echocardiogram before DCCV. Electrocardiographic and clinical data were acquired at baseline, before cardioversion, and at each clinic visit.

RESULTS

Of the 95 patients (64 male; mean age, 63 ± 12 years), history of systemic hypertension, diabetes mellitus, heart failure, and transient ischemic attack/stroke was present in 60 (63%), 14 (15%), 27 (28%), and 5 (5%) patients, respectively. Mean duration from AF diagnosis to DCCV was 3.5 ± 5.0 years. At 6 months after DCCV, 53 (56%) had reverted to AF. RAVI had superior predictive ability (area under the receiver operator characteristic curve: RAVI, 0.77; left atrial diameter, 0.54; LAVI, 0.64; and BAVI, 0.70). RAVI ≥ 42 mL/m(2) provided the best accuracy for prediction of recurrence (76% accuracy, 71% sensitivity, 83% specificity, 90% positive predictive value, and 56% negative predictive value). Best accuracy for LAVI was ≥ 48 mL/m(2) (70% accuracy, 53% sensitivity, 79% specificity, 85% positive predictive value; 43% negative predictive value).

CONCLUSIONS

RAVI is superior to LAVI for the prediction of AF recurrence at 6 months after DCCV.

Prolonged PR interval and risk of recurrence of atrial fibrillation after catheter ablation

It has been demonstrated that a prolonged PR interval is associated with an increased risk of AF. However, the impact of a prolonged PR interval on recurrence of paroxysmal atrial fibrillation (AF) after catheter ablation is not clear. A total of 112 patients with a prolonged PR interval (PR > 200 ms) (PPR group) and 112 age- and gender-matched control patients (on a 1:1 basis) with a normal PR interval (NPR group) were included in this study. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting more than 30 seconds beyond 3 months after catheter ablation in the absence of any antiarrhythmic treatment. During a mean follow-up period of 10.9 ± 5.5 months (range, 3-18 months), 61 patients (27.2%) developed recurrence of AF. The recurrence rate was higher in the PPR group than in the NPR group (33.9% versus 20.5%, respectively; P = 0.018). Cox regression analysis with adjustment for age, body mass index, valvular heart disease, left atrial diameter, and pulmonary vein isolation identified only a prolonged PR interval as an independent predictor of recurrence of AF (hazard ratio, 1.81; 95% confidence interval, 1.07-3.05; P = 0.027). Patients with a prolonged PR interval were at an increased risk of AF recurrence after catheter ablation.

Reference right atrial dimensions and volume estimation by steady state free precession cardiovascular magnetic resonance

BACKGROUND

Cardiovascular magnetic resonance (CMR) steady state free precession (SSFP) cine sequences with high temporal resolution and improved post-processing can accurately measure RA dimensions. We used this technique to define ranges for normal RA volumes and dimensions normalized, when necessary, to the influence of gender, body surface area (BSA) and age, and also to define the best 2D images-derived predictors of RA enlargement.

METHODS

For definition of normal ranges of RA volume we studied 120 healthy subjects (60 men, 60 women; 20 subjects per age decile from 20 to 80 years), after careful exclusion of cardiovascular abnormality. We also studied 120 patients (60 men, 60 women; age range 20 to 80 years) with a clinical indication for CMR in order to define the best 1D and 2D predictors of RA enlargement. Data were generated from SSFP cine CMR, with 3-dimensional modeling, including tracking of the atrioventricular ring motion and time-volume curves analysis.

RESULTS

In the group of healthy individuals, age influenced RA 2-chamber area and transverse diameter. Gender influenced most absolute RA dimensions and volume. Interestingly, right atrial volumes did not change with age and gender when indexed to body surface area. New CMR normal ranges for RA dimensions were modeled and displayed for clinical use with normalization for BSA and gender and display of parameter variation with age. Finally, the best 2D images-derived independent predictors of RA enlargement were indexed area and indexed longitudinal diameter in the 2-chamber view.

CONCLUSION

Reference RA dimensions and predictors of RA enlargement are provided using state-of-the-art CMR techniques.

Atrial Remodelling : Role in Atrial Fibrillation Ablation

There have been considerable advances in understanding the relationship of atrial fibrillation (AF) and atrial remodelling suggesting that remodelling states have a significant impact on treatment results. Therefore, we reviewed the literature about the role of atrial remodelling in AF treatment, focussing on AF ablation. Atrial fibrillatory activity, dominant frequencies (DF), complex fractionated atrial electrograms (CFAE) as well as function, volume, and fibrosis of the - especially left - atrium are most important characteristics for electrical, contractile, and structural remodelling predicting success of AF treatment. In particular, the results of AF ablation, either using catheter-based or surgical techniques, predominantly depend on the degree of structural remodelling, namely dilatation and fibrosis of the left atrium. The available data suggest that recognizing parameters of remodelling as predictors for AF treatment facilitates differentiation between patients who may or may not benefit from the procedure and individualization of AF treatment by adapting lesion sets, by ablating additional targets, by reducing left atrial size, or by applying extended pharmacological treatment.