Cardiac magnetic resonance imaging assessment of regional and global left atrial function before and after catheter ablation for atrial fibrillation

Electro-Mechanical Alterations in Atrial Fibrillation: Structural, Electrical, and Functional Correlates

Atrial fibrillation is the most common arrhythmia encountered in clinical practice affecting both patients’ survival and well-being. Apart from aging, many cardiovascular risk factors may cause structural remodeling of the atrial myocardium leading to atrial fibrillation development. Structural remodelling refers to the development of atrial fibrosis, as well as to alterations in atrial size and cellular ultrastructure. The latter includes myolysis, the development of glycogen accumulation, altered Connexin expression, subcellular changes, and sinus rhythm alterations. The structural remodeling of the atrial myocardium is commonly associated with the presence of interatrial block. On the other hand, prolongation of the interatrial conduction time is encountered when atrial pressure is acutely increased. Electrical correlates of conduction disturbances include alterations in P wave parameters, such as partial or advanced interatrial block, alterations in P wave axis, voltage, area, morphology, or abnormal electrophysiological characteristics, such as alterations in bipolar or unipolar voltage mapping, electrogram fractionation, endo-epicardial asynchrony of the atrial wall, or slower cardiac conduction velocity. Functional correlates of conduction disturbances may incorporate alterations in left atrial diameter, volume, or strain. Echocardiography or cardiac magnetic resonance imaging (MRI) is commonly used to assess these parameters. Finally, the echocardiography-derived total atrial conduction time (PA-TDI duration) may reflect both atrial electrical and structural alterations.

Left atrium phasic impairments in paroxysmal atrial fibrillation patients assessed by cardiovascular magnetic resonance feature tracking

Atrial fibrillation (AF) is an abnormal and irregular heartbeat caused by uncoordinated electrical impulses in the left atrium (LA), which could induce lasting changes in the heart tissue or could be a consequence of underlying cardiac disease. This study aimed to assess the left atrial phasic function and deformation in paroxysmal AF (PAF) patients—who had not received radiofrequency ablation and had no signs of permanent AF—using the cardiovascular magnetic resonance (CMR) feature-tracking (FT) technique. Fifty subjects (27 PAF patients and 23 controls) were included and examined with CMR. Their LA volume, LA function, LA longitudinal strain (LS) and LA strain rate were assessed in the LA reservoir, conduit, and contractile phases. PAF patients exhibited higher LA volumes than controls, while their LA emptying fraction and LA LS was significantly lower in all three phases. In contrast, the corresponding emptying volumes (total, passive and active) were similar in both groups. The LA volumetric rates from CMR-derived volume curves differed significantly in PAF patients vs controls in the reservoir and contractile phases. In contrast, the equivalent LV volumetric rates were similar. This study suggests that assessing the LA phasic function could offer insight into early LA impairments for PAF patients.

Localized Pulmonary Vein Scar Promotes Atrial Fibrillation in High Left Atrial Pressure

Background

Pulmonary vein (PV) ablation is unsuccessful in atrial fibrillation (AF) patients with high left atrial (LA) pressure. Increased atrial stretch by increased pressure is proarrhythmic for AF, and myocardial scar alters wall deformation. We hypothesized that localized PV scar is proarrhythmic for AF in high LA pressure.

Methods

Radiofrequency energy was delivered locally in the right PV of healthy sheep. The sheep recovered for 4 months. Explanted hearts (n = 9 PV scar, n = 9 controls) were perfused with 1:4 blood:Tyrode's solution in a four-chamber working heart setup. Programmed PV stimulation was performed during low (∼12 mmHg) and high (∼25 mmHg) LA pressure. An AF inducibility index was calculated based on the number of induction attempts and the number of attempts causing AF (run of ≥ 20 premature atrial complexes).

Results

In high LA pressure, the presence of PV scar increased the AF inducibility index compared with control hearts (0.83 ± 0.20 vs. 0.38 ± 0.40 arb. unit, respectively, p = 0.014). The diastolic stimulation threshold in high LA pressure was higher (108 ± 23 vs. 77 ± 16 mA, respectively, p = 0.006), and its heterogeneity was increased in hearts with PV scar compared with controls. In high LA pressure, the refractory period was shorter in PV scar than in control hearts (178 ± 39 vs. 235 ± 48 ms, p = 0.011).

Conclusion

Localized PV scar only in combination with increased LA pressure facilitated the inducibility of AF. This was associated with changes in tissue excitability remote from the PV scar. Localized PV ablation is potentially proarrhythmic in patients with increased LA pressure.

Rhythm Control in Heart Failure Patients with Atrial Fibrillation

AF and heart failure (HF) commonly coexist. Left atrial ablation is an effective treatment to maintain sinus rhythm (SR) in patients with AF. Recent evidence suggests that the use of ablation for AF in patients with HF is associated with an improved left ventricular ejection fraction and lower death and HF hospitalisation rates. We performed a systematic search of world literature to analyse the association in more detail and to assess the utility of AF ablation as a non-pharmacological tool in the treatment of patients with concomitant HF.

Concomitant Obesity and Metabolic Syndrome Add to the Atrial Arrhythmogenic Phenotype in Male Hypertensive Rats

Background

Besides hypertension, obesity and the metabolic syndrome have recently emerged as risk factors for atrial fibrillation. This study sought to delineate the development of an arrhythmogenic substrate for atrial fibrillation in hypertension with and without concomitant obesity and metabolic syndrome.

Methods and Results

We compared obese spontaneously hypertensive rats (SHR‐obese, n=7–10) with lean hypertensive controls (SHR‐lean, n=7–10) and normotensive rats (n=7–10). Left atrial emptying function (MRI) and electrophysiological parameters were characterized before the hearts were harvested for histological and biochemical analyses. At the age of 38 weeks, SHR‐obese, but not SHR‐lean, showed increased body weight and impaired glucose tolerance together with dyslipidemia compared with normotensive rats. Mean blood pressure was similarly increased in SHR‐lean and SHR‐obese when compared with normotensive rats (178±9 and 180±8 mm Hg [not significant] versus 118±5 mm Hg, P<0.01 for both), but left ventricular end‐diastolic pressure was more increased in SHR‐obese than in SHR‐lean. Impairment of left atrial emptying function, increase in total atrial activation time, and conduction heterogeneity, as well as prolongation of inducible atrial fibrillation durations, were more pronounced in SHR‐obese as compared with SHR‐lean. Histological and biochemical examinations revealed enhanced triglycerides and more pronounced fibrosis in the left atrium of SHR‐obese. Besides increased expression of profibrotic markers in SHR‐lean and SHR‐obese, the profibrotic extracellular matrix protein osteopontin was highly upregulated only in SHR‐obese.

Conclusions

In addition to hypertension alone, concomitant obesity and metabolic syndrome add to the atrial arrhythmogenic phenotype by impaired left atrial emptying function, local conduction abnormalities, interstitial atrial fibrosis formation, and increased propensity for atrial fibrillation.

Effect of ablation pattern on mechanical function in the atrium

BACKGROUND

Atrial fibrillation (AF) is often treated with catheter ablation, which induces scar formation to isolate misfiring electrical signals in the left atrium. Successful ablation restores sinus rhythm at the cost of replacing viable myocardium with scar. The impact of ablation scar on mechanical function of the left atrium is poorly understood.

OBJECTIVE

We used a computational model to simulate various ablation patterns and determine their effect on atrial global and regional mechanical function.

METHODS

A coupled finite-element and hemodynamic circuit model of the left atrium that represents the regional and global mechanics in paroxysmal AF patients was modified to simulate different ablation patterns: step-wise pulmonary vein isolation (PVI), wide area circumferential ablation (WACA), and a posterior ablation developed by nContact, Inc (Morrisville, NC, USA). Atrial pressure-volume relationships and regional wall motion were compared among the models.

RESULTS

Ablation increased passive stiffness and decreased active work performed by the atrium. Active emptying volume decreased with increasing scar by up to 44% (11 mL) at a scar volume of 31%. At matched scar volumes, WACA decreased active emptying more severely than PVI and nContact. Similarly, wall motion was depressed most in the WACA model because WACA involved portions of the lateral wall with higher baseline motion.

CONCLUSION

Simulated ablation depressed atrial mechanical function to an extent that depended on both scar volume and location, primarily through reducing active emptying. Placing ablation scar in regions with high baseline motion resulted in greater depression of active function, while ablation of the posterior wall was less disruptive.

MRI of the left atrium at 3T: evaluation of measurement reproducibility in healthy volunteers and patients with cardiovascular disease

Background Left ventricular (LV) function has traditionally been the focus for cardiac magnetic resonance imaging (MRI) investigations, but similar methods can also be applied to the left atrium (LA). Previous studies elsewhere have almost entirely involved the use of 1.5T systems, but 3T MRI can provide faster data acquisition with thinner image slices, and may be more suitable for quantifying the structure and function of the LA. Purpose To evaluate 3T-MRI for LA volume assessments in: (i) healthy volunteers (HV); (ii) patients with LV-hypertrophy and ischemia (LVHI); and (iii) patients with LV-hypertrophy and diabetes (LVHD). Material and Methods Participants were imaged using a balanced steady-state free precession sequence. Healthy volunteers were scanned twice and patients were scanned on one occasion. Volumes were segmented by two observers, and coefficients of repeatability (CoR) were derived. Results For LA volumes (indexed to body surface area), CoRs were in the range of 1.3-4.6 mL/m². The LVHI patients had enlarged LA volumes (diastolic, 46.4 mL/m²; systolic, 25.9 mL/m²) and reduced ejection fraction (EF) (44.9%) relative to the HV (diastolic, 39.0 mL/m²; systolic, 17.8 mL/m²; EF, 54.5%) and LVHD groups (diastolic, 41.4 mL/m²; systolic, 20.2 mL/m²; EF, 50.7%). LA volumes were moderately correlated with LV mass in the HV group (R²= 0.59 for LA end-systolic volume), but became weaker (R²≤ 0.17) for patient groups. Conclusion 3T-MRI derived LA volume measurements are simple and repeatable, and can elicit clear differences between LVHI patients and HVs. These MRI endpoints provide scope for improved radiological interpretation of LA structure and function, and the high degree of repeatability validates their use for longitudinal investigations where precision work is essential.

Making better scar: Emerging approaches for modifying mechanical and electrical properties following infarction and ablation

Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function - maintaining integrity of the heart wall against enormous mechanical forces - but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches.

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.

The value of magnetic resonance imaging in catheter ablation of atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Catheter ablation is now a recognized treatment for those with symptomatic AF refractory to drug therapy. Innovations in magnetic resonance imaging (MRI) have empowered clinicians to improve ablation efficacy while reducing the risk of complications. It is demonstrated that late gadolinium enhancement MRI has additional advantages over modalities such as echocardiography and computed tomography, due to its ability to assess the structural remodeling directly. As a result, MRI has become an indispensable imaging tool to personalize the AF ablation strategy, assess the efficacy and potential complications of AF ablation, and guide the repeat procedure.

Effects of radiofrequency catheter ablation on left ventricular structure and function in patients with atrial fibrillation: a meta-analysis

INTRODUCTION

Radiofrequency catheter ablation (RFCA) is an effective therapy for atrial fibrillation (AF). This study was designed to investigate the effects of RFCA on left ventricular (LV) structure and function in AF patients.

METHODS AND RESULTS

A systematic literature search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was performed to identify trials involving changes of LV structure and function in AF patients undergoing RFCA. Effect size was expressed as weighted mean difference (WMD) with 95% confidence interval (CI). LV end-diastolic diameter (LVEDD), LV end-systolic diameter (LVESD), LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were estimated. A total of 21 trials including 1,135 participants were qualified for this meta-analysis. Compared to the baseline values, there were significant decreases in LVEDV (WMD, -6.39 ml; 95%CI, -12.46 to -0.33) and LVESV (WMD, -6.39 ml; 95%CI, -11.35 to -1.42) and a significant improvement in LVEF (WMD, 6.23%; 95%CI, 3.70 to 8.75), but no significant changes were observed in LVEDD (WMD, -0.64 mm; 95%CI, -2.40 to 1.13) and LVESD (WMD, -0.38 mm; 95%CI, -1.32 to 0.56) after RFCA. Subgroup analysis demonstrated that patients with low LVEF (WMD, 11.90%; 95%CI, 9.16 to 14.64) gained more benefits than those with normal LVEF (WMD, 1.56%; 95%CI, 0.38 to 2.74). Besides, patients with chronic AF (WMD, 10.96%; 95%CI, 4.92 to 17.01) improved more than those with paroxysmal AF (WMD, 1.93%; 95%CI, -0.27 to 4.12).

CONCLUSIONS

RFCA in AF patients could reverse LV structural remodeling and improve LV systolic function, especially in patients with low LVEF and chronic AF.

Role of magnetic resonance imaging in atrial fibrillation ablation

OPINION STATEMENT

Ablation therapy is widely used for treatment of drug-resistant atrial fibrillation (AF). Ablation success for AF, however, is relatively low, often requiring repeated procedures for long-term suppression of the arrhythmia. Utilization of imaging techniques that visualize cardiac anatomy, function, and tissue characteristics may improve ablation results. Compared to other imaging modalities, cardiac magnetic resonance (CMR) has several advantages, including the lack of ionizing radiation and unsurpassed soft tissue resolution. Chamber morphology images can be registered onto electroanatomic maps acquired during the procedure, thus improving procedural safety and efficacy. In addition, the ability of CMR to characterize myocardial tissues may optimize patient selection for ablation and thromboembolic risk stratification. Post-procedure CMR can be used to detect potential complications, and with improved resolution, it has the potential to assess the integrity of ablation lesions. In this paper we will review the role of CMR in the pre-ablation diagnostic workup of AF patients as well as during and after catheter ablation.

Quantitative description of the 3D regional mechanics of the left atrium using cardiac magnetic resonance imaging

The left atrium (LA) plays an important role in the maintenance of hemodynamic and electrical stability of the heart. One of the conditions altering the atrial mechanical function is atrial fibrillation (AF), leading to an increased thromboembolic risk due to impaired mechanical function. Preserving the regions of the LA that contribute the greatest to atrial mechanical function during curative strategies for AF is important. The purpose of this study is to introduce a novel method of regional assessment of mechanical function of the LA. We used cardiac MRI to reconstruct the 3D geometry of the LA in nine control and nine patients with paroxysmal atrial fibrillation (PAF). Regional mechanical function of the LA in pre-defined segments of the atrium was calculated using regional ejection fraction and wall velocity. We found significantly greater mechanical function in anterior, septal and lateral segments as opposed to roof and posterior segments, as well as a significant decrease of mechanical function in the PAF group. We suggest that in order to minimize the impact of the AF treatment on global atrial mechanical function, damage related to therapeutic intervention, such as catheter ablation, in those areas should be minimized.

Updating the evidence for the effect of radiofrequency catheter ablation on left atrial volume and function in patients with atrial fibrillation: a meta-analysis

Objectives

To systematically review the effects of radiofrequency catheter ablation (RFCA) on left atrial (LA) size, volumes and function in patients with atrial fibrillation (AF).

Methods

We searched MEDLINE, EMBASE, ScienceDirect, Highwire, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and the reference lists of retrieved reports in July 2012.

Setting

China

Participants

Twenty-six studies (enrolling 1821 patients) were included in the final analysis.

Main outcome measures

Changes of LA size or volumes and/or function in patients with AF after RFCA.

Results

Compared to pre-ablation values, there were significant decreases in LA diameter and LA volumes at post-ablation follow-up. However, compared to pre-ablation values, there were no significant differences in LA ejection fraction/LA active emptying fraction and LA strain at post-ablation follow-up. Decreases in LA diameter and LA volumes remained significant in those without AF recurrence but not in those with AF recurrence. LA ejection fraction/LA active emptying fraction did not decrease in patients without AF recurrence, whereas they decreased in patients with AF recurrence. As for LA strain, it seems that LA strain increases in patients without AF recurrence, with less fibrosis and with more LA volumes decrease, but the differences were not significant.

Conclusions

Successful RFCA in patients with AF significantly decreases LA size and volumes and does not seem to adversely affect LA function.

Impact of pulmonary vein antrum isolation on left atrial size and function in patients with atrial fibrillation

PURPOSE

The success of PVAI in eliminating AF has been proven; however, its impact on the LA remains uncertain. This study aimed to determine the impact of pulmonary vein antrum isolation (PVAI) on left atrial (LA) size and function in patients with atrial fibrillation (AF).

METHODS

Consecutive patients with AF were included (n = 206). Magnetic resonance imaging (MRI) was performed before and after PVAI in all patients. A subgroup (n = 52) underwent delayed enhancement MRI. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) were assessed by Simpson's rule. LA function was determined by calculating LA ejection fraction (LA EF). LA fibrosis was manually encircled and summed in the region of interest.

RESULTS

Single procedure success rate was 64 %. LAVmax decreased post-ablation in all patients (125.1 to 111.9 ml, p < 0.001). LAVmin only decreased in patients with a successful outcome post-ablation (65.6 to 58.8 ml, p < 0.001). As a result, LA EF only showed a marked reduction in patients with AF recurrences (42.7 % to 37.9 %, p < 0.001). Post-ablation LA fibrosis could be visualized in 77 % of patients who underwent delayed enhancement MRI (mean amount 1.4 cm(3)). LA fibrosis showed no correlation with the decrease in LAVmax or LA EF.

CONCLUSIONS

PVAI resulted in a reduction of LAVmax in all patients, indicating an effect of ablation induced fibrosis. LAVmin only decreased in patients with a successful outcome, indicating an effect of reverse atrial remodeling. As a result, LA function post-ablation was preserved in patients with a successful outcome and decreased in patients with AF recurrence.

Wall-motion based analysis of global and regional left atrial mechanics

Atrial fibrillation is an increasingly prevalent cardiovascular disease; changes in atrial structure and function induced by atrial fibrillation and its treatments are often spatially heterogeneous. However, spatial heterogeneity of function is difficult to assess with standard imaging techniques. This paper describes a method to assess global and regional mechanical function by combining cardiac magnetic resonance imaging and finite-element surface fitting. We used this fitted surface to derive measures of left atrial volume, regional motion, and spatial heterogeneity of motion in 23 subjects, including healthy volunteers and atrial fibrillation patients. We fit the surfaces using a Newton optimization scheme in under 1 min on a standard laptop, with a root mean square error of 2.3 ± 0.5 mm, less than 9% of the mean fitted radius, and an inter-operator variability of less than 10%. Fitted surfaces showed clear definition of the phases of left atrial motion (filling, passive emptying, active contraction) in both volume-time and regional radius-time curves. Averaged surfaces of healthy volunteers and atrial fibrillation patients provided evidence of substantial regional variation in both amount and timing of regional motion, indicating spatial heterogeneity of function, even in healthy adults.

Role of cardiac computed tomography and cardiovascular magnetic resonance imaging in guiding management and treatment of patients with atrial fibrillation: state of the art review

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with high morbidity and mortality. In view of an aging population, the prevalence and incidence of AF are on the rise and are expected to double in the coming decades, posing a huge economic burden on already strained resources. New innovative therapies such as pulmonary vein isolation and percutaneous closure of the left atrial appendage have emerged. The current applications of such therapies would not have been possible without the pivotal role of multimodality cardiovascular imaging. The role of echocardiography in guiding therapy has been extensively reviewed. However, there are new data in support of other complementary imaging modalities, mainly cardiac computed tomography and cardiovascular magnetic resonance imaging, which will be the focus of this review.

The use of cardiac magnetic resonance imaging in the diagnostic workup and treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and imposes a huge clinical and economic burden. AF is correlated with an increased morbidity and mortality, mainly due to stroke and heart failure. Cardiovascular imaging modalities, including echocardiography, computed tomography (CT), and cardiovascular magnetic resonance (CMR), play a central role in the workup and treatment of AF. One of the major advantages of CMR is the high contrast to noise ratio combined with good spatial and temporal resolution, without any radiation burden. This allows a detailed assessment of the structure and function of the left atrium (LA). Of particular interest is the ability to visualize the extent of LA wall injury. We provide a focused review of the value of CMR in identifying the underlying pathophysiological mechanisms of AF, its role in stroke prevention and in the guidance of radiofrequency catheter ablation. CMR is a promising technique that could add valuable information for therapeutic decision making in specific subpopulations with AF.

Effect of repeated radiofrequency catheter ablation on left atrial function for the treatment of atrial fibrillation

Radiofrequency catheter ablation (RFCA) is a potential curative treatment for atrial fibrillation (AF) by eliminating the arrhythmia and inducing left atrial (LA) reverse remodeling. However, the effect on LA function, especially after repeated procedures, has scarcely been studied. The aim of this study was to evaluate the impact of RFCA on LA size and function in patients with AF after a first and a repeated procedure. RFCA was performed in 154 patients with symptomatic drug-refractory AF. LA volumes and function were assessed with real-time 3-dimensional echocardiography before and 6 months after the procedure. Recurrence of the arrhythmia was defined as any atrial tachyarrhythmia lasting >30 seconds, clinically documented or by 24-hour Holter recording, after the first 6 months after ablation. Of the 154 patients, 104 (67%) required only a first ablation, and 50 (33%) required redo RFCA. LA volume was reduced after first RFCA (from 60 ± 19 to 52 ± 17 ml for 3-dimensional LA maximum volume, p <0.001, and from 38 ± 18 to 33 ± 15 ml for 3-dimensional LA minimum volume, p <0.000) without impairment of LA contractile function, measured as the active emptying percentage of total volume (39 ± 25% vs 43 ± 26%, p = NS). After repeated RFCA procedures, 3-dimensional LA maximum volume was reduced (from 57 ± 18 to 52 ± 18 ml, p = 0.04), also without further LA contractile function impairment (active emptying percentage of total volume) (36 ± 24% vs 36 ± 25% of total volume, p = NS). This effect was similar in paroxysmal and persistent AF. In conclusion, RFCA induces reductions in LA volumes without a deleterious impact on contractile function, even after repeated ablation.