A comparison of intracardiac and transesophageal echocardiography to detect left atrial appendage thrombus in a swine model

Purpose

Transesophageal echocardiography (TEE) is the gold standard in the evaluation for left atrial appendage (LAA) thrombus in patients with atrial fibrillation (AF) and is often performed prior to AF ablation. We routinely use intracardiac echocardiography (ICE) to assist in AF ablation; however, standard right atrial views do not provide adequate visualization of the LAA. As the incidence of thrombus in this population is relatively low, TEE incurs additional risk, cost, and patient discomfort. Novel views of the LAA with ICE may obviate the need for TEE in this population. We tested the hypothesis that due to their proximity, imaging the LAA from the pulmonary artery (PA) would provide equivalent sensitivity and specificity to TEE in detecting LAA thrombus in a swine model.

Methods

Five domestic swine were utilized. Baseline images of the LAA with TEE were obtained. An 8Fr ICE catheter was placed in the left main PA, and imaging of the LAA was repeated. After transseptal puncture, an admixture of 2 cm³ blood and 1,000 IU of thrombin was injected into the LAA, and imaging of the LAA was repeated. Two blinded, independent reviewers experienced in ICE assessed the images and adjudicated both the presence of thrombus and the subjective image quality.

Results

The presence or absence of thrombus was correctly identified in all cases by both reviewers. Both reviewers rated the subjective quality of ICE images superior to TEE.

Conclusions

ICE is equivalent to TEE in imaging LAA thrombus in a porcine model. Whether ICE can provide similar diagnostic accuracy and safety for detecting LAA thrombus in humans remains unproven.     

Impact of left atrial appendage ridge ablation on the complex fractionated electrograms in persistent atrial fibrillation

Background

The left atrial appendage (LAA) is a possible key contributor to the maintenance of persistent atrial fibrillation (PsAF). The effect of LAA ostial ablation on global left atrial higher-frequency sources remains unclear.

Methods

Complex fractionated electrograms (CFEs) and dominant frequency (DF) maps acquired with a NavX system in 58 PsAF patients were enrolled and examined before and after LAA posterior ridge ablation, which followed a stepwise linear ablation.

Results

High-density left atrial mapping identified continuous CFE sites in 50 % and high-DFs (≥8 Hz) in 53 % of patients at the LAA posterior ridge. In 44 patients in whom AF persisted despite pulmonary vein isolation (PVI) and linear ablation, LAA ablation significantly increased the mean CFE cycle length from 98?±?29 to 108?±?30 ms (P?P?90 mL/m²) (median 0 vs 4.8 %; P?P?Conclusion These findings suggested that an approach incorporating an LAA posterior ridge ablation was effective in modifying higher-frequency sources in the global LA in PsAF patients, but a lesser effect was documented in patients with electroanatomical remodeling of the LA.     

Anatomical analysis of the left atrial appendage using segmented, three-dimensional cardiac CT: a comparison of patients with paroxysmal and persistent forms of atrial fibrillation

Purpose

Successful implantation of percutaneous left atrial appendage (LAA) occlusion devices requires an accurate understanding of LAA anatomy and orifice dimensions. We sought to quantitatively compare LAA anatomy in patients with paroxysmal and persistent patterns of atrial fibrillation (AF).

Methods

Fifty-nine consecutive patients undergoing catheter ablation for AF underwent pre-procedural multislice cardiac computed tomography (CT) scans. Maximal LAA orifice dimensions and left atrial and LAA volumes were measured from three-dimensional segmented CT reconstructions. Thirty-six patients with paroxysmal and 23 with persistent AF were analysed.

Results

The mean maximal LAA orifice dimension was larger in persistent (27.2?±?4?mm) than paroxysmal AF (22.9?±?3?mm, p?r?=?0.76), maximal LAA orifice dimension (r?=?0.63) and left atrial volume.

Conclusions

Increased LAA orifice dimension is associated with left atrial enlargement in AF. This finding may impact LAA occlusion device sizing.     

Fibrosis and electrophysiological characteristics of the atrial appendage in patients with atrial fibrillation and structural heart disease

Purpose

This study was conducted to investigate the degree of fibrosis in atrial appendages of patients with and without atrial fibrillation (AF) undergoing cardiac surgery. In addition, we hypothesized that areas of atrial fibrosis can be identified by electrogram fractionation and low voltage for potential ablation therapy.

Methods

Interstitial fibrosis from right (RAA) and/or left atrial appendages (LAA) was studied in patients with sinus rhythm (SR, n?=?8), paroxysmal (n?=?21), and persistent AF (n?=?20) undergoing coronary artery bypass and/or aortic or mitral valve surgery. Atrial fibrosis quantification was performed with Masson trichrome staining. Intraoperative bipolar epicardial electrophysiological measurements were performed to correlate fibrosis to electrogram fractionation, voltage, and AF cycle length.

Results

The average degree of fibrosis was 11.2?±?7.2 % in the LAA and 22.8?±?7.6 % in the RAA (p?<?0.001). Fibrosis was not significantly higher in paroxysmal AF patients compared to SR subjects (18.2?±?8.7 versus 20.7?±?5.3 %). Persistent AF patients had a higher degree of LAA and RAA fibrosis compared to paroxysmal AF patients (LAA 14.6?±?8.7 versus 8.6?±?4.7 %, p?=?0.02, and RAA 28.2?±?7.9 versus 18.2?±?8.7 %, respectively, p?=?0.04). The left atrial end diastolic volume index was higher in persistent AF patients compared to SR controls (38.3?±?16.4 and 28?±?11 ml/m², respectively, p?=?0.04). No correlation between atrial fibrosis and electrogram fractionation or voltage was found.

Conclusion

Patients with structural heart disease undergoing cardiac surgery have more fibrosis in the RAA than in the LAA. Furthermore, RAA fibrosis is increased in persistent AF but not paroxysmal AF patients compared to control subjects. Electrogram fractionation and low voltage did not provide accurate identification of the fibrotic substrate.     

Filling defects of the left atrial appendage on multidetector computed tomography: their disappearance following catheter ablation of atrial fibrillation and the detection of LAA thrombi by MDCT

Filling defects of the left atrial appendage (LAA) on multidetector computed tomography (MDCT) are known to occur, not only due to LAA thrombi formation, but also due to the disturbance of blood flow in the LAA of patients with atrial fibrillation (AF). The purpose of this study was to evaluate the impact of the maintenance of sinus rhythm via ablation on the incidence of LAA filling defects on MDCT in patients with AF. A total of 459 consecutive patients were included in the present study. Prior to ablation, MDCT and transesophageal echocardiography (TEE) were performed. AF ablation was performed in patients without LAA thrombi confirmed on TEE. The LAA filling defects were evaluated on MDCT at 3 months after ablation. LAA filling defects were detected on MDCT in 51 patients (11.1 %), among whom the absence of LAA thrombi was confirmed in 42 patients using TEE. The LAA Doppler velocity in patients with LAA filling defects was lower than that of patients without filling defects (0.61 ± 0.19 vs. 0.47 ± 0.21 m/s; P < 0.0001). The sensitivity, specificity and negative predictive value of MDCT in the detection of thrombi were 100, 91 and 100 %, respectively. No LAA filling defects were observed on MDCT at 3 months after ablation in any of the patients, including the patients in whom filling defects were noted prior to the procedure. MDCT is useful for evaluating the presence of LAA thrombi and the blood flow of the LAA. The catheter ablation of AF not only suppresses AF, but also eliminates LAA filling defect on MDCT suggesting the improvement of LAA blood flow.     

Continuous warfarin versus periprocedural dabigatran to reduce stroke and systemic embolism in patients undergoing catheter ablation for atrial fibrillation or left atrial flutter

Purpose

Left atrial catheter ablation for patients with atrial fibrillation (AF) requires periprocedural anticoagulation to minimize thromboembolic complications. High rates of major bleeding complications using dabigatran etexilate for periprocedural anticoagulation have been reported, raising concerns regarding its safety during left atrial catheter ablation. We sought to evaluate the safety and efficacy of a dabigatran use strategy versus warfarin, at a single high-volume AF ablation center.

Methods

We performed a retrospective analysis on consecutive patients undergoing left atrial ablation at Vanderbilt Medical Center from January 2011 through August 2012 with a minimum follow-up of 3 months. Patient cohorts were divided into two groups, those utilizing dabigatran etexilate pre- and post-ablation and those undergoing ablation on dose-adjusted warfarin, with or without low-molecular-weight heparin bridging. Dabigatran was held 24–30 h pre-procedure and restarted 4–6 h after hemostasis was achieved. We evaluated all thromboembolic and bleeding complications at 3 months post-ablation.

Results

A total of 254 patients underwent left atrial catheter ablation for atrial fibrillation or left atrial flutter. Periprocedural anticoagulation utilized dabigatran in 122 patients and warfarin in 135 patients. Three late thromboembolic complications occurred in the dabigatran group (2.5 %), compared with one (0.7 %) in the warfarin group (p?=?0.28). The dabigatran group had similar minor bleeding (2.5 vs. 7.4 %, p?=?0.07), major bleeding (1.6 vs. 0.7 %, p?=?0.51), and composite of bleeding and thromboembolic complications (6.6 vs. 8.9 %, p?=?0.49) when compared to warfarin. There were no acute thromboembolic complications in either group (<24 h post-ablation).

Conclusions

In patients undergoing left atrial catheter ablation for AF or left atrial flutter, use of periprocedural dabigatran etexilate provides a safe and effective anticoagulation strategy compared to warfarin. A prospective randomized study is warranted.     

Catheter ablation of atrial fibrillation guided by a 3D electroanatomical mapping system: a 2-year follow-up study from the Italian Registry On NavX Atrial Fibrillation ablation procedures (IRON-AF)

Aims

Clinical trials have established that atrial fibrillation (AF) catheter ablation improves symptoms in appropriately selected patients. Confirmation of these results by long-term prospective observational studies is needed. This registry was created to describe the experience of 16 Italian centers with a large cohort of AF patients treated with catheter ablation guided by the NavX 3D mapping system.

Methods

From November 2006 to May 2008, 545 consecutive patients (age 60.4?±?9.8, 67 % male) with paroxysmal (44 %), persistent (43 %), and long-standing persistent (13 %) AF referred for catheter ablation guided by the NavX system, were included in this registry. For this paper, follow-up was censored at 24 months; however, patients are being followed in the ongoing registry.

Results

Before the ablation, 80 % of patients failed to respond to at least one antiarrhythmic drug aimed at rhythm control. Pulmonary vein (PV) isolation guided by a circular mapping catheter was performed in 70 % of patients whereas non potential-guided PV encircling was performed in 30 % of patients. In 67 % of patients, additional left atrial (LA) substrate modification was performed. Image integration was performed in 9.2 % of patients. Considering a 3-month blanking period, after a single-ablation procedure, the patients had 1- and 2-year freedom from AF recurrence of 67.4 and 57.0 % (36.1 % off antiarrhythmic drugs), respectively. Cox regression analysis showed that AF recurrences during blanking (HR 2.1), and previous AF ablation (HR 3.3) were independent predictors of AF recurrences. Major procedure-related complications occurred in 53 patients (9.7 %). In 35 patients (6.7 %), a repeat procedure was performed at a median of 5 months after the initial procedure.

Conclusions

This prospective, multicenter clinical experience provides significant insights into current ablation care of patients with AF. Despite favorable outcomes, real-world complication rates appear higher than previously recognized.     

Hemodynamic impact of percutaneous left atrial appendage closure in patients with paroxysmal atrial fibrillation

Purpose

Percutaneous left atrial appendage (LAA) closure has become a valid alternative to anticoagulation therapy for the prevention of thromboembolic events in patients with atrial fibrillation (AF). However, scarce data exist on the impact of LAA closure on left atrial and ventricular function. We sought to assess the acute hemodynamic changes associated with percutaneous LAA closure in patients with paroxysmal AF.

Methods

The study population consisted of 31 patients (mean age 73?±?10 years; 49% women) with paroxysmal AF who underwent successful percutaneous LAA closure. All patients were in sinus rhythm and underwent 2D transthoracic echocardiography at baseline and the day after the procedure. A subset of 14 patients underwent preprocedural cardiac computed tomography (CT) with 3D LA and LAA reconstruction.

Results

Left ventricular systolic function parameters and LA volumetric indexes remained unchanged after the procedure. No significant changes in left ventricular stroke volume (72.4?±?16.0 vs. 73.3?±?15.7 mL, p?=?0.55) or LA stroke volume (total 15.6?±?4.2 vs. 14.6?±?4.2 mL, p?=?0.21; passive 9.0?±?2.8 vs. 8.3?±?2.6 mL, p?=?0.31; active 10.3?±?5.6 vs. 10.0?±?6.4 mL, p?=?0.72) occurred following LAA closure. Mean ratio of LAA to LA volume by 3D CT was 10.2?±?2.3%. No correlation was found between LAA/LA ratio and changes in LA stroke volume (r?=?0.35, p?=?0.22) or left ventricular stroke volume (r?=?0.28, p?=?0.33).

Conclusions

The LAA accounts for about 10% of the total LA volume, but percutaneous LAA closure did not translate into any significant changes in LA and left ventricular function.

     

Left atrial appendage obliteration in atrial fibrillation patients undergoing bioprosthetic mitral valve replacement

Background

Left atrial appendage (LAA) obliteration is a proven stroke-preventive measure for patients with nonvalvular atrial fibrillation (AF). However, the efficacy of LAA obliteration for patients with AF after bioprosthetic mitral valve replacement (MVR) remains unclear.

Aim

This study aimed to estimate the efficacy of LAA obliteration in preventing embolism and to investigate the predictors of thromboembolism after bioprosthetic MVR.

Methods

We retrospectively studied 173 AF subjects with bioprosthetic MVR; among them, 81 subjects underwent LAA obliteration using an endocardial running suture method. The main outcome measure was the occurrence of thrombosis events (TEs). The mean follow-up time was 40?±?17 months.

Results

AF rhythm was observed in 136 patients postoperatively. The incidence rate of TEs was 13.97?% for postoperative AF subjects; a dilated left atrium (LA; >?49.5 mm) was identified as an independent risk factor of TEs (OR?=?10.619, 95?% CI?=?2.754–40.94, p?=?0.001). For postoperative AF patients with or without LAA, the incidence rate of TEs was 15.8?% (9/57) and 12.7?% (10/79; p?=?0.603), respectively. The incidence rate of TEs was 2.7?% (1/36) and 4.2?% (2/48) for the subgroup patients with a left atrial diameter of <?49.5 mm, and 38.1?% (8/21) and 25.8?% (8/31) for those with a left atrial diameter of >?49.5 mm (p?=?0.346).

Conclusion

Surgical LAA obliteration in patients with valvular AF undergoing bioprosthetic MVR did not reduce TEs, even when the CHA₂DS₂-VASc score (a score for estimating the risk of stroke in AF) was ≥?2 points.

     

Left atrial wall thickness and outcomes of catheter ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy

Purpose

Catheter ablation of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is still challenging, and it is unclear whether the difficulty is caused by the hypertrophy of left atrial (LA) myocardial wall thickness. The objective of the study was to compare the LA wall thickness and AF ablation outcomes between patients with HCM and those without structural heart disease.

Methods

The present study enrolled 17 consecutive HCM patients (63?±?12 years) with drug-refractory AF and 34 control patients without any detectable heart disease, whose age, gender, type of AF, and LA dimension were matched to the HCM patients. The myocardial wall thickness of 11 distinct LA locations, measured using 64-slice computed tomography images, and AF ablation outcomes were compared between the two groups.

Results

The LA wall thickness did not differ at 9 of the 11 locations and was significantly thinner in the HCM patients than in the control patients at the mid-posterior wall (1.44?±?0.17 vs. 1.58?±?0.22, p?=?0.04) and infero-posterior wall (1.62?±?0.16 vs. 1.74?±?0.18, p?=?0.03). Although antiarrhythmic drugs were used more frequently in the HCM patients (p?=?0.008), the rate of maintaining sinus rhythm during the follow-up did not differ between the HCM and control patients (53 vs. 56 % after the initial ablation [log-rank p?=?0.78] and 82 and 88 % after the repeat procedure [log-rank p?=?0.35]).

Conclusions

The LA wall in the HCM patients with AF was not thicker than that of the matched patients without structural heart disease. Catheter ablation of AF showed favorable outcomes in both patient groups.     

A multi-purpose spiral high-density mapping catheter: initial clinical experience in complex atrial arrhythmias

Purpose

There is an increasing need for catheter ablation procedures to treat complex atrial tachycardias (AT) and atrial fibrillation (AF), often requiring detailed endocardial mapping. The sequential point-to-point contact mapping of complex arrhythmias is time-consuming and may not always be feasible. We assessed the utility of a novel spiral duo-decapolar high-density (HD) mapping catheter to delineate complex arrhythmia substrates for ablation.

Methods

The patients underwent HD mapping using a spiral catheter (AFocusII) and the EnSite NavX system, during catheter ablation procedures, to treat atrial arrhythmias.

Results

In 26 patients, a total of 32 atrial arrhythmias were mapped and ablated, comprising of five focal AT, eight macroreentrant AT, 11 persistent AF and eight paroxysmal AF. The HD catheter was used to acquire endocardial surface geometries in all cases and to map the pulmonary veins in patients undergoing AF ablation. In persistent AF, HD catheter mapping permitted the creation of highly detailed complex fractionated electrogram maps (left atrium 449?±?128 points in 7.2?±?2.6 min; right atrium 411?±?113 points in 6.7?±?1.6 min). In AT, activation mapping was performed with the acquisition of 305?±?158 timing points in 7.3?±?2.6 min, guiding successful ablation in all cases. During the follow-up of 7.0?±?2.6 months, all AT patients remained free of significant arrhythmia.

Conclusions

High-density contact mapping with a novel spiral multipolar catheter allows rapid assessment of focal and macroreentrant AT, and complex fractionated electrical activity in the atria. It has further multi-functional capabilities as a pulmonary vein mapping catheter and for accurate geometry creation when used with a 3D mapping system.     

Effect of pulmonary vein isolation on atrial fibrillation recurrence after ablation of paroxysmal supraventricular tachycardia in patients with high dispersion of atrial refractoriness

Purpose

This study aimed to assess pulmonary vein isolation (PVI) efficacy on atrial fibrillation (AF) recurrence and to determine a predictive dispersion of atrial refractoriness (dERP) value for performing PVI in paroxysmal supraventricular tachycardia (PSVT) patients.

Methods

Of 67 PSVT patients with past AF episodes who underwent accessory pathway (AP) or slow pathway of atrioventricular node ablation, 63 (4 lost to follow-up or death) were assigned into two groups (A and B; 29 and 34 patients, respectively) based on whether they underwent or not subsequent PVI, and all were followed-up up to 3 years. Atrial effective refractory period (AERP) and dERP were measured during the ablation procedure.

Results

In receiver operating characteristic (ROC) curve analysis, dERP?=?74.5 ms effectively predicted AF recurrence in PSVT patients (p?=?0.003). Difference in AF recurrence rate between groups did not reach statistical significance (17.2 %, 5/29 vs. 29.4 %, 10/34, p?=?0.203). AF recurrence rate was lower in patients with dERP >74.5 ms who underwent AP or slow-pathway ablation with vs. without PVI (18.2 %, 2/11 vs. 77.8 %, 7/9, p?=?0.012).

Conclusions

PVI addition after successful AP or slow pathway of atrioventricular node ablation significantly reduced AF recurrence in PSVT patients with high atrial vulnerability (dERP >74.5 ms).     

Recurrence of paroxysmal atrial fibrillation after cryoisolation of the pulmonary veins. Is a “redo” procedure using the cryoballoon useful?

Background

Pulmonary vein (PV) isolation with the cryoballoon technique is an effective and safe method to treat patients with paroxysmal atrial fibrillation (AF). However, the optimal treatment strategy for patients with recurrences after this ablation is unclear.

Aims

The aim of this single centre study was to evaluate the efficacy and safety of a “redo” procedure using the cryoballoon in this patient cohort. The secondary study objectives were to determine the rate of reconduction for individual PVs of the patients undergoing “redo” ablation and potential predictors of persistent PV isolation (PVI).

Methods

Between April 2006 and September 2009, all patients with paroxysmal AF recurrences after cryoballoon ablation a “redo” ablation with the cryoballoon was offered. PV conduction was determined and cryoapplications were performed in all reconnected PVs. Every 3 months, 7-day Holter ECG, symptom-driven transtelephonic ECG recordings, and questionnaires were collected for 12 months.

Results

Forty-seven patients underwent “redo” cryoballoon ablation. In all these patients, at least one PV with reconduction was found. Recurrent conduction was documented in 63 % of the left superior PV, 56 % of the left inferior PV, 43 % of the right superior PV, and 56 % of the right inferior PV. In 28 of the 47 patients (60 %), no AF recurrence was detectable during the 12-month follow-up (after 3 months blanking period). Rate of severe complications was low and not significantly different from that of the initial ablations.

Conclusion

“Redo” ablation using cryoballoon technology may be an effective and safe method to treat patients with recurrence of paroxysmal AF after cryoballoon PVI.     

Bifocal right ventricular pacing: an alternative way to achieve resynchronization when left ventricular lead insertion is unsuccessful

Purpose

To explore the effects on atrial and ventricular function of restoring sinus rhythm (SR) after epicardial cryoablation and closure of the left atrial appendage (LAA) in patients with mitral valve disease and atrial fibrillation (AF) undergoing surgery.

Methods

Sixty-five patients with permanent AF were randomized to mitral valve surgery combined with left atrial epicardial cryoablation and LAA closure (ABL group, n?=?30) or to mitral valve surgery alone (control group, n?=?35). Two-dimensional and Doppler echocardiography were performed before and 6?months after surgery.

Results

At 6?months, 73% of the patients in the ABL group and 46% of the controls were in SR. Patients in SR at 6?months had a reduction in their left ventricular diastolic diameter while the left ventricular ejection fraction was unchanged. In patients remaining in AF, the left ventricular ejection fraction was lower than at baseline. The left atrial diastolic volume was reduced after surgery, more in patients with SR than AF. In patients in SR, the peak velocity during the atrial contraction and the reservoir function were lower in the ABL group than in the control group.

Conclusions

In patients in SR, signs of atrial dysfunction were observed in the ABL but not the control group. Atrial dysfunction may have existed before surgery, but the difference between the groups implies that the cryoablation procedure and/or closure of the LAA might have contributed.     

Left atrial thrombus despite continuous direct oral anticoagulant or warfarin therapy in patients with atrial fibrillation: insights into rates and timing of thrombus resolution

Purpose

Left atrial thrombus (LAT) may be detected by transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF) or flutter (AFL) despite continuous anticoagulation therapy. We sought to examine the rates and timing of LAT resolution in response to changes in anticoagulation regimen.

Methods

A retrospective study of 1517 consecutive patients on ≥?4 weeks continuous oral anticoagulation (OAC) undergoing TEE prior to either direct current cardioversion or catheter ablation for AF or AFL was performed. Patients who had LAT on index TEE imaging and had follow-up TEEs were analyzed.

Results

Despite ≥?4 weeks of continuous anticoagulation therapy, 63 (4.2%) patients had LAT. Forty-four patients (median age 67 [IQR 58, 74]; 33 [75%] male; 25 [57%] on direct oral anticoagulant [DOAC]) had follow-up TEEs performed. Upon detection of LAT on index TEE, 8 patients switched from warfarin to a DOAC, 21 patients switched from a DOAC to warfarin or another DOAC, and 15 patients remained on the same OAC. Over median 4.2 months (IQR 2.9, 6.6), LAT resolution was seen in 25 (57%) patients. Of the 25 patients who had LAT resolution, 7 (28%) required TEE imaging >?6 months after index TEE to show clearance of thrombus. Rates of LAT resolution were similar between patients who had alterations in OAC and those who did not (52 vs. 60%; P?=?0.601).

Conclusions

After initial detection of left atrial thrombus despite uninterrupted anticoagulation for atrial fibrillation or flutter, >?40% patients have persistent clot despite additional extended anticoagulation.

     

Left atrial strain as predictor of successful outcomes in catheter ablation for atrial fibrillation: a two-dimensional myocardial imaging study

Background

The objective of this study was to investigate atrial myocardial properties through two-dimensional (2D) myocardial imaging in patients with atrial fibrillation (AF) and its predictive role for recurrence after catheter ablation.

Methods and results

Echocardiographic examinations were performed in 40 patients with paroxysmal AF before catheter ablation and 40 age- and gender-matched healthy control subjects. Using a software package, bidimensional acquisitions were analyzed to measure longitudinal strain and strain rate for the left atrium (LA). Systolic strain and strain rate in all eight segments, and its average values, were significantly reduced in AF patients compared to controls. During 9 months of follow-up after catheter ablation for AF, 11 of 40 AF patients had AF recurrence. AF recurrence was associated with gender, LA volume index, and average values of systolic strain and strain rate. By multivariate analysis, only average strain was an independent predictor of AF recurrence (OR?=?0.88, 95% CI 0.79-0.98, p?=?0.018).

Conclusions

Lower systolic strain of LA was strongly associated with recurrence after catheter ablation. Thus, diverse adjunctive ablation strategies should be considered to reduce recurrence in patients with lower systolic strain.     

Outcome of pulmonary vein isolation ablation for paroxysmal atrial fibrillation: predictive role of left atrial mechanical dyssynchrony by speckle tracking echocardiography

Introduction

Although few clinical variables have been associated with recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) the role of left atrial (LA) mechanical function in the outcome of catheter ablation of AF is not adequately defined. The aim of our study was to determine whether LA mechanical dyssynchrony as evaluated by speckle tracking echocardiography can predict outcome of PVI ablation procedure in patients with paroxysmal AF.

Methods

Twenty-five patients (age 58?±?11 years, [mean ± standard deviation], 17 males) with paroxysmal AF who met specific enrollment criteria pertaining to clinical presentation and follow-up, assessment of LA mechanical dyssynchrony, and strategy of catheter ablation procedure were enrolled. For LA mechanical dyssynchrony assessment, the time to peak longitudinal strain (TPk) in opposing walls in the midportion of the LA walls at peak atrial contraction in standard two- and four-chamber echocardiographic views by vector velocity imaging (VVI) was measured. Outcome of PVI procedure, whether no recurrence (NR) or AF recurrence (AFR) after 3 months of post-procedural blanking period, was evaluated based on AF-related symptoms and documentation of AF by electrocardiogram, continuous 24-h Holter, and intermittent event monitor recordings.

Results

During a follow-up period of 20.3?±?8.6 months, 18 out of 25 (72 %) patients had no recurrence (NR group), and 7 out of 25 (28 %) patients had recurrence of AF (AFR group). Significant gender difference was observed in terms of outcome such that all AFR patients were men and no woman had recurrence of AF. Between the NR and AFR groups, neither the left atrial diameter, 4.0?±?0.3 and 4.2?±?0.2 cm, respectively (p?=?0.2), nor the left atrial volume indexes, 45?±?15 and 48?±?20 ml/m², respectively (p?=?0.56), were statistically significantly different. For LA mechanical function, compared to the patients in NR group who had maximum opposing wall TPk delay of 39.9?±?12.0 ms, those in the AFR group demonstrated significantly more LA mechanical dyssynchrony with maximum opposing wall TPk delay of 64.4?±?17.0 ms prior to ablation (p?=?0.007). Using receiver operative characteristic analyses of the data that had an area under the curve of 0.865, we identified a maximum opposing wall delay cutoff value of 51 ms which predicted AF recurrence with sensitivity and specificity values of 89 and 72 %, respectively (p?=?0.005).

Conclusions

Speckle tracking strain analysis echocardiography can evaluate the LA mechanical dyssynchrony quantitatively. The severity of LA mechanical dyssynchrony by VVI can predict the outcome of PVI catheter ablation for paroxysmal AF.     

Why atrial fibrillation recurs in patients who obtained current ablation endpoints with longstanding persistent atrial fibrillation

Purpose

Although several techniques for modification of atrial fibrillation (AF) substrate, such as linear ablation and complex fractionated atrial electrograms (CFAEs) ablation, have been proposed for longstanding persistent AF (LS-AF) and improved the outcome, there was still a certain recurrence rate, even if current ablation endpoints of these techniques were completely achieved. The purpose of this study was to describe the determinants of recurrent AF in patients who obtained current ablation endpoints with LS-AF.

Methods and results

In all, 208 consecutive patients who obtained current ablation endpoints with LS-AF were studied. The current ablation endpoints were defined as complete pulmonary vein isolation, bidirectional block of lines, and disappearance of CFAEs. After a follow-up of 19.9?±?4.1 months, the patients were classified as AF recurrence group and non-AF recurrence group (including patients with sinus rhythm and atrial tachycardia), and 34 (16 %) patients were in the AF recurrence group. The patients in AF recurrence group had higher rates of right atrium (RA) enlargement (67.7 vs. 45.4 %, p?=?0.018) and ≥2 procedure times (58.8 vs. 27.0 %, p?<?0.001), longer AF duration (82.4?±?44.8 vs. 50.8?±?42.8 months, p?<?0.001), and larger left atrium (LA) diameter (49.4?±?6.2 vs. 46.5?±?5.3 mm, p?=?0.007). In the multivariate analysis, RA enlargement, ≥2 procedure times, and AF duration were independent predictors of AF recurrence.

Conclusion

RA enlargement, ≥2 procedure times, and AF duration played important roles in AF recurrence in patients who obtained current ablation endpoints. For these patients with AF recurrence who had already underwent ≥2 procedure times, enlarged RA may contribute to other AF foci and/or substrate, and the ablation strategy may be transformed from LA to RA in the next ablation procedures.     

Magnetically guided irrigated gold-tip catheter ablation of persistent atrial fibrillation—techniques, procedural parameters and outcome

Purpose

Magnetically guided irrigated ablation has been introduced for atrial fibrillation (AF) ablation. However, data on ablation of persistent AF is scarce, and first-generation platinum–iridium catheters were burdened by char formation at the catheter tip. Furthermore, energy transmission of these catheters may be suboptimal. Irrigated gold-tip catheters have been introduced to overcome these problems.

Methods

Antral pulmonary vein (PV) isolation (PVAI) was performed using a 5-mm irrigated gold-tip magnetic catheter (power setting, 48 °C maximum, 50 W, 15 s lesion duration; flow-rate, 30 mL/min). The catheter tip was guided by a uniform magnetic field and a motor drive. Left atrial maps were created using an impedance-based left atrial reconstruction and fused with a preprocedural CT or an intraprocedural rotational angiography-based scan.

Results

Fifty-seven patients (42 male, 61.9?±?8.8 years) underwent PVAI for symptomatic, drug-refractory persistent AF. PVAI was performed successfully in all patients confirmed by entrance block. Procedure time (skin-to-skin) was 214?±?47 min (104–354 min). Fluoroscopy time was 31?±?21 min. Ablation time was 4,153?±?1,350 s. No char or thrombus formation was found at the catheter tip. One pericardial tamponade was observed. Freedom from atrial tachyarrhythmias could be achieved in 57.9 % of the patients included in a follow-up of 11.6?±?4.2 month. There was a trend to a better outcome in patients without previous attempts of AF ablation (n?=?48; 60.4 % vs. 44.4 %, p?=?0.47).

Conclusions

Remote magnetic navigation for PVAI seems to be safe and feasible using an irrigated gold-tip catheter. Effectiveness of this novel technique can be confirmed by mid-term outcome.     

Increase in pulmonary arterial pressure after atrial fibrillation ablation: incidence and associated findings

Purpose

The stiff left atrial (LA) syndrome is defined as pulmonary hypertension (PH) secondary to reduced LA compliance and has recently been shown to be one cause of PH after atrial fibrillation (AF) ablation. We aimed to determine the incidence of an increase in pulmonary arterial (PA) pressure post-ablation and examine the clinical and echocardiographic associations.

Methods

Patients who underwent AF ablation between 1999 and 2011 were included if they had both an echocardiogram pre-ablation and 3 months post-ablation. Patients were then separated into two groups with the increased PA pressure group defined as patients with >10 mmHg increase in right ventricular systolic pressure (RVSP) post-ablation and a post-ablation RVSP >35 mmHg.

Results

Of the 499 patients meeting the study criteria, 41 (8.2 %) had an increase in RVSP >10 mmHg and RVSP >35 mmHg post-ablation. On echocardiogram, the two groups had similar E/A and E/e’ ratios pre-ablation. However, post-ablation, the increased PA pressure group had higher E/A (2.12 vs. 1.49, p?<?0.01) and E/e’ (14.7 vs. 11.2, p?<?0.01) ratios. LA expansion index values were lower in the increased PA pressure group pre-ablation (51 vs. 92 %, p?<?0.01), but not significantly different post-ablation (82 vs. 88 %, p?=?0.44).

Conclusions

Around 8 % of patients develop an increase in estimated PA pressure after AF ablation. Echocardiographic parameters suggest that patients who develop increased PA pressure are developing (or unmasking) left ventricular diastolic dysfunction.