Left Atrial Catheter Ablation Research Articles

Atrial fibrillation burden, symptoms and medication use after left bundle branch area pacing combined with AV-node ablation in patients with symptomatic atrial fibrillation

Abstract Background AV node ablation combined with permanent pacing is an established therapy for rate control in patients with symptomatic atrial fibrillation (AF) refractory or intolerant to pharmacological rate or rhythm control and not eligible for rhythm control by left atrial catheter ablation. The threshold for performing this so-called "pace-and-ablate" strategy has decreased since the introduction of conduction system pacing, and especially left bundle branch area pacing (LBBAP). Purpose To investigate the AF burden, AF related symptoms and anti-arrhythmic drug (AAD) use after AV-node ablation combined with LBBAP. Methods Consecutive patients with symptomatic AF, intolerant or refractory to pharmacological rate and symptom control and deemed not eligible for left atrial catheter ablation, were included. At baseline, AF related symptoms classified according to the EHRA classification and AAD use were scored. After DDD-pacemaker implantation with an LBBAP lead and subsequent AV-node ablation device detected AF burden was assessed six weeks, six months and twelve months later. AF burden at six weeks after AV-node ablation was considered the baseline measurement for AF burden. AF related symptoms and AAD use were collected at twelve months follow-up. Results Twenty-four patients (67% female, mean age 79±4 years) scheduled for pace-and-ablate therapy were prospectively included. Eighteen patients had persistent (75%) and three long-standing persistent (12.5%) AF with enlarged left atria (left-atrial volume index (LAVI) 52 ± 18ml/m2) and EHRA class IIb or higher in twenty (69%) patients. Twenty-three patients (96%) used at least one AAD with fifteen patients (63%) using >1 AAD at baseline, fig. 1. AF burden did not change at six months (-1.3 [-17, 15] %, p=0.87) and twelve months (-2.9 [-40,35] %, p=0.86) follow-up relative to six weeks follow-up, fig 2A. AF symptoms were significantly reduced with most patients in EHRA class I (6, 25%) or class IIa (17, 71%; p<0.001) at twelve months follow-up, fig 2B. There was a significant reduction in AAD use with fourteen patients (58%) using no AAD at twelve months follow-up and no patients using >1 AAD at twelve months follow up (p<0.001), fig 2C. Conclusion AV node ablation followed by permanent LBBAP did not reduce AF burden in an AF population with advanced disease. However, a significant reduction in AF symptoms and medication use was demonstrated with this therapy. Figure 2. AF burden (panel A), symptoms (panel B) and AAD use (panel C) at baseline and twelve months after ‘pace-and-ablate’ therapy. AF = atrial fibrillation; EHRA = EHRA = European Heart Rhythm Association symptom classification for AF; AAD = anti-arrhythmic drug. *relative to AF burden at six weeks follow-up.Baseline characteristicsBaseline and follow-up measurements

Echocardiographic follow-up after AV node ablation combined with left bundle branch area pacing for patients with symptomatic atrial fibrillation

Abstract Background AV node ablation combined with permanent pacing is an established therapy for rate control in patients with symptomatic atrial fibrillation (AF) refractory or intolerant to pharmacological rate or rhythm control and not eligible for rhythm control by left atrial catheter ablation. The threshold for performing this so-called "pace-and-ablate" strategy has decreased since the introduction of conduction system pacing, and especially left bundle branch area pacing (LBBAP). Purpose To investigate the change of the left-ventricular (LV) ejection fraction (EF) and left-atrial volume index (LAVI) in patients with symptomatic AF, twelve months after LBBAP and AV-node ablation. Methods Consecutive patients with symptomatic AF intolerant or refractory to pharmacological rate and symptom control and deemed not eligible for left atrial catheter ablation were included. At baseline, the EHRA score was noted and the LVEF and LAVI were measured echocardiographically. Patients were subdivided in a normal baseline LV ejection fraction (LVEF >50%) or diminished baseline LVEF (LVEF <50%) group. After LBBAP, patients underwent AV node ablation in the same procedure or four weeks later. After twelve months, the LVEF and LAVI were reassessed in the entire cohort and the two subgroups. Results Twenty-two patients (68% female, mean age 79±4 years) scheduled for pace-and-ablate therapy were prospectively included. Three (14%) had paroxysmal, sixteen patients (72%) had persistent AF and three patients (14%) long-standing persistent AF. An EHRA class IIb or higher was found in eighteen patients (82%). At baseline, the mean LVEF was 51 ± 7%, the mean LVEDD 47 ± 6 mm and LAVI 54 ± 18 ml/m2. Twelve patients (55%) had a preserved LVEF, whereas ten patients (45%) had an LVEF <50%, fig. 1. After twelve months, the overall ejection fraction increased to 54 ± 5% (p=0.016), fig. 2A. This was mostly attributed to the increase in LVEF to 51 ± 5% in the subgroup with a reduced baseline LVEF (p=0.009 compared to baseline 44 ± 5%), fig. 2A. The LVEF was unaffected in the other group (57 ± 3% vs. 57 ± 4%, p=0.63), fig. 2A. The LAVI was not significantly reduced in the overall cohort or the subgroups (54 ± 18 ml/m2 to 51 ± 19 ml/m2, p=0.16), fig 2B. Conclusion AV node ablation combined with LBBAP results in a significant improvement in LVEF at twelve months follow-up. This is mainly driven by an improvement in LVEF in those patients with a diminished LVEF at baseline. The data suggests that the therapy can reverse a tachycardiomyopathy without inducing a pacing-induced cardiomyopathy. No significant reduction in LAVI was found.Baseline characteristicsChanges in LVEF (A) and LAVI (B)

Two-year safety and effectiveness of hybrid ablation versus catheter ablation in patients with non-paroxysmal AF: mid-term results of the CEASE-AF trial

Abstract Background Hybrid Ablation for atrial fibrillation (AF) combines epicardial and endocardial ablation through a Heart Team approach to target durable, transmural isolation of the pulmonary veins (PV) and left atrial posterior wall (LAPW). While the primary efficacy endpoint at 12 months was met with a significant benefit increase for hybrid ablation, we now report the midterm durability of those results. Purpose To evaluate 24-months safety and effectiveness of Hybrid Ablation with left atrial appendage exclusion (LAAE) versus Catheter Ablation in patients with persistent AF/enlarged left atrium and longstanding persistent AF (LSPAF). Methods CEASE-AF is a prospective, multi-center, 2:1 randomized controlled trial. Eligible patients were 18-75 years of age, had symptomatic, drug-refractory persistent AF and enlarged left atrium (>4 cm) or LSPAF, and were undergoing a first ablation. Hybrid Ablation consisted of two stages: thoracoscopic epicardial radiofrequency (RF) ablation for PV and LAPW isolation and epicardial LAAE followed by endocardial ablation 91-180 days later. Catheter Ablation consisted of minimum PV isolation by endocardial RF ablation, and repeat ablation was allowed between 91-180 days. In both arms, additional lesions were permitted according to institutional practices. Effectiveness was freedom from AF/atrial flutter (AFL)/atrial tachycardia (AT) off anti-arrhythmic drugs (AAD) (except AADs not exceeding doses which previously failed) and was assessed through 48-h Holter monitoring reviewed by an independent core laboratory blinded to the study. Safety was major adverse events throughout the study, adjudicated by an independent Clinical Events Committee. Results There were 102 Hybrid Ablation and 52 Catheter Ablation patients; 26% were female, mean age was 60.7±7.9 years, mean LAD was 4.7±0.4 cm, and 19% had LSPAF with no differences between arms. The 12- and 24-month results are shown for comparison (Table). Through 24-months, effectiveness was 66.3% (63/95) in the Hybrid Arm and 33.3% (17/51) in the Catheter Arm (absolute difference 33.0% [95% CI 14.3%, 48.3%; p<0.001]). Major adverse event rates through 24-months were statistically similar at 10.8% (11/102) in the Hybrid Arm and 9.6% (5/52) in the Catheter Arm (p=1.0). Through 24-months, repeat ablations were performed in 7.4% (7/95) of the Hybrid Arm versus 37.3% (19/51) of the Catheter Arm (p<0.001), and cardioversions were performed in 14.7% (14/95) of the Hybrid Arm versus 29.4% (15/51) of the Catheter Arm (p=0.034) Conclusions: CEASE-AF demonstrated that superior effectiveness of Hybrid Ablation including LAAE versus Catheter Ablation was durable through 24-month follow-up, with 33% absolute improvement in freedom from AF/AFL/AT. Safety rates continued to be similar between arms. Three-year follow-up is ongoing.

Left atrial strain measurement in patients with heart failure and atrial fibrillation compared to a control group

Abstract Background Left atrial (LA)-strain measurement is a non-invasive and widely available echocardiographic method to detect atrial cardiomyopathy as a process of structural and functional remodeling. The aim of this study is to measure LA-strain in patients with heart failure (HF) and atrial fibrillation (AF), compared to patients without structural heart disease and to evaluate whether or not LA-Strain could be part of a multi-modality assessment that influences therapy strategies and prognosis in patients suffering AF. Methods This study includes 18 patients with HF in sinus rhythm who underwent CRT implantation (HF group), 25 patients with persistent AF and preserved ejection fraction (EF) who underwent left atrial catheter ablation (AF group) and 22 patients without structural heart disease or AF who underwent electrophysiological study (control group). All subjects received measurement of reservoir (LASr), conduit (LAScd) and contraction (LASct) LA strain imaging using two-dimensional speckle tracking echocardiography (2D-STE). Results Patient characteristics in the HF-group showed mean age 68y (SD 10,6), mean EF 29% (SD 6,8), 66% male compared to the AF-group with mean age 66y (SD 8.0), mean EF 60% (SD 5.1), 68% male. The control-group showed mean age 55y (SD 13.8), mean EF 60% (SD 5.4), 55% male. For LASr we found normal values in the control groups and reduced values in the HF und AF group (HF: mean 20% [9 – 45%], AF: mean 24% [7 – 52%], control: mean 42% [30 – 67%]). In LASr, LAScd and LASct there was a statistically significant difference between the HF and the control group (p < 0.001) as well as the AF and control group (p < 0.001), whereas there was no difference between AF and HF group (p = 0.444). Discussion Patients with persistent AF show similar LA-strain compared to patients with HF and patients without structural heart disease present significant better LA strains. The findings of this study suggest, that LA strain analysis might contribute to comprehensive assessment of patients with AF especially as a simple imaging method. A limitation of our results could be the significant younger age of our control group (p = 0.004) as fibrotic remodeling increases in advanced age. It remains to be analyzed whether early AF treatment could prevent further fibrotic remodeling and whether measuring LA strain could provide further information for risk stratification and the definition of therapeutic intervention strategies.

Left atrial strain defines functional and structural remodeling in patients with persistent atrial fibrillation

Abstract Background Left atrial (LA) strain is an echocardiographic method to detect atrial dysfunction as a process of structural and functional remodeling of the atria. In patients with persistent atrial fibrillation (AF), functional changes and an enlargement of the LA due to structural remodeling has been described. The aim of our study was 1) the echocardiographic assessment of LA function using LA strain and 2) to investigate the correlation between LA strain and left atrial size index (LAVI) using 3D reconstruction of the LA from multi-detector computed tomography (CT). Methods This study includes patients with persistent AF who underwent LA catheter ablation without prior treatment. All subjects underwent measurement of reservoir (LASr), conduit (LAScd) and contraction (LASct) LA strain using imaging using two-dimensional speckle tracking echocardiography (2D-STE) and cardiac CT. A 3D reconstruction of the LA from the CT was done using EnSite Verismo (Abbott, USA). The LA volume obtained at the end-systole included LA appendage reconstruction and excluded the pulmonary veins. LAVI was calculated by dividing LA volume by body surface area. Results The study included 36 patients (mean age 69 yrs [49 to 80 yrs], 27 male, mean LV-EF 56% [40 to 78%). We found the following LA strain measurement: mean LASr 21% [6 to 52%], mean LAScd -12% [-32 to -0,25%] and mean LASct -9% [-32 to -1%]. LAVI: mean 82 ml/m² [38 to 127 ml/m²]. There is a statistically significant negative correlation between LASr (p = 0.002, r = -0.503) and a statistically positive correlation between LASct (p = 0.003, r = 0.482) compared to the LA volume, whereas there is no statistically significant correlation between LAScd and the LA volume (p = 0.088, r = 0.288). Discussion LA strain in patients with persistent AF as an expression of functional remodeling is reduced compared to normal values in literature. Correlation of LA strain and LAVI are statistically significant for LASr as well as LASct. The correlation between LAScd and LAVI did not reach statistical significance but shows a trend towards a positive correlation. Whether early treatment of AF could prevent further fibrotic remodeling with reducing LA volume and improving LA strain needs further research.

Safety and feasibility of atrial fibrillation ablation after left atrial appendage closure: A single‐center experience of the left atrial appendage closure first strategy

AbstractBackgroundPatients with atrial fibrillation (AF) who are not suitable for long‐term anticoagulant therapy undergo percutaneous left atrial appendage closure (LAAC). The safety and feasibility of left atrial catheter ablation (CA) procedures after LAAC remain unclear. This study aimed to clarify the feasibility and safety of CA after LAAC, including in the early phase within 180 days.MethodsCharacteristics and clinical outcomes of 46 patients with AF who had undergone both CA and LAAC within 2 years (mean age, 72 years; 29 men) were compared between those who had undergone CA‐first (31 patients) and LAAC‐first (15 patients).ResultsThe mean CHA₂DS₂‐VASc and HAS‐BLED scores were 4.8 and 3.3 points, respectively. The LAAC‐first strategy was often used in patients with prior major bleeding and LAA thrombosis or sludge. In the LAAC‐first group, the mean duration between both procedures was 212 days, and all LAAC‐first patients, including seven patients in the early phase, could undergo CA without LAAC device‐related complications; moreover, no cardiovascular adverse events were reported after both procedures (mean periods: 420 days). After CA post‐LAAC, no device‐related adverse events (device‐related thrombosis, new peri‐device leak appearance, peri‐device leak increase, or device dislodgement) were observed, whereas, after LAAC post‐CA, 3 new peri‐device leak appearance events and 1 peri‐device leak increase event were observed, especially patients who underwent LAAC in the early phase post‐CA.ConclusionBased on single‐center experience, left atrial CA in the presence of an LAAC device implanted including the early phase was safe and feasible.

The impact of ultrasound-guided vascular access for catheter ablation of left atrial arrhythmias in a high-volume centre.

Vascular complications are a common occurrence during atrial fibrillation ablation. Observational studies indicate that the utilization of ultrasound (US)-guided puncture may decrease the incidence of vascular complications; however, its routine use is not established in many centres. Patients undergoing catheter ablation for atrial fibrillation were included sequentially. All patients receiving US-guided punctures were prospectively enrolled (US group), while patients who underwent the procedure with standard puncture technique served as control group (No-US group). Periprocedural vascular complications requiring intervention within 30days of the procedure were defined as the primary endpoint. A total of 599 patients (average age: 69 ± 11years, 62.9% male) were analysed. The incidence of vascular complications was lower with the US-guided puncture than with the anatomic landmark-guided puncture (14/299 [4.7%] vs. 27/300 [9%], p = 0.036). The US-guided vascular access significantly reduced the rate of false aneurysms (3/299 [1%] vs. 12/300 [4%], p = 0.019). In addition, the occurrence of arteriovenous fistula (2/299 [0.7%] vs. 4/300 [1.3%], p = 0.686) and haematoma requiring treatment (9/299 [3%] vs. 11/300 [3.7%], p = 0.655) were also lower in the US group. US-guided puncture did not prolong the procedure time (mean procedure time: 57.48 ± 24.47min vs. 56.09 ± 23.36min, p = 0.478). Multivariate regression analysis identified female gender (OR 2.079, CI 95% 1.096-3.945, p = 0.025) and conventional vascular access (OR 2.079, CI 95% 1.025-3.908, p = 0.042) as predictors of vascular complications. The implementation of US-guided vascular access for left atrial catheter ablation resulted in a significant decrease of the overall vascular complication rate.

Renal function and periprocedural complications in patients undergoing left atrial catheter ablation: A comparison between uninterrupted direct oral anticoagulants and phenprocoumon administration.

Data regarding uninterrupted oral anticoagulation in patients with chronic kidney disease (CKD) during catheter ablation for left atrial arrhythmias is limited. This study aimed to evaluate the safety and efficacy of periprocedural uninterrupted direct oral anticoagulants (DOAC) compared with uninterrupted phenprocoumon in patients with CKD undergoing left atrial catheter ablation. We conducted a retrospective single-center study of patients who underwent left atrial catheter ablation between 2016 and 2019 with underlying chronic kidney disease (glomerular filtration rate (GFR) between 15 and 45ml/min). The primary objective of this study was to investigate whether direct oral anticoagulant (DOAC) therapy or warfarin presents a superior safety profile in patients with chronic kidney disease (CKD) undergoing left atrial catheter ablation. We compared periprocedural complications (arteriovenous fistula, aneurysm, significant hematoma (> 5cm)) and/or bleeding (drop in hemoglobin of >2g/dl, pericardial effusion, retroperitoneal bleeding, other bleeding, stroke) between patients receiving either uninterrupted DOAC or warfarin therapy. Secondary analysis included patient baseline characteristics as well as procedural data. A total of 188 patients (female n = 108 (57%), mean age 75.3 ± 8.1years, mean GFR 36.8 ± 6ml/min) were included in this study. Underlying arrhythmias were atrial fibrillation (n = 104, 55.3%) and atypical atrial flutter (n = 84, 44.7%). Of these, n = 132 patients (70%) were under a DOAC medication, and n = 56 (30%) were under phenprocoumon. Major groin complications including pseudoaneurysm and/or AV fistula occurred in 8.9% of patients in the phenprocoumon group vs. 11.3% of patients in the DOAC group, which was not statistically significant (p = 0.62). Incidence of cardiac tamponade (2.3% vs. 0%; p = 0.55) and stroke (0% vs. 0%) were low in both DOAC and phenprocoumon groups with similar post-procedural drops in hemoglobin levels (1.1±1g/dl vs 1.1±0.9g/dl; p= 0.71). The type of anticoagulation had no significant influence on bleeding or thromboembolic events as well as groin complications in this retrospective study. Despite observing an increased rate of groin complications, the uninterrupted use of DOAC or phenprocoumon during left atrial catheter ablation in patients with CKD appears to be feasible and effective.

Assessment of fibrosis in heart failure and atrial fibrillation using TIMP- 1 serum levels

Abstract Background Tissue inhibitor of metalloproteinase- 1 (TIMP-1) levels are strongly associated with cardiac extracellular matrix accumulation and atrial fibrosis. The aim of this study was 1) to compare the TIMP-1 plasma levels in heart failure (HF) and atrial fibrillation (AF) patients and 2) to search for a local production in the heart. Methods This study included 13 patients with HF who underwent CRT implantation (CRT- group), 13 patients with persistent AF who underwent left atrial catheter ablation (AF- group) and 13 patients without structural heart disease or AF, who underwent electrophysiological study (control group). Blood was collected at the begin of the procedures from the coronary sinus (CS), superior vena cava (SVC) and aorta (Ao). Level of TIMP-1 in the CS (TIMP-1-CS), RA (TIMP-1-SVC) and aorta (TIMP-Ao) was measured. Results Patients characteristics: CRT- group: mean age 74y, 8 male, LV- EF 32%, 3 with a history of atrial fibrillation. AF- group: mean age 68y, 9 male, LV- EF 55%. Control- group: mean age 54y, 9 male, LV- EF 65%. The levels of TIMP-1 in the SVC was in the CRT group significantly higher 213 ± 70 ng/ml vs 160 ± 23 ng/ml in controls (p= 0,03). The level of TIMP-1 in the AF- group (191 ± 73 ng/ml) was not significantly different from the control group (p= 0,195) (figure 1). At the various collection sites (CS, SVC and aorta), no significant differences between the 3 groups were noted. Discussion: TIMP-1 serum levels in HF patients are significantly elevated compared to a control group without structural heart disease. No significant differences in levels of TIMP-1 were seen between AF patients and the control group. This is an expression of the advanced disease in the HF patients. The source of serum TIMP-1 are unclear as differences in the level of TIMP-1 between CS, SVC and aorta were not detectable.

Regional levels of tenascin- C in patients with heart failure and atrial fibrillation

Abstract Background Tenascin-C (TNC) is an extracellular matrix glycoprotein that is upregulated at high levels during active tissue remodeling. The serum concentration of TNC has been reported to be increased in patients with several cardiac diseases. The aim of this study was 1) to measure the TNC plasma level in heart failure (HF) and atrial fibrillation (AF) patients compared to patients without structural heart disease and 2) to search for a local production in the heart. Methods This study included 13 patients with HF who underwent CRT- implantation (CRT- group), 13 patients with persistent AF who underwent left atrial catheter ablation (AF- group) and 13 patients without structural heart disease or AF, who underwent electrophysiological study (Control- group). Blood was collected at the beginning of the procedures from the coronary sinus (CS), superior vena cava (SVC) and aorta (Ao). Level of TNC-B (ng/dl) in the CS (TNC-CS), SVC (TNC-SVC) and aorta (TNC-Ao) was measured. Results Patients characteristics: CRT- group: mean age 74y, 8 male, LV- EF 32%, 3 with a history of atrial fibrillation. AF- group: mean age 68y, 9 male, LV- EF 55%. Control- group: mean age 54y, 9 male, LV- EF 65%. The TNC level in the SVC was in the CRT group significant elevated (6125 ± 2030 ng/ml vs 475 ± 238 ng/ml in controls (p<0.01). In the AF group the TNC level in the SVC as well was significantly higher 4983 ± 1814 ng/ml vs 475 ± 238 ng/ml in controls (p<0.01). The TNC level of the CRT- and the AF- group were not significant different (p= 0.219) (Figure 1). No significant differences were noted at the various collection sites (CS, SVC and aorta) between the 3 groups (p = 0.38). Discussion The TNC serum levels in HF- and AF- patients are elevated compared to a control group without structural heart disease and without a history of AF. We could not determinate, the source of serum TNC, differences in the level of TNC between CS and SVC and aorta were not visible. Whether an effective treatment of HF and AF will lower TNC levels and slow the disease progression needs to be evaluated in further studies.

Detection of brain lesions after catheter ablation depends on imaging criteria: insights from AXAFA-AFNET 5 trial.

Left atrial catheter ablation is well established in patients with symptomatic atrial fibrillation (AF) but associated with risk of embolism to the brain. The present analysis aims to assess the impact of diffusion-weighted imaging (DWI) slice thickness on the rate of magnetic resonance imaging (MRI)-detected ischaemic brain lesions after ablation. AXAFA-AFNET 5 trial (NCT02227550) participants underwent MRI using high-resolution (hr) DWI (slice thickness: 2.5-3 mm) and standard DWI (slice thickness: 5-6 mm) within 3-48 h after ablation. In 321 patients with analysable brain MRI (mean age 64 years, 33% female, median CHA2DS2-VASc 2), hrDWI detected at least one acute brain lesion in 84 (26.2%) patients and standard DWI in 60 (18.7%; P < 0.01) patients. High-resolution diffusion-weighted imaging detected more lesions compared to standard DWI (165 vs. 104; P < 0.01). The degree of agreement for lesion confirmation using hrDWI vs. standard DWI was substantial (κ = 0769). Comparing the proportion of DWI-detected lesions, lesion distribution, and total lesion volume per patient, there was no difference in the cohort of participants undergoing MRI at 1.5 T (n = 52) vs. 3 T (n = 269). The pre-specified AXAFA-AFNET 5 sub-analysis revealed significantly increased rates of MRI-detected acute brain lesions using hrDWI instead of standard DWI in AF patients undergoing ablation. In comparison to DWI slice thickness, MRI field strength had a no significant impact in the trial. Comparing the varying rates of ablation-related MRI-detected brain lesions across previous studies has to consider these technical parameters. Future studies should use hrDWI, as feasibility was demonstrated in the multicentre AXAFA-AFNET 5 trial.

Safety of an esophageal deviator for atrial fibrillation catheter ablation.

Esophageal thermal injury is a complication of atrial fibrillation (AF) ablation, and it can be avoided by esophageal deviation during left atrial posterior wall radiofrequency catheter ablation. This study aimed to evaluate the safety of a nitinol-based mechanical esophageal displacement device (MEDD) and its performance. This preclinical safety study was conducted on 20 pigs, with 10 undergoing radiofrequency AF ablation using the MEDD and 10 serving as a control group under anticoagulation but without radiofrequency application. Esophageal traumatic injuries were classified from 0 to 4 and were grouped as absent (grade 0), minor (grade 1 or 2), moderate (grade 3), or major risk lesions (grade 4) by anatomopathological study. Grades 1 and 2 were considered acceptable. Fluoroscopy was used to measure displacement. Five (25%) pigs developed traumatic lesions, 4 with grade 1 and 1 with grade 2 (2-mm superficial ulcer). There was no difference in lesion occurrence between the radiofrequency and control groups (30% and 20%, respectively; P = .43). Under rightward displacement, the right edge moved 23.9 (interquartile range [IQR] 21.3-26.3) mm and the left edge moved 16.3 (IQR 13.8-18.4) mm (P < .001) from baseline. Under leftward displacement, the right edge moved 13.5 (IQR 10.9-15.3) mm and the left edge moved 16.5 (IQR 12.3-18.5) mm (P = .07). A perforation to the pharyngeal diverticulum occurred in 1 pig, related to an accidental extubation. In pigs, the MEDD demonstrated safety in relation to esophageal tissue, and successful deviation. Esophageal traumatic injuries were acceptable, but improper manipulation led to pharyngeal lesion.

Risk factors and management strategies for atrial fibrillation

Atrial fibrillation (AF) is a cardiac arrhythmia characterised by the irregular and frequently fast depolarization of the atrial myocardium resulting from a disturbance of the usual electrical conduction routes within the atria, which causes disorganised and ineffective atrial contractions. The management of AF involves a multidisciplinary approach that includes identifying and treating underlying risk factors, managing symptoms, and preventing complications. The risk factors for AF include age, hypertension, obesity, diabetes mellitus, valvular heart disease, coronary artery disease, congestive heart failure, alcohol consumption, sleep apnea, and family history. The management strategies for AF include rate control, rhythm control, anticoagulation, left atrial appendage closure, lifestyle modifications, surgical ablation, catheter ablation, cardioversion, and education and support. The choice of management strategy should be tailored to the individual patient’s risk profile, comorbidities, and other factors. Further research is needed to improve our understanding of the pathophysiology of AF and to develop more effective management strategies for this condition.

PO-01-005 GANGLIONATED PLEXI MEDIATED BRADYCARDIA RESPONSES: A PRE-CLINICAL STUDY OF DIFFERENCES BETWEEN PULSED FIELD AND RADIOFREQUENCY ABLATION IN THE LEFT ATRIUM

During left atrial catheter ablation procedures, the peri-atrial neural network of ganglionated plexi (GP) can be affected by the ablative energy. Bradycardic responses (BR) from GP stimulation have been reported during both radiofrequency (RF) and pulsed field (PF) ablation procedures. To assess differences in BR between RF and PF during canine left atrial ablation. Healthy canines (n=14) underwent transeptal access under general anesthesia. A multielectrode spherical array catheter (Globe PF System; Kardium Inc., Canada) capable of both cardiac mapping and ablation with either RF or PF was deployed in the left atrium. For each application, electroanatomic maps with ostial tags, contact maps based on blood flow detection, and animated voltage maps were created to help verify isolation. Either temperature-controlled RF ablation (63°C for 3 minutes) or PF ablation (1.7-1.8 kV) was used to circumferentially isolate two PVs/animal and create a linear and focal lesion along the posterior wall and roof of the left atrium. GP stimulation as evidenced by BR was recorded if either sinus bradycardia or AV block was noted during and/or immediately after the pulse train (Figure). A total of 11 and 3 animals underwent PF and RF ablation, respectively. All ablations were successfully delivered to all locations without adverse events. Of the animals treated with RF, none (0 of 3) displayed any evidence of GP stimulation at any locations. All animals treated with PF showed evidence of GP stimulation: all animals (11 of 11,100%) exhibited BR during ablation at the inferior common vein, with 6 of 10 (60%) animals demonstrating BR at the roof and posterior wall (Table). BR of less severity was noted during subsequent pulse trains but remained most frequent at the inferior common vein. Ganglionated plexi-mediated bradycardic responses occur with PF ablation, with evidence of some degree of stunning when repeated pulse trains are delivered. This pre-clinical model with ablation at this location will serve as a good model to further our understanding of this phenomenon. The lack of any bradycardic responses with RF either represents a lack of stimulation (perhaps because of the inability of the RF energy to reach the epicardial GPs, unlike the volumetric nature of the pulsed electrical fields) or, complete ablation without stimulation. Further work is needed to explore these differences.

A Referral Center Experience with Cerebral Protection Devices: Challenging Cardiac Thrombus in the EP Lab

Cerebral protection devices (CPD) are designed to prevent cardioembolic stroke and most evidence that exists relates to TAVR procedures. There are missing data on the benefits of CPD in patients that are considered high risk for stroke undergoing cardiac procedures like left atrial appendage (LAA) closure or catheter ablation of ventricular tachycardia (VT) when cardiac thrombus is present. This work aimed to examine the feasibility and safety of the routine use of CPD in patients with cardiac thrombus undergoing interventions in the electrophysiology (EP) lab of a large referral center. The CPD was placed under fluoroscopic guidance in all procedures in the beginning of the intervention. Two different CPDs were used according to the physician's discretion: (1) a capture device consisting of two filters for the brachiocephalic and left common carotid arteries placed over a 6F sheath from a radial artery; or (2) a deflection device covering all three supra-aortic vessels placed over an 8F femoral sheath. Retrospective periprocedural and safety data were obtained from procedural reports and discharge letters. Long-term safety data were obtained by clinical follow-up in our institution and telephone consultations. We identified 30 consecutive patients in our EP lab who underwent interventions (21 LAA closure, 9 VT ablation) with placement of a CPD due to cardiac thrombus. Mean age was 70 ± 10 years and 73% were male, while mean LVEF was 40 ± 14%. The location of the cardiac thrombus was the LAA in all 21 patients (100%) undergoing LAA-closure, whereas, in the 9 patients undergoing VT ablation, thrombus was present in the LAA in 5 cases (56%), left ventricle (n = 3, 33%) and aortic arch (n = 1, 11%). The capture device was used in 19 out of 30 (63%) and the deflection device in 11 out of 30 cases (37%). There were no periprocedural strokes or transitory ischemic attacks (TIA). CPD-related complications comprised the vascular access and were as follows: two cases of pseudoaneurysm of the femoral artery not requiring surgery (7%), 1 hematoma at the arterial puncture site (3%) and 1 venous thrombosis (3%) resolved by warfarin. At long-term follow-up, 1 TIA and 2 non-cardiovascular deaths occurred, with a mean follow-up time of 660 days. Placement of a cerebral protection device prior to LAA closure or VT ablation in patients with cardiac thrombus proved feasible, but possible vascular complications needed to be taken into account. A benefit in periprocedural stroke prevention for these interventions seemed plausible but has yet to be proven in larger and randomized trials.

Efficacy of left atrial low-voltage area-guided catheter ablation of atrial fibrillation: An updated systematic review and meta-analysis

This study aimed to evaluate the efficacy of low-voltage area (LVA)-guided substrate modification catheter ablation in patients with atrial fibrillation (AF). Systematic searches of the PubMed, EMBASE, and Cochrane databases were performed from inception to July 2022 for all available studies. The effect estimates were combined with the Mantel-Haenszel random-effects model. Subgroup analyses, sensitivity analysis, and meta-regression were conducted to explore the sources of statistical heterogeneity. A total of 16 studies involving 1942 subjects (mean age: 61 ± 10 years, 69% male) were identified. All studies included patients with paroxysmal AF, non-paroxysmal AF, or both. At a mean follow-up of 18.9 months, patients who underwent LVA-guided substrate modification ablation had significantly higher freedom from all-atrial tachycardia recurrence than patients who underwent control ablation [67.7% vs. 48.9%, risk ratios (RR) 0.64, 95% confidence interval (CI) 0.55-0.76, P < 0.001], with 36% relative risk and 18.7% absolute risk reductions in all-atrial tachycardia recurrence. Subgroup analysis based on AF types demonstrated that the decreased risk of all-atrial tachycardia recurrence was present predominantly in non-paroxysmal AF compared with paroxysmal AF (RR 0.60, 95% CI 0.52-0.69 vs. RR 0.96, 95% CI 0.81-1.13). Low-voltage area-guided substrate modification ablation combined with PVI appears to have a significant beneficial effect of improving freedom from all-atrial tachycardia recurrence, especially in patients with non-paroxysmal AF.

An Esophageal Cooling Device During Radiofrequency Ablation for Atrial Fibrillation-A Comparison Between Reactive and Proactive Esophageal Cooling.

Esophageal thermal injury is one of the most feared risks of ablation of the posterior left atrium despite the various devices used to monitor esophageal temperature or deviate the esophagus. Reactive cooling, in which cold water is manually instilled into the esophagus via an orogastric tube in response to rises in luminal esophageal temperature (LET), has been used by operators, but the availability of a dedicated esophageal cooling device offers the ability to provide proactive esophageal cooling without having to react to individual temperature rises in the esophagus. The objective of this study was to evaluate the feasibility of using a commercially available esophageal cooling device to provide esophageal protection during left atrial catheter ablation, then to compare this approach to standard LET monitoring with reactive cooling via manual cold-water instillation. In this study, we randomized 6 patients undergoing catheter ablation for atrial fibrillation. Three patients received the standard of care for our site (use of a single-sensor temperature probe, with adjunct ice-water instillation for any temperature increases of >1°C). Three patients underwent standard ablation after placement of the esophageal cooling device at a circulating water temperature of 4°C, without the use of any esophageal temperature monitoring. All patients underwent transesophageal echocardiography and esophagogastroduodenoscopy on the day prior to the ablation, followed by a second esophagogastroduodenoscopy the day after. The 6 patients in this study were enrolled between March and August 2018. In the 3 control patients, 1 had no evidence of esophageal mucosal damage, 1 had diffuse sloughing of the esophageal mucosa and multiple ulcerations, and 1 had a superficial ulcer with a large clot. Both patients with lesions were classified as 2a cases using the Zargar grading scheme for caustic injury. In the 3 patients treated with the cooling device, 1 had no evidence of esophageal mucosal damage, 1 had esophageal erythema (Zargar grade 1), and 1 had a solitary Zargar grade 2a lesion. At 3 months of follow-up, 1 patient in each group had recurrence of atrial fibrillation. Although a number of subsequent studies have confirmed the reduction of esophageal injury with the use of proactive esophageal cooling, this study is the only one to date to compare reactive cooling (via manual cold-water instillation) and proactive cooling (via a dedicated esophageal cooling device). Moreover, this is the first study to support the feasibility of using a dedicated cooling device for this purpose and provides the basis for further investigation.

Limitations of Baseline Impedance, Impedance Drop and Current for Radiofrequency Catheter Ablation Monitoring: Insights from In silico Modeling.

Background: Baseline impedance, radiofrequency current, and impedance drop during radiofrequency catheter ablation are thought to predict effective lesion formation. However, quantifying the contributions of local versus remote impedances provides insights into the limitations of indices using those parameters. Methods: An in silico model of left atrial radiofrequency catheter ablation was used based on human thoracic measurements and solved for (1) initial impedance (Z), (2) percentage of radiofrequency power delivered to the myocardium and blood (3) total radiofrequency current, (4) impedance drop during heating, and (5) lesion size after a 25 W–30 s ablation. Remote impedance was modeled by varying the mixing ratio between skeletal muscle and fat. Local impedance was modeled by varying insertion depth of the electrode (ID). Results: Increasing the remote impedance led to increased baseline impedance, lower system current delivery, and reduced lesion size. For ID = 0.5 mm, Z ranged from 115 to 132 Ω when fat percentage varied from 20 to 80%, resulting in a decrease in the RF current from 472 to 347 mA and a slight decrease in lesion size from 5.6 to 5.1 mm in depth, and from 9.2 to 8.0 mm in maximum width. In contrast, increasing the local impedance led to lower system current but larger lesions. For a 50% fat–muscle mixture, Z ranged from 118 to 138 Ω when ID varied from 0.3 to 1.9 mm, resulting in a decrease in the RF current from 463 to 443 mA and an increase in lesion size, from 5.2 up to 7.5 mm in depth, and from 8.4 up to 11.6 mm in maximum width. In cases of nearly identical Z but different contributions of local and remote impedance, markedly different lesions sizes were observed despite only small differences in RF current. Impedance drop better predicted lesion size (R2 > 0.93) than RF current (R2 < 0.1). Conclusions: Identical baseline impedances and observed RF currents can lead to markedly different lesion sizes with different relative contributions of local and remote impedances to the electrical circuit. These results provide mechanistic insights into the advantage of measuring local impedance and identifies potential limitations of indices incorporating baseline impedance or current to predict lesion quality.

Algorithm for determining the fibrosis stage using high-density mapping

Aims. To develop an algorithm for assessing the stage of fibrosis based on high-density endocardial mapping. To study the effect of the stage of left atrial (LA) fibrosis on the results of atrial fibrillation (AF) catheter ablation.Methods. The study included 64 patients with paroxysmal or persistent AF, who underwent high-density LA mapping and catheter ablation. After the intervention procedure, we analyzed the electroanatomical maps of the left atrium, assessed the prevalence of low-voltage areas according to the developed algorithm. Patients were divided into 4 groups depending on the prevalence of areas of low voltage based on the Utah score.Results. The follow-up period was 14.5 ± 6.7 months. AF recurrence developed in 18 (28.1%) patients after the ablation procedure. AF recurrence after ablation was more frequent in patients with a low-voltage area of more than 20% than in patients with a low-voltage left atrial area of less than 20%, 6 (15.4%) versus 12 (48%), p=0.02. A logistic regression analysis was performed to identify AF recurrence predictors in the postoperative period. As a result, only widespread areas of low-amplitude activity were an independent predictor of AF recurrence after the pulmonary veins isolation, this predictive model was significant (p=0.026). Significant statistical differences between groups I, II and III,I V are the ejection fractions and the duration of the P-wave. Patients with low-voltage regions have lower left ventricular ejection fraction (62.8±6.9% versus 58.1±5.7%, p=0.01), and longer P-wave duration (84.7±8,2 ms versus 101.5±11.0 ms, p=0.01).Conclusion. LA high-density mapping before AF ablation makes it possible to determine the prevalence of low-voltage areas. After regression analysis, it was proved that common low-voltage areas are an independent predictor of AF recurrence after pulmonary vein isolation. Patients with low-voltage areas of more than 20% of the LA surface have longer P-wave duration and lower left ventricular ejection fraction.

Safety and Efficacy of Left Atrial Catheter Ablation in Patients with Left Atrial Appendage Occlusion Devices.

Background: Left atrial appendage occlusion (LAAO) is an alternative to oral anticoagulation for thromboembolic prevention in patients with atrial fibrillation (AF). Left atrial (LA) catheter ablation (CA) in patients with LAAO devices has not been well investigated. Here, we report on the safety and efficacy of LA CA in patients with nitinol cage or plug LAAO devices. Methods: A total of 18 patients (aged 67 ± 11 years; 14 males; 5 paroxysmal AF) with LAAO devices (nitinol cage, n = 10; nitinol plug, n = 8) and symptomatic LA tachyarrhythmias were included. Periprocedural and follow-up data were assessed. Results: A total of 20 LA CA procedures were performed at a median of 130 (63, 338) days after LAAO. The strategy of CA consisted of circumferential pulmonary vein isolation (n = 16), linear lesions (n = 14) and complex fractionated atrial electrogram ablation (n = 6). No major adverse events occurred periprocedurally. Repeated transesophageal echocardiography showed no device-related thrombus, newly developed peridevice leakage or device dislodgement. After a median follow-up period of 793 (376, 1090) days, four patients (22%) experienced LA tachyarrhythmias recurrence and two received redo LA CA. No patients suffered stroke or major bleeding events during follow-up. Conclusions: LA CA in patients with LAAO devices (either nitinol cages or nitinol plugs) seems to be safe and efficient in our single-center experience.