Left Atrium Volume Measured with Multislice Computed Tomography as a Prognostic Predictor for Atrial Fibrillation Catheter Ablation Outcomes

Background: Current guidelines consider atrial fibrillation (AF) type as the prognostic factor for a recommendation of catheter ablation. We aimed to determine whether LA and LA appendage (LAA) volumes measured using multislice computed tomography (MSCT) were related to long-term outcomes in AF following radiofrequency catheter ablation (RFCA). Methods: We evaluated 152 consecutive patients with drug-refractory AF (median age, 55.8 ± 9.6 years), including 110 male patients, who underwent RFCA in a single center. All patients underwent MSCT imaging for anatomical assessment. The endpoint of this study was documented AF recurrence after RFCA. Results: The overall procedure success rate was 77.6% (n = 118) during a mean follow-up period of 12.6 months. The LA volume was significantly larger for those who experienced AF recurrence after RFCA than for the patients without recurrent AF after the procedure (153.8 ± 29.9 mL vs. 139.2 ± 34.1 mL, p = 0.025). However, LAA volumes were nearly equivalent between the patients with and without AF recurrence after RFCA (16.2 ± 6.3 mL and 14.7 ± 6.5 mL, respectively; p = 0.235). LA volume ≥ 153.2 mL was the optimal cutoff value for estimating AF recurrence after RFCA, with 94% sensitivity and 66% specificity. LA volume remained an independent predictor of both AF recurrence and permanent AF. Conclusions: LA volume as assessed by MSCT might be helpful for identifying patients likely to achieve successful AF ablation. LA volume ≥ 153.2 mL, but not LAA volume, showed good accuracy in predicting AF recurrence after RFCA.

Left atrial volume by cardiac CTA prior to catheter ablation: comparison to echocardiography and association with recurrent atrial fibrillation

OBJECTIVE

Left atrial volume index (LAVI) by echocardiography can be challenging and its accuracy is highly dependent on image quality. Cardiac computed tomography angiography (CTA) can overcome echocardiographic LAVI measurement challenges; however, data are limited. Therefore, we evaluated the reproducibility of LAVI by CTA, its correlation to echocardiography, and its association with recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) in this retrospective cohort study of patients who underwent CTA prior to PVI. LAVI was measured by CTA and echocardiography using the area length method.

RESULTS

74 patients had echocardiography and CTA within 6 months and were included in this study. The interobserver variability of LAVI measured by CTA was low (1.2%). CTA correlated with echocardiography but found larger LAVI values by a factor of 1.6. Also, LAVI cut off of ≥ 55 ml/m² measured by CTA correlated with recurrent AF after PVI (adjusted Odds Ratio 3.47, p = 0.033).

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 atrial-left ventricular angle, a new measure of left atrial and left ventricular remodeling

We assessed the left atrial-left ventricular (LA-LV) long axis angulation value as a new measure of LA remodeling, and studied its predictors, its effect on two-dimensional LA volume (2D LAVol) estimation, and optimization techniques for 2D LAVol values. Retrospective electrocardiogram-gated coronary computed tomographic angiograms of 164 consecutive patients were reviewed. The LA–LV angle was measured in reconstructed 3-chamber views, and its predictors were determined. The LAVol measured by the area-length method after image optimization along the LV long axis (AL) and the LA long axis (AC–AL), was compared with that measured by the three-dimensional (3D)-volumetric method. LAVol calculation was modified to minimize differences from the 3D values. LA–LV angles ranged from 0° to 63°. In the univariate analysis, decreasing angulation was significantly associated with increasing LV end-diastolic volume (LVEDV), mitral regurgitation grade, LV and LA anteroposterior dimensions, and decreasing LV ejection fraction (LVEF). On multivariate analysis, increasing LVEDV, MR, and LA anteroposterior dimension inversely correlated with angulation; LVEF was positively correlated. The AL and 3D methods significantly differed only for patients with angles ≤ 29.9°. Conversely, LAVol was overestimated for all angules by AC–AL. Modification of AL LAVol using a regression equation, or by substituting the shortest with the longest and average LA lengths in patients with angles ≤ 29.9° and 30–39.9°, respectively neutralized the difference. The LA–LV angle is a new measure of LA and LV remodeling predicted by LV size and function, MR, and LA-anteroposterior dimension. AL formula modifications based on angulation in LV-optimized views better correlate with the 3D method than LA-view modification.

Atrial remodeling and atrial fibrillation recurrence after catheter ablation : Past, present, and future developments

The term "atrial remodeling" is used to describe the electrical, mechanical, and structural changes associated with the presence of an arrhythmogenic substrate for atrial fibrillation. Rhythm control therapy may slow down or even reverse progressive atrial remodeling. Atrial remodeling has long been recognized as an important predictor of clinical outcomes and therapeutic success, but recent advances have highlighted its clinical relevance and revealed the implications of specific anatomical changes such as atrial asymmetry or shape. This has opened the path to computational precision medicine that captures these data in detail and combines them with other factors, to provide patient-specific solutions. The goal of precision medicine lies in improving clinical outcomes, reducing costs, and avoiding unnecessary procedures. In this article, we review the history of atrial remodeling and we summarize the insights from our research on anatomical atrial remodeling and its association with rhythm outcomes after catheter ablation. Finally, we present recent advances in the field, reflecting the beginning of a new technological era that will enable us to improve patient care by personalized patient-specific medicine.

Distorted assessment of left atrial size by echocardiography in patients with increased aortic root diameter

Background

Left atrial (LA) size is frequently assessed by posterior-anterior linear measurement of LA (LAD P-A) in the parasternal long axis to expedite examination. Aging, changes in body surface area, and several cardiovascular pathologies can affect aortic root (AoR) size, thereby affecting LA anatomical shape. We hypothesized that AoR dilatation influences LAD P-A and consequently correct assessment of LA size.

Results

We tested our hypothesis in a study of 70 patients with AoR diameter ranging from 2.7 to 4.8 cm. LA size assessed in parasternal long axis view as LAD P-A was compared to that with LA width and length acquired in the apical two and four chamber view. Simpson’s method of discs was used as standard measurement to assess LA volume.

We observed that LAD P-A in the parasternal long axis decreases when AoR diameter increases. Thus, the increase in LA size assessed in parasternal long axis did not correlate with the increase of LA volume. Further analysis revealed that a significant positive correlation was observed when LAV was plotted as a function of LAD P-A only for those with a normal size AoR. In contrast, LA volume increase correlated with LA diameters assessed in the apical two and four chamber view regardless of AoR size.

Conclusions

Our study documents that increases in AoR impact on the linear measurement of LA, resulting in an underestimated LAD P-A. LA size ought to be calculated from the apical two and four chambers view parameters, especially in patients with AoR dilatation.

A novel predictive model for late recurrence after catheter ablation for atrial fibrillation using left appendage volume measured by cardiac computed tomography

Larger left atrial appendage (LAA) volume is associated with a higher risk of late recurrence (LR) in patients undergoing radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). However, it is unclear whether LAA volume predicts LR, independent of established risk factors. We sought to evaluate the value of LAA volume in predicting LR after RFCA for AF and to develop a score prediction model including LAA volume for these patients. We retrospectively studied 992 patients who underwent RFCA for AF and cardiac computed tomography before RFCA at a single center. At 3 years after RFCA, 362 patients (36.5 %) experienced recurrence. The multivariate Cox regression model showed that age ≥ 75 years (10 points), non-paroxysmal AF (9 points), diabetes mellitus (4 points), left atrial volume index (1 point per 10 ml/m² rounded to the nearest integer), and the second (4.7 to < 7 ml/m²; 4 points) and third (≥ 7 ml/m²; 5 points) tertiles of the LAA volume index were independent risk factors LR. The above-mentioned risk factors were included in the integrated score model, and the C-index of the proposed score model was 0.715 (95 % confidence interval [CI] 0.679-0.752). LAA volume is an independent predictor of LR and the predictive model including LAA volume showed good discrimination power. These findings provide evidence for the inclusion of LAA volume in the risk stratification for AF recurrence in patients undergoing RFCA for AF.

Left atrial sphericity as a marker of atrial remodeling: Comparison of atrial fibrillation patients and controls

BACKGROUND

Left atrial (LA) sphericity has been proposed as a more sensitive marker of atrial fibrillation (AF)-associated atrial remodeling compared to traditional markers such as LA size. However, mechanisms that underlie changes in LA sphericity are not fully understood and studies investigating the predictive value of LA sphericity for AF ablation outcome have yielded conflicting results. The present study aimed to assess correlates of LA sphericity and to compare LA sphericity in subjects with and without AF.

METHODS

Measures of LA size (LA diameter, LA volume, LA volume index), LA sphericity and thoracic anteroposterior diameter (APd) at the level of the LA were determined using computed tomography (CT) imaging data in 293 AF patients (62% paroxysmal AF) and 110 controls.

RESULTS

LA diameter (40.1 ± 6.8 mm vs. 35.2 ± 5.1 mm; p < 0.001), LA volume (116.0 ± 33.0 ml vs. 80.3 ± 22.6 ml; p < 0.001) and LA volume index (56.1 ± 15.3 ml/m² vs. 41.6 ± 11.1 ml/m²; p < 0.001) were significantly larger in AF patients compared to controls, also after adjustment for covariates. LA sphericity did not differ between AF patients and controls (83.7 ± 2.9 vs. 83.9 ± 2.4; p = 0.642). Multivariable linear regression analysis demonstrated that LA diameter, LA volume, female sex, body length and thoracic APd were independently associated with LA sphericity.

CONCLUSIONS

The present study suggests that thoracic constraints rather than the presence of AF determine LA sphericity, implying LA sphericity to be unsuitable as a marker of AF-related atrial remodeling.

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.

3D electroanatomical mapping is less sensitive to atrial remodeling in estimation of true left atrial volume than echocardiography

Background

Left atrial (LA) enlargement has been identified as a predictor of worse clinical outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence of LA size parameters assessed by echocardiography, CT and 3D electroanatomical mapping in patients with AF treated by catheter ablation.

Methods

We analyzed echocardiographic LA volume measurements by disc summation method (LAV_DISC), computed tomography (LAV_CT) and 3D electroanatomical mapping (LAV_CARTO) in 100 pts. (71% males; aged 63 ± 8 years; paroxysmal AF in 55% of patients).

Results

Mean LAV_DISC was 83 ± 25 ml (median: 115; IQR: 98–140 ml), mean LAV_CT was 120 ± 34 ml (median: 115; IQR: 98–140 ml) and mean LAV_CARTO was 123 ± 36 ml (median: 118; IQR: 99–132 ml). Pearson’s correlation coefficient between LAV_DISC a LAV_CT was 0.6 (p < 0.0001) and between LAV_CARTO and LAV_CT was 0.79 (p < 0.0001). There was a significant difference between the two correlation coefficients (p < 0.004). The absolute difference between LAV_CARTO and LAV_CT (3.5 (95% CI -42 – 43) ml) was significantly lower (p < 0.0001) as compared to LAV_DISC and LAV_CT (− 39 (95% CI -102 – 24) ml). In opposite to LAV_DISC, the bias between LAV obtained by CT and CARTO did not differentiate according to presence of spherical remodeling (1.7 ± 28 vs. vs. 5.1 ± 31 ml). Only presence of sinus rhythm was significant and independent covariate of the difference between CARTO and CT-derived LAVs by multivariate regression analysis.

Conclusions

Even though LA volumes evaluated by 3D-electroanatomical mapping have quite good accuracy, the precision is low. For volumes estimated by echocardiography, both precision and accuracy are low.

A decade of atrial fibrillation ablation : Shifts in patient characteristics and procedural outcomes

Background

Over the past decade, radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) has evolved into a frequently performed procedure. The aim of this study was to monitor changes in patient characteristics, procedural characteristics, outcomes and complications over the past 10 years.

Methods

All consecutive patients who underwent primary RFCA treatment of AF in the University Medical Center Utrecht from 2005–2015 were included. In all patients, the primary ablation strategy was pulmonary vein (PV) antrum isolation without additional substrate modification. Baseline patient and procedure characteristics, and 1‑year follow-up data of 975 patients were prospectively collected.

Results

In 2005, 73.4% of patients suffered from paroxysmal AF, which decreased to 45.3% in 2014. Mean age increased from 54 ± 9 to 61 ± 10 years and CHA₂DS₂-VASc score ≥2 from 18 to 40.6%. History of AF decreased significantly from 7 to 4 years. Mean procedure duration was 237 ± 53 min in 2005 and 163 ± 41 min in 2014. Fluoroscopy time significantly decreased from 41 ± 17 to 19 ± 8 min and total radiation exposure from 465 (263–687) to 210 (118–376) mGy. One-year success remained similar (2005: 55.6%, 2014: 54.8%), as did the amount of PV reconnection observed during redo procedures. Due to a marked reduction in vascular complications and moderate PV stenosis, the total complication rate decreased significantly.

Conclusion

Over the past decade, AF ablation has increasingly been performed in older patients with persistent AF and more comorbidity. Moreover, it has been performed earlier after AF diagnosis. Although several performance parameters, such as procedure duration and complication rate, improved, 1‑year single procedure success remained unchanged.

Disparity between two-dimensional echocardiographic and electroanatomic left and right atrial volumes in patients undergoing catheter ablation for long-standing persistent atrial fibrillation

Left atrial (LA) volume (LAV) is used for the selection of patients with atrial fibrillation (AF) to rhythm control strategies. Calculation of LAV from the LA diameters and areas by two-dimensional (2D) echocardiography may result in significant error. Accuracy of atrial volume assessment has never been studied in patients with long-standing persistent AF (LSPAF) and significant atrial remodeling. This study investigated correlation and agreement between 2D echocardiographic (Simpson method) and electroanatomic (CARTO, Biosense Webster) left and right atrial (RA) volumes (LAV(ECHO) vs. LAV(CARTO) and RAV(ECHO) vs. RAV(CARTO)) in patients undergoing catheter ablation for LSPAF. The study enrolled 173 consecutive subjects (females: 21 %, age: 59+/-9 years). There was only modest correlation between LAV(ECHO) (92+/-31 ml) and LAV(CARTO) (178+/-37 ml) (R=0.57), and RAV(ECHO) (71+/-29 ml) and RAV(CARTO) (173+/-34 ml) (R=0.42), respectively. LAV(ECHO) and RAV(ECHO) underestimated LAV(CARTO) and RAV(CARTO) with the absolute bias (+/-1.96 standard deviation) of -85 (-148; -22) ml and -102 (-169; -35) ml, respectively, and with the relative bias of -48 (-75; -21) % and -59 (-88; -30) %, respectively (all P<0.000001 for their mutual difference). Significant confounders of this difference were not identified. In patients with LSPAF, 2D echocardiography significantly underestimated both LA and RA volumes as compared with electroanatomic reference. This disagreement was independent of clinical, echocardiographic and mapping characteristics.

Predictors of arrhythmia recurrence after balloon cryoablation of atrial fibrillation: the value of CAAP-AF risk scoring system

PURPOSE

In the present study, we aimed to test the value of CAAP-AF score for prediction of atrial fibrillation (AF) recurrence at follow-up in a group of our patients treated by balloon cryoablation.

METHODS

A total of 283 symptomatic drug-refractory AF patients [261 (92%) with paroxysmal AF] who underwent pulmonary vein isolation (PVI) with second-generation cryoballoon between April 2012 and October 2016 were included. The CAAP-AF score was calculated for every patient.

RESULTS

A total of 283 patients [68 female (20%), mean age 59.8 ± 11.4 years] were included in the present analysis. Eighty-nine patients (31%) had hypertension and 13 (4%) had coronary artery disease. The mean left atrial diameter and left ventricular ejection fraction were 40.6 ± 7.0 mm and 60.0 ± 9.1%, respectively. The mean CHA₂DS₂-VASc score was 1.2 ± 1.1, and mean number of prior failed antiarrhythmic drugs was 1.4 ± 0.8. At 18 ± 6 months follow-up, 25 patients (8.87%) developed AF recurrence. The recurrence rate was as follows: 3.17% (score 0-3), 8.47% (score 4), 16.28% (score 5), 6.67% (score 6), 23.08% (score 7), and 36.36% (score ≥8). The recurrence rate was 4.86% at a score <5 and 16.49% at a value ≥5; a score cutoff ≥5 predicted AF recurrence with a sensitivity 64% and specificity 68%.

CONCLUSIONS

The present analysis suggests the usefulness of CAAP-AF scoring system, with its simple and easily obtained six clinical variables, to predict AF recurrence after PVI by means of second-generation cryoballoon. A score value ≥5 predicted AF recurrence with a sensitivity 64% and specificity 68%.

US-guided percutaneous laser ablation of refractory metastatic retroperitoneal lesions: A care-compliant case report

RATIONALE

Retroperitoneal metastatic lymph node is rare but severe, which has important structures like the gastrointestinal tract and large blood vessels around and may challenge excision, inducing serious complications like hemorrhage, intestinal adhesion, and even death after injury.

PATIENT CONCERNS

We described the case of a 60-year-old man with a history of right liver resection in 2010, pulmonary wedge resection in 2012, and transarterial chemoembolization twice in 2014, in which the postoperative pathology suggested the mixed liver cancer, and poorly differentiated lung cancer from liver metastasis.

DIAGNOSES

Preoperative magnetic resonance (MR) imaging scan showed a refractory retroperitoneal metastatic lymph node.

INTERVENTIONS

Then this patient repeatedly received 4 ablations with US-guided laser ablation within a month.

OUTCOMES

After 4 ablations due to residual tumor, MR, and CT images of 5-month follow-up showed the partial response. No obvious side effects were discovered in this case during these procedures.

LESSONS

This suggested US-guided laser ablation appears to be a useful technique for retroperitoneal metastatic lymph node with poor general condition or those refusing surgical therapy.

Effect of left atrial volume and pulmonary vein anatomy on outcome of nMARQ™ catheter ablation of paroxysmal atrial fibrillation

PURPOSE

Left atrial volume (LA) and pulmonary vein (PV) anatomy may potentially relate to technical challenges in achieving stable and effective catheter position in case of atrial fibrillation (AF) ablation by means of "one-shot" catheters. The aim of this study was to investigate whether LA volume and PV anatomy, evaluated by computed tomography (CT) or magnetic resonance (MR) prior to ablation, predict acute and midterm outcome of AF ablation by nMARQ™.

METHODS

We included 75 patients (mean age 58 ± 11 years, 67 % male) with symptomatic paroxysmal AF. All patients underwent CT/MR scanning prior to catheter ablation to evaluate LA volume and PV anatomy. All the patients underwent PV isolation by nMARQ™, an open-irrigated mapping and radiofrequency (RF) decapolar ablation catheter. Ablation was guided by electroanatomic mapping allowing RF energy delivery in the antral region of PVs from ten irrigated electrodes simultaneously.

RESULTS

Mean LA volume was 75 ± 40 ml. A normal anatomy (4 PVs) was documented in 40 (53 %) patients and abnormal anatomy (common truncus or accessory PVs) in 35 patients. Mean procedural and fluoroscopy times were 94 ± 55 and 8 ± 5 min, respectively, without significant differences among patients with normal or abnormal anatomy (92 ± 45 vs 95 ± 64 min, p = 0.85 and 6 ± 3 vs 8 ± 4 min, p = 0.65, respectively). Mean ablation time was 14 ± 3 min, and 99 % of the targeted veins were isolated with a mean of 23 ± 5 RF pulses per patient. After a mean follow-up of 17 ± 8 months, 23 (31 %) patients had an atrial arrhythmia recurrence. Neither LA volume nor PV anatomy was a predictor of outcome.

CONCLUSIONS

LA volume and PV anatomy did not affect procedural data and outcome in patients who underwent PV isolation by an open-irrigated mapping and RF decapolar ablation catheter.

Reversal of pulmonary vein remodeling after catheter ablation of atrial fibrillation

Background

Pulmonary veins (PV) and the atria undergo electrical and structural remodeling in atrial fibrillation (AF). This study aimed to determine PV and left atrial (LA) reverse remodeling after catheter ablation for AF assessed by chest computed tomography (CT).

Methods

PV electrophysiologic studies and catheter ablation were performed in 63 patients (68% male; mean ± SD age: 56 ± 10 years) with symptomatic AF (49% paroxysmal, 51% persistent). Chest CT was performed before and 3 months after catheter ablation.

Results

At baseline, patients with persistent AF had a greater LA volume (91 ± 29 cm³vs. 66 ± 27 cm³; P = 0.003) and mean PV ostial area (241 ± 43 mm²vs. 212 ± 47 mm²; P = 0.03) than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients (76%) were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume (77 ± 31 cm³ to 70 ± 28 cm³; P < 0.001) and mean PV ostial area (224 ± 48 mm² to 182 ± 43 mm²; P < 0.001). Patients with persistent AF had more reduction in LA volume (11.8 ± 12.8 cm³vs. 4.0 ± 11.2 cm³; P = 0.04) and PV ostial area (62 mm²vs. 34 mm²; P = 0.04) than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume (r = 0.38, P = 0.03).

Conclusions

Catheter ablation of AF improves structural remodeling of PV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.

Multivariate Analysis of Correspondence between Left Atrial Volumes Assessed by Echocardiography and 3-Dimensional Electroanatomic Mapping in Patients with Atrial Fibrillation

Background

Left atrial (LA) enlargement is a predictor of worse outcome after catheter ablation for atrial fibrillation (AF). Widely used two-dimensional (2D)-echocardiography is inaccurate and underestimates real LA volume (LAV). We hypothesized that baseline clinical characteristics of patients can be used to adjust 2D-ECHO indices of LAV in order to minimize this disagreement.

Methods

The study enrolled 535 patients (59 ± 9 years; 67% males; 43% paroxysmal AF) who underwent catheter ablation for AF in three specialized centers. We investigated multivariately the relationship between 2D-echocardiographic indices of LA size, specifically LA diameter in M-mode in the parasternal long-axis view (LAD), LAV assessed by the prolate-ellipsoid method (LAV_Ellipsoid), LAV by the planimetric method (LAV_Planimetry), and LAV derived from 3D-electroanatomic mapping (LAV_CARTO).

Results

Cubed LAD of 106 ± 45 ml, LAV_Ellipsoid of 72 ± 24 ml and LAV_Planimetry of 88 ± 30 ml correlated only modestly (r = 0.60, 0.69, and 0.53, respectively) with LAV_CARTO of 137 ± 46 ml, which was significantly underestimated with a bias (±1.96 standard deviation) of -31 (-111; +49) ml, -64 (-132; +2) ml, and -49 (-125; +27) ml, respectively; p < 0.0001 for their mutual difference. LA enlargement itself, age, gender, type of AF, and the presence of structural heart disease were independent confounders of measurement error of 2D-echocardiographic LAV.

Conclusion

Accuracy and precision of all 2D-echocardiographic LAV indices are poor. Their agreement with true LAV can be significantly improved by multivariate adjustment to clinical characteristics of patients.

Study on Left Atrial Dimension and Function After Modified Endoscopic Procedure for Atrial Fibrillation at Two Years' Follow-Up

BACKGROUND

Modified endoscopic procedures for atrial fibrillation (AF) have a greater success rate because of the increased number of linear lesions. Concerns have been raised about the impact of ablation scars on the left atrium. This study aimed to examine the impact of ablation on left atrial dimension and systolic function after modified endoscopic procedures with echocardiographic measurement.

METHODS

Of 107 patients undergoing modified endoscopic ablation, 58 had paroxysmal AF and 49 had persistent or long-standing AF. The procedure was performed on the beating heart through three ports on the left chest wall. Three circular and two linear lesions were made on the left atrium. The left atrial appendage was excised by stapler. Echocardiography was performed preoperatively and at the 2-year follow-up.

RESULTS

Most patients (86.9%) patients were in sinus rhythm (SR) postoperatively. Fourteen patients (5 with paroxysmal AF and 9 with persistent/long-standing AF) failed to maintain SR. Echocardiographic data indicated that the left atrial diameter decreased only in the patients with postoperative SR but continued to increase in patients with fail SR maintenance. Left atrial function was also improved after the procedure, especially in patients with preoperative nonparoxysmal AF or with postoperative SR maintenance. Furthermore, left atrial function in patients who failed to restore SR was not worsened even with left atrial appendage excision.

CONCLUSIONS

Modified endoscopic procedure for AF improved post-procedural left atrial function of patients with SR maintenance. The left atrial function of patients with failed SR maintenance was also not worsened after left atrial appendage excision.

Prediction of improvement in left atrial function index after catheter ablation for atrial fibrillation

PURPOSE

Although left atrial function index is reportedly a possible predictor of hospitalization for heart failure and of stroke irrespective of the presence or not of atrial fibrillation (AF), the effects of catheter ablation on left atrial function index have not yet been reported.

METHODS

We performed catheter ablation on 55 patients (age 56.6 ± 9.6 years; 44 men; 30 with paroxysmal and 25 with persistent, long-standing AF) and evaluated them by transthoracic echocardiography preoperatively and 3 monthly for 12-24 months after catheter ablation. We then compared clinical characteristics and echocardiographic variables before catheter ablation between two groups: the 42 subjects with the most recent left atrial function index <30 and the 13 in which it was ≥30.

RESULTS

Left atrial function index improved after catheter ablation in both groups, plateauing 6 months after the procedure. Univariate analysis showed statistically significant differences in the prevalence of chronic AF and left atrial emptying fraction, diameter, and maximum and minimum volume (prevalence of chronic AF, p < 0.05; others, p < 0.01) between the groups. Multivariate analysis showed that only maximum left atrial volume predicts left atrial function index after catheter ablation (p < 0.05). In addition, we used ROC analysis to calculate a cutoff value for LA maximum volume as a good predictor and found that a good cutoff value was 63.5 mL, the sensitivity and specificity being 0.75 and 0.75, respectively.

CONCLUSIONS

Catheter ablation improves left atrial function index. However, in patients with left atrial maximum volume of over 63.5 mL on echocardiography, the index did not recover to within the normal range after catheter ablation.

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.

Impact of left atrial volume on outcomes of pulmonary vein isolation in patients with non-paroxysmal (persistent) and paroxysmal atrial fibrillation

Using a novel graded outcomes scale, the investigators evaluated whether left atrial (LA) volume measured by cardiac computed tomographic angiography is a predictor of pulmonary vein isolation success in patients with nonparoxysmal atrial fibrillation (AF) and paroxysmal AF (PAF). Data from 45 patients who underwent electrocardiographically gated computed tomographic angiography before pulmonary vein isolation for AF were used. LA volume was measured in the ventricular systolic and diastolic phases, defined as 40% and 75% of the interval between consecutive R waves. Outcomes were graded at 0 to 3, 3 to 6, 6 to 12, and 12 to 24 months after pulmonary vein isolation and scored on a 5-point scale: 1 = no AF recurrence off antiarrhythmic drug, 2 = no AF recurrence on antiarrhythmic drug, 3 = rare AF (<1 episode in 3 months), 4 = asymptomatic recurrent AF, and 5 = no reductions in AF frequency or severity. LA volumes were significantly larger in the nonparoxysmal AF group compared with the PAF group in systole (159.2 vs 128.2 ml, p <0.001) and diastole (137.1 vs 104.0 ml, p <0.001). In patients with PAF, larger LA volume was correlated with worse clinical outcomes in the first 12 months, but the results did not reach statistical significance (systole r = 0.25 to 0.41, diastole r = 0.20 to 0.34). In conclusion, these results show a significant difference in LA volume in patients with nonparoxysmal AF and PAF in systole and diastole. Additionally, there was a correlation between LA volume and clinical outcomes in patients with PAF, although this did not reach statistical significance.

[Cardiac computed tomography and ablation of atrial fibrillation]

Both cardiac computed tomography (CT) and interventional electrophysiology (EP) have evolved considerably in recent years. Technical improvements in CT have significantly reduced the radiation dose in cardiac applications. This imaging technology plays an important role in preprocedural planning and guidance of the procedures in many EP centers worldwide. Furthermore, CT is the imaging modality of choice to diagnose relevant complications in ablation of atrial fibrillation, e.g. pulmonary vein stenosis or atrioesophageal fistula. In anatomically driven ablation procedures, such as balloon-based procedures in atrial fibrillation, detailed analysis of the relevant cardiac structures is absolutely crucial not only to reduce radiation exposure and procedure times but also to improve ablation success and to reduce the occurrence of complications. Current software applications enable 3-dimensional reconstruction of cardiac images and the integration into electroanatomical navigation systems. This article reviews the available evidence in this field and highlights recent developments in image guidance for ablation of atrial fibrillation.

Predictors of Recurrence After Radiofrequency Ablation of Persistent Atrial Fibrillation

Radiofrequency catheter ablation that targets the pulmonary veins is well established as a mainstay for drug-refractory, paroxysmal atrial fibrillation (AF). However, in patients with persistent AF, the ideal approach remains elusive. Further, despite the various additional ablation strategies that have been investigated in patients with persistent AF, the rate of recurrent atrial tachyarrhythmias after ablation remains relatively high. In this review, the predictors of recurrent atrial tachyarrhythmias after catheter ablation of persistent AF will be discussed.

Morphologies of the atria and pulmonary veins in relation to lone atrial fibrillation progression: a dual-source computed tomography scan study

Atrial Remodeling and Lone Atrial Fibrillation.

BACKGROUND

We sought to investigate the role of anatomic remodeling of the atria and pulmonary veins (PVs) in the progression of lone atrial fibrillation (AF) using dual-source computed tomography (DSCT).

METHODS AND RESULTS

From 1,308 consecutive patients referred for an index ablation procedure for AF, we prospectively enrolled 29 consecutive patients with recently developed (<3 months) lone persistent AF (PsAF) and 23 consecutive patients with short-lasting (6-12 months) lone PsAF, all of whom had a history of paroxysmal AF (PAF). The control group consisted of 33 patients with lone PAF. On DSCT, the recently developed PsAF group showed more extensive atrial anatomic remodeling than the PAF group as shown by ∼40% higher spot biatrial volume, even though the mean duration of continuous AF was only 6 weeks. In contrast, the DSCT variables in the recently developed PsAF group and the short-lasting PsAF group were comparable, despite the fact that the mean duration of continuous AF in the latter group was 8 months. Series of cross-sectional areas of the ostial 1.5 cm of PV trunks were comparable in the PAF and PsAF groups in all but 3 ostial planes. A higher spot left atrial volume was the only independent factor associated with the progression of lone PAF to PsAF (OR: 1.06, 95% CI: 1.03-1.09, P<0.0001) on logistic regression.

CONCLUSIONS

Prominent anatomic remodeling of the atria, rather than the PVs, underlies the mechanism of recent progression of lone paroxysmal AF to the persistent variety.

The Role of Atrial Structural Remodeling in Atrial Fibrillation Ablation:An Imaging Point of View for Predicting Recurrence

Atrial fibrillation (AF) is the most common arrhythmia and is associated with a significant morbidity and mortality. Invasive catheter ablation of AF has emerged as an effective therapy for patients with symptomatic AF. Atrial remodeling, particularly structural remodeling, is important not only for AF persistence but also for AF recurrence after ablation. Atrial dilation and fibrosis are two of the core processes involved in atrial structural remodeling. Increased automaticity and triggered activity occur in atrial structural remodeling, which may cause difficulty in maintaining sinus rhythm after ablation. Furthermore, an enlarged left atrium (LA) may increase the difficulty in achieving catheter stability and thereby require more energy to complete AF ablation. AF causes similar remodeling in both the left and right atria (RA), and myocardial changes in both atria influence AF recurrence. A non-invasive assessment of fibrotic structural remodeling helps predict the outcome of AF ablation. A varie ty of cardiac imaging modalities, such as two- or three-dimensional echocardiography or multi-detector row computed tomography, have been used to estimate the magnitude of atrial structural remodeling by measuring atrial volume or LA function. Furthermore, delayed enhanced cardiac magnetic resonance imaging has been used to detect not only atrial fibrosis but also the effect of the ablation point. Thus, atrial remodeling, particularly structural remodeling, plays an important role in AF recurrence. These non-invasive imaging modalities are significant tools for estimating atrial enlargement to improve patient selection for AF ablation at the point of paroxysmal AF, and for estimating atrial fibrosis to select the AF treatment including ablation strategy at the point of development to persistent or permanent AF.

2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

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

BACKGROUND

Left atrial (LA) remodeling is a factor in atrial fibrillation (AF) recurrence after pulmonary vein catheter ablation (CA), but right atrium (RA) remodeling has not been investigated for possible associations to AF recurrence.

METHODS AND RESULTS

Using 64-slice multidetector computed tomography, RA and LA volumes were measured 3-dimensionally before CA in 65 patients with initially proven idiopathic paroxysmal AF (mean age, 60±10 years, 81.5% men). The CA procedure was guided by CARTO Merge atrial electroanatomic mapping. Sixteen patients (24.6%) had AF recurrence within the 6-month period after the CA. The recurrence was associated with a large RA volume [odds ratio, 1.04; 95% confidence interval (CI), 1.02 to 1.07, P<0.0001], a large LA volume with 1.04 [95% CI, 1.01 to 1.06, P=0.002], and low LA mean voltage with 1.03 [95% CI, 1.01 to 1.05, P=0.002]. After adjustment for potential confounding variables, RA and LA volumes remained predictive of AF recurrence. Large atrial volumes (mL) (RA ≥87 or LA ≥99) predicted AF recurrence (sensitivity of RA volume: 81.3% in 13 of 16 patients with AF recurrence; specificity: 75.5% in 37 of 49 patients without AF recurrence; sensitivity of LA volume: 81.3% in 13 of 16 patients with AF recurrence; specificity: 69.4% in 34 of 49 patients without AF recurrence), and the combined estimate of both atrial volumes was incremental and additive prognostic power (sensitivity: 75% in 12 of 16 patients with AF recurrence; specificity: 93.9% in 46 of 49 patients without AF recurrence).

CONCLUSIONS

Both LA and RA remodeling are equally associated with post-CA AF recurrence.

A simplified method to determine left atrial volume and transport function using multi-slice computed tomography in patients with atrial fibrillation: comparison with transthoracic echocardiography

Although left atrial volumes (LAVs) and transport function can be accurately measured by multi-slice computed tomography (MSCT) during sinus rhythm, limited data are available for in patients with atrial fibrillation (AF). The aims of our study were to compare LAVs and function assessed by MSCT and transthoracic echocardiography (TTE) during AF, and to validate a simplified method to determine LAVs and functions using MSCT. A total of 150 consecutive AF patients who were scheduled to undergo catheter ablation were enrolled in this study. All subjects underwent MSCT and TTE on the same day. LAVs were measured by MSCT at every 10% of the R-R interval (10-phase analysis). LA transport function was assessed by measuring changes in LAVs. LAVs and functions were also assessed by TTE using a modified Simpson's method and an area-length method. Fifty patients were in sinus rhythm (SR) and 100 were in AF during their examinations. Although TTE underestimated the maximal LAV (LAV(max), by 38.3%) and overestimated the total LA emptying fraction (LAEF(total), by 61.1%) compared with MSCT, there were excellent correlations between TTE and MSCT. LAV(max) and the minimal LAV (LAV(min)) based on MSCT were determined at relatively constant cardiac phases during AF as well as SR (LAV(max); 40%, LAV(min); 100% of R-R interval, fixed-phase analysis). LAVs and LAEF(total) assessed by 10-phase analysis showed good correlations with those assessed by fixed-phase analysis (P < 0.001). LAVs and function assessed by MSCT correlated well with LAVs and functions assessed by TTE, irrespective of the underlying rhythm. Our results indicate that in the context of MSCT, fixed-phase analysis is a simple and reliable method to determine LAVs and function in patients with AF.

Can we change the operative criteria for the MAZE procedure combined with valve surgery in the era of radiofrequency devices?

PURPOSE

After radiofrequency (RF) ablation became available, the indication of MAZE procedure conducted with bipolar RF was expanded. We examined the efficacy and feasibility of the RF MAZE procedure in valve surgery and identified the predictors of atrial fibrillation (AF) recurrence.

METHODS

Forty-four patients had permanent AF at the time of operation and underwent a biatrial RF MAZE procedure. Univariate and multivariate analysis for the predictor of permanent AF recurrence and follow-up studies were performed.

RESULTS

Of the patients, 37 (84.1%) were in non-AF rhythm at discharge and 25 (80.6%) were at the latest follow-up (mean, 2.1 ± 1.2 years). In stepwise multivariate analysis, left atrial dimension (LAD) > 61.5 mm was an independent predictor of early-term recurrence of AF (P = 0.006) and late-term recurrence (P = 0.038) as well. F-wave voltage <0.1 mV was significant in univariate analysis but was not significant in multivariate analysis for predictor of late-term AF recurrence. Avoidance of AF in the late term was 56% for LAD > 60 mm whereas it was 91% for LAD ≤ 60 mm (P = 0.043), 67% for F-wave < 0.1 mV compared to 100% for F-wave ≥ 0.1 mV (P = 0.031), and 43% for LAD > 60 mm and F-wave < 0.1 mV compared to 91% for LAD ≤ 60 mm and/or F-wave ≥ 0.1 mV (P = 0.016), respectively. Although avoidance of AF in the late term was lower in patients with LAD > 60 mm or F-wave < 0.1 mV, more than half of these patients were free from AF in the late term.

CONCLUSION

LA size was assumed to be a simple and strong predictor of recurrent AF in this procedure. Predictive criteria that had been widely employed for the "cut-and-sew" MAZE procedure accompanied with valve surgery can be expanded in the MAZE procedure with RF devices.

Association between plaque thickness of the thoracic aorta and recurrence of atrial fibrillation after ablation

Background and Objectives

Several predictors of recurrence of atrial fibrillation (AF) after ablation have been identified, including age, type of AF, hypertension, left atrial diameter and impaired left ventricular ejection fraction. The aim of this study was to investigate whether the atherosclerotic plaque thickness of the thoracic aorta is associated with a recurrence of AF after circumferential pulmonary vein ablation (CPVA).

Subjects and Methods

Among patients with drug-refractory paroxysmal or persistent AF, 105 consecutive (mean age 58±11 years, male : female=76 : 29) patients who underwent transesophageal echocardiography and CPVA were studied. The relationships between the recurrence of AF and variables, including clinical characteristics, plaque thickness of the thoracic aorta, laboratory findings and echocardiographic parameters were evaluated.

Results

A univariate analysis showed that the presence of diabetes {hazard ratio (HR)=3.425; 95% confidence interval (CI), 1.422-8.249, p=0.006}, ischemic heart disease (HR=4.549; 95% CI, 1.679-12.322, p=0.003), duration of AF (HR=1.010; 95% CI, 1.001-1.018, p=0.025), type of AF (HR=2.412, 95% CI=1.042-5.584, p=0.040) and aortic plaque thickness with ≥4 mm (HR=9.514; 95% CI, 3.419-26.105, p<0.001) were significantly associated with the recurrence of AF after ablation. In Cox multivariate regression analysis, only the aortic plaque thickness (with ≥4 mm) was an independent predictor of recurrence of AF after ablation (HR=7.250, 95% CI=1.906-27.580, p=0.004).

Conclusion

Significantly increased aortic plaque thickness can be a predictable marker of recurrence of AF after CPVA.

Left atrial volume and function assessment by magnetic resonance imaging

Left Atrial Volume and Function Assessment. 

INTRODUCTION

In patients with atrial fibrillation undergoing catheter ablation, magnetic resonance imaging (MRI) can determine left atrial (LA) volume and function before and after ablation. The most accurate, but time consuming, method to determine LA volume is the multiple slice method (MSM), which involves manual tracing of LA area on each slice. The area length method (ALM) offers a simplified, but unvalidated, alternative for LA volume assessment by MRI. The aim of this study was to compare LA volume and function assessment by ALM with MSM.

METHODS AND RESULTS

MRI was performed before and after catheter ablation in 40 patients with atrial fibrillation (30 male, mean age 57 years). All patients had sinus rhythm during imaging. In total, 72 MRI scans were available. LA end-diastolic and end-systolic volumes (EDV, respectively ESV) were measured by both methods. LA function was determined by calculating LA ejection fraction (EF = (EDV-ESV)/EDV). Measured by ALM, mean LA EDV and ESV were significantly lower than using MSM (102 mL and 49 mL vs 111 mL and 65 mL, respectively, P < 0.001) with a larger difference in mean ESV than EDV (16 mL vs 9 mL). This resulted in an overestimation of LA EF by ALM with a mean of 11% (54% by ALM and 42% by MSM, P < 0.001). ALM correlated well with MSM for LA EDV and ESV (r = 0.77, respectively 0.85), and showed no significant difference in intraobserver and interobserver variability.

CONCLUSION

ALM significantly underestimates LA volumes and overestimates LA function, but correlates well with the more accurate MSM.

Effect of pulmonary vein anatomy and left atrial dimensions on outcome of circumferential radiofrequency catheter ablation for atrial fibrillation

Multislice computed tomography (MSCT) is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) to plan and guide the procedure. MSCT allows accurate measurement of the left atrial (LA) and pulmonary vein (PV) dimensions and classification of the PV anatomy. The aim of the present study was to investigate the effect of LA dimensions, PV dimensions, and PV anatomy on the outcome of circumferential RFCA for AF. A total of 100 consecutive patients undergoing RFCA for AF (paroxysmal 72%, persistent 28%) were studied. The LA dimensions, PV dimensions, and PV anatomy were evaluated three dimensionally using MSCT. The PV anatomy was classified as normal or atypical according to the absence/presence of a common trunk or additional veins. After a mean follow-up of 11.6 ± 2.8 months, 65 patients (65%) maintained sinus rhythm. The enlargement of the left atrium in the anteroposterior direction on MSCT was related to a greater risk of AF recurrence. No relation was found between the PV dimensions and the outcome of RFCA. In addition, normal right-sided PV anatomy was related to a greater risk of AF recurrence compared to atypical right-sided PV anatomy. Multivariate analysis showed that an anteroposterior LA diameter on MSCT (odds ratio 1.083, p = 0.027) and normal right-sided PV anatomy (odds ratio 6.711, p = 0.006) were independent predictors of AF recurrence after RFCA. In conclusion, enlargement of the anteroposterior LA diameter and the presence of normal anatomy of the right PVs are independent risk factors for AF recurrence. No relation was found between the PV dimensions and outcome of RFCA.