Thoracoscopic radiofrequency ablation for lone atrial fibrillation: Box-lesion technique

BackgroundWe report the feasibility and outcomes of box-lesion ablation technique to treat stand-alone atrial fibrillation (AF).MethodsThere were 31 patients with a mean age of 63.3 ± 8.4 years who underwent bilateral totally thoracoscopic ablation of symptomatic paroxysmal AF (n = 8; 25.8%) and long-standing persistent AF (n = 23; 75.2%). The box-lesion procedure included bilateral pulmonary vein and left atrial posterior wall ablation using irrigated bipolar radiofrequency with documentation of conduction block.ResultsThere were no intra- or perioperative ablation-related complications. There was no operative mortality, no myocardial infarction, and no stroke. Skin-to-skin procedure time was 152.1 ± 36.7 min and the postoperative average length of stay was 6.26 ± 1.24 days. At discharge, 29 patients (93.5%) were in sinus rhythm. Median follow-up time was 20.4 ± 8.3 months. At three months postsurgery, 20 patients of 30 (66.6%) were free from AF without the need of antiarrhythmic drugs. Six patients (20%) underwent catheter reablation. Twenty-three patients (76.6%) were in sinus rhythm at one year after the last performed ablation (surgical ablation or catheter reablation).ConclusionThe thoracoscopic box-lesion ablation procedure is a safe, effective, and minimally invasive method for the treatment of isolated (lone) AF. This procedure provided excellent short-term freedom from AF.     

Usefulness of ablation of complex fractionated atrial electrograms using nifekalant in persistent atrial fibrillation

BackgroundAdditional ablation of complex fractionated atrial electrograms (CFAE) after pulmonary vein isolation (PVI) has been shown to improve the success of ablation of persistent atrial fibrillation (AF). However, extensive ablation is often necessary to eliminate all CFAE or to terminate AF. We assessed the usefulness of the administration of an antiarrhythmic drug (AAD) before CFAE ablation.Methods and resultsOne-hundred and ten patients with persistent AF first underwent PVI, roof and floor linear ablation (box isolation). One hundred patients who remained in AF after box isolation were then randomized to either receive (AAD group, n = 50) or not receive (no-AAD group, n = 50) intravenous nifekalant (0.3 mg/kg) followed by a CFAE ablation. In the AAD group, nifekalant terminated AF in 19 (38%) patients and ablation of localized CFAE was performed in 31 patients who remained in AF after nifekalant, and terminated AF in 11 (35%) patients. In the no-AAD group, ablation of CFAE terminated AF in 13 (26%) patients. The AAD group had a significantly lesser number of radio frequency applications at CFAE sites (18 ± 12 versus 36 ± 10, p < 0.0001) and shorter procedure time (162 ± 34 versus 197 ± 29 min, p < 0.0001) compared with the no-AAD group. However, there was no significant difference in success rate at 12 months after a single ablation procedure between the two groups (AAD group, 74% versus no-AAD group, 76%).ConclusionsAn approach to ablation using nifekalant may be useful in localizing areas of CFAE, reducing the number of applications at CFAE sites and procedure time. Ablation of only CFAE localized with nifekalant may be sufficient for clinical outcome.     

Bi-directional block is superior to non-inducibility in predicting freedom from atrial fibrillation after pulmonary vein isolation

BackgroundThere is variability in the endpoints used with the different approaches to pulmonary vein (PV) isolation. Elimination of PVP recorded inside the targeted PV antrum indicates inlet block and is considered the 1st indicator of a successful PV isolation, however this may not be sufficient to predict non recurrence of AF.AimTo compare the efficacy of two end points, pulmonary vein (PV) entrance block with non-inducibility (NI) Vs achieving PV bi-directional (BD) block in terms of freedom of AF after PV isolation (PVI) for paroxysmal/persistent atrial fibrillation (AF).MethodWe included 58 consecutive patients (pts) who underwent PVI for symptomatic AF. In all pts, the end point of ablation was abolishing PV potentials (PVP) in the PVs followed by testing for bidirectional block (defined by both loss of PVP and failure to conduct to the LA by pacing at 10 mA and from 10 bipolar pairs of electrodes on a circular catheter positioned at the entrance of the PV) and/or NI of AF (by burst atrial pacing).ResultsBidirectional block was achieved in 40 patients (69%) while Non inducibility was achieved in 36 (58.5%) patients with an overlap of achieving both endpoints in 18 (31%) patients. Over a follow up period of 17 ± 11 months, 34 pts (85%) in group I Vs 22 (62%) in group II were free of AF. Correlation showed significant relation between BD block (OR = 8.07, P = 0.004) Vs NI of AF post-PVI (OR = 2.8, P = 0.095) in predicting freedom from AF at follow up.ConclusionAchieving BD block improves results and may predict maintenance of sinus rhythm more than NI of AF after PVI. It can be used as an electrophysiological endpoint alternative to or in conjunction with non inducibility in AF ablation procedures.     

El fracaso de la ablación por catéter de la fibrilación auricular se asocia con mayor remodelado y menos eficacia de una posterior ablación toracoscópica

Introduction and objectivesRecent observations suggest that patients with a previous failed catheter ablation have an increased risk of atrial fibrillation (AF) recurrence after subsequent thoracoscopic AF ablation. We assessed the risk of AF recurrence in patients with a previous failed catheter ablation undergoing thoracoscopic ablation.MethodsWe included patients from 3 medical centers. To correct for potential heterogeneity, we performed propensity matching to compare AF freedom (freedom from any atrial tachyarrhythmia > 30 s during 1-year follow-up). Left atrial appendage tissue was analyzed for collagen distribution.ResultsA total of 705 patients were included, and 183 had a previous failed catheter ablation. These patients had fewer risk factors for AF recurrence than ablation naïve controls: smaller indexed left atrial volume (40.9 ± 12.5 vs 43.0 ± 12.5 mL/m², P = .048), less congestive heart failure (1.5% vs 8.9%, P = .001), and less persistent AF (52.2% vs 60.3%, P = .067). However, AF history duration was longer in patients with a previous failed catheter ablation (6.5 [4-10.5] vs 4 [2-8] years; P < .001). In propensity matched analysis, patients with a failed catheter ablation were at a 68% higher AF recurrence risk (OR, 1.68; 95%CI, 1.20-2.15; P = .034). AF freedom was 61.1% in patients with a previous failed catheter ablation vs 72.5% in ablation naïve matched controls. On histology of the left atrial appendage (n = 198), patients with a failed catheter ablation had a higher density of collagen fibers.ConclusionsPatients with a prior failed catheter ablation had fewer risk factors for AF recurrence but more frequently had AF recurrence after thoracoscopic AF ablation than ablation naïve patients. This may in part be explained by more progressed, subclinical, atrial fibrosis formation.     

Is radiofrequency energy a necessary and safe complement to cryotherapy for successful pulmonary vein isolation?

IntroductionPulmonary vein (PV) isolation is considered the cornerstone of atrial fibrillation (AF) catheter ablation. PV isolation (PVI) by means of cryotherapy has emerged as a promising technique due to both a low thrombogenicity and reduced risk of PV stenosis. The evaluation (need/efficiency/safety) of hybrid therapy (defined as the use of cryotherapy followed by that of radiofrequency energy in a given patient) is the aim of the present study.MethodsThirty-four consecutive patients (26 men, mean age: 56.7 ± 9.3 years) with symptomatic drug-refractory paroxysmal AF underwent PVI using a balloon-cryotherapy (BCT). A maximum of four cryotherapy applications was applied per PV and disconnection assessed thereafter using a circular LASSO® catheter. When necessary, PV disconnection was then performed using a 4 mm irrigated-tip catheter. All patients underwent CT-scan evaluation before discharge to detect acute PV stenosis.ResultsPVI could be achieved in all patients. Mean procedure duration was 230 ± 42 min and mean fluoroscopy time was 52 ± 13 min. Hybrid therapy was needed to achieve PVI in 26 of 34 (76%). With cryoablation solely, PVI was achieved in 90 of 136 (66%) targeted veins, efficacy being higher in superior as compared to inferior PVs (87% vs. 46%, p < 0.001). Besides one patient with permanent right phrenic nerve injury, no other procedure-related complications were observed. After a mean follow-up period of 8 ± 3 months, 28 patients (82%) did not experience AF recurrence (including six patients on antiarrhythmic drugs).ConclusionsOur study suggests that hybrid ablation therapy is necessary in most patients to achieve PV disconnection after a maximum of four blinded applications of balloon-cryotherapy (especially in inferior PVs), with a significant short-term success rate.     

Hybrid surgical ablation for persistent or long standing persistent atrial fibrillation: A French single centre experience

BackgroundHybrid ablation for the treatment of atrial fibrillation is a single combined procedure consisting in a minimally thoracoscopic surgical ablation followed by a catheter ablation. This promising technique is recommended in persistent atrial fibrillation according to the current guidelines but is not routinely performed in France, mainly due to the absence of reimbursement by the French National Health Insurance.AimsThe aim of this prospective and single-centre study was to analyse, for the first time in France, the feasibility, efficacy and complication rates of hybrid ablation in patients with persistent atrial fibrillation.MethodsHybrid ablation was performed in 15 consecutive patients (13 men, mean age 61 ± 6 years) with persistent (7 patients) or long standing persistent (8 patients) atrial fibrillation.ResultsHybrid ablation was completed in 14/15 patients. Eleven patients returned in sinus rhythm during the procedure. Two patients (13%) had major per-procedural complications and 2 had minor complications. During an average follow-up of 25 ± 6 months, 6 patients (40%) underwent a redo catheter ablation because of atrial tachycardia, mainly peri-mitral atrial flutter. At 1 year follow up, 14/15 patients were in sinus rhythm, including 11 free of antiarrhythmic drugs.     

MMP-9 in atrial remodeling in patients with atrial fibrillation

IntroductionAtrial fibrillation (AF) is the most common arrhythmia and is associated with significant morbidity and mortality. The impact of matrix metalloproteinases (MMPs) on structural atrial remodeling and sustainment of AF in patients with persistent and permanent AF is unresolved.ObjectivesThe aim was to evaluate MMP-9 and its tissue inhibitor-1 (TIMP-1) as markers of atrial remodeling in patients with persistent AF (PAF) who underwent electrical cardioversion (ECV) and in patients with permanent AF (continuous AF, CAF).Patients and methodsPlasma levels of MMP-9 and TIMP-1, clinical findings, and echocardiographic parameters were evaluated in 39 patients with AF and in 14 controls with sinus rhythm.ResultsThe concentrations of MMP-9 were significantly higher in patients with PAF and CAF compared to controls. There was a significant increase of MMP-9 after ECV in the persistent AF group. The values of TIMP-1 were not significantly different between the groups. In patients with AF, MMP-9 levels were positively related to posterior wall thickness of the LV (r = 0.356, P = 0.049) and body mass index (r = 0.367, P = 0.046).ConclusionElevated levels of MMP-9 were related to the occurrence and maintenance of AF. This suggests that MMP-9 can be a marker of atrial remodeling in patients with AF. Regulation of the extracellular collagen matrix might be a potential therapeutic target in AF.     

El tejido adiposo epicárdico no es un predictor independiente de recurrencia de fibrilación auricular tras ablación con catéter

Introduction and objectivesPrevious studies have suggested that epicardial adipose tissue (EAT) could exert a paracrine effect in the myocardium. However, few studies have assessed its role in the risk of atrial fibrillation (AF) recurrence. This study aimed to evaluate the association between EAT volume, and its attenuation, with the risk of AF recurrence after AF ablation.MethodsA total of 350 consecutive patients who underwent AF ablation were included. The median age was 57 [IQR 48-65] years and 21% had persistent AF. Epicardial fat was quantified by multidetector computed tomography using Syngo.via Frontier-Cardiac Risk Assessment software, measuring pericardial fat volume (PATV), EAT volume, and attenuation of EAT posterior to the left atrium. AF recurrence was defined as any documented episode of AF, atrial flutter, or atrial tachycardia more than 3 months after the procedure.ResultsAfter a median follow-up of 34 [range, 12-57] months, 114 patients (33%) had AF recurrence. Univariable Cox regression showed that patients with an EAT volume ≥ 80 mL had an increased risk of AF recurrence (HR, 1.65; 95%CI, 1.14-2.39; P = .007). However, after multivariable adjustment, EAT volume did not remain an independent predictor of AF recurrence (HR, 1.24; 95%CI, 0.83-1.87; P = .3). Similar results were observed with PATV. Patients with lower attenuation of EAT did not have a higher risk of AF recurrence (log-rank test, P = .75).ConclusionsEAT parameters including the evaluation of EAT volume, PATV and EAT attenuation were not independent predictors of AF recurrence after catheter ablation.     

Women with atrial fibrillation and type 2 diabetes have a higher incidence of hospitalization and undergo ablation or pacemaker implantation less frequently than men

BackgroundWe reviewed trends from 2004 to 2013 in the incidence and outcomes for atrial fibrillation (AF) in Spanish patients with type 2 diabetes mellitus (T2DM) comparing women and men.MethodsWe used national hospital discharge data including all T2DM patients discharged from the hospital after AF. Patients with AF in the primary diagnosis field were selected. Discharges were grouped by sex. Incidence was calculated overall and stratified by sex. We analyzed diagnostic and therapeutic procedures, patient comorbidities, CHA2DS2-VASc score, length of hospital stay, readmission rates and in-hospital mortality (IHM).ResultsWe identified a total of 214,457 admissions for AF. Patients with T2DM accounted for 21.1% (19,505 men and 25,954 women). Women with T2DM had a significantly higher incidence of AF compared to men over the study period (IRR 1.33;95%CI 1.31–1.35). Women were significantly older (77.24 ± 8.69 years) than men (72.62 ± 10.28 years), had higher prevalences of obesity and hypertension, and higher CHA2DS2-VASc score. Women less frequently underwent ablation (3.21% vs. 1.54%; p < 0.001) and received an implanted pacemaker (14.3% vs. 8.16%; p < 0.001) than men. Crude IHM was 2.81% for women and 2.48% for men (p = 0.030). Sex was not associated with a higher IHM after multivariable adjustment.ConclusionsOur study demonstrates an increase in hospitalization for AF in diabetic women. Women were older, had a higher comorbidity index and had CHAD2DS2-VASc score than men. Women with AF and T2DM undergo ablation or pacemaker implantation less frequently than their male counterparts. After multivariable adjustment sex did not predict mortality during admissions for AF.     

Estimated glomerular filtration rate and proteinuria are associated with persistent form of atrial fibrillation: Analysis in Japanese patients

BackgroundSeveral reports have identified that decline in renal function and presence of proteinuria are closely associated with incidence of atrial fibrillation (AF). However, it is still unclear whether these kidney-related markers are associated with the progression of AF from paroxysmal to persistent form.Methods and resultsAmong the new patients who visited the Cardiovascular Institute Hospital between 2004 and 2010 (Shinken Database 2004–2010, n = 15,227), both estimated glomerular filtration rate (eGFR) and proteinuria were measured in 1074 AF patients (paroxysmal/persistent 579/495, respectively), who were divided into tertiles of eGFR (the borderlines were 60.07 and 73.67 ml [min^?1] 1.73 [m^?2], respectively), and then further divided into the two categories with/without proteinuria. The average value of eGFR was lower (63.1 ml [min^?1] 1.73 [m^?2] vs. 68.8 ml [min^?1] 1.73 [m^?2], p < 0.001) and the detection rate of proteinuria was higher (13.7% vs. 8.5%, p = 0.006) in patients with persistent AF than in those with paroxysmal AF, respectively. In the multivariate analysis without parameters of echocardiography [left ventricular ejection fraction (LVEF) and left atrial dimension (LAD)], both eGFR and proteinuria were independently associated with persistent AF, but the association was abolished when the model included LAD and LVEF.ConclusionsIn the present analysis with cross-sectional design, both eGFR and proteinuria were apparently linked to the persistent form of AF, but their role in the pathogenesis does not seem to exceed the atrial stretch and remodeling, represented by LAD and LVEF.     

Arrhythmia recurrence in patients following cardiac surgery with concomitant therapy of atrial fibrillation – Experience of our cardiac center

IntroductionSurgical treatment of atrial fibrillation (AF) is a common and time-proven treatment method for this type of arrhythmias both as a separate procedure and as a procedure related to cardiac surgery for another indication (concomitant procedure). Patients experience arrhythmia recurrence despite highly efficient surgical treatment. These arrhythmias are often resistant to pharmacological treatment (due to an extensive fibrous substrate); therefore, electroanatomical mapping accompanying catheter ablation is significantly more effective. The arrhythmogenic fibrous substrate is a result of both a primary cardiac disease (an underlying disease causing atrial dilation) and surgical intervention (incision, cannula insertion sites, MAZE lines with a renewed spread of electrical signal in these blocks).Method and patientsElectroanatomical mapping and ablation were performed in 92 patients with arrhythmia recurrence following concomitant surgical treatment for AF between January 2010 and November 2015. The Cox maze procedure was performed using a disposable cryoablation catheter. The heart rhythm in patients following radiofrequency ablation procedure was monitored in half-year intervals (24-h Holter ECG, 7-day loop recorder, in some patients also by means of implanted pacemakers or implantable loop recorders). The average left atrial size (PLAX) was 50 mm, 59% of patients underwent mitral valve surgery, 54% of patients had tricuspid valve surgery, 16% were operated for congenital developmental disorders, in 17% of patients, repeated cardiac surgery was performed. The above-mentioned facts show that these are patients with an extensive arrhythmogenic substrate.ResultsThe Cox maze procedure resulted in an extensive fibrous arrhythmogenic substrate in the atrium (arrhythmia recurrence following the maze procedure is more often regular atrial tachycardias while AF is predominant among arrhythmias for which the maze procedure was indicated). All patients had a follow-up visit after 12 months, 80% of patients presented for a follow-up visit after 24 months. Early recurrence after ablation (within 3 months following the procedure) was found in 21% of patients. Early recurrence after ablation was statistically significantly related to arrhythmia recurrence within 12 months (p = 0.003) and arrhythmia recurrence within 24 months (p = 0.003). 73% of patients had no recurrent AF or atrial tachycardia (AT) after 12 months and 53% after 24 months. A total of 146 arrhythmias were ablated, i.e. 1/3 of patients had more than 1 arrhythmia. These were persistent AF found in 24% of patients, paroxysmal AF seen in 13% of patients and regular AT detected in 53% of patients. More than one half of regular AT originated in LA (as perimitral atrial flutter in most cases). Remaining arrhythmias originated from the right atrium (as typical atrial flutter in half of the cases). 57% of patients had a renewed spread of signal in the mitral isthmus (ablation of the coronary sinus was necessary in 1/3 of patients). No domination in the number of reconnections was found for any of the pulmonary veins. The finding of a significantly reduced signal amplitude in the entire LA was associated with a higher risk of acute ablation failure (p = 0.001). Acute ablation failure was associated with a higher risk of arrhythmia recurrence after 12 months (p = 0.07). There was a trend of a higher AT incidence originating from the RA in patients who underwent surgery for a congenital heart defect (p = 0.06). The diagnosis of arterial hypertension was associated with a higher risk of arrhythmia recurrence (p = 0.13). The finding of persistent AF on ECG (compared to other findings, i.e. paroxysmal AF and regular AT) before ablation did not increase the risk of recurrence after ablation.ConclusionIn patients after cardiac surgery, catheterization performed to treat arrhythmia recurrence is a effective method of subsequent treatment, despite an extensive arrhythmogenic substrate. A rather large number of AT cases originate from the right atrium, in particular in patients after surgery for congenital heart defects. Patients with a significantly reduced signal in the larger part of the atrium due to an extensive arrhythmogenic substrate present the most complicated cases.     

Thoracoscopic ablation of atrial fibrillation – Should we still be concerned about periprocedural complications?

IntroductionMinimally invasive surgical ablations are becoming an interesting treatment option for patients with stand-alone atrial fibrillation (AF). However, they are in general connected with higher rates of perioperative complications. The aim of this study was to summarize the complications of all such procedures performed in our center and compare them with similar recent papers.Material and methodsAll perioperative and 30-days complications of thoracoscopic ablations of AF performed in our center were collected and analyzed. Recent literature was searched for studies describing the outcomes of thoracoscopic and hybrid ablations. Rates of complications were then compared with our outcomes and also with catheter ablations.ResultsA total of 112 patients underwent a thoracoscopic ablation of AF in our center between 2006 and 2017, with use of three different devices. Mean age was 61.4 ± 8.8 years, 66% were males and 53% of patients had long-standing persistent AF. A life-threatening complications occurred in 2 (1.8%) patients, including 1 conversion to sternotomy and 1 stroke. Severe complications occurred in 6 (5.4%) patients including 2 re-explorations for bleeding, 3 cases of phrenic nerve palsy and 1 respiratory failure. A minor od moderate complications occurred in 17 (15.2%) patients. Twenty-seven suitable papers were identified in recent literature for comparison (total of 1869 patients). The rates of significant complications varied between 0 and 16% over different centers, mean rate was 4.8%. Regarding the catheter ablation studies, 5–7% of patients suffer from some severe complication after ablation of AF.ConclusionsRates of 30-days, life-threatening and severe complications are comparable between mini-invasive surgical and catheter ablations of AF. Rates of minor complications appear to be higher in surgical ablations. To keep the rates low or even to decrease them, those surgical or hybrid procedures should be performed in experienced centers.     

The incidence and types of atrial tachyarrhythmias occurring after hybrid ablation procedures

BackgroundDespite successful creation of box lesions during hybrid ablations, reoccurrence of atrial fibrillation (AF) and/or regular atrial arrhythmias (ATs) still occur. The goal of this study was to describe the incidence and types of regular ATs that occur after successful hybrid ablations.MethodsPatients after hybrid ablation for persistent or long-standing persistent AF were enrolled. Patients, in whom regular AT occurred, were recommended for electrophysiological study and re-ablation. The mechanism of regular AT was described using activation and entrainment mapping.ResultsRegular AT occurred in 5 (10%) patients from 50 patients, in whom hybrid ablation has been performed. Peri-mitral flutter was found to be the mechanism of clinical AT in 4 patients, in the last patient, a typical right sided isthmus-dependent flutter was present. After ablation of the clinical arrhythmia, other ATs were inducible and ablated in two patients resulting in non-inducibility of any arrhythmia at the end of the procedure in all patients. All patients with regular AT were free of symptoms and free of any further tachyarrhythmia or AF during follow-up of 285 ± 122 days.ConclusionThe incidence of regular AT in patients after hybrid ablation procedure was 10%, with the majority of them being associated with re-entry around the mitral annulus.     

Impact of catheter ablation on P-wave parameters on 12-lead electrocardiogram in patients with atrial fibrillation

BackgroundCatheter ablation has emerged as a widely used treatment modality for atrial fibrillation (AF). P-wave abnormalities have been described in the patients with AF, and catheter ablation may potentially further impact P-wave parameters due to ablation of atrial tissue.MethodsWe reviewed data on P-wave parameters (P-wave duration, amplitude and P-wave duration and amplitude product) in leads V1 and aVF and changes in the P-terminal force (Ptf; product of duration and amplitude of terminal part of P-wave) in lead V1 from 12-lead electrocardiograms obtained prior to and after CA of a total of 46 (28 paroxysmal and 18 persistent) AF patients.ResultsThe median age of patients in our study was 63 (range: 30–77) years. We noticed a significant reduction in the P-wave duration (from 87.39 ± 28.62 ms at baseline to 72.09 ± 24.59 ms; p = 0.0072) and the product of P-wave duration and amplitude in lead V1 (12.16 ± 5.54 mV ms at baseline to 8.30 ± 5.78 mV ms, p = 0.0015) after CA. There was also a significant decrease in P-wave duration (from 92.57 ± 19.67 ms at baseline to 76.48 ± 16.32 ms after CA, p = 0.0001) and P-wave duration and amplitude product in lead aVF (12.61 ± 4.05 mV ms at baseline to 9.77 ± 3.86 m V ms after CA, p = 0.0001). CA also led to a significant decrease in Ptf (from 4.56 ± 1.88 at baseline to 2.85 ± 1.42 mV ms, p < 0.0001).ConclusionRadiofrequency catheter ablation of AF leads to modification of P-wave parameters with substantial diminution in both the amplitude and duration of the P-wave in leads V1 and aVF. This likely represents reduction in electrically active atrial tissue after ablation, and may serve as a marker for the extent of ablated atrial tissue.     

Cuantificación de la fibrosis auricular derecha mediante resonancia magnética cardiaca: verificación del método para la estandarización de umbrales

Introduction and objectivesLate gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) allows noninvasive detection of left atrial fibrosis in patients with atrial fibrillation (AF). However, whether the same methodology can be used in the right atrium (RA) remains unknown. Our aim was to define a standardized threshold to characterize RA fibrosis in LGE-CMR.MethodsA 3 Tesla LGE-CMR was performed in 53 individuals; the RA was segmented, and the image intensity ratio (IIR) calculated for the RA wall using 1 557 767 IIR pixels (40 994 ± 10 693 per patient). The upper limit of normality of the IIR (mean IIR + 2 standard deviations) was estimated in healthy volunteers (n = 9), and patients who had undergone previous typical atrial flutter ablation (n = 9) were used to establish the dense scar threshold. Paroxysmal and persistent AF patients (n = 10 each) were used for validation. IIR values were correlated with a high-density bipolar voltage map in 15 patients undergoing AF ablation.ResultsThe upper normality limit (total fibrosis threshold) in healthy volunteers was set at an IIR  =  1.21. In the postablation group, 60% of the maximum IIR pixel (dense fibrosis threshold) was calculated as IIR  =  1.29. Endocardial bipolar voltage showed a weak but significant correlation with IIR. The overall accuracy between the electroanatomical map and LGE-CMR to characterize fibrosis was 56%.ConclusionsAn IIR  >  1.21 was determined to be the threshold for the detection of right atrial fibrosis, while an IIR  >  1.29 differentiates interstitial fibrosis from dense scar. Despite differences between the left and right atria, fibrosis could be assessed with LGE-CMR using similar thresholds in both chambers.     

Hybrid dual stage closed chest ablation of persistent atrial fibrillation

The hybrid ablation (HABL) of atrial fibrillation which combines endoscopic, minimally invasive, closed chest epicardial ablation with endocardial CARTO-guided accuracy was introduced to overcome limitations of current therapeutic options for patients with persistent (PSAF) and long-standing persistent atrial fibrillation (LSPAF). The purpose of this single-centre, prospective clinical registry was to evaluate procedural safety and feasibility as well as effectiveness of the HABL in patients with PSAF and LSPAF 1-year post-procedure. From 07.2009 to 12.2014, ninety (n = 90) patients with PSAF (n = 39) and LSPAF (n = 51) underwent HABL. Mean AF duration was 4.5 ± 3.7 years. At 6 months post-procedure 78% patients were in SR. At 12 months post-procedure 86% patients were in SR and 62.3% in SR and of class I/III AADs. These results suggest that combination of epicardial and endocardial RF ablation should be considered as a treatment option for patients with persistent and long-standing persistent atrial fibrillation as it is safe and effective in restoring sinus rhythm.     

Poor relationship between left atrial diameter and volume in patients with atrial fibrillation

BackgroundLeft atrial (LA) enlargement is a predictor of worse outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence between single LA diameter (LAd) and LA volume (LAV) in patients undergoing catheter ablation for AF.MethodsTotal 782 patients (aged 58±11 yrs; 70% males; 56% paroxysmal AF) were enroled in 2 centres in the period of 2007–2011. Echocardiographic antero-posterior LAd was assessed in parasternal long-axis view and LAV was derived from electroanatomic 3 D reconstruction of LA (183±50 CARTO mapping points; 55% CT image registration).ResultsMean LAd was 45±6 mm (median: 45; IQR: 41–49; range: 25–73 mm) and mean LAV was 134±42 ml (median: 128; IQR: 103–160; range: 46–313 ml). Correlation between both variables was weak (r=0.56; p <0.0001) and area under the ROC curve for the LAd-based prediction of LAV >130 was 0.76. Accordingly, severe dilation of LA (LAV >160 ml; upper quartile) was found only in 56% of patients with LAd >50 mm while it appeared in 11% of those with LAd<45 mm. In multivariate regression analysis, age, gender, and type of AF were independent covariates of LAV yielding the equation of LAV (ml)=68+0.41.cube LAd (cc)+15 (if male)+0.48.age (yrs) – 21 (if paroxysmal AF). Substantial between-centre bias was also found reflecting subjective nature of echocardiographic readings. Adjustment for all covariates improved the correspondence between LAd-predicted and true LAV only modestly (AUC increased from 0.76 to 0.83) with wide 95% limits of agreement (?58 to +60 ml).ConclusionsConsiderable disagreement between echocardiographic LAd and 3D mapping LAV was observed in patients with non-valvular atrial fibrillation. Single LA dimension should not be considered relevant criterion for the indication of rhythm/rate control therapy and, particularly, for the selection of suitable candidates for catheter ablation.     

Resultados de la ablación con catéter con mínimo o nulo empleo de fluoroscopia en pacientes pediátricos con taquiarritmias supraventriculares

Introduction and objectivesIonizing radiation exposure in catheter ablation procedures carries health risks, especially in pediatric patients. Our aim was to compare the safety and efficacy of catheter ablation guided by a nonfluoroscopic intracardiac navigation system (NFINS) with those of an exclusively fluoroscopy-guided approach in pediatric patients.MethodsWe analyzed catheter ablation results in pediatric patients with high-risk accessory pathways or supraventricular tachycardia referred to our center during a 6-year period. We compared fluoroscopy-guided procedures (group A) with NFINS guided procedures (group B).ResultsWe analyzed 120 catheter ablation procedures in 110 pediatric patients (11 ± 3.2 years, 70% male); there were 62 procedures in group A and 58 in group B. We found no significant differences between the 2 groups in procedure success (95% group A vs 93.5% group B; P = .53), complications (1.7% vs 1.6%; P = .23), or recurrences (7.3% vs 6.9%; P = .61). However, fluoroscopy time (median 1.1 minutes vs 12 minutes; P < .0005) and ablation time (median 96.5 seconds vs 133.5 seconds; P = .03) were lower in group B. The presence of structural heart disease was independently associated with recurrence (P = .03).ConclusionsThe use of NFINS to guide catheter ablation procedures in pediatric patients reduces radiation exposure time. Its widespread use in pediatric ablations could decrease the risk of ionizing radiation.     

Registro Español de Ablación con Catéter. XX Informe Oficial de la Asociación del Ritmo Cardiaco de la Sociedad Española de Cardiología (2020)

Introduction and objectivesThis article reports the results of the 2020 Spanish Catheter Ablation Registry, a year marked by the SARS-CoV-2 pandemic.MethodsData were collected retrospectively through completion and return of a specific form by the participating centers.ResultsData from 97 centers (67 public, 30 private) were analyzed. A total of 15 169 ablation procedures were reported with a mean of 155 ± 117 and a median [interquartile range] of 115 [62-227]. Because of the SARS-CoV-2 pandemic, both procedures and participating centers markedly decreased (−3380 procedures, −18%) and there were 5 centers less than in 2019. The most common procedure continued to be atrial fibrillation ablation (4513; 30%), well ahead of the remaining substrates, followed by ablation of the cavotricuspid isthmus (3188; 21%), and intranodal re-entry tachycardia (2808; 18%). Ablation of these 3 substrates continued to form the bulk of the procedures. The total success rate was slightly lower than in previous years (88%) with a similar complication rate (n = 309; 2%) and mortality (n = 7; 0.04%). A total of 243 procedures were performed in pediatric patients (1.6%).ConclusionsThe Spanish Catheter Ablation Registry systematically and continuously reflects the national trajectory, which, in 2020, was markedly affected by the SARS-CoV-2 pandemic. Although slightly lower than in previous years, the success rate remained high, with a low complication rate.Full English text available from:www.revespcardiol.org/en     

Middle-term results of hybrid atrial fibrillation ablation using AtriCure system

IntroductionLong-term results of catheter ablation (CA) for persistent and long-standing persistent atrial fibrillation (AF) are disappointing. The hybrid approach is currently one of options for overcoming the limitations of CA.AimTo evaluate the safety and medium-term efficacy of the hybrid approach in patients with persistent and long-standing persistent AF.MethodsAll patients underwent epicardial thoracoscopic radiofrequency (RF) pulmonary vein (PV) isolation using the AtriCure clamp followed by left atrial (LA) linear lesions (using a linear pen), Marshall ligament disruption, and LA appendage exclusion using an Atriclip. All patients underwent an electrophysiological study (EPS) and RF CA 2–3 months after the initial surgery to eliminate recurrent conductions from/to the PVs or across the linear lesions, and to eliminate all spontaneous and inducible atrial arrhythmias. 7-Day ECG Holter monitoring was performed every 3 months during the first year and every 6 months afterwards to evaluate possible recurrent arrhythmias.ResultsSeventy patients (49 male, median 63.5 years) took part in the study. EPS was performed 87 days (median) after the thoracoscopic surgery. Seventy-six percent of patients were in normal sinus rhythm (SR) at the start of the EPS, 7% had typical atrial flutter, 11% had atrial tachycardia, and 6% were in AF. After completion of the hybrid approach, all PVs were isolated, while a complete conduction block across the linear lines was achieved in 88.6% of patients. Twelve months after the procedure, 77.1% of patients had a stable SR without any anti-arrhythmic medication or re-ablation. If we included those on anti-arrhythmic drugs and re-ablation procedures, SR was achieved in 96.5% of patients during follow-up (936 ± 432 days).ConclusionThe sequential hybrid approach is probably the most effective and relatively safe invasive treatment for persistent and long-term persistent AF with very low medium- to long-term recurrences. Introduction of the hybrid approach to clinical practice requires extensive cooperation between cardiologic and cardiothoracic teams.