Ablation Procedures Research Articles

A straightforward assessment of anterior mitral isthmus lines block

Abstract Background Complex atrial fibrillation (AF) and left atrial flutter (LAFL) ablation procedures often involve creating lines on the anterior wall of the left atrium, such as the anterior septal and lateral mitral isthmus lines. Purpose This study aims to evaluate the role of a simplified criteria to demonstrate the achievement of conduction block across the anterior wall of the left atrium ("anterior mitral isthmus") after linear ablation (LA). Methods Patients scheduled for persistent AF or LAFT ablation were prospectively recruited. The procedure employed a homogeneous LA strategy that included the anteromedial, anterolateral and roof lines. The following intervals were measured before and after LA, placing a multipolar catheter in the left atrial appendage (LAA) in order to register the earliest egm in a reproducible position: 1) P-LAA: conduction time from the sinus P wave onset to the LAA, 2) IASp-LAA: conduction time pacing at CL 500 ms from the interatrial septum to the LAA, 3) CSp-LAA: conduction time pacing at CL 500 ms from the distal CS to the LAA, 4) LAA-QRS onset. Patients with linear ablation were further divided according to the presence or block (BG) or non-block group (NBG) in the anterior at the end of the procedure, demonstrated with a high-density activation map. A parallel control group (CG) of patients with paroxysmal AF without LA was also included for comparison. Statistical analysis involved the Kruskal-Wallis and Mann-Whitney test with Bonferroni correction. Results 21 patients were enrolled in the study: mean age 66.67 years (± 8.48), 80% male sex. Among them, 16 had AF and AFL and underwent LA, while the remaining 5 constitute the CG. Baseline measures before LA did not exhibit significant differences compared to the CG with mean values for P-LAA at 93±20 ms (P=2.35), IASs-LAA at 82±27 ms (P=1.94), CSs-LAA at 52±17 ms (P=0.91), and LAA-QRS at 80±27 ms (P=1.82). However, upon comparing the BG and NBG, significant differences emerged in P-LAA (82±10 ms vs. 11±5 ms (P=0.002) and IAS-LAA (83±17 ms vs. 27±24 ms (P=0.004), while no significant differences were observed in the remaining intervals. In comparisons between the BG and the CG, significant differences were noted in P-LAA (82±10 ms vs. 16±10 ms (P=0.01) and IAS-LAA (83±17 ms vs. 1.2±17 ms (P=0.01), without differences in the other intervals. Conversely, when comparing NB to the CG, no significant differences were observed in any of the intervals. Finally, P-LAA >70 ms and the IASp-LAA >55 ms showed a sensitivity of 100 % and specifitity of 100 vs. 87% respectively to discriminate anterior wall block. Conclusion The simple measurement of the P-LAA and IAS-LAA interval proves highly valuable in evaluating anterior mitral isthmus lines block, serving as a complementary approach to conventional maneuvers. P-LAA >70 ms and IASp-LAA > 55 ms could be usefull to discriminate anterior wall block.Anterior linear ablation with block

Left atrial low-voltage areas, but not volume, predict the recurrence of atrial fibrillation in repeat ablation procedures

Abstract Background Left atrial (LA) low voltage areas (LVA) are a controversial target in atrial fibrillation ablation procedures. However, LVA and LA volume are good predictors of arrhythmia recurrence in ablation-naïve patients. Their predictive value in pre-ablated, myopathic atria is uncertain. Purpose Patient selection for repeat ablations is sometimes difficult. Predicting factors of rhythm outcome might help with the decision. Methods Consecutive patients with recurrent atrial fibrillation (AF) or atrial tachycardia (AT) scheduled for repeat LA ablation were included in the prospective Bernau ablation registry between 2016 and 2020. All patients received a complete LA ultra-high-density map before ablation. Maps were analyzed for LA size, LVA percentage and distribution. The predictive value of demographic, anatomic and mapping variables on AF recurrence was analyzed in univariate logistic regression and integrated in a multivariate Cox regression if the p-value was <0.250. Results 160 patients (50.6% male, 1.3 pre-ablations, 60% persistent AF) with complete LA voltage maps were included. Mean follow-up time was 16 ± 11 months. Mean recorded electrograms (EGMs) per map were 9754 ± 5808, mean LA volume was 176.1 ± 35.9 ml and mean rate of LVAs < 0.5 mV was 30.6% ± 23.1%. Baseline characteristics are depicted in table 1. During follow-up recurrence rate of AF or AT > 30 seconds was 55.6%. Patients with recurrence had a significant higher percentage of LVAs (40.0% vs. 18.8%, p<.001) but no relevant difference in LA volume (172 vs. 178 ml, p=.299). ROC curves revealed a cut-off of 22% LVAs with highest sensitivity (73.0%) and specificity (71.8%). Based on this cut-off event free survival was significantly higher in the Low LVA group (p<0.01), Figure 1. Other relevant clinical, anatomic or laboratory predictors could not be found in multivariate Cox regression analysis. Conclusion The amount of left atrial LVA is a good predictor for arrhythmia recurrence, even in a cohort of repeat ablations with progressively diseased atria. EAM derived left atrial volume has minor impact on recurrence in this group and should not solely guide the decision in favor or against further invasive treatment. Accomplishing a thorough 3D map of the left atrium to account for LVA should be mandatory in all repeat procedures.Baseline CharacteristicsKaplan-Meier for recurrence and voltage

Neural network for automatic ICD-EGMs matching in pace-mapping and ablation of ventricular arrhythmias

Abstract Background Mapping of the ventricular arrhythmias (VA) is often not possible due to the non-inducibility of the electrophysiological study (EPS). Since twelve-lead electrocardiograms (ECG) of the clinical ventricular tachycardia (VT) are also often not available, therefore stored implantable cardioverter-defibrillator (ICD) electrograms (EGMs) of the clinical VT are often the only documentation. The pace mapping matching to the stored ICD-EGM template of the clinical VT can help to identify the VT exit site. Automatic objective computing of similarity scores between EGMs is impossible because ICD programmer devices do not have any interface allowing the export of digital EGMs. Therefore, images can only be accessed for similarity by subjective eyeballing. The MatcherNet Siamese neural network takes a pair of EGM images and predicts their similarity. Purpose This study aimed to assess the feasibility of the automatic ICD-EGMs matching by MatcherNet neural network for pace mapping of VT/premature ventricular contraction (PVC) exit site. Methods Consecutive patients undergoing VT ablation or ablation of ventricular fibrillation, triggered by PVC were included in the study, if the clinical VT/PVC was not inducible during EPS but ICD-EGMs of clinical VT/PVC were stored in the device. Electro-anatomical mapping was performed to reveal substrates (low-voltage areas, abnormal potentials, DEEP-potentials, conduction crowding). Subsequently, the low-output pacing from various locations tagged on the 3D map of LV was performed, and the paced ICD-EGM images were stored from the ICD programmer device for offline analysis and calculation of the similarity. RF ablation was conducted based on the substrate map findings, including the area of the most remarkable similarity between paced ICD-EGMs and clinical ICD-EGM templates assessed by eyeballing. The ICD-EGMs similarity scores (Manhattan similarity and Pearson correlation) were predicted by MatcherNet for each pacing site offline and transferred to the 3D map for the assessment of similarity distribution (Figure 1). Results We included 7 patients with VA episodes registered and stored by their ICD. The clinical characteristics are presented in Table1. In all patients, we were able to find the sites of highest ICD-EGM similarity to the clinical template with gradual decrementing of the similarity score at the increasingly distant pacing areas. The site of the highest similarity was collocated with VT substrate and ablation areas in all patients. Abrupt change of the similarity score at the adjacent pacing sites was detected in the 2 cases, indicating the possible protected VT isthmus. After ablation procedure only one patient with DCM experienced VA recurrence. Conclusion This technology opens new possibilities for the utilization of ICD-EGMs during the pace mapping of ventricular tachycardia, especially in the cases of non-inducibility during electrophysiological study.Figure 1Table 1

Long-term outcomes in hybrid versus standalone thoracoscopic ablation in patients with atrial fibrillation: a systematic review and reconstructed individual patient data meta-analysis

Abstract Background Both hybrid and standalone thoracoscopic atrial fibrillation (AF) ablation techniques have demonstrated favorable outcomes in the management of (long-standing) persistent AF patients, as compared to catheter ablation. However, it is currently unknown whether there is a difference in long-term freedom from AF when comparing these two procedures. Purpose To compare long-term freedom from atrial tachyarrhythmias (ATA) in patients undergoing hybrid and standalone thoracoscopic AF ablation. Methods A systematic search encompassing PubMed, EMBASE, and the Cochrane Library databases from January 1, 2012, to September 6, 2023, was performed using the following search terms: 'thoracoscopic ablation,' 'hybrid ablation,' 'atrial fibrillation,' and various alternative spellings. Articles were included for pooled analysis of freedom from ATA after meeting the criteria of reporting on consecutive patients and presenting Kaplan-Meier (KM) curves. Individual time-to-event data were reconstructed from the KM curves and included in a multivariable Cox and frailty Cox model with adjustments for age, sex, type of AF, AF duration, and study (frailty term in the frailty Cox model). Results In total, 18 studies were included in the meta-analysis for long-term freedom from ATA, comprising 2215 patients. Patients undergoing hybrid thoracoscopic ablation were older (62.0 vs. 58.8 years old, p=0.046), had less frequently paroxysmal AF-history (9.6% vs. 32.1%, p<0.01), and had a longer duration of AF-history (7.0 vs. 5.3 years, p=0.04), as compared to patients undergoing standalone thoracoscopic ablation. There were no significant differences between the two ablation procedures regarding short-term outcomes including early mortality (0.6% vs. 1.0%, p=0.07) and early stroke (1.9% vs 0.9%, p=0.11). Adjusted analysis revealed that hybrid thoracoscopic ablation was significantly associated with greater freedom from ATA (Hazard Ratio [HR]=0.59, 95%CI: 0.43-0.83, p<0.001) compared to standalone thoracoscopic ablation (see Figure 1A). Additionally, older age (HR=1.07, 95%CI: 1.03-1.12, p=0.002) and a higher percentage of male patients (HR=1.02, 95% CI: 1.01-1.03, p<0.001) were significantly associated with ATA recurrence. Adjusted freedom from ATA at 1 year, 3 years, and 5 years was 71.6%, 55.1%, and 46.8% for thoracoscopic ablation, and 82.0%, 69.9%, and 63.6% for hybrid ablation (see Figure 1B). Conclusion Hybrid thoracoscopic AF-ablation is associated with a higher level of freedom from ATA when compared to standalone thoracoscopic ablation.Figure 1

Survival predictors after pacemaker implantation in a very elderly population

Abstract Background Electrophysiological studies and ablation procedures are the most prevalent activities in electrophysiology. However, device implantation represents a great deal of the daily activity. In several European regions, aging populations are becoming a big concern, not only increasing the number of pacemakers implantations but also raising the age threshold for implantation. Purpose Assessment of survival rates after device implantations on patients over ninety years of age. Are there any markers that could help us infer survival rates? How prevalent are complications? What key performance indicators should be paying attention to? Methods Observational retrospective study of a cohort of 903 patients referred to the arrhythmia unit of our institution for pacemaker implantation, during the period from 2016 to 2019. Cox regression analysis performed over that cohort. Hazard-ratio (HR) and confidence intervals (CI 95%)calculated. Survival curves represented with Kaplan-Meier method and statistical significance estimated with log-rank test. Results Out of the 903 patients, 82 (9.1%) are nonagenarians. Follow-up was 3.97 ± 4.98 years. The mean age at the time of pacemaker implantation was 78.94 ± 10.11 years. Some complications were observed in 9.9% of patients under 90 years of age, compared to 4.9% in those over that age. At the time of the follow-up, 82.5% of the patients were alive. In the univariate analysis, the following predictors of mortality were identified: age; atrial fibrillation (AF); renal function; anemia; comorbidity, estimated by Charlson score; underlying heart disease; type of pacemaker implanted; and, whether the patient was institutionalized. In the multivariate analysis, the following were independent predictors of mortality: age (HR 1.129; 95% CI 1.1-1.159; p<0.001), comorbidity reflected as a Charlson score ≥ 5 (HR 4.116; 95% CI 2.349 -7.212; p<0.001); heart disease (HR 2.496; 95% CI 1.725-3.612; p<0.001); institutionalization of the patient (HR 2.794; 95% CI 1.632-4.783; p<0.001); and the single-chamber pacemaker (HR 2.201; 95% CI 1.455-3.329; p<0.001). In the group of nonagenarian patients, the univariate analysis showed the following variables as predictors of lower survival: age; serum creatinine; comorbidity, estimated by the Charlson score; and, underlying heart disease. In the multivariate analysis, the following were identified as independent predictors of mortality: comorbidity, reflected as a Charlson score ≥ 5 (HR 7.299; 95% CI 2.468-21.589; p<0.001); age (HR: 1.193; 95% CI 1.063- 1.339; p 0.003) and institutionalization of the patient (HR 3.033; 95% CI 1.237- 7.439; p 0.015). Conclusions Comorbility estimated by Charlson score is the most powerful survival predictor after pacemaker implantation, both in the general population and in those over 90 years of age. Being institutionalized is an independent survival predictor in both groups. Nonagenarian patients do not show a higher complication rate.Baseline characteristics >90 y.o.Survival curves K-M

Electrocardiographic characteristics and catheter ablation of premature ventricular complex- mediated ventricular fibrillation

Abstract Background Premature ventricular contractions (PVCs) can trigger ventricular fibrillation (VF) in patients with/or without structural heart disease. There are limited data on coexisting electrocardiographic (ECG) features and catheter ablation outcomes in these patients which could suggest the concomitant presence of an abnormal electrical and structural substrate. Purpose We investigated ECG and electroanatomic characteristics and clinical outcomes in patents who underwent catheter ablation of PVCs triggering VF. Methods We analyzed data from a consecutive series of patients who underwent catheter ablation between 08/2019 and 04/2023 for PVCs triggering VF. On the 12-lead ECG, we assessed the following abnormalities: (a) Early repolarization (ER) pattern in either inferior or lateral leads (Figure 1), or (b) QRS Notching of either the native sinus beat or PVC (Figure 2). Post-ablation follow up outcomes were collected using a combination of ICD interrogation, remote transmission and clinical follow up. Results The cohort included 15 patients: age 52.1±16.8 years, 46.7% females, and 26.7% presenting with VF storm. On average, there were 3.8 HV shocks/per patient from an ICD prior to the index ablation procedure (range: 0-19 shocks). On the 12-lead ECG, the mean coupling interval of the PVC leading to VF was 204±82 ms, and an overall narrow PVC morphology with a mean QRS duration of 107±17 ms. We observed early repolarization (ER) in 6 (40%) of the cohort. In most patients (n=11; 73.3%), at least one of the 2 ECG abnormalities were present. An endocardial-only approach was adequate in all patients, and during catheter ablation, Purkinje potentials were targeted in 10 (66%) of the patients. Based on activation and pace-mapping, the PVCs were localized to the following sites: (a) left ventricular (LV) septum in 11 (73.3%), (b) papillary muscles in 2 (13.3%), and (c) other sites such as the Moderator band and right ventricular outflow tract in the remaining 2 (13.3%) patients. The ablation locations on the LV septum extended from basal to mid-septum. After an average of 1.7 ablation procedures targeting PVC-triggering VF, 12 (80%) patients remained free of sustained ventricular arrhythmias and ICD shocks, over a mean follow up of 479±395 days. Conclusion In most patients with PVCs-triggering VF, there was an evidence of an ECG abnormality either in the form of an ER pattern or notching of either the Sinus QRS or the PVC complex on pre-ablation ECG. During ablation, Purkinje potentials and PVCs were mapped to and ablated in the region of the LV interventricular septum and papillary muscles. Over long-term follow up, catheter ablation seemed durable and effective in reducing VF episodes and ICD shocks.Presence of Early Repolarization patternPresence of a notching pattern in the Si

Sex differences at diagnosis and in one-year outcomes in patients with early atrial fibrillation

Abstract Background Little is known about differences in clinical phenotype between men and women with atrial fibrillation (AF). Our aim was to explore phenotypical sex differences at diagnosis and at one-year follow-up, in patients with early AF. Methods We used data from 5,469 participants of the DUTCH-AF registry; a nationwide prospective registry of patients with early AF or atrial flutter (diagnosis ≤ 6 months before inclusion) in the Netherlands, aged ≥ 18 years. We describe sex differences in clinical phenotype at diagnosis and at one-year follow-up, including the following outcomes: i) ischemic and bleeding events, ii) all-cause mortality, iii) AF-related hospital admissions, including ablation and cardioversion, and iv) AF progression patterns. Results At inclusion, women were older than men (median 73 vs. 69 years, p<0.001), had more often paroxysmal AF (66% vs. 55%, p<0.001), and less often persistent AF (27% vs. 37%, p<0.001). They also had hypertension more often (59% vs. 53%, p<0.001), and less often vascular disease (12% vs. 21%, p<0.001, and reported more often symptoms at inclusion and in the month before follow-up; 56% vs. 46%, p<0.001, and 31% vs. 23%, p<0.001, respectively. Women underwent cardioversion and ablation procedures less often than men (14% vs. 21% p<0.001 and 3% vs. 5%, p<0.001, respectively). Moreover, for the combined rhythm control intervention cardioversion and ablation, women also underwent this rhythm control outcome less often than men (unadjusted odds ratio was 0.63 95% CI (0.55-0.73)), regardless of age, and the type of AF (i.e., paroxysmal or persistent AF) at inclusion (adjusted odds ratio 0.77 95% CI (0.62-0.92)). No differences were observed for ischemic and bleeding events, all-cause mortality, or AF progression patterns, but the number of these events was small. Conclusion Men and women with early AF differ in age, comorbidities, symptoms, and management. These findings are building blocks for individualized sex-specific AF care and research.

Pulmonary hypertension is associated with increased recurrence of atrial fibrillation post-pulmonary vein isolation: a multicenter study insights

Abstract Background Pulmonary vein isolation (PVI) has become an essential therapeutic approach for managing paroxysmal and persistent atrial fibrillation. Besides the fact its application increases, a substantial proportion of patients will suffer from arrhythmia recurrence. Objectives This study aims to determine the clinical and echocardiographic factors that predict fibrillation recurrence following pulmonary vein isolation. Methods In this prospective, multicenter study carried out across 14 medical centers in Israel, we included a cohort of 1002 patients who underwent pulmonary vein isolation from 2019 to 2022. The study involved an assessment of patients' baseline characteristics, electrocardiographic and echocardiographic data, laboratory results, details of the procedure, and their clinical outcomes. We monitored these clinical outcomes for one year after the ablation procedure, focusing mainly on the recurrence of atrial fibrillation, which was verified using electrocardiographic evidence during the post-blanking period. A multivariable analysis revealed the clinical and echocardiographic predictors for atrial fibrillation recurrence post-PVI. Results Our study evaluated 1002 patients with an average age of 64.4 ±11.3 years, including 37.5% females (376 patients). The cohort predominantly, about two-thirds, had paroxysmal AFIB, with an average arrythmia duration of 4.1 years. Frequent pre-existing conditions included ischemic heart disease in 17.3% and congestive heart failure in 13.8% of the patients. Additionally, diabetes was present in a quarter of the cohort, with 9% having a prior cerebrovascular event. The median LVEF was 60 (IQR 53-60), and the average left atrial diameter was 42.6 mm±8.8. The median pulmonary artery pressure was noted at 31 (IQR 25-38), with 13% of patients exhibiting elevated levels above 45 mmHg. Within the first year after the ablation, 11.7% of patients experienced AFIB recurrence in the post-blanking period. Our multivariate COX analysis established clinical and echocardiographic models for predicting post-PVI AFIB recurrence. Gender was a significant predictor, with women showing a higher recurrence rate (HR 1.85, 95% CI 1.29-2.7, P<0.01), in addition to persistent AFIB and a non-sinus rhythm at the time of the procedure. Echocardiographic predictors of recurrence included a left atrial diameter greater than 40 mm (HR 2.16, 95% CI 1.3-3.6, P<0.01) and pulmonary hypertension, notably when pulmonary artery pressure exceeded 55 mmHg, which correlated with almost a fourfold increase in AFIB recurrence risk within the first-year post-procedure (HR 4.25, 95% CI 1.57-11.5, P<0.01). Conclusions Pulmonary hypertension, especially with pulmonary artery pressure above 55 mmHg, significantly elevates the risk of atrial fibrillation recurrence post-pulmonary vein isolation, underscoring its importance in patient prognosis and management.

Epicardial catheter ablation of ventricular tachycardia in patients of acm - from a university hospital report in switzerland

Abstract Background Arrhythmogenic left ventricular cardiomyopathy (ALVC) as a subtype of arrhythmogenic cardiomyopathy (ACM) is increasingly being recognized. Cardiac magnetic resonance (CMR) has emerged as the primary imaging modality for the diagnosis of ACM. In patients with right-dominant ACM (ARVC) and recurrent sustained ventricular tachycardia (VT), endocardial +/-epicardial ablation yields good clinical outcomes in the long-term. However, studies on VT ablation in ACM with LV involvement are scarce. Purpose We sought to investigate clinical outcomes of VT ablation in ACM patients with LV involvement. Methods The study included patients from the Zurich ACM Registry who met 2020 "Padua Criteria" for ACM and underwent VT ablation between January 2018 and July 2023. Epicardial ablation was performed in patients with recurrent sustained VT despite endocardial ablation, those lacking and endocardial substrate or if the ECG of the VT / substrate on CMR was suggestive of an epicardial origin. Catheter ablation was guided by activation/entrainment mapping for mappable VT, and pace mapping/voltage mapping during sinus rhythm for unmappable VT. Consecutive follow-up of all patients was performed according to our protocol. Results Twenty-one ACM patients underwent n=24 VT ablation procedures. Of those 20 patients, 6 patients (30%) had LV involvement on CMR. Eight (33%) patients underwent epicardial +/- endocardial ablation. Among patients receiving epicardial ablation, 3 patients (38%) had LV involvement. These three underwent a single ablation procedure, which was epicardial only. Total follow-up was 30 months (range 4-43). Three-month sustained VT/VF recurrence rates were 12% in the ACM group with LV involvement vs 25% in ACM without LV involvement. All patients with sustained VT/VF recurrence underwent repeat ablation via an epicardial approach within 3 months and were free of sustained VT/VF thereafter during a median follow-up of 12 months. One-year recurrence rate did not differ between ACM patients with LV involvement vs. without LV involvement (7.7% vs 8.3%, P＝0.117). Seven out of eight epicardial ablations achieved freedom from VT/VF after one-year follow-up. One ARVC patient with previous endocardial ablation had recurrent VT one month after epicardial ablation, which was free of VT after Flecainide combined with beta-blocker. No significant differences were found in the use of beta-blockers and antiarrhythmic drugs between both groups (ACM with LV involvement vs. without LV involvement) at baseline and during one-year follow-up. Conclusions Single or adjuvant epicardial substrate ablation of VT in arrhythmogenic cardiomyopathy is promising in terms of postprocedural VT free survival, especially in patients with left ventricular involvement demonstrated by CMR.Figure 1Figure 2

Clinical impact of catheter ablation for atrial fibrillation on heart failure parameters

Abstract Background Catheter ablation for atrial fibrillation have already been an established therapy to maintain sinus rhythm in patients with or without heart failure. Atrial fibrillation is often associated with functional valve regurgitations, left ventricular dysfunction and biomarkers of HF. However, it is still unclear how often such parameters improve after catheter ablation. Purpose The aim of this study is to clarify the clinical impact of catheter ablation on heart failure in patients with atrial fibrillation. Methods We retrospectively analysed 139 consecutive patients who underwent catheter ablation for atrial fibrillation and cardiac echocardiography before and one-year after catheter ablation. Patients who underwent hemodialysis or previous valve surgery were excluded. Results Mean age was 69.8±9.5 years and 84(60.4%) patients had persistent atrial fibrillation before ablation procedure. Fourteen (10.1%) patients had severe left ventricular dysfunction (EF<40%). Thirty-four (24.5%) and 37(26.6%) patients had moderate or greater mitral and tricuspid valve regurgitation (MR and TR), respectively. BNP or NTproBNP was significantly elevated in 93(66.9%) patients before catheter ablation. During one-year follow-up, 11 (7.9%) patients underwent second procedure and atrial fibrillation were remained in 2 (1.4%) patients. Additional medications for heart failure were prescribed in 19 (13.7%) of patients after initial procedure. One year after catheter ablation, 19/34(55.9%) and 20/37(54.1%) of moderate or greater functional MR and TR improved to mild or less. Furthermore, 5/14 (35.7%) patients with severe left ventricular dysfunction improved to normal with combined optimal medical treatment. In 64/93 (68.8%) with elevated BNP or NTproBNP, the increase was no longer significant. Even in patients with still elevated BNP or NTproBNP one-year after catheter ablation, their values were decreased by more than 50% in 17/29 (58.6%) patients. Conclusion Catheter ablation for atrial fibrillation can improve heart failure parameters including valve function, systolic ventricular function and biomarkers.

Heart rate dynamics after pulmonary vein isolation: pulsed-field vs. radiofrequency ablation

Abstract Background The autonomic nervous system (ANS) plays a pivotal role in the onset and maintenance of atrial fibrillation (AF). During thermal ablation, the epicardial ganglionated plexi (GP) can inadvertently be affected, as indicated by a post-ablation increase in heart rate (HR), potentially impacting post-procedural outcomes. Pulsed-field ablation (PFA) offers a safer and potentially more effective alternative, as lesion transmurality is not inversely related to safety as in thermal ablation. However, PFA's tissue selectivity may limit its effectiveness in ablating potential AF triggers like GP. Purpose We aimed to assess the impact of PF and RF energy on GP ablation by examining HR changes following PVI procedures. Methods We examined consecutive paroxysmal AF patients undergoing PVI at a single center, using either a variable-loop circular PFA catheter, as part of the inspIRE trial, or a conventional point-by-point RF catheter (1:2 ratio). ECGs were collected before and after ablation at multiple time points, including 1-hour, 1-day, 1-month, and 3-month intervals, with a 24-hour Holter ECG at 3 months. Patients without obtainable sinus rhythm ECGs at these time points were excluded. We also gathered data on post-ablation antiarrhythmic drug and beta-blocker usage. Data are reported as mean±SD, and analysis employed Student’s t-tests, paired t-tests, chi-squared tests, and multiple linear regression analysis to identify influencing factors. Results A total of 105 patients were included (PF = 35, RF = 70). Baseline demographics were similar (Table A). In the RF group, HR significantly increased at all measured time-points. In contrast, this trend was not observed in the PF group (Figure A and B). Following the procedure, the RF cohort exhibited a significantly higher HR compared to PF (7.3±10.3 vs. 0.8±11 at 1-day, p=0.018), and this difference persisted after 3 months (8.5±10.1 vs. 0.9±9, p<0.001, Figure C). These findings remained consistent when HR was assessed using Holter ECG data (HR at 3 months: mean 72.1±8.8 vs 65.8±9.4, min 55.2 vs 48.9; p=0.002, p=0.001, Figure D). The use of RF energy was the only predictor of HR increase after the ablation procedure (β = 7.687, p < 0.001, Table B). Conclusion Our findings indicates that PFA does not increase resting HR as seen with thermal RF ablation, suggesting limited effect on ANS modulation. The role of adjunctive GP ablation during PVI procedures remains a topic of debate.While PFA shows promising improvement in lesion durability, current evidence does not conclusively establish its advantage over RF. This invites contemplation about whether the addition of GP ablation in RF procedures could be a contributing factor. The absence of HR acceleration may pose issues for patients with sick sinus syndrome or pure vagally mediated AF. Further research is essential to confirm these findings and their clinical implications.Central illustrationTables

Assessing the impact of 3D imaging assistance on efficiency and safety in atrial fibrillation cryoablation

Abstract Introduction Pulmonary vein (PV) isolation is a cornerstone therapy for symptomatic atrial fibrillation (AF). Current 3D-navigation technologies used with radiofrequency (RF) ablation allow drastic reduction of X-ray exposure and better anatomical characterization improving acute and long-term procedural results. Cryoballoon ablation (CA) procedures typically rely on conventional fluoroscopy, resulting in significant X-ray exposure. Although contemporary fluoroscopy technologies allow for potential 3D imaging integration, their specific utility in improving procedural guidance during CA remains undefined. Method Using semi-automatic segmentation obtained from pre-procedural cardiac computed tomography, 3D segmentations of the left atrium, including PV, spine and primary bronchi walls were fused on the real-time fluoroscopy acquisitions in three standard positions (AP, LAO, RAO), acquired at the beginning of the procedure (Figure1). We compared procedural characteristics of CA performed with 3D-fusion imaging to conventional fluoroscopy-guided procedures. Results Thirty-six patients (aged 60±13 yo, 85% male) with paroxysmal AF treated with CA were included in the study: 18 in the control group (conventional fluoroscopy) and 18 in the 3D-assisted group. Acute PV isolation was achieved in all patients. The 3D-assisted CA was associated with significantly shorter procedure duration (mean 97.8±15.5 vs 82.1±16.1 min, p=0.0048); left-sided dwelling time (mean 77±15.2 vs 65.1±14.4 min, p=0.0351); and lower X-ray energy delivered to the patient (Dose Area product) with mean 661±373.1 vs 378.1±316.8 cGy*cm2 (p=0.013). Interestingly, we found that 72.2% of 3D guided procedures were done in less than 90min, while 77.8% of conventional cases required more than 90min to be completed (Figure 2D). Conclusion 3D-fusion imaging integration is feasible and allows for an exact PV anatomy depiction on fluoroscopy. Our data illustrates that it might significantly improve CA efficiency (shorter procedure duration) and safety (lower X-ray exposure and left-sided dwelling time). Our approach could also impact long-term results since it might reduce the likeability of missing intermediate PVs. Further research is needed to evaluate the incremental value of 3D imaging in long term efficacy.Figure 1Figure 2

Atrial fibrillation cryoablation guided by pressure waveform: a prospective multicentre registry

Abstract Background Cryoballoon ablation (CA) procedures require optimal occlusion of the pulmonary veins (PV), which is conventionally evaluated by iodine contrast injection through the catheter tip. This technique has some weaknesses such as risk of allergic reactions, nephrotoxicity, requirement of fluoroscopy (sometimes at high doses), requirement of a second operator, among others. PV pressure waveform assessment is an alternative method for confirming occlusion, however, multicentre assessment of periprocedural efficacy and safety is lacking. Purpose To describe the intra-procedural performance and safety of routine pressure-based CA. Methods In this independent prospective multicentre observational study, baseline and procedure data from consecutive pressure-guided CB ablations were collected. Operators were not required to have experience in pressure-guided CA for participating in the registry. They were asked to classify the pressure waveform curves into type 1 (presence of "a-wave" and/or symmetric "v-wave", meaning incomplete PV occlusion) and type 2 (absence of "a-wave" and asymmetric "v-wave", meaning complete PV occlusion), Figure 1. The primary endpoint was PV isolation in all veins without use of contrast. Procedure performance and adverse events were also analyzed. Results A total of 150 patients (mean age: 61 ± 10 y.) with paroxysmal (62%) or persistent AF (38%) were included and underwent pressure-guided CA in 9 centres from Spain. Complete PV isolation was achieved in 148 patients (98%). The operators switched to contrast use in 14 cases (9%), mainly to double check the occlusion. Total procedure and fluoroscopy time were 97 ± 39 and 19 ± 10 min respectively. There were 7 (4.7%) procedure related adverse events: 4 phrenic nerve palsy (3 of them were transient), 1 transient coronary ST elevation (before ablation), 1 gastroparesis and 1 femoral pseudoaneurysm. Most relevant results are summarized in Figure 2. Conclusion In this multicentre and multi-brand assessment, CA guided by pressure waveforms provided outstanding procedural outcomes, which were equivalent to those reported with the conventional approach. All operators could easily obtain and identify the waveform without a specific learning curve, avoiding the use of iodine contrast in most cases. The long-term efficacy of this approach will be presented in future analyses.Pressure waveforms types in cryoablationProcedural data

Clinical accuracy of a 3-dimensional multielectrode non-invasive ECG mapping vest in premature ventricular contraction ablation procedures

Abstract Background Invasive 3D mapping is the current gold standard in determining premature ventricular contraction (PVC) localization. However, given its invasive nature, unawareness of PVC origin beforehand may lead to prolonged procedure times and increased complications risk. Purpose In this study, we compared the diagnostic accuracy of a non-invasive 3-dimensional mapping ECG vest (MECGV) with invasive 3D mapping and ablation successful points as a reference. We also evaluated 12-lead ECG based pre-procedural PVC localization accuracy of 2 expert operators blinded to clinical findings. Methods In 15 consecutive adult patients between the ages of 35 to 69 (male n: 9, median age: 48), MECGV and subsequently a 3D mapping with uneventful successful PVC RF catheter ablation were performed and included in the study. PVC localization estimations of MECGV method and the EP experts' locatization predictions were compared separately with invasive 3D ablation results using the Cohen's kappa method and with the help of a 16-segmentation model we created for the ease of the analyses . Results Results were presented on Table-1. MECGV was found to be highly compatible (Cohen's kappa 0.968, p<0.001) with the RF ablation results. However operators assessments were found to be less coherent with invasive 3D mapping (Operator 1 Cohen's kappa 0.571, p 0.033, Operator 2 Cohen's kappa 0.618, p: 0.019, respectively). MECGV accuracy was %87 in pinpointing the PVC focus. The only 2 localizations that MECGV failed were on the septal aspects of the heart (Picture-2 Failure of defining the focus on LVOT septal instead of RVOT septal) Conclusion MECGV method seems to be highly compatible with invasive 3D mapping techniques in detection of PVC localization and bests EP expert estimates in this regard. However, it also seem to have some pitfalls especially on septal aspects of the heart.Table-1 and segmentation schemePicture-1

Digital health in the electrophysiological lab: Initial experience, safety and feasibility using remote support for arrhythmia ablation-Results of REMOTE-VA study

Abstract Background In most electrophysiology (EP) labs, electroanatomical mapping (EAM) systems are operated on site by qualified staff or field technical engineers (FTE). Due to lack of skilled personnel, the FTE usually must travel between different hospitals and procedures must be planned in advance. Ablation of ventricular arrhythmias (VA) represents the most complex procedure in the field. The use of remote support (RS) to guide complex EP procedures has the potential to increase flexibility, reduce travel times and maximise healthcare resources. Purpose To evaluate the safety and feasibility of RS as compared to on-site support guided catheter ablation procedures for VA. Methods All patients undergoing ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation using remote support were included. The electronical system of the hospital was searched for 30 days postprocedural emergency department (ED) visits, unplanned ambulatory presentations, and readmissions. RS guided three-dimensional (3D) mapping was achieved by connecting the EAM software with an integrated audio-visual solution for remote support. Internet connection-based headphones and high-resolution cameras ensured the communication between the operator and the FTE, who worked exclusively from home office. The control group consisted of an equal number of patients matched for the type of procedure and undergoing on-site guided procedures. All ablations were performed using high density 3D mapping, as per institutional standard. Results Between October 2022 and October 2023, a total of 25 patients underwent VT (32%) or PVC ablation in our centre using RS and were compared to 25 patients undergoing the same procedures under on-site guidance. In the RS group one patient underwent epicardial VT ablation and another one bipolar ablation for VT Storm. The demographic data were similar between the groups. The median procedure time was 120 (93, 143) minutes in the RS group and 112 (95, 138) minutes in the control group (p=0.95), while the fluoroscopy time was 11.4 (7.0, 14.0) and 7.26 (5.0, 10.9) minutes respectively (p=0.08). The procedural success was achieved in 96% procedures in the RS group and in 100% in the control group. No technical issues or changes to on-site support were reported. One minor intraprocedural complication was noted among the control patients, while 24% of the patients in each group developed minor complications until discharge. Two patients in the RS group and one in the control group had ED visits, while only one patient in the control group had an unplanned ambulatory presentation. One unplanned readmission was reported in the control group (Table 1). Conclusions Even in the most complex procedures including epicardial ablation, the use of RS was feasible and safe in this single centre study. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times, and maximise healthcare resources.

A patient-based realistic simulation platform to train future electrophysiologists to complex ablation procedures

Abstract Title An immersive catheter ablation platform based on patients’ 3D heart model for the simulation and training of future electrophysiologists. Background Arrhythmias are on the rise worldwide due to the ageing of the population. Projections urge to train the next generation of electrophysiologists (EPs) to perform catheter (CATH) ablation (CA) of arrhythmias. Training of future EPs relies mostly on a companionship, where teaching of CATH steerability is made on patients (pts) referred for procedures. While several other domains have established the utility of simulators to speed up learning process, increase safety and establish procedure road maps, dedicated simulators for EPs based on pts’ real anatomy do not exist yet. Purpose To speed up the handling of steerable CATH on MRI-based 3D heart models to optimize ablation road maps in pts referred for complex arrhythmias. Methods ARTS is an Artificial Intelligence and Augmented Reality-based platform comprising two key components: HeARTS and ARTSim. HeARTS is designed to automatically generate 3D heart models from pts’ MRI scans. ARTSim is a CA simulator that utilizes the 3D heart models of the pts for the planning and simulation of CA procedures. This simulator incorporates innovative techniques for digitizing and tracking the movements of a physical catheter in real time, and enabling its navigation within a completely virtual heart. With this technology, the CATH can be precisely steered to various heart locations, including the right and left (LA) atrium, the coronary sinus, and the right and left (LV) ventricles. Results Panel A of the figure shows the mannequin used for the simulator, where a real ablation CATH is introduced within the pt’s heart through a venous introducer. Panel B shows right anterior oblique (RAO) and modified RAO views of a pt suffering from a typical right atrial flutter. Note the presence of yellow tags positioned along the cavotricuspid isthmus (CTI) that the trainee must reach for a programmable duration using the shaft and the handle of the CATH shown in panel A. Panel C shows the virtual ablation CATH in green positioned on the target dots of the CTI. The pink color indicates that the trainee reached the desired target, which became red when the CATH remained stable at the same location for a duration of 5 sec (i.e. stability) with a force >5g (i.e. efficacy) and <20g (i.e. safety). Conclusions Herein, we present ARTS, a realistic CA simulation platform for the training of future EPs, that offers all the typical characteristics of 3D navigation including steerability, stability measurements and the force applied. Importantly, ARTS is based on the true anatomy of the pts, hence might be used to establish and discuss roadmaps to optimize procedures efficacy and safety. Version 2.0, foreseen early 2024, will include 3D late gadolinium enhancement and transseptal puncture for virtual LA and LV procedures, and later on activation times and myocardial voltage.Figure

Catheter ablation of papillary muscle arrhythmias: procedural characteristics and long term outcome

Abstract Background Ventricular arrhythmias (VA) originating from the papillary muscles can occur both in patients with and without structural heart disease. Although catheter ablation is the treatment of choice, ablation success remains challenging and long-term outcomes for this origin of VA are still unsatisfactory. Methods and Results All patients undergoing catheter ablation for premature ventricular contractions or ventricular tachycardia between june 2009 and november 2022 were analyzed. 66 patients (26 female (39%), mean age 60±15 years) undergoing catheter ablation of VA originating from the papillary muscle were identified. 21/66 (32%) patients had a reduced or mildly reduced left ventricular ejection fraction at time of initial presentation. While mitral valve regurgitation was present in 32/66 (48%) patients, mitral valve prolapse was observed in only 2/66 (3%) patients. 6/66 (9%) patients presented with non-sustained ventricular tachycardia (VT) and 1/66 (2%) patient presented with sustainend VT prior to catheter ablation. 61/66 (92%) patients underwent ablation of PVCs of the left ventricular papillary muscles (22/66 (33%) patients anterolateral; 39 (59%) patients posteromedial). 5/66 patients underwent ablation of premature ventricular complex (PVC) originating from the papillary muscles of the right ventricle. In 13/66 (19.7%) patients only a retrograde approach was used, in 26/66 (39.5%) patients a retrograde and an additional transeptal approach and in only 10/66 (15.2%) patients solely a transeptal approach. Mean PVC QRS duration was 152.5 ± 3.5 msec. Ablation was acutely successful in 44/66 (67%) patients. Mean procedure time was 145.8 ± 63.7 minutes and mean number of radiofrequency applications was 21.3 ± 16.7 (25 to 55 Watts, 37764.2 ± 27824.1 Joules). Overall, procedural complications occurred in 4/66 (6%) patients Follow up data were obtained from Holter ECGs, review of medical records, patient consultation, or via structured follow-up within the prospective TRUST registry. All information was combined to assess recurrence of PVC/VT. Recurrence of VA originating from the papillary muscles occurred in 11/66 (17%) patients. 9/66 patients (14%) underwent re-ablation due to recurrence of VA originating from the papillary muscles after previous ablation procedures. Conclusion Catheter ablation of papillary muscle arrhythmias is associated with a single procedural success rate of 67% with a procedural complication rate of 6%. 14% of patients underwent re-ablation due to recurrence of papillary muscle arrhythmias.

Clinical characteristics and genetic substrate of lone atrial fibrillation: a single center experience

Abstract Background Juvenile-onset lone atrial fibrillation (LAF) may be the initial manifestation of a concealed channelopathy or cardiomyopathy (CMP) or it may be due to an atrial specific genetic susceptibility. Clinical characteristics, genetic background and proper management are still largely unknown. Purpose Aim of the present study is to describe the clinical and genetic characteristics of patients with juvenile-onset LAF. Methods We enrolled patients referred to our center for ablation between 1/2018 and 11/2023 with a first diagnosis of LAF before the age of 60, a structurally normal heart (absence of known CMP, ischemic, valvular, congenital heart disease) and no overt channelopathy. A concealed Brugada syndrome was systematically excluded. Genetic testing was performed using Next Genome Sequencing and a dedicated gene panel. Results 89 patients were included (84% male, LAF onset 43 ± 8 years, BMI 25 ± 7 kg/m2): 32% had a first-degree family history of AF (including 15% below 60 years), 18% of sudden death, 8% of cardiac conduction disorders and 2% of CMP. Cardiovascular risk factors included arterial hypertension in 24%, smoking in 47% and obstructive sleep apnea syndrome in 4%; 20% were competitive athletes. Most patients (89%) presented with paroxysmal AF and 92% were symptomatic (mainly palpitations). At presentation LVEF was 61±5% and LAVI 35±14 ml/m2. Median follow-up time after the first AF episode was 6 years (IQR 4-10). Most patients (81, 91%) underwent at least one transcatheter ablation procedure after failed anti-arrhythmic drug (AAD) therapy (mostly IC). The first procedure (73% radiofrequency, 27% cryoablation) included pulmonary veins isolation (PVI) in all and additional lesions in 5%; the second procedure (n=18, 22% of the ablation group) included PV re-isolation in all (mostly due to multiple vein reconnections) and additional lesions in 17%; the third procedure (n=8, 10% of the ablation group) included PV re-isolation in 25% and additional lesions in 75%. The remaining 8 patients were treated with AAD only (mostly IC). By the last follow-up, 7% of patients in the ablation group and 25% in the AAD group had documented recurrences (even though 50% of those who received ablation were still on AAD). Among the 35 patients subjected to genetic investigation, 10 have available results: 30% tested positive for C4-C5 variants (2 for KCNQ1, 1 for TTN), 50% for C3 variants (RYR2, ABCC9, LMNA, KCNH2 and RMB20) and 20% were negative. Conclusions In the present single center cohort of patients with juvenile-onset LAF, a positive family history was found in almost one third of patients. Despite prompt diagnosis and treatment (including >1 ablation in 20% of patients), recurrences rate is not trivial. The yield of genetic test so far is high, supporting its use in this population.

J-curved phenomenon between the prevalence of left atrial low-voltage areas and body mass index existed in patients with atrial fibrillation ablation

Abstract Background Left atrial low-voltage areas (LVAs) were known to be associated with atrial fibrosis and atrial fibrillation (AF) recurrence after catheter ablation. However, the association between body mass index (BMI) and prevalence of LVAs has not been fully elucidated. We hypothesized that LVAs were more frequently found in patients with abnormal BMI than in those with normal BMI. Purpose The purpose of this study was to clarify the association between body mass index (BMI) and the prevalence of LVAs in patients with AF ablation. Methods Between December 2014 and March 2022, 1,479 (age, 68±10 years; female, 500 [34%]) consecutive patients who underwent initial AF ablation were enrolled. BMI was divided into four groups, namely <18.5 kg/m², 18.5-25 kg/m², 25-30 kg/m², ≥30 kg/m². LVAs was defined as areas with bipolar voltage of <0.5 mV covered ≥5 cm² of left atrium. Rhythm outcome following the catheter ablation procedure was also followed for 24 months. Results LVAs were found in 349 (24%) patients. J-curved phenomenon existed between BMI and the prevalence of LVAs (Figure 1). In particular, BMI <18.5 kg/m² was an independent predictor of LVAs on multivariate analysis (odds ratio, 1.9; 95% confidence interval: 1.01–3.5; p=0.046). As for rhythm outcome, there was significant difference in freedom from AF recurrence among groups stratified by BMI (Figure 2). Conclusions Between BMI and the prevalence of LVAs, J-curved phenomenon existed in patients with AF ablation. There was significant difference in rhythm outcome following AF ablation among groups stratified by BMI.Figure 1Figure 2

Long-term outcome after catheter ablation for fascicular ventricular tachycardia in a single high-volume center in Germany

Abstract Background Idiopathic Fascicular Ventricular Tachycardia (IFVT) accounts for less than 10% of all VTs and represents the most common idiopathic ventricular tachycardia of the left ventricle. This study reports on clinical and procedural characteristics and the long-term outcome of patients undergoing catheter ablation of premature ventricular complexes (PVC) and ventricular tachycardias (VTs) arising in proximity of the left ventricular conduction system. Methods and results This study includes 27 patients (17 male, 45 ± 17 years; 10 females, 50 ± 11 years) who underwent electrophysiological examinations at a tertiary ablation center over a period of 14 years (2009 to 2022). Follow-up was performed via regular Holter-ECGs and clinical evaluations, or via structured follow-up within the prospective TRUST registry. In 21/27 patients (77.8%), the left posterior fascicle (LPF) was involved in the IFVT. In 4 (14.8%) the left anterior fascicle (LAF) was involved and in 2 (7.4%) patients an origin in the upper septal (US) area was demonstrated. 22/27 (81.5%) patients had a preserved left ventricular ejection fraction (LVEF) and only 5 (18.5%) patients had a LVEF less than 50% at the time of presentation. 14/27 (51.9%) patients presented with PVC or non-sustained VTs with the following distribution: 10 (71.4%) originating from the LPF, 3 (21.4%) from the LAF and 1 (7.1%) from the US. 21/27 (77.8%) patients presented with sustained VTs: 16 (76.2%) arising from the LPF, 4 (19%) from the LAF and 1 (4.8%) from the US. However, only 2 (7.4%) patients presented in sustained VT at the beginning of the EP procedure. In 16 (59.3%) patients a sustained VT was induced during the EP study via isoprenaline and/or programmed ventricular stimulation. Mean QRS duration of the VT was 124.5 ± 14.6 msec. In 21 (77.7%) patients only a retrograde approach was used, in 3 (11.1%) patients a retrograde and an additional transeptal approach and in only 3 (11.1%) patients solely a transeptal approach. Mean number of radiofrequency applications was 11.8 ± 12.6 (30 to 40 Watts, 27545.6 ± 30524.4 Joules). FVT ablation was acutely successful in 24 patients (88.9%). In 2 patients (7.4%) no ablation was performed due to inability to induce VT under sedation. 3/27 patients (11.1%) underwent re-ablation due to FVT recurrence after previous ablation procedures. Moreover, 3 (11.1%) additional patients underwent repeated VT ablations during follow-up, but the arrhythmia originated from a different LV area. No procedure-related complication occurred. In 4 patients (14.8%) left fascicular posterior block was caused by ablation and in 3 (11.1%) patients a complete left bundle block. Mean procedure time was 130 ± 48.9 minutes. Conclusion Ablation of FVT in a tertiary ablation center is associated with a high single procedural success rate of 88.9% during long-term follow-up, with a mild risk of fascicular injury. 11.1% of patients underwent re-ablation due to FVT recurrence.