Left atrial volumetry from routine diagnostic work up prior to pulmonary vein ablation is a good predictor of freedom from atrial fibrillation

Potential Role of Left Atrial Strain to Predict Atrial Fibrillation Recurrence after Catheter Ablation Therapy: A Clinical and Systematic Review

Pulmonary vein isolation (PVI) with catheter ablation (CA) represents an effective therapy for atrial fibrillation (AF). Unfortunately, it is still not exempt from severe complications. The balance of risks and benefits should be assessed, and a patient-tailored approach is desirable. So far, several clinical and cardiac imaging parameters have been evaluated to investigate pre- and post-procedural features that could help clinicians in the selection of patients at high risk of a poor outcome after CA. This clinical and systematic review analyses the potential role of new LA parameters, such as LA reservoir strain, to predict AF recurrence after CA therapy. Notably, LA reservoir strain gains substantial clinical importance in patients with paroxysmal AF and when a low CHADS2-VASc score is retrieved. LA reservoir strain provides data concerning the risk of AF recurrence after PVI and, thus, in the management of long-term medical therapy in this patient's group.

Using machine learning to enhance prediction of atrial fibrillation recurrence after catheter ablation

Background

Traditional risk scores for recurrent atrial fibrillation (AF) following catheter ablation utilize readily available clinical and echocardiographic variables and yet have limited discriminatory capacity. Use of data from cardiac imaging and deep learning may help improve accuracy and prediction of recurrent AF after ablation.

Methods

We evaluated patients with symptomatic, drug-refractory AF undergoing catheter ablation. All patients underwent pre-ablation cardiac computed tomography (cCT). LAVi was computed using a deep-learning algorithm. In a two-step analysis, random survival forest (RSF) was used to generate prognostic models with variables of highest importance, followed by Cox proportional hazard regression analysis of the selected variables. Events of interest included early and late recurrence.

Results

Among 653 patients undergoing AF ablation, the most important factors associated with late recurrence by RSF analysis at 24 (+/-18) months follow-up included LAVi and early recurrence. In total, 5 covariates were identified as independent predictors of late recurrence: LAVi (HR per mL/m2 1.01 [1.01-1.02]; p < .001), early recurrence (HR 2.42 [1.90-3.09]; p < .001), statin use (HR 1.38 [1.09-1.75]; p = .007), beta-blocker use (HR 1.29 [1.01-1.65]; p = .043), and adjunctive cavotricuspid isthmus ablation [HR 0.74 (0.57-0.96); p = .02]. Survival analysis demonstrated that patients with both LAVi >66.7 mL/m2 and early recurrence had the highest risk of late recurrence risk compared with those with LAVi <66.7 mL/m2 and no early recurrence (HR 4.52 [3.36-6.08], p < .001).

Conclusions

Machine learning-derived, full volumetric LAVi from cCT is the most important pre-procedural risk factor for late AF recurrence following catheter ablation. The combination of increased LAVi and early recurrence confers more than a four-fold increased risk of late recurrence.

Association of Atrial Fibrillation Recurrence with Right Coronary Atherosclerosis and Increased Left Arterial Epicardial Fat Following Catheter Ablation-Results of a Multimodality Study

BACKGROUND

Identification of predictors for atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) can lead to better long-term results. Our aim was to investigate the association between novel CT imaging markers reflecting the severity of coronary atherosclerosis and the risk of recurrence following PVI.

METHODS

This study included 80 patients with paroxysmal/persistent AF who underwent PVI. The patients were divided into two groups: Group 1-23 patients with recurrence and Group 2-57 patients without recurrence.

RESULTS

Patients with recurrence presented with a more enlarged left atrial diameter and reduced left ventricle EF, as assessed by echocardiography. Elevated calcium scores and right coronary artery (RCA) stenosis were correlated with a higher risk of AF recurrence (25.38 ± 4.1% vs. 9.76 ± 2.32%, p = 0.001). Patients with AF recurrence presented a higher left atrial volume index (LAVI) (61.38 ± 11.12 mm3/m2 vs. 46.34 ± 12.27 mm3/m2, p < 0.0001). The bi-atrial volume index (BAVI) was similarly higher in the AF recurrence group (98.23 ± 14.44 mm3/m2 vs. 76.48 ± 17.61 mm3/m2, p < 0.0001). Increased EAT volumes located around the LA (EAT-LA) were correlated with recurrence (25.55 ± 6.37 vs. 15.54 ± 8.44, p < 0.0001).

CONCLUSIONS

RCA stenosis, together with atrial volumes and EAT-AS evaluated by CCTA, is associated with the risk of AF recurrence following PVI.

Sacubitril/valsartan attenuates atrial structural remodelling in atrial fibrillation patients

Aims

Radiofrequency catheter ablation (RFCA) is now an established therapeutic option for patients with atrial fibrillation (AF), but the long‐term recurrence rate of AF is still high. Sacubitril/valsartan (Sac/Val) is superior to valsartan in attenuating ventricular remodelling and improving clinical outcomes in heart failure patients, but whether this additional benefit exists in reversing atrial remodelling and reducing AF recurrence of RFCA‐treated AF patients remains uncovered.

Methods and results

Patients that had undergone RFCA were enrolled and randomly assigned 1:1 to valsartan (160 mg/day) or Sac/Val (200 mg/day) treatment group, in addition to other standard treatment of AF. Patients were followed up for 24 weeks. Echocardiography and ambulatory Holter monitoring for 24 h was performed at 24 weeks after RFCA. The primary end point was the change of atrial diameter from baseline to 24 weeks after RFCA. Second end points included the recurrence rate of AF, all‐cause hospitalization and all‐cause death. A total of 64 AF patients were enrolled, 32 of which received Sac/Val and 32 received valsartan treatment. There was no difference in the age (64.8 ± 9.8 vs. 63.7 ± 9.0, P = 0.634), gender (per cent of male: 59.4% vs. 50.0%, P = 0.616), heart rate (84.7 ± 4.1 b.p.m. vs. 80.9 ± 2.6 b.p.m., P = 0.428), systolic (127.5 ± 15.4 mmHg vs. 130.0 ± 17.8 mmHg, P = 0.549) or diastolic (81.7 ± 9.8 mmHg vs. 79.9 ± 12.6, P = 0.537) blood pressure upon admission between valsartan and Sac/Val treatment groups. The percentage of persistent AF was also comparable (43.8% vs. 53.1%, P = 0.617) in both treatment groups. Patients receiving Sac/Val treatment displayed significant decrease in the left atrial diameter (4.3 ± 0.5 cm to 3.8 ± 0.5 cm, P < 0.001), volume index (48.0 ± 6.4 mL/m² to 41.7 ± 7.0 mL/m², P < 0.001), and right atrial diameter (4.4 ± 0.8 cm to 3.9 ± 0.7 cm, P = 0.017) from baseline to 24 weeks after RFCA. This effect was not observed in valsartan treatment group. There was a numerical decrease in AF recurrence rate in the Sac/Val group compared with valsartan group (9.4% vs. 15.6%), although this difference did not reach a statistical significance (P = 0.708). No difference in all‐cause hospitalization rate (6.3% in each group) or all‐cause death rate (0% in each group) was observed.

Conclusions

Our data indicate that Sac/Val is superior to valsartan in attenuating atrial structural remodelling in catheter ablation‐treated AF patients.

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail.

The Association of Cardio-Ankle Vascular Index (CAVI) with Biatrial Remodeling in Atrial Fibrillation

AIM

Arterial stiffness results in elevated left ventricular filling pressure and can promote atrial remodeling due to chronic pressure overload. However, the impact of arterial stiffness on the process of atrial remodeling in association with atrial fibrillation (AF) has not been fully evaluated.

METHODS

We enrolled 237 consecutive patients diagnosed with AF who had undergone ablation; data from 213 patients were analyzed. Cardio-ankle vascular index (CAVI) was used as a marker of arterial stiffness. The left atrial (LA) and right atrial (RA) volumes were determined by computed tomography imaging; atrial conduction and voltage amplitude were evaluated using a three-dimensional electromapping system used to guide the ablation procedure.

RESULT

In univariate analysis, CAVI significantly correlated with atrial structural and electrical remodeling (LA volume index, r=0.297, P=0.001; RA volume index, r=0.252, P=0.004; LA conduction velocity, r=0.254, P= 0.003; LA mean voltage, r=-0.343, P=0.001, RA mean voltage; r=-0.245, P=0.015). Multivariate regression analysis revealed that CAVI and plasma levels of N-terminal B-type natriuretic peptide were independent determinants of LA and RA remodeling, respectively. On the other hand, age and LA conduction velocity were independent variables with respect to CAVI. Age-adjusted CAVI was highest in long-standing persistent AF when compared with measures of persistent or paroxysmal AF.

CONCLUSION

CAVI was closely associated with biatrial remodeling in patients diagnosed with AF. These results suggest that arterial stiffness may play a significant role with respect to disease progression.

Impact of right atrial structural remodeling on recurrence after ablation for atrial fibrillation

BACKGROUND

Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is associated with left atrial (LA) remodeling; however, its association with right atrial (RA) remodeling remains unclear.

OBJECTIVE

This study aimed to identify whether RA structural remodeling could predict recurrence of AF after PVI.

METHODS

This study prospectively analyzed 245 patients with AF who had undergone PVI. RA and LA volumes were determined by contrast-enhanced computed tomography. Atrial structural remodeling was defined as an atrial volume of ≥110 mL according to previous reports and receiver operating characteristic curve analysis.

RESULTS

After excluding 32 patients, 213 patients were analyzed. During a follow-up period of 12 months, 41 patients (19%) demonstrated atrial arrhythmia recurrence after PVI. With the Cox proportional-hazards model, RA structural remodeling was the only predictor of arrhythmia recurrence (hazard ratio, 1.012; 95% confidence interval 1.003-1.021; P = .009). Kaplan-Meier analysis showed that arrhythmia recurrence was more frequent in the RA structural remodeling group compared with the group without RA remodeling (log-rank, P < .001), and the arrhythmia-free survival rates in these groups at 12 months were 68.0% and 91.4%, respectively. Additionally, there was a significant difference in recurrence-free survival after RA structural remodeling in each type of AF (log-rank, P < .001).

CONCLUSIONS

RA structural remodeling is a useful predictor of clinical outcome after PVI regardless of the type of AF. Our results suggest that patients without RA structural remodeling may be good candidates for successful ablation with PVI.

Atrial fibrillation and cardiac fibrosis

The understanding of atrial fibrillation (AF) evolved from a sole rhythm disturbance towards the complex concept of a cardiomyopathy based on arrhythmia substrates. There is evidence that atrial fibrosis can be visualized using late gadolinium enhancement cardiac magnetic resonance imaging and that it is a powerful predictor for the outcome of AF interventions. However, a strategy of an individual and fibrosis guided management of AF looks promising but results from prospective multicentre trials are pending. This review gives an overview about the relationship between cardiac fibrosis and AF focusing on translational aspects, clinical observations, and fibrosis imaging to emphasize the concept of personalized paths in AF management taking into account the individual amount and distribution of fibrosis.

Cardiac Computed Tomography-Derived Left Atrial Volume Index as a Predictor of Long-Term Success of Cryo-Ablation in Patients With Atrial Fibrillation

Patients with symptomatic, drug-refractory atrial fibrillation (AF) are frequently treated with catheter ablation. Cryo-ablation has been established as an alternative to radiofrequency ablation but long-term outcome data are still limited. This study aimed at elucidating the influence of the left atrial volume index (LAVI), derived from cardiac computed tomography (cCT) data, on the long-term outcome of ablation-naïve AF patients, after their first cryo-ablation. 415 patients (n = 290 [69.90%] male, 60.00 [IQR: 53.00 to 68.00] years old) who underwent a cCT and subsequent cryo-ablation index procedure were included in this single centre retrospective data analysis. A composite end point was defined (AF on electrocardiogram and/or electric cardioversion and/or re-do). Patients were closely followed for a year and then contacted for long-term follow-up after a median of 53.00 months (IQR: 34.50 to 73.00). Statistical analyses of the outcome and predictors of AF recurrence were conducted. In 224 patients (53.98%) no evidence of AF recurrence could be found. LAVI differed significantly between the positive and adverse (AF recurrence) outcome group (49.96 vs 56.07 ml/m², p < 0.001). Cox regression analyses revealed cCT LAVI (HR: 1.022, 95% CI: 1.013 to 1.031, p < 0.001), BMI (HR: 1.044, 95% CI: 1.005 to 1.084, p < 0.05) and the type of AF (HR: 1.838 for nonparoxysmal AF, 95% CI: 1.214 to 2.781, p < 0.01) to be effective predictors of AF recurrence. A prognostic cCT LAVI cut-off value of 51.99 ml/m² was calculated and must be validated in future prospective studies. In conclusion, LAVI is an accurate, yet underutilized predictor of AF recurrence after pulmonary vein isolation with cryo-energy and scores for calculating AF recurrence or progression risks might underemphasize the importance of CT-derived LAVI as a predictive factor.

Higher Pulmonary Arterial Pressure Was Related to Non-Pulmonary Vein Atrial Tachyarrhythmia

Recurrence of atrial tachyarrhythmias (ATA) following catheter ablation for atrial fibrillation (AF) is often associated with the recovery of conduction into previously isolated pulmonary veins (PVs). Little evidence concerning repeat PV isolation (PVI) and non-PV ATA ablation has been reported. This study aimed to explore the clinical outcome of recurrent ATA ablation after PVI and the difference between patients with and without non-PV ATA.A total of 49 patients without structural heart diseases who received catheter ablation for recurrent AF between January 2014 and December 2018 were recruited (prior ablation with PVI only 71.4% and PVI with cavotricuspid isthmus line ablation 28.6%). Patients were divided into two groups according to the presence or absence of non-PV ATA.Most patients (53.1%) experienced very late recurrence with a median duration of 15 months. A total of 15 patients had non-PV ATA and received non-PV ATA ablation whereas 34 patients received only repeat PVI for reconnected PVs. A higher pulmonary arterial systolic pressure (PASP) was associated with non-PV ATA (odds ratio: 1.161; 95% confidence interval: 1.021-1.321; P = 0.023). During 4.7 ± 1 months, 4/15 (26.7%) and 1/34 (2.9%) patients with and without non-PV ATA, respectively, had ATA recurrence (P = 0.011). The cumulative incidence of ATA recurrence after repeat ablation was significantly lower in patients without non-PV ATA (P = 0.013).In our study, a high PASP was associated with non-PV ATA in patients with recurrent AF. Repeat PVI had a high rate of maintenance of sinus rhythm in patients without non-PV ATA.

Catheter Ablation for Atrial Fibrillation in Adults With Congenital Heart Disease: Lessons Learned From More Than 10 Years Following a Sequential Ablation Approach

OBJECTIVES

This study aimed to evaluate the impact, safety, and success of atrial fibrillation (AF) ablation in adults with congenital heart disease (ACHD) transferring ablation strategies established in normal hearts.

BACKGROUND

AF is an emerging arrhythmia in ACHD.

METHODS

Fifty-seven consecutive ACHD (median age 51.1 ± 14.8 years) with drug-refractory AF were analyzed who underwent catheter ablation between 2004 and 2017. CHD was classified according to its complexity into mild (61.4%), moderate (17.5%), and severe (21.1%) lesions. AF ablation was performed in 104 procedures following a sequential ablation approach.

RESULTS

Of the 57 patients, 30 underwent corrective surgery, 6 underwent palliative surgery, 5 had catheter interventions, and 16 were natural survivors. Follow-up was available for all patients (median 41 ± 36 months). The median duration of cyanosis was 9.2 ± 19.7 years, and the time of volume or pressure overload prior to corrective surgery or intervention was 26.1 ± 21.2 years and 18.1 ± 15.8 years, respectively. The Kaplan-Meier estimate for arrhythmia-free survival following the index ablation procedure was 63% for 1 year and 22% for 5 years. Performing subsequent ablation procedures (2.0 ± 0.5), the Kaplan-Meier estimate significantly improved, with 99% for 1 year and 83% for 5 years (p < 0.01). Five patients died during follow-up due to their underlying CHD condition or underwent transplantation.

CONCLUSIONS

AF ablation strategies established in normal hearts can be transferred to ACHD. The treatment is safe and effective with acceptable long-term results. Varying anatomical pre-conditions and the heterogeneous population itself are challenging and contribute toward a higher reablation rate. Therefore, AF ablation in ACHD should be reserved for dedicated and highly specialized teams.

Clinical and anatomic predictors of need for repeat atrial fibrillation ablation

AIM

To identify predictors of need for repeat procedures after initial atrial fibrillation (AF) ablation.

METHODS

We identified a cohort undergoing first time AF ablation at our institution from January 2004 to February 2014 who had cardiac magnetic resonance (CMR) imaging performed prior to ablation. Clinical variables and anatomic characteristics (determined from CMR) were assessed as predictors of need for repeat ablation. The decision regarding need for and timing of repeat ablation was at the discretion of the treating physician.

RESULTS

From a cohort of 331 patients, 142 patients (43%) underwent repeat ablation at a mean of 13.6 ± 18.4 mo after the index procedure. Both male gender (81% vs 71%, P = 0.05) and lower ejection fraction (57.4% ± 10.3% vs 59.8% ± 9.4%, P = 0.04) were associated with need for repeat ablation. On pre-ablation CMR, mean pulmonary vein (PV) diameters were significantly larger in all four PVs among patients requiring repeat procedures. In multivariate analysis, increased right superior PV diameter significantly predicted need for repeat ablation (odds ratio 1.08 per millimeter increase in diameter, 95%CI: 1.00-1.16, P = 0.05). There were also trends toward significance for increased left and right inferior PV sizes among those requiring repeat procedures.

CONCLUSION

Increased PV size predicts the need for repeat AF ablation, with each millimeter increase in PV diameter associated with an approximately 5%-10% increased risk of requiring repeat procedures.

Multimodality Cardiac Imaging for the Assessment of Left Atrial Function and the Association With Atrial Arrhythmias

Several cardiac imaging modalities are able to visualize the left atrium (LA) and, therefore, allow for quantification of both structural and functional properties of this cardiac chamber. In echocardiography, only the maximal LA volume is included in the assessment of diastolic function at the current moment. Numerous studies, however, have shown that functional measures may be superior to the maximal LA volume in several aspects and to possess clinical value even in the absence of structural abnormalities. Such functional measures could prove particularly useful in the setting of predicting atrial fibrillation, which will be a point of focus in this review. Pivotal cardiac magnetic resonance imaging studies have revealed high correlation between LA fibrosis and risk of atrial fibrillation recurrence after catheter ablation, and subsequent multimodality imaging studies have uncovered an inverse relationship between LA reservoir function and degree of LA fibrosis. This has sparked an increased interest into the application of advanced imaging modalities, including both speckle tracking echocardiography and tissue tracking by cardiac magnetic resonance imaging. Even though increasing evidence has supported the use of functional measures and proven its superiority to the maximal LA volume, they have still not been adopted in clinical guidelines. The reason for this discrepancy may rely on the fact that there is little to no agreement on how to technically perform deformation analysis of the LA. Such technical considerations, limitations, and alternate imaging prospects will be addressed in this review.

Clinical, electrophysiological and imaging predictors of atrial fibrillation ablation outcome

INTRODUCTION

Significant technological advances for catheter ablation of atrial fibrillation (AF) have occurred over the last decade, with a consequent increase in numbers of patients referred for AF ablation worldwide. Despite this, long-term success rates, particularly in those with persistent AF, remain modest. The patient population presenting for AF ablation are heterogeneous with regard to age, type of AF and presence of associated cardiovascular disease. Improved understanding of factors predicting response to AF ablation may therefore help to improve patient selection for ablation procedures. Areas covered: This review outlines the clinical, electrophysiological and imaging predictors of response to radiofrequency ablation for AF in contemporary practice. Recently developed scoring systems incorporating these parameters are examined, as are factors identified thus far which may predict the outcome of cryoballoon ablation. Expert commentary: Traditional clinical factors associated with ablation outcomes serve as surrogates rather than direct measures of the underlying arrhythmia substrate. An improved understanding of this substrate could improve the prediction of response to radiofrequency ablation. Continued development of methods for characterising the arrhythmia substrate, including atrial cardiac magnetic resonance imaging and invasive voltage mapping, may inform patient risk assessment and help guide selection for catheter ablation on an increasingly individualistic basis.

Strain echocardiographic assessment of left atrial function predicts recurrence of atrial fibrillation

AIMS

We evaluated if a dispersed left atrial (LA) contraction pattern was related to atrial fibrillation (AF) in patients with normal left ventricular (LV) function, and normal or mildly enlarged left atrium.

METHODS AND RESULTS

We included 61 patients with paroxysmal AF (PAF). Of these, 30 had not while 31 had recurrence of AF after radiofrequency ablation (RFA). Twenty healthy individuals were included for comparison. Echocardiography was performed in patients in sinus rhythm the day before RFA. LA volume was calculated. Peak negative longitudinal strain was assessed in 18 LA segments during atrial systole. Contraction duration in 18 LA segments was measured as the time from peak of the P wave on electrocardiogram to maximum myocardial shortening in each segment. The standard deviation of contraction durations was defined as LA mechanical dispersion (LA MD). LA size was rather preserved in patients with PAF (LA volume 25 ± 10 mL/m(2)). LA MD was more pronounced in patients with recurrence of AF after RFA compared with those without recurrence and controls (38 ± 14 ms vs. 30 ± 12 ms vs. 16 ± 8 ms, both P < 0.001). LA MD was a predictor of PAF [OR 7.84 (95%CI 2.15-28.7), P < 0.01, per 10 ms increase] adjusted for age, LA volume, e', and LA function. LA function by strain was reduced in both patients with and without recurrent AF after RFA compared with controls (-14 ± 4% vs. -16 ± 3% vs. -19 ± 2%, both P < 0.05).

CONCLUSION

LA MD was pronounced, and LA deformation was reduced in patients with PAF with apparently normal LV structure and function, and normal or mildly enlarged LA. LA MD may be useful as a predictor of AF recurrence after RFA.

The Convergent Procedure - A Standardised and Anatomic Approach Addresses the Clinical and Economic Unmet Needs of the Persistent Atrial Fibrillation Population

A standardised treatment management approach is needed to address the escalating worldwide prevalence of atrial fibrillation (AF). The persistent and longstanding persistent AF patient population particularly needs this standardised treatment option to manage their AF. These patients have underlying structural heart disease that result in increased hospitalizations, long-term medical management that increases the cost burden of the healthcare system. Approximately 100 patients have undergone the Convergent Procedure at our center since its introduction 2 years ago, as a treatment option for AF patients. The epicardial and endocardial ablation procedures performed sequentially in a single setting has shown a single procedure success rate of 80%, similar to published success rates at other centers. The epicardial posterior wall isolation silences a majority of known substrates and the endocardial procedure completes the pulmonary vein isolation, creates the cavotricuspid line and provides diagnostic confirmation. The Convergent Procedure should be considered as a first line treatment option for the persistent and longstanding persistent AF patient population who have very limited or no treatment options for the long-term successful management of their AF.

Right Atrial Volume is Increased in Corrected Tetralogy of Fallot and Correlates with the Incidence of Supraventricular Arrhythmia: A CMR Study

The aim of this study was to evaluate right atrial (RA) volume in corrected Tetralogy of Fallot (cTOF) and assess its correlation with the occurrence of supraventricular (SV) arrhythmia. Cardiac magnetic resonance imaging (CMR) and 24-h Holter were performed in n = 67 consecutive cTOF patients (age 30 ± 11.3 years). The CMR protocol included standard HASTE, SSFP cine, and blood flow measurements. Correlations between arrhythmia in ECG, heart volume, and functional parameters were investigated by negative binominal regression. Patients' characteristics (mean ± SD) included mean RA volume of 49 ± 19 ml/m(2) (HASTE sequence), mean right ventricular (RV) end-diastolic volume of 98 ± 27 ml/m(2), mean pulmonary valve regurgitation fraction (PR) of 21 ± 19 %, BMI of 25 kg/m(2), and heart rate of 75/min. Twenty-eight out of 67 patients experienced SV arrhythmia including SV couplets or bigeminus or longer non-sustained SV tachycardia (SVT) episodes. RA volume index was identified as an independent risk factor for different degrees of SV arrhythmia (SV couplets/bigeminus p < 0.001, SVT p < 0.001). Further risk factors for SV arrhythmia were male gender (p = 0.023) and decreased left ventricular (LV) ejection fraction (EF) (LV EF p < 0.001). RA volume is increased in adult patients with cTOF with larger RA volumes relating to higher incidence of SV arrhythmia. SV arrhythmia also appeared more often in male patients and those with decreased LV EF. Risk stratification according to these parameters could help to optimize early prevention and adjusted individual therapy to improve patient outcome and quality of life.

The Effect of Catheter Ablation on Left Atrial Size and Function for Patients with Atrial Fibrillation: An Updated Meta-Analysis

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) is now an important therapeutic modality for patients with AF. However, data regarding changes in left atrial (LA) function after CA have indicated conflicting results depending on the AF types, follow-up period, and the analytical imaging tools. The objective of this review was to analyze the effect of CA on the LA size and function for patients with AF.

METHODS

We searched for studies regarding LA size and function pre- and post-ablation in PubMed, Embase, the Cochrane Library, and Web of Knowledge through May 2014. LA function was measured by LA ejective fraction (LAEF), LA active ejective fraction (LAAEF), or both. Total and subgroup analyses were implemented using Cochrane Review Manager Version 5.2. Weighted mean differences with 95% confidence intervals were used to express the results of continuous outcomes using fixed or random effect models. I2 was used to calculate heterogeneity. To assess publication bias, Egger's test and Begg's funnel plot were performed using Stata 12.0.

RESULTS

Twenty-five studies (2040 enrolled patients) were selected for this meta-analysis. The LA diameter (LAD), maximum LA volume, and minimal LA volume were significantly decreased post-ablation, as compared with those at a pre-ablation visit. Compared with the pre-ablation outcomes, we found no significant differences in LAEF/LAAEF at a post-ablation follow-up. Decreases in LA volume and LAEF remained significant post-ablation for paroxysmal AF (PAF); however, the LAEF was insignificant changes in persistent AF (PeAF). Heterogeneity was significant in spite which individual study was excluded. A publication bias was not found. In a meta-regression analysis, we did not find any factor that contributed to the heterogeneity.

CONCLUSION

With CA, LA volumes and LAD were decreased significantly in patients with AF; LAEF was not significant changes in patients with PeAF but decreased in those with PAF.

Topographic variability of the left atrium and pulmonary veins assessed by 3D-CT predicts the recurrence of atrial fibrillation after catheter ablation

BACKGROUND

Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). However, the assessment of anatomical information and predictors of AF recurrence remain unclear. We investigated the relationship between anatomical information on the left atrium (LA) and pulmonary veins (PVs) from three-dimensional computed tomography images and the recurrence of AF after CA.

METHODS

Sixty-seven consecutive AF patients (mean age: 62±10 years, median AF history: 42 (12; 60) months, mean LA size: 41±7 mm, paroxysmal: 56%) underwent CA and were followed for 19±10 months. The segmented surface areas (antral, posterior, septal, and lateral) and dimensions (between the anterior and posterior walls, the right inferior PV and mitral annulus [MA], the right superior PV and MA, the left superior PV and MA, and the mitral isthmus) of the LA were evaluated three dimensionally using the NavX system. The cross-sectional areas of the PVs were also evaluated.

RESULTS

After the follow-up period, 49 patients (73%) remained free from AF. A multivariate analysis showed that the diameter of the mitral isthmus and cross-sectional area of the right upper PV were associated with AF recurrence (odds ratio: 1.070, CI: 1.02-1.12, p=0.001; odds ratio: 0.41, CI: 0.21-0.77, p=0.006).

CONCLUSION

Enlargement of the mitral isthmus and a smaller right superior PV cross-sectional area were associated with AF recurrence.

In vivo contact force measurements and correlation with left atrial anatomy during catheter ablation of atrial fibrillation

AIMS

Lesion formation during catheter ablation crucially depends on catheter-tissue contact. We sought to evaluate the impact of anatomical characteristics of the left atrium (LA) and the pulmonary veins (PVs) on contact force (CF) measurements.

METHODS AND RESULTS

An anatomical map of the LA was obtained in 25 patients prior to catheter ablation of atrial fibrillation. Contact force (operator blinded) and local bipolar electrogram amplitudes (EGM) were measured in eight pre-defined segments around the PVs. After unblinding, points with low CF (≤5 g) were corrected to CF >5 g, and the distance between points was measured. In a pre-procedural computed tomography of the heart, LA volume as well as sizes and circumferences of the PV ostia were measured and correlated to CF measurements. Four hundred and twenty-six points in eight pre-defined LA locations were assessed. Low CF (<5 g) was found in 25.0% (43.5%) of points superior, 33.3% (66.7%) anterior, 32.1% (44.4%) inferior, and 15.5% (15.9%) posterior to the right (left) PVs. The mean distance after correction was 5.8 ± 3.4 mm. Local bipolar electrogram amplitudes between low- and high-CF points did not differ (1.21 ± 1.54 vs. 1.13 ± 1.3 mV, P = ns). The mean CF at the left PVs was significantly lower than at the right PVs (7.91 ± 3.74 vs. 13.95 ± 6.34 g, P < 0.001), with the lowest CF anterior to the left PVs (5.2 ± 3.6 g). Contact force measurements did not correlate to LA volume, size, and circumference of the PVs.

CONCLUSION

Contact force during LA mapping significantly differs according to the location within the LA. These differences are independent of LA volume and anatomy of the PV ostia.

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.

Computed tomography angiography for prediction of atrial fibrillation after coronary artery bypass grafting: proof of concept

BACKGROUND

Postoperative atrial fibrillation (AF) is a serious complication of coronary artery bypass grafting (CABG). There are scant data on the application of coronary computed tomography angiography (CCTA) for prediction of postoperative AF.

METHODS

A total of 102 patients (77 male, mean age: 64±10 years) with pre-procedural CCTA undergoing isolated CABG were enrolled. Clinical risk factors were collected. Qualitative and quantitative CCTA analysis of the atria, pulmonary veins (PV), and epicardial adipose tissue (EAT) along the left atrium (LA) was performed to determine the predictors for postoperative AF. The primary endpoint was defined as any in-hospital AF requiring treatment.

RESULTS

Postoperative AF occurred in 24% of patients. Patients with AF had higher body mass index (29.7±4.8kg/m(2) vs 27.3±3.9kg/m(2), p=0.013), larger right atrial area (25.4±5.3cm(2) vs 22.3±6.4cm(2), p=0.035), LA systolic volume (114.7±32.8ml vs 96.8±30.4ml, p=0.015), LA EAT volume (5.6±3ml vs 4±2.5ml, p=0.009), and right superior PV ostium area (3.8±1.3cm(2) vs 3±1cm(2), p=0.021) compared to non-AF patients. By multivariable analysis, only LA EAT volume [odds ratio (OR): 1.21, 95% confidence interval (CI): 1.01-1.44, p=0.036] and right superior PV ostium area (OR: 1.63, 95% CI: 1.06-2.50, p=0.026) were independent predictors of AF. The optimal cut-offs for LA EAT volume and right superior PV ostium were >3.4ml and >4.1cm(2), respectively (max. sensitivity: 83%, max. specificity: 86%).

CONCLUSIONS

Increased LA EAT and right superior PV ostial size are independently associated with AF after CABG. CCTA might be used as a noninvasive prediction tool for AF in patients undergoing CABG.

Measurement of Left Atrial Pressure is a Good Predictor of Freedom From Atrial Fibrillation

Background

It is suggested that an elevated left atrial pressure (LAP) promotes ectopic beats emanating in the pulmonary veins (PVs) and that LAP might be a marker for structural remodeling. This study aimed to identify if the quantification of LAP correlates with structural changes of the LA and may therefore be associated with outcomes following pulmonary vein isolation (PVI).

Methods

We analysed data from 120 patients, referred to PVI due to drug-refractory atrial fibrillation (AF) (age 63±8; 57% men). The maximum (mLAP) and mean LAP (meLAP) were measured after transseptal puncture.

Results and Conclusions

Within a mean follow-up of 303±95 days, 60% of the patients maintained in sinus rhythm after the initial procedure and 78% after repeated PVI. Performing univariate Cox-regression analysis, type of AF, LA-volume (LAV), mLAP and the meLAP were significant predictors of recurrence after PVI (p=0.03; p=0.001; p=0.01). In multivariate analysis mLAP>18mmHg, LAV>100 ml and the presence of persistent AF were significant predictors (p=0.001; p=0.019; p=0.017). The mLAP >18 mmHg was associated with a hazard ratio of 3.8. Analyzing receiver-operator characteristics, the area under the curve for mLAP was 0.75 (p<0.01). mLAP >18 mmHg predicts recurrence with a sensitivity of 77 % and specificity of 60 %. There was a linear correlation between the LAV from MDCT and mLAP (p = 0.01, R2 = 0.61). The mLAP measured invasively displays a significant predictor for AF recurrence after PVI. There is a good correlation between LAP and LAV and both factors may be useful to quantify LA remodeling.

Characterization of Pulmonary Vein Dimensions Using High-Definition 64-Slice Computed Tomography prior to Radiofrequency Catheter Ablation for Atrial Fibrillation

Background. Contrast-enhanced computed tomography is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AFib) to guide the procedure. We analyzed pulmonary vein (PV) ostial diameter and volumes on a high-definition 64-slice CT (HDCT) scanner in patients with AFib prior to RFCA. Methods and Results. This retrospective study included 50 patients (mean age 60.2 ± 11.4 years, 30 males) undergoing cardiac HDCT scanning before RFCA for drug refractory AFib and 50 age-, BMI-, and sex-matched controls with normal sinus rhythm undergoing HDCT. PV ostial diameter and volume were measured and calculated using a semiautomatic calliper tool. Total ostial PV volume was significantly increased in patients with AFib as compared to controls (P < 0.005). Similarly, total ostial PV diameter was significantly increased in AFib compared to controls (P < 0.001). In AFib, the largest PV volume and diameters were measured in right superior PV (P < 0.05 versus controls). The difference in PV volume between patients and controls was most pronounced in right superior PVs (P = 0.015). Right middle PVs were found more often in patients with AFib (16/50; 32%) than in normal subjects (7/50; 14%). Conclusion. Enlargement of PV ostial area and enlargement of volume are frequent findings in patients with drug refractory AFib. These parameters may add to the risk stratification for AFib recurrence following RFCA.

Feasibility study of electrocardiographic and respiratory gated, gadolinium enhanced magnetic resonance angiography of pulmonary veins and the impact of heart rate and rhythm on study quality

BACKGROUND

We aimed to assess the feasibility of 3 dimensional (3D) respiratory and ECG gated, gadolinium enhanced magnetic resonance angiography (MRA) on a 3 Tesla (3 T) scanner for imaging pulmonary veins (PV) and left atrium (LA). The impact of heart rate (HR) and rhythm irregularity associated with atrial fibrillation (AF) on image and segmentation qualities were also assessed.

METHODS

101 consecutive patients underwent respiratory and ECG gated (ventricular end systolic window) MRA for pre AF ablation imaging. Image quality (assessed by PV delineation) was scored as 1 = not visualized, 2 = poor, 3 = good and 4 = excellent. Segmentation quality was scored on a similar 4 point scale. Signal to noise ratios (SNRs) were calculated for the LA, LA appendage (LAA), and PV. Contrast to noise ratios (CNRs) were calculated between myocardium and LA, LAA and PV, respectively. Associations between HR/rhythm and quality metrics were assessed.

RESULTS

35 of 101 (34.7%) patients were in AF at time of MRA. 100 (99%) patients had diagnostic studies, and 91 (90.1%) were of good or excellent quality. Overall, mean ± standard deviation (SD) image quality score was 3.40 ± 0.69. Inter observer agreement for image quality scores was substantial, (kappa = 0.68; 95% confidence interval (CI): 0.46, 0.90). Neither HR adjusting for rhythm [odds ratio (OR) = 1.03, 95% CI = 0.98,1.09; p = 0.22] nor rhythm adjusting for HR [OR = 1.25, 95% CI = 0.20, 7.69; p = 0.81] demonstrated association with image quality. Similarly, SNRs and CNRs were largely independent of HR after adjusting for rhythm. Segmentation quality scores were good or excellent for 77.3% of patients: mean ± SD score = 2.91 ± 0.63, and scores did not significantly differ by baseline rhythm (p = 0.78).

CONCLUSIONS

3D respiratory and ECG gated, gadolinium enhanced MRA of the PVs and LA on a 3 T system is feasible during ventricular end systole, achieving high image quality and high quality image segmentation when imported into electroanatomic mapping systems. Quality is independent of HR and heart rhythm for this free breathing, radiation free, alternative strategy to current MRA or CT based approaches, for pre AF ablation imaging of PVs and LA.

The clinical benefits of adding a third dimension to assess the left ventricle with echocardiography

Three-dimensional echocardiography is a novel imaging technique based on acquisition and display of volumetric data sets in the beating heart. This permits a comprehensive evaluation of left ventricular (LV) anatomy and function from a single acquisition and expands the diagnostic possibilities of noninvasive cardiology. It provides the possibility of quantitating geometry and function of LV without preestablished assumptions regarding cardiac chamber shape and allows an echocardiographic assessment of the LV that is less operator-dependent and therefore more reproducible. Further developments and improvements for widespread routine applications include higher spatial and temporal resolution to improve image quality, faster acquisition, processing and reconstruction, and fully automated quantitative analysis. At present, three-dimensional echocardiography complements routine 2DE in clinical practice, overcoming some of its limitations and offering additional valuable information that has led to recommending its use for routine assessment of the LV of patients in whom information about LV size and function is critical for their clinical management.

Prolonged P-wave duration is associated with atrial fibrillation recurrence after successful pulmonary vein isolation for paroxysmal atrial fibrillation

Pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) is successful in ∼70-80 % after repeated procedures. This suggests a subgroup of PAF patients where electrical abnormalities outside the pulmonary veins are important. Prolonged P-wave duration (PWD), a marker of atrial remodelling, may identify this subgroup. This study's aim was to assess the association of PWD on standard 12 lead ECG with AF recurrence post PVI.

METHODS

Retrospectively, ECGs were blindly analysed on PVI patients from August 2007-August 2011; patients with persistent AF, mitral valve disease, undergoing redo procedures or no sinus rhythm (SR) ECG within 1 year of PVI were excluded. ECGs were directly uploaded at 300 dpi, amplified ×10, and then PWD measured in all leads. Prolonged PWD was as priori defined as maximum PWD ≥ 140 ms.

RESULTS

The selective cohort consisted of 100 patients out of a total of 170 PVI: age 58 ± 11 years, 72 % male, LVEF 62 ± 9 %, 18 % ischaemic heart disease and 13 % diabetic. Thirty-five had prolonged PWD, which was associated with greater AF recurrence rates compared to those without prolonged PWD (63 vs. 38 %, p < 0.05). Similarly, AF recurrence was associated with greater maximum PWD (139 ± 17 vs. 129 ± 14, p < 0.01), P-wave dispersion (58 ± 21 vs. 49 ± 15, p < 0.01), left atrium (LA) dimension (41 ± 6 vs. 38 ± 5, p < 0.05) and LA volumes (40 ± 14 vs. 34 ± 11, p < 0.05) compared to those who remained in SR. None of these variables were independent predictors of AF recurrence by multivariate analysis.

CONCLUSION

The presence of pre-existent prolonged PWD is associated with a higher risk of AF recurrence post PVI for paroxysmal AF.