Elisabetta Toso

Radiofrequency catheter ablation of atrial fibrillation: A cause of silent thromboembolism? Magnetic resonance imaging assessment of cerebral thromboembolism in patients undergoing ablation of atrial fibrillation

Background— Radiofrequency left atrial catheter ablation has become a routine procedure for treatment of atrial fibrillation. The aim of this study was to assess with preprocedural and postprocedural cerebral magnetic resonance imaging the thromboembolic risk, either silent or clinically manifest, in the context of atrial fibrillation ablation. The secondary end point was the identification of clinical or procedural parameters that correlate with cerebral embolism. Methods and Results— A total of 232 consecutive patients with paroxysmal or persistent atrial fibrillation who were candidates for radiofrequency left atrial catheter ablation were included in the study. Pulmonary vein isolation or pulmonary vein isolation plus linear lesions plus atrial defragmentation with the use of irrigated-tip ablation catheters was performed. All of the patients underwent preprocedural and postablation cerebral magnetic resonance imaging. A periprocedural symptomatic cerebrovascular accident occurred in 1 patient (0.4%). Postprocedural cerebral magnetic resonance imaging was positive for new embolic lesions in 33 patients (14%). No clinical parameters such as age, hypertension, diabetes mellitus, previous history of stroke, type of atrial fibrillation, and preablation antithrombotic treatment showed significant correlation with ischemic cerebral embolism. Procedural parameters such as activated clotting time value and, in particular, electric or pharmacological cardioversion to sinus rhythm correlated with an increased incidence of cerebral embolism. Cardioversion was also associated with an increased risk of 2.75 (95% confidence interval, 1.29 to 5.89; P=0.009). Conclusions— Radiofrequency left atrial catheter ablation carries a low risk of symptomatic cerebral ischemia but is associated with a substantial risk of silent cerebral ischemia detected on magnetic resonance imaging. Independent risk factors for cerebral thromboembolism are the level of activated clotting time and, in particular, the electric or pharmacological cardioversion to sinus rhythm during the procedure.

Prevalence of silent cerebral ischemia in paroxysmal and persistent atrial fibrillation and correlation with cognitive function.

OBJECTIVES The aim of this study was to compare the prevalence of silent cerebral ischemia (SCI) and cognitive performance in patients with paroxysmal and persistent atrial fibrillation (AF) and controls in sinus rhythm. BACKGROUND Large registries have reported a similar risk for symptomatic stroke in both paroxysmal and persistent AF. The relationship among paroxysmal and persistent AF, SCI, and cognitive impairment has remained uncharted. METHODS Two hundred seventy subjects were enrolled: 180 patients with AF (50% paroxysmal and 50% persistent) and 90 controls. All subjects underwent clinical assessment, neurological examination, cerebral magnetic resonance, and the Repeatable Battery for the Assessment of Neuropsychological Status. RESULTS At least 1 area of SCI was present in 80 patients (89%) with paroxysmal AF, 83 (92%) with persistent AF (paroxysmal vs. persistent, p = 0.59), and 41 (46%) controls (paroxysmal vs. controls and persistent vs. controls, p < 0.01). The number of areas of SCI per subject was higher in patients with persistent AF than in those with paroxysmal AF (41.1 ± 28.0 vs. 33.2 ± 22.8, p = 0.04), with controls reporting lower figures (12.0 ± 26.7, p < 0.01 for both). Cognitive performance was significantly worse in patients with persistent and paroxysmal AF than in controls (Repeatable Battery for the Assessment of Neuropsychological Status scores 82.9 ± 11.5, 86.2 ± 13.8, and 92.4 ± 15.4 points, respectively, p < 0.01). CONCLUSIONS Patients with paroxysmal and persistent AF had a higher prevalence and number of areas of SCI per patient than controls and worse cognitive performance than subjects in sinus rhythm.

Ablation of atrial fibrillation: does the addition of three-dimensional magnetic resonance imaging of the left atrium to electroanatomic mapping improve the clinical outcome?A randomized comparison of Carto-Merge vs. Carto-XP three-dimensional mapping ablation in patients with paroxysmal and persistent atrial fibrillation

AIMS To compare in a randomized and prospective fashion the outcome of atrial fibrillation (AF) ablation either after one procedure or after two procedures using the Carto-XP vs. the Carto-Merge mapping system in two different AF populations. METHODS AND RESULTS Two hundred and ninety-nine patients with paroxysmal and persistent AF were enrolled in the study. One hundred and fifty patients with paroxysmal or persistent AF were randomly assigned to the Carto-Merge group and 149 patients to the Carto-XP group. The Carto-Merge patients underwent magnetic resonance imaging (MRI) of left atrium (LA) the day before the ablation. The ablation scheme included electrical disconnection of the pulmonary veins plus linear lesions. In the Carto-Merge patients, the three-dimensional MRI of the LA reconstruction merged with the electroanatomical map, and in the Carto-XP patients, the electroanatomical map guided the procedure. Considering the overall population with paroxysmal AF, 54% maintained sinus rhythm (SR), whereas in the persistent AF population, SR was present in 43% of the patients at the 12-month follow-up. In patients with paroxysmal AF, 52% in the Carto-XP group and 55% in the Carto-Merge group maintained SR without drugs. Procedure durations and exposure to X-ray in the Carto-XP group were 94.6 +/- 17.5 and 40.4 +/- 13.5 min, respectively. In the Carto-Merge group, duration and X-ray exposure were 89 +/- 41.6 and 22.1 +/- 11.4 min, respectively. Considering the patients with persistent AF at the12-month follow-up, 44% in the Carto-XP group and 42% in the Carto-Merge group maintained SR without drugs. Procedure durations and X-ray exposure in the Carto-XP group were 102.9 +/- 22.9 and 58 +/- 8.7 min, respectively. In the Carto-Merge group, both duration and X-ray exposure were 114.4 +/- 50.9 and 28.8 +/- 14.3 min, respectively. CONCLUSION Image integration using Carto-Merge in patients undergoing catheter ablation for paroxysmal and persistent AF does not significantly improve the clinical outcome, but shortens the X-ray exposure.

Incidence of cerebral thromboembolic events during long-term follow-up in patients treated with transcatheter ablation for atrial fibrillation.

AIMS Net clinical benefit of long-term oral anticoagulation therapy (OAT) continuation after successful atrial fibrillation (AF) ablation is still controversial. To evaluate long-term thromboembolic (TE) and haemorrhagic events incidence according to OAT strategy used after AF transcatheter ablation. METHODS AND RESULTS Three months after AF ablation, OAT was discontinued in patients with CHADS2 ≤ 1 if no recurrences were documented, while OAT was maintained in patients with CHADS2 ≥ 2 regardless of AF recurrences. CHA2DS2VASc and HAS-BLED scores have been retrospectively evaluated. Seven hundred and sixty-six patients were followed for a median of 60.5 months. Six (6/267 = 2.2%) and five (5/499 = 1%) TE events occurred in the ON and the OFF-OAT patients, respectively (P = 0.145), all in concomitance with the AF recurrence. CHADS2 and CHA2DS2VASc ≥ 2 were associated with high TE incidence (P = 0.047 and P = 0.020). Among patients with a CHADS2 score of 0 or 1, a CHA2DS2VASc score ≥ 2 was predictive of TE events (P = 0.014). Overall, the incidence of the TE events in patients with CHA2DS2VASc ≥ 2 was 0.6 per 100 patient-years whereas seven haemorrhagic events occurred, all of them in the ON-OAT patients (7/267 = 2.6%). CONCLUSION Patients with AF undergoing transcatheter ablation have a lower incidence of TE events as compared with the general AF population, regardless of OAT maintenance. The unpredictable risk of AF recurrence, mandate the routine use of the CHADS2, CHA2DS2VASc, and HAS-BLED scores to guide clinical decision regarding OAT management in this peculiar setting of patients. The potential protective role of rhythm control strategy in the TE events needs to be confirmed by future large randomized trials.

Long-term progression from paroxysmal to permanent atrial fibrillation following transcatheter ablation in a large single-center experience

BACKGROUND The natural history of atrial fibrillation (AF) is characterized by gradual increase in duration and frequency of relapses until a definitive shift to permanent AF. Heart disease and comorbidities modulate AF progression. However, to date the influence of catheter ablation on AF evolution has rarely been investigated. OBJECTIVE The purpose of this study was to identify long-term predictors of AF progression in a large cohort of patients undergoing AF transcatheter ablation (AFTCA). METHODS A total of 889 patients (mean age 57 ± 11 years; 53.3% paroxysmal AF, 40.5% persistent AF, 6.2% long-standing AF) underwent AFTCA. All patients underwent pulmonary vein isolation, with linear lesions and complex fractionated atrial electrogram ablation reserved for patients with persistent/long-standing AF and/or confirmed structural heart disease. RESULTS After median follow-up of 64 months (range 41-84 years), AF progression despite AFTCA occurred in 57 cases (6.4%). However, AF progression was much more pronounced in patients with persistent (10%) or long-standing persistent AF (14.6%) than in those with paroxysmal AF (2.7%, P <.001). Furthermore, AF progression was more frequently reported in patients who presented with underlying comorbidities/cardiomyopathies (9.1%) than in those who presented with lone AF (29.9%, P <.001). At multivariate analysis, comorbidities/cardiomyopathies and baseline persistent/long-standing AF proved to be independent predictors of progression (odds ratio 11.3, 95% confidence interval 2.6-48.0, P <.001, and odds ratio 1.6, 95% confidence interval 1.2-2.1, P <.001, respectively). CONCLUSION The presence of comorbidities/cardiomyopathies and persistent/long-standing AF seem to predict AF progression in patients undergoing AFTCA. Performing AFTCA in the paroxysmal phase of the arrhythmia may reduce progression of AF to its permanent form.

Long-term events following atrial fibrillation rate control or transcatheter ablation: a multicenter observational study.

Background Atrial fibrillation increases thromboembolic risk. Oral anticoagulation with antivitamin K (AVK) reduces thromboembolic event rate, but increases hemorrhagic risk. Objective The aim of the present study was to describe long-term cerebral thromboembolic/hemorrhagic event rates in atrial fibrillation patients managed by rhythm control, pursued by atrial fibrillation transcatheter ablation (AFTCA), and rate control strategy. Methods and results One thousand and five hundred consecutive patients referring to three medical care centers for atrial fibrillation were retrospectively divided into three groups: AFTCA maintaining AVK (group A); AFTCA discontinuing AVK (group B); and rate control strategy and AVK (group C). Thromboembolic and hemorrhagic events were recorded in 60 ± 28 months of follow-up. Thromboembolic events did not differ between the groups (5/500, 1% group A; 7/500, 1.4% group B; 11/500, 2.2% group C; P = 0.45), and hemorrhagic events were greater in group A (9/500, 1.8%) and C (12/500, 2.4%) than in group B (no events; P = 0.003). Among patients with CHA2DS2 VASc score 2 or less, thromboembolic events did not differ in the group discontinuing AVK (group B, 4/388, 1%) or not (group A, 1/319, 0.3%; P = 0.38), whereas hemorrhagic events were more common in patients on AVK (5/319, 1.5% group A and 3/175, 1.7% group C; P = 0.02) compared with those discontinuing AVK (0/388, group B). Following AFTCA (groups A and B), 299/1000 experienced atrial fibrillation relapses; all thromboembolic events (12/299, 4%) occurred within these patients (P < 0.001). Conclusion Considering this multicenter design study, AVK continuation following AFTCA, especially within patients with low-to-intermediate thromboembolic risk, confers a hemorrhagic risk greater to the thromboembolic protective effect. All thromboembolic events following AFTCA occur within patients experiencing atrial fibrillation relapses; therefore, in patients with high thromboembolic risk routine rhythm monitoring is essential after AVK discontinuation.

Berberine behind the thriller of marked symptomatic bradycardia

Patients with chronic aortic dissections are at high risk of catheter-induced complications. We report a Berberine is used in traditional Chinese medicine for the treatment of congestive heart failure, hypertension, diabetes, and dyslipidaemia and has a good safety profile. We report a case of a 53-year-old sportsman referred to our hospital for the onset of fatigue and dyspnoea upon exertion after he started berberine to treat hypercholesterolaemia. An electrocardiogram showed sinus bradycardia (45 bpm), first-degree atrioventricular block, and competitive junctional rhythm. An ergometric stress test showed slightly reduced chronotropic competence and the presence of runs of competitive junctional rhythm, atrial tachycardia, and sinus pauses in the recovery. After 10 d of wash-out from berberine, the patient experienced a complete resolution of symptoms, and an ergometric stress test showed good chronotropic competence. An electrocardiogram Holter showed a latent hypervagotonic state. This is the first case report that shows that berberine could present certain side effects in hypervagotonic people, even in the absence of a situation that could cause drug accumulation. Therefore, berberines use should be carefully weighed in hypervagotonic people due to the drugs bradycardic and antiarrhythmic properties, which could became proarrhythmic, exposing patients to potential health risks.

Delaying cardioversion following 4-week anticoagulation in case of persistent atrial fibrillation after a transcatheter ablation procedure to reduce silent cerebral thromboembolism: a single-center pilot study.

Background Symptomatic cerebral thromboembolism occurs in 0.4% of transcatheter atrial fibrillation ablation procedures. Silent cerebral events, instead, have recently been reported in up to 14%, especially clustered within patients undergoing cardioversion at the end of the procedure. The present study reports the incidence of silent cerebral thromboembolism, assessed by cerebral MRI, delaying electrical cardioversion, in case of lack of sinus rhythm restoration at the end of the procedure, after 4 weeks of effective anticoagulation. Methods and results Ninety-five consecutive patients with antiarrhythmic drug refractory atrial fibrillation were referred for transcatheter ablation and enrolled in the study. All patients underwent pre-ablation and post-ablation cerebral MRI. Overall, post-ablation cerebral MRI registered new thromboembolism in six (6%) patients. Fifty-five (58%) patients remained in sinus rhythm throughout the procedure and 40 (42%) reported persistent atrial fibrillation, yielding a silent thromboembolism incidence of 5 and 8%, respectively. In particular, silent thromboembolism was registered in one (4%) of the 25 patients achieving sinus rhythm by catheters, in two (18%) of the 11 patients spontaneously restoring sinus rhythm shortly following the procedure and in none of the four patients cardioverted following 4-week anticoagulation. In a matched reference population, a significantly higher percentage of patients (15, 16% vs. 6, 6%; P = 0.03) suffered from a new post-ablation thromboembolism; particularly within patients terminating the procedure in atrial fibrillation. Delaying cardioversion reduced silent cerebral thromboembolism from 38 to 13%. Conclusion Delaying electrical cardioversion after a 4-week anticoagulation period reduced the risk of silent cerebral thromboembolism and is a viable and safer option in patients terminating a transcatheter ablation procedure in atrial fibrillation.

NOACs and atrial fibrillation: Incidence and predictors of left atrial thrombus in the real world

AIMS Despite optimal oral anticoagulation with vitamin K antagonist, left atrial (LA) thrombus could be detected in the left appendage (LAA) in >2% of patients with atrial fibrillation (AF) and CHA2DS2-VASc score≥1 but few data are available for patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). We evaluated the occurrence and predictors of LA thrombi by means of transesophageal echocardiography (TOE) in consecutive patients with non-valvular AF who received for at least 3weeks Apixaban, Dabigatran, or Rivaroxaban. METHODS This study included 414 consecutive patients (male 252, 60.6%, mean age 67.3years) referred to our Centers for catheter ablation of AF (n=220, 53.1%) or scheduled electrical cardioversion (n=194, 46.9%). Patients were on Dabigatran (n=160), Rivaroxaban (n=150) or Apixaban (n=104). TOE was performed in all cases within 12h prior to ablation or cardioversion. RESULTS Preprocedural TOE revealed LA thrombus in 15/414 patients (3.6%), all located in the LAA (Apixaban 3/104 2.9%, Dabigatran 5/160 3.1%, and Rivaroxaban 7/150 4.7%, p=0.69). Of these, 14 patients had persistent AF. Patients with LAA thrombus had a mean CHA2DS2-VASc score of 3 (3-4). Higher CHA2DS2-VASc score (p=0.02), but not the type of NOAC, significantly predicted the presence of LA thrombus. CONCLUSION The incidence of LAA thrombus in a cohort of patients anticoagulated with NOACs is low but not negligible, in any case similar among the 3 drugs. Preprocedural TOE should be considered in patients with a CHA2DS2-VASc score>3.

Incidence of thromboembolic events following atrial fibrillation catheter ablation and rate control strategies according to the kind of oral anticoagulation: A systematic review and meta-analysis

INTRODUCTION Anticoagulantion therapy (OAT) represents the cornerstone to reduce thromboembolic events for atrial fibrillation (AF). Recent studies suggest that AF catheter ablation on top of OAT may be useful to further reduce the thromboembolic risk in AF patients. The aim of the present study is to compare the long-term risk of thromboembolic events and treatment-related complications in patients with AF treated by OAT strategies and catheter ablation. METHODS Pubmed, Cochrane and Google Scholar were searched for studies including >500 patients evaluating AF patients treated with OAT (VKA: vitamin K antagonist or DOAC: Direct oral anticoagulants) and/or AF ablation. Pooled incidence of stroke/year was the primary end point, while that of stroke, of all cause bleeding and of major bleeding the secondary ones. All the analyses were stratified according to the CHADS2 score of included patients. RESULTS Overall, 27 studies were selected, including 50,973 patients in the AF catheter ablation group; 281,595 patients in the VKA group; 54,811 patients in the DOAC group. After a mean follow-up of 2.4 (1.5-3.8) years, the overall incidence of stroke and thromboembolic events was 0.63 per 100 patients/year in AF ablation group, 2.09 per 100 patients/year in VKA group and 1.24 per 100 patients/year in DOAC group (p < 0.001). After stratification in 4 groups according to CHADS2 score, the incidence of thromboembolic events remained lower in patients included in the AF ablation, followed by DOAC and VKA respectively (p < 0.001), for each CHADS2 cluster. Both the incidence of all cause bleedings and major bleedings resulted lower in AF ablation group (p < 0.001). The incidence of all-cause mortality in the AF ablation group was significant lower than in the group of OAT (p < 0.0001). CONCLUSION AF catheter ablation significantly reduces the incidence of long-term thromboembolic events compared to both VKA and DOAC. This reduction is maintained in all CHADS2 score clusters and is strengthened by the concomitant reduction in hemorrhagic complications provided by AF ablation.