Effect of Non-fluoroscopic Catheter Tracking on Radiation Exposure during Pulmonary Vein Isolation: Comparison of Four ablation systems

Background

A novel non-fluoroscopic catheter tracking system (Mediguide) can be used in combination with a 3D mapping system for atrial fibrillation (AF) ablation. However, the benefit on radiation exposure of the Mediguide system compared to other ablation systems is unknown.

Methods

We retrospectively enrolled consecutive 73 patients (51 men; 59±11 years; 60 paroxysmal AF) undergoing pulmonary vein isolation by the same operator. Radiation time, radiation effective dose, procedure time, AF recurrence after ablation, and procedure-related complications were compared among 4 different ablation systems.

Results

Mediguide was used in 16 patients (group A), CARTO™ in 17 (group B), Cryoballoon in 30 (group C), and Multi-electrode Pulmonary Vein Ablation Catheter (PVAC) in 10 (group D). Although procedure time was shorter in patients with Cryoballoon (median 110 [interquartile range 99-120] min) and PVAC (123 [112-146] min) compared to those with Mediguide (181 [168-214] min) and CARTO (179 [160-195] min) (P<0.001), radiation exposure time and effective dose were decreased in patients with Mediguide compared to the other ablation systems (A: 5 [3-6] min; B: 14 [11-16] min; C: 14 [11-18] min; D: 20 [16-24] min, P<0.001 and A: 1.1 [0.8-2.0] mSv; B: 2.5 [1.3-3.8] mSv; C: 2.0 [1.4-2.5] mSv; D: 1.7 [1.4-3.6] mSv, P=0.015, respectively). AF recurrence rates and procedure-related complications were comparable among the 4 groups.

Conclusion

The Mediguide system reduces radiation exposure compared to other ablation systems without increasing AF recurrence or procedure-related complications.

The Impact of Advances in Atrial Fibrillation Ablation Devices on the Incidence and Prevention of Complications

The number of patients with atrial fibrillation currently referred for catheter ablation is increasing. However, the number of trained operators and the capacity of many electrophysiology labs are limited. Accordingly, a steeper learning curve and technical advances for efficient and safe ablation are desirable. During the last decades several catheter-based ablation devices have been developed and adapted to improve not only lesion durability, but also safety profiles, to shorten procedure time and to reduce radiation exposure. The goal of this review is to summarise the reported incidence of complications, considering device-related specific aspects for point-by-point, multi-electrode and balloon-based devices for pulmonary vein isolation. Recent technical and procedural developments aimed at reducing procedural risks and complications rates will be reviewed. In addition, the impact of technical advances on procedural outcome, procedural length and radiation exposure will be discussed.

Mobile phones in cryptogenic strOke patients Bringing sIngle Lead ECGs for Atrial Fibrillation detection (MOBILE-AF): study protocol for a randomised controlled trial

Background

Recently published randomised clinical trials indicate that prolonged electrocardiom (ECG) monitoring might enhance the detection of paroxysmal atrial fibrillation (AF) in cryptogenic stroke or transient ischaemic attack (TIA) patients. A device that might be suitable for prolonged ECG monitoring is a smartphone-compatible ECG device (Kardia Mobile, Alivecor, San Francisco, CA, USA) that allows the patient to record a single-lead ECG without the presence of trained health care staff. The MOBILE-AF trial will investigate the effectiveness of the ECG device for AF detection in patients with cryptogenic stroke or TIA. In this paper, the rationale and design of the MOBILE-AF trial is presented.

Methods

For this international, multicentre trial, 200 patients with cryptogenic stroke or TIA will be randomised. One hundred patients will receive the ECG device and will be asked to record their ECG twice daily during a period of 1 year. One hundred patients will receive a 7-day Holter monitor.

Discussion

The primary outcome of this study is the percentage of patients in which AF is detected in the first year after the index ischaemic stroke or TIA. Secondary outcomes include markers for AF prediction, orally administered anticoagulation therapy changes, as well as the incidence of recurrent stroke and major bleeds. First results can be expected in mid-2019.

Trial registration

ClinicalTrials.gov, ID: NCT02507986. Registered on 15 July 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2131-0) contains supplementary material, which is available to authorized users.

Limited left atrial surgical ablation effectively treats atrial fibrillation but decreases left atrial function

AIMS

Limited left atrial (LA) surgical ablation with bipolar radiofrequency is considered to be an effective procedure for treatment of atrial fibrillation (AF). We studied whether limited LA surgical ablation concomitant to cardiac surgery is able to maintain LA function.

METHODS AND RESULTS

Thirty-six consecutive patients (age 66 ± 12 years, 53% male, 78% persistent AF) scheduled for valve surgery and/or coronary revascularization and concomitant LA surgical ablation were included. Epicardial pulmonary vein isolation (PVI) and additional endo-epicardial lines were performed using bipolar radiofrequency. An age- and gender-matched control group (n = 36, age 66 ± 9 years, 69% male, 81% paroxysmal AF) was selected from patients undergoing concomitant epicardial PVI only. Left atrial dimensions and function were assessed on two-dimensional echocardiography preoperatively and at 3- and 12-month follow-up. Sinus rhythm (SR) maintenance was 67% for limited LA ablation and 81% for PVI at 1-year follow-up (P = 0.18). Left atrial volume decreased from 72 ± 21 to 50 ± 14 mL (31%, P < 0.01) after limited LA ablation and from 65 ± 23 to 56 ± 20 mL (14%, P < 0.01) after PVI. Atrial transport function was restored in 54% of patients in SR after limited LA ablation compared with 100% of patients in SR after PVI. Atrial strain and contraction parameters (LA ejection fraction, A-wave velocity, reservoir function, and strain rate) significantly decreased after limited LA ablation. After PVI, strain and contraction parameters remained unchanged.

CONCLUSION

Even limited LA ablation decreased LA volume, contraction, transport function, and compliance, indicating both reverse remodelling combined with significant functional deterioration. In contrast, surgical PVI decreased LA volume while function remained unchanged.

Outcome of stand-alone thoracoscopic epicardial left atrial posterior box isolation with bipolar radiofrequency energy for longstanding persistent atrial fibrillation

Introduction

Catheter ablation of longstanding (> 1 year) persistent atrial fibrillation (AF) is associated with poor outcome. This might be due to remodelling and fibrosis formation, mainly located in the posterior left atrial (LA) wall. Therefore, we adopted a thoracoscopic epicardial box isolation of the posterior left atrium using bipolar RF energy with intraoperative testing of conduction block.

Methods and results

Bilateral thoracoscopic box isolation was performed with a bipolar RF clamp. Entrance block was defined as absence of a conducted electrogram within the box, while exit block was confirmed by pacing at 10.0 V/2 ms. Ablation outcome was evaluated after 3, 6, 12 and 24 months with 12-lead ECGs and 24-hour Holter recordings.

Twenty-five consecutive patients were included (58 ± 7 years, persistent AF duration 1.8 ± 0.9 years). Entrance block was achieved in all patients and exit block confirmed if sinus rhythm was achieved. After 17 ± 7 months, 76 % of the patients (n = 19) were free of AF recurrence. One patient died within 1 month and was considered an ablation failure. Four patients with AF recurrences regained sinus rhythm with additional catheter ablation or antiarrhythmic drugs.

Conclusions

Treatment of longstanding persistent AF with thoracoscopic epicardial LA posterior box isolation using bipolar RF energy with intraoperative testing of conduction block is feasible and highly effective.

Reassessing noninducibility as ablation endpoint of post-infarction ventricular tachycardia: the impact of left ventricular function

BACKGROUND

Noninducibility is frequently used as procedural end point of ventricular tachycardia (VT) ablation after myocardial infarction. We investigated the influence of left ventricular (LV) function on the predictive value of noninducibility for VT recurrence and cardiac mortality.

METHODS AND RESULTS

Ninety-one patients (82 men, 67±10 years) with post-myocardial infarction VT underwent ablation between 2009 and 2012. Fifty-nine (65%) had an LV ejection fraction (EF) >30% (mean 41±7) and 32 (35%) an LVEF≤30% (mean 20±5). Thirty patients (51%) with EF>30% and 13 (41%) with EF≤30% were noninducible after ablation (P=0.386). During a median follow-up of 23 (Q1-Q3 16-36) months, 35 patients (38%) experienced VT recurrences and 17 (18%) cardiac death. At 1 year follow-up, survival free from VT recurrence and cardiac death for patients with LVEF>30% was 80% (95% confidence interval [CI], 70-90) compared with 42% (95% CI, 33-51) for those with LVEF≤30% (P=0.001). Noninducible patients with LVEF>30% had a recurrence-free survival from cardiac death of 90% (95% CI, 71-100) compared with 65% (95% CI, 47-83) for inducible patients (P=0.015). In the subgroup of patients with LVEF≤30%, the survival free from VT recurrence and cardiac death was 31% (95% CI, 0%-60%) for noninducible compared with 39% (95% CI, 27-52) for those who remained inducible (P=0.842).

CONCLUSIONS

Noninducible patients with moderately depressed LV function have a favorable outcome compared with patients who remained inducible after ablation. On the contrary, patients with severely depressed LV function have a poor prognosis independent of the acute procedural outcome.

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.

Natriuretic peptide levels predict recurrence of atrial fibrillation after radiofrequency catheter ablation

BACKGROUND

the presence of atrial fibrillation (AF) is related to increased levels of natriuretic peptides. In addition, increased natriuretic peptide levels are predictive of the development of AF. However, the role of natriuretic peptides to predict recurrence of AF after radiofrequency catheter ablation (RFCA) is controversial.

OBJECTIVE

the study aimed to investigate the role of natriuretic peptides in the prediction of AF recurrence after RFCA for AF.

METHODS

pre-procedural amino-terminal pro-atrial natriuretic peptide (NT-proANP) and amino-terminal-pro-B-type natriuretic peptide (NT-proBNP) plasma levels were determined in 87 patients undergoing RFCA for symptomatic drug-refractory AF. In addition, a comprehensive clinical and echocardiographic evaluation was performed at baseline. Left atrial volumes, left ventricular volumes, and function (systolic and diastolic) were assessed. During a 6-month follow-up period, AF recurrence was monitored and defined as any registration of AF on electrocardiogram or an episode of AF longer than 30 seconds on 24-hour Holter monitoring. The role of natriuretic peptide plasma levels to predict AF recurrence after RFCA was studied.

RESULTS

During follow-up, 66 patients (76%) maintained sinus rhythm, whereas 21 patients (24%) had AF recurrence. Patients with AF recurrence had higher baseline natriuretic peptide levels than patients who maintained sinus rhythm (NT-proANP 3.19 nmol/L [2.55-4.28] vs 2.52 nmol/L [1.69-3.55], P = .030; NT-proBNP 156.4 pg/mL [64.1-345.3] vs 84.6 pg/mL [43.3-142.7], P = .036). However, NT-proBNP was an independent predictor of AF recurrence, whereas NT-proANP was not. Moreover, NT-proBNP had an incremental value over echocardiographic characteristics to predict AF recurrence after RFCA.

CONCLUSION

baseline NT-proBNP plasma level is an independent predictor of AF recurrence after RFCA.

Relationship between obstructive coronary artery disease and abnormal stress testing in patients with paroxysmal or persistent atrial fibrillation

Atrial fibrillation (AF) has been linked to the presence of underlying coronary artery disease (CAD). However, whether the higher burden of CAD observed in AF patients translates into higher burden of myocardial ischemia is unknown. In 87 patients (71% male, mean age 61 ± 10 years) with paroxysmal or persistent AF and without history of CAD, MSCT coronary angiography and stress testing (exercise ECG test or myocardial perfusion imaging) were performed. CAD was classified as obstructive (≥50% luminal narrowing) or not. Stress tests were classified as normal or abnormal. A population of 122 patients without history of AF, similar to the AF group as to age, gender, symptomatic status and pre-test likelihood, served as a control group. Based on MSCT, 17% of AF patients were classified as having no CAD, whereas 43% showed non-obstructive CAD and the remaining 40% had obstructive CAD. A positive stress test was observed in 49% of AF patients with obstructive CAD. Among non-AF patients, 34% were classified as having no CAD, while 41% showed non-obstructive CAD and 25% had obstructive CAD (P = 0.013 compared to AF patients). A positive stress test was observed in 48% of non-AF patients with obstructive CAD. In conclusion, the higher burden of CAD observed in AF patients is not associated to higher burden of myocardial ischemia.

Prevalence of Coronary Artery Disease Assessed by Multislice Computed Tomography Coronary Angiography in Patients With Paroxysmal or Persistent Atrial Fibrillation

Background— Although atrial fibrillation (AF) has been linked to underlying coronary artery disease (CAD), data supporting this association have been based on ECG and clinical history for the definition of CAD rather than direct visualization of atherosclerosis.

Methods and Results— The prevalence of CAD among patients with paroxysmal or persistent AF and without history of CAD was evaluated using multislice computed tomography. Multislice computed tomography was performed in 150 patients with AF (61�11 years, 67% males, 58% asymptomatic) with predominantly low (59%) or intermediate (25%) pretest likelihood of CAD. CAD was classified as obstructive (≥50% luminal narrowing) or not. A population of 148 patients without history of AF, similar to the AF group as to age, gender, symptomatic status, and pretest likelihood, served as a control group. Logistic regression analysis was applied to evaluate the relationship between demographic and clinical data and the presence of obstructive CAD. On the basis of multislice computed tomography, 18% of patients with AF were classified as having no CAD, whereas 41% showed nonobstructive CAD and the remaining 41% had obstructive CAD. Among patients without AF, 32% were classified as having no CAD, whereas 41% showed nonobstructive CAD and 27% had obstructive CAD ( P =0.010 compared with patients with AF). At logistic regression analysis, age, male gender, and the presence of AF were significantly related to obstructive CAD.

Conclusion— A higher prevalence of obstructive CAD was observed among patients with AF, confirming the hypothesis that AF could be a marker of advanced coronary atherosclerosis.

Acute effects of right ventricular apical pacing on left ventricular synchrony and mechanics

BACKGROUND

Chronic right ventricular (RV) apical pacing has a detrimental effect on left ventricular (LV) function. However, the acute effects of RV apical pacing on LV mechanics remain unclear. The purpose of the study was to assess the acute impact of RV apical pacing on global LV function, evaluating LV contraction synchrony and LV shortening and twist, using 2D speckle-tracking strain imaging.

METHODS AND RESULTS

A group of 25 patients with structural normal hearts referred for electrophysiological study were studied. Two-dimensional echocardiography was performed at baseline and during RV apical pacing at the time of the electrophysiological study. Changes in LV synchrony and mechanics (longitudinal shortening and twist) were assessed using speckle-tracking strain imaging. In addition, 25 controls matched by age, sex, and LV function were studied during sinus rhythm. The group of patients (44+/-12 years, 10 men) and the group of controls (48+/-3 years, 8 men) showed comparable LV synchrony, LV longitudinal shortening, and LV twist at baseline. However, during RV apical pacing, a more dyssynchronous LV contraction was observed in the patients (from 21 ms [Q(1):10, Q(3):53] to 91 ms [Q(1):40, Q(3):204], P<0.001) together with an impairment in LV longitudinal shortening (from -18.3+/-3.5% to -11.8+/-3.6%, P<0.001) and in LV twist (from 12.4+/-3.7 degrees to 9.7+/-2.6 degrees , P=0.001).

CONCLUSIONS

During RV apical pacing, an acute induction of LV dyssynchrony is observed. In addition, LV longitudinal shortening and LV twist are acutely impaired.