Assessing left atrial intramyocardial fat infiltration from computerized tomography angiography in patients with atrial fibrillation

Epicardial Adipose Tissue and Heterogeneity Parameters Combined with Inflammatory Cells to Predict the Value of Heart Failure with Preserved Ejection Fraction Patients Post Myocardial Infarction

BACKGROUND AND PURPOSE

Epicardial adipose tissue (EAT) comprises three distinct lipid components, each exerting differential effects on cardiovascular diseases. During disease progression, dynamic alterations in lipid composition and spatial distribution contribute to the inherent heterogeneity of EAT. The excessive activation of inflammatory cells may contribute to chronic inflammation, promoting atherosclerosis and cardiac diseases. However, the role of EAT in patients with myocardial infarction (MI) who develop heart failure with preserved ejection fraction (HFpEF) remains unclear. This study aims to quantify the overall and perivascular volumes of EAT using cardiac magnetic resonance (CMR) imaging and assess its heterogeneity, exploring the predictive value of EAT heterogeneity and different EAT volumes combined with inflammatory cells for the occurrence of HFpEF in MI patients with normal left ventricular ejection fraction (LVEF).

METHODS

This retrospective cohort study enrolled patients diagnosed with MI with preserved LVEF via clinical assessment and CMR at the Second Affiliated Hospital of Kunming Medical University between January 2015 and July 2023. Patients who did not undergo percutaneous coronary intervention (PCI) were followed, with the incidence of HFpEF serving as the primary endpoint. The cohort was stratified into two groups: those without HFpEF and those who developed HFpEF.Cardiac structure, function, EAT volume, and infarct volume parameters were obtained using the CMR post-processing software CVI-42, while EAT heterogeneity parameters entropy were derived using Python software. Independent sample t-tests, non-parametric tests, and chi-square tests were employed to analyze the differences in clinical baseline data and CMR metrics between the two groups. Spearman's rank correlation was utilized to analyze the associations between EAT parameters and inflammatory cells, inflammatory markers, and diastolic dysfunction indicators. Furthermore, we conducted univariate and multivariate Cox regression analyses to determine the predictive value of each parameter for the development of HFpEF in MI patients. Time-dependent ROC curves were generated to evaluate the efficacy of each parameter in predicting HFpEF, the AIC values of each parameter and the final model were calculated to evaluate the predictive performance. The optimal cut-off values were identified using time-dependent ROC curves in R software, and Kaplan-Meier event-survival curves were plotted to illustrate the event-free rates based on these optimal thresholds.The median follow-up time was calculated using the reverse Kaplan-Meier method.

RESULTS

A total of 203 MI patients with normal LVEF were included, with 74 in the HFpEF group and 129 in the non-HFpEF group. No significant differences were observed between the two groups regarding age, sex, and infarct volume; however, significant statistical differences were noted in BMI, diabetes, renal failure, leukocytes, neutrophils, monocytes, total EAT, EAT entropy, left ventricular EAT (LV EAT), left atrial end-systolic volume (LAESV), triglycerides, NHR, MHR and LACI(Left atrioventricular coupling index) (P < 0.05). Both overall and local EAT volumes showed a positive correlation with leukocytes and monocytes,as well as with the inflammatory markers MHR and SIRI. Furthermore, EAT volume exhibited a positive correlation with the LACI, a marker of diastolic dysfunction. Univariate and multivariate Cox regression analyses indicated that BMI, diabetes, monocyte, LV EAT, and EAT entropy are independent risk factors for HFpEF. And the AIC value of the multivariate regression model was the smallest.Further time-dependent ROC analysis revealed that the maximum AUC for BMI was 0.67, while the AUC for LV EAT was 0.63, and EAT entropy was 0.60, the maximum AUC for monocyte was 0.70, and the combined prediction of LV EAT and EAT entropy had a maximum AUC of 0.70. After a median follow-up of 34 months, Kaplan-Meier survival curves demonstrated that LV EAT greater than 21.23 mL was associated with the occurrence of HFpEF, whereas EAT entropy was not.

CONCLUSIONS

In patients with chronic MI, normal LVEF, and no prior PCI, the occurrence of HFpEF is not correlated with infarct volume; however, BMI, diabetes, monocyte, LV EAT, and EAT entropy are independent risk factors for HFpEF with significant predictive value, with the highest predictive efficacy observed monocyte and when combining EAT entropy and LV EAT. Additionally, both overall and local EAT volumes exhibit a moderate positive correlation with leukocytes,monocytes and inflammatory markers, and were also positively correlated with diastolic dysfunction. This suggests that, in clinical practice, beyond traditional indicators, there should be an increased focus on EAT heterogeneity and perivascular EAT in MI patients with normal LVEF who have not undergone PCI to to reduce the incidence of HFpEF.

The use of cardiac imaging in patients undergoing atrial fibrillation ablation

Cardiac imaging (CI), including echocardiography, multidetector computed tomography (MDCT), and cardiac magnetic resonance (CMR), is gaining increasing interest to aid atrial fibrillation (AF) ablation procedures, from pre-procedural planning to intra-procedural guidance. Transthoracic echocardiography is widely used for imaging, especially for preprocedural assessment, while transesophageal and intracardiac echocardiography (ICE) are used for intraprocedural guidance during transseptal puncture. Cardiac MDCT, leveraging its high spatial resolution, offers a detailed anatomical visualization of cardiac chambers and adjacent structures; moreover, left atrial wall thickness assessed by MDCT may guide radiofrequency energy titration to enhance procedural safety and efficiency. At the same time, CMR allows for detailed myocardial tissue characterization and the detection of fibrosis. ICE, MDCT, and CMR also permit intra-procedural image integration with electroanatomical maps, allowing to be aware of a greater amount of intra-procedural real-time information regarding the anatomy and the local characteristics of the tissue in contact with the ablation catheter. One of the primary objectives of performing CI-aided AF ablations is to increase procedural safety and to permit more personalized procedures, according to the characteristics of each patient. This review offers a comprehensive overview of the current applications of CI during the different phases of AF ablation and explores the potential future applications of CI in this context.

Catheter Ablation of Atrial Fibrillation: Technique and Future Perspectives

Atrial fibrillation is the most common sustained cardiac arrhythmia with a significant impact on quality of life in terms of symptoms and reduction of functional status. Also, it is associated with an increased risk of mortality, stroke, and peripheral embolism. Catheter ablation for atrial fibrillation has become a well-established treatment, improving arrhythmia outcomes without increasing the risk of serious adverse events compared to antiarrhythmic drug therapy. The field has undergone significant advancements in recent years, yet pulmonary vein isolation continues to be the cornerstone of any atrial fibrillation ablation procedure. The purpose of this review is to provide an overview of the current techniques, emerging technologies, and future directions.

Differential and synergistic effects of right and left atrial ganglionated plexi ablation in patients undergoing cardioneuroablation: results from the ELEGANCE multicenter study

BACKGROUND

Cardioneuroablation (CNA) treats reflex syncope by ablating ganglionated plexi (GPs) either confined to the right (RA) or left atrium (LA), or accessible from both. We assessed whether GP ablation in one atrium affects parasympathetic modulation in the other and how ablation sequence (RA then LA, or vice-versa) impacts efficacy.

METHODS

Two propensity-matched groups of patients with reflex syncope or functional bradycardia were analyzed. Group 1 received CNA in the RA first, followed by LA. Group 2 in the reverse order.

RESULTS

Thirty-four patients were enrolled. In group 1, RA ablation prompted a heart rate (HR) increase (49.8 ± 10.6 vs. 61.2 ± 13.8 bpm; p < 0.01) that was enhanced after LA ablation (60.3 ± 14.5 vs. 64.5 ± 14.4 bpm; p = 0.02). RA ablation did not reduce PR interval in any patient or modify the Wenckebach point (WP) (596 ± 269 vs. 609 ± 319 ms; p = 0.68), while additional LA ablation reduced PR interval in 3 patients and mean WP (611 ± 317 vs. 482 ± 191 ms; p = 0.03). In group 2, LA ablation increased HR (56.7 ± 6.6 vs. 76.4 ± 13.8 bpm; p < 0.01), with an additional effect of RA ablation (76.0 ± 16.5 vs. 85.4 ± 15.9 bpm; p < 0.01). LA ablation decreased PR interval in 3 patients and mean WP (512 ± 182 vs .399 ± 85 ms; p = 0.01). Further RA ablation did not decrease PR or WP. CNA success was 82% in group 1 and 100% in group 2 (p = 0.552). After 24.5 ± 6.1 months, 2 patients in group 1 vs. no patients in group 2 experienced symptom recurrence.

CONCLUSIONS

Bi-atrial CNA provides incremental benefits after both RA and LA ablation. Starting ablation in the LA provides the most significant effect on vagal modulation.

Left atrial intramyocardial fat at pulmonary vein reconnection sites during atrial fibrillation redo ablation

AIMS

Electrical reconnections between pulmonary veins (PVs) and the left atrium (LA) are frequently responsible for atrial fibrillation (AF) recurrences after pulmonary vein isolation (PVI). Multidetector computed tomography (MDCT)-derived images can be post-processed to detect intramyocardial fat (inFAT) by signal radiodensity thresholding. The role of inFAT on PV-LA reconnections remains unknown. The aim of this study was to analyse the relationship between inFAT localization at pre-procedural MDCT-derived inFAT maps from first AF ablation and PV-LA reconnections in patients with AF recurrence undergoing redo ablation.

METHODS AND RESULTS

We included 45 consecutive patients who underwent AF redo ablation presenting at least one PV-LA reconnection. First AF ablation pre-procedural MDCT-derived data were post-processed with ADAS 3D™ to create 3D LA inFAT maps, which were loaded into CARTO3 navigation system and merged with the electroanatomical map for reconnection site analysis. In 103 out of 156 (66.0%), PV-LA reconnection points inFAT was identified in the 6 mm diameter tag point depicted in the navigation system. When dividing the PVI line into standardized segments, those identified as containing PV-LA reconnection points (i.e. reconnection segments) exhibited significantly higher total inFAT volumes compared with non-reconnection segments (8.05 ± 6.56 vs. 5.40 ± 5.18 μL, P < 0.001). Additionally, reconnection segments showed greater volumes of inFAT components, specifically dense inFAT (0.06 ± 0.06 vs. 0.03 ± 0.04 μL, P < 0.001) and fat-myocardial admixture (7.98 ± 6.52 vs. 5.37 ± 5.16 μL, P < 0.001).

CONCLUSION

Intramyocardial fat is co-localized with two-thirds of PV-LA reconnection points in patients undergoing AF redo ablation. Reconnection segments exhibit significantly higher inFAT volumes compared to non-reconnection segments. This proof-of-concept study suggests that inFAT may play a role in PV-LA electrical reconnections following PVI.

Correlation Between Voltage and Impedance Mapping in Patients with Atrial Fibrillation

Background. Pulmonary vein isolation (PVI) represents the cornerstone of paroxysmal (PAF) and persistent atrial fibrillation (PsAF) ablation. Impedance values provide insights on tissue conductive properties. Methods. Consecutive patients undergoing PAF and PsAF ablation were prospectively enrolled. All the patients underwent a preprocedural multidetector computed tomography (MDCT) to evaluate left atrial wall thickness (LAWT). Electroanatomic maps were acquired with the ablation catheter, and impedance values (Ω) and voltage amplitude (mV) of bipolar electrograms were collected. Results. A total of 60 patients (40 with PAF and 20 with PsAF) were included in the study. In all PAF cases, no voltage value lower than 0.5 mV was found at LA mapping; the corresponding mean impedance value was 151.5 ± 5.4 Ω. In PsAF cases, voltage values inferior to 0.05 mV have been reported in 19/20 patients. PsAF patients showed a mean impedance value of 129.1 ± 3.8 Ω. The correlation analysis between bipolar voltage and impedance reported an rs value of 0.4166 (p < 0.001), showing a positive correlation between the two variables. On the contrary, no direct correlation was found between voltage and LAWT and between impedance and LAWT (rsv-t = 0.1838; rsi-t = 0.1133, respectively). Conclusions. This research study suggests a correlation between voltage amplitude and impedance values, so that impedance might be used for arrhythmogenic substrate characterization.

Glucagon-like peptide-1 receptor agonist semaglutide reduces atrial fibrillation incidence: A systematic review and meta-analysis

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are new anti-hyperglycaemic drugs with proven cardiovascular (CV) benefit in diabetic and non-diabetic patients at high CV risk. Despite a neutral class effect on arrhythmia risk, data on semaglutide suggest a possible drug-specific benefit in reducing atrial fibrillation (AF) occurrence.

OBJECTIVE

To perform a meta-analysis of randomized clinical trials (RCTs) to assess the risk of incident AF in patients treated with semaglutide compared to placebo.

METHODS AND RESULTS

Ten RCTs were included in the analysis. Study population encompassed 12,651 patients (7285 in semaglutide and 5366 in placebo arms), with median follow-up of 68 months. A random effect meta-analytic model was adopted to pool relative risk (RR) of incident AF. Semaglutide reduces the risk of AF by 42% (RR .58, 95% CI .40-.85), with low heterogeneity across the studies (I2 0%). At subgroup analysis, no differences emerged between oral and subcutaneous administration (oral: RR .53, 95% CI .23-1.24, I2 0%; subcutaneous: RR .59, 95% CI .39-.91, I2 0%; p-value .83). In addition, meta-regression analyses did not show any potential influence of baseline study covariates, in particular the proportion of diabetic patients (p-value .14) and body mass index (BMI) (p-value .60).

CONCLUSIONS

Semaglutide significantly reduces the occurrence of incident AF by 42% as compared to placebo in individuals at high CV risk, mainly affected by type 2 diabetes mellitus. This effect appears to be consistent independently of the route of administration of the drug (oral or subcutaneous), the presence of underlying diabetes and BMI.

The Ablate-by-LAWT multicentre prospective study: Personalized paroxysmal atrial fibrillation ablation with ablation index adapted to local left atrial wall thickness

BACKGROUND

Personalized radiofrequency (RF) ablation for paroxysmal atrial fibrillation (PAF), adapting the ablation index (AI) to local left atrial wall thickness (LAWT), proved to be highly efficient maintaining high arrhythmia-free survival rates. However, multicentre data are lacking. This multicentre, prospective, non-randomized study was conducted at 5 tertiary hospitals and sought to assess the safety, efficacy, and reproducibility of the LAWT-guided ablation for PAF.

METHODS

Consecutive patients referred for first-time PAF were prospectively enrolled. The LAWT maps were obtained from preprocedural multidetector computed tomography and integrated into the navigation system. AI was titrated according to the local LAWT, and the ablation line was personalized to avoid the thickest regions while encircling the pulmonary veins (PVs).

RESULTS

A total 109 patients (60.1 ± 9.4 years, 64.2% male) were enrolled. Median procedure time was 61.7 min (48.4-83.8), fluoroscopy time was 1.0 min (0.4-3.3), and RF time was 13.9 min (12.3-16.8). Median AI tailored to the local LAWT was 393 (374-412) for the anterior wall and 340 (315-378) for the posterior wall. Right and left PVs first-pass isolation was achieved in 89% and 91.7% of the patients, respectively. At 12-month follow-up, freedom from any atrial arrhythmia was 93.4% (95% CI 88.7-98.1), without differences across centres (P = 0.169). One patient experienced femoral artery pseudoaneurysm, with no other serious procedural-related complication.

CONCLUSION

The Ablate-by-LAWT study proved that LAWT-guided PV isolation for PAF is safe, effective, and efficient in a multicentre setting. Twelve-month recurrence-free survival exceeded 90% (NCT04218604).

Low-Voltage Area Ablation in Addition to Pulmonary Vein Isolation in Patients with Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background: Low-voltage area (LVA) ablation, in addition to pulmonary vein isolation (PVI), has been proposed as a new strategy in patients with atrial fibrillation (AF), but clinical trials have shown conflicting results. We performed a systematic review and meta-analysis to assess the impact of LVA ablation in patient undergoing AF ablation (PROSPERO-registered CRD42024537696). Methods: Randomized clinical trials investigating the role of LVA ablation in addition to PVI in patients with AF were searched on PubMed, Embase, and the Cochrane Library from inception to 22 April 2024. Primary outcome was atrial arrhythmia recurrence after the first AF ablation procedure. Secondary endpoints included procedure time, fluoroscopy time, and procedure-related complication rate. Sensitivity analysis including only patients with LVA demonstration at mapping and multiple subgroups analyses were also performed. Results: 1547 patients from 7 studies were included. LVA ablation in addition to PVI reduced atrial arrhythmia recurrence (odds ratio [OR] 0.65, 95% confidence interval [CI] 0.52-0.81, p < 0.001) with a number needed to treat to prevent recurrence of 10. No difference in procedure time (mean difference [MD] -5.32 min, 95% CI -19.01-8.46 min, p = 0.45), fluoroscopy time (MD -1.10 min, 95% CI -2.48-0.28 min, p = 0.12) and complication rate (OR 0.81, 95% CI 0.40-1.61, p = 0.54) was observed. Consistent results were demonstrated when considering only patients with LVA during mapping and in prespecified subgroups for AF type (paroxysmal vs. persistent), multicentric vs. monocentric trial, and ablation strategy in control group. Conclusions: In patients with AF, ablation of LVAs in addition to PVI reduces atrial arrhythmia recurrence without a significant increase in procedure time, fluoroscopy time, or complication rate.

Personalized pulmonary vein isolation with very high-power short-duration lesions guided by left atrial wall thickness: the QDOT-by-LAWT randomized trial

AIMS

Pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) using very high-power short-duration (vHPSD) radiofrequency (RF) ablation proved to be safe and effective. However, vHPSD applications result in shallower lesions that might not be always transmural. Multidetector computed tomography-derived left atrial wall thickness (LAWT) maps could enable a thickness-guided switching from vHPSD to the standard-power ablation mode. The aim of this randomized trial was to compare the safety, the efficacy, and the efficiency of a LAWT-guided vHPSD PVI approach with those of the CLOSE protocol for PAF ablation (NCT04298177).

METHODS AND RESULTS

Consecutive patients referred for first-time PAF ablation were randomized on a 1:1 basis. In the QDOT-by-LAWT arm, for LAWT ≤2.5 mm, vHPSD ablation was performed; for points with LAWT > 2.5 mm, standard-power RF ablation titrating ablation index (AI) according to the local LAWT was performed. In the CLOSE arm, LAWT information was not available to the operator; ablation was performed according to the CLOSE study settings: AI ≥400 at the posterior wall and ≥550 at the anterior wall. A total of 162 patients were included. In the QDOT-by-LAWT group, a significant reduction in procedure time (40 vs. 70 min; P < 0.001) and RF time (6.6 vs. 25.7 min; P < 0.001) was observed. No difference was observed between the groups regarding complication rate (P = 0.99) and first-pass isolation (P = 0.99). At 12-month follow-up, no significant differences occurred in atrial arrhythmia-free survival between groups (P = 0.88).

CONCLUSION

LAWT-guided PVI combining vHPSD and standard-power ablation is not inferior to the CLOSE protocol in terms of 1-year atrial arrhythmia-free survival and demonstrated a reduction in procedural and RF times.