Abstract Funding Acknowledgements No funding acknowledgements OnBehalf VT and sudden cardiac death Background The scar and the amount of border zone measured by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) has been proposed as an independent predictor of ventricular arrhythmias in patients with ischemic and non-ischemic cardiomyopathy. However, at the present time, the guidelines are based only on the ejection fraction to recommend an implantable cardioverter defibrillator (ICD) in primary prevention, and only a minority of these patients receive appropriate therapies. So, prevention needs to be improved. Purpose To identify predictors of appropriate therapies in patients with a primary prevention ICD using cardiac magnetic resonance imaging and a dedicated software (ADAS-3D) to characterize the scar. Methods All consecutive patients who underwent a LGE-MR prior to ICD implantation in primary prevention were prospectively included. Clinical and cardiac imaging characteristics were collected. The myocardium was segmented with ADAS-3D software in 10 layers (from endocardium to epicardium). The scar, border zone, core and conducting channels were automatically measured in grams by the software. Results Since 2008 to 2017, 206 patients were included. Mean age was 67 +/- 28 years, 80% men, mean ejection fraction 26%+/-9, 52% with ischemic cardiomyopathy and 48% non-ischemic. The primary endpoint was appropriate therapies and/or sudden cardiac death (SCD). Median follow-up was 46,33 months. 46 patients (22%) reached the primary endpoint. Greater scar mass (36,05 grams vs 21,5 grams; HR 1.04; 95% CI (1.03-1-05), p <0.001), core mass (9,8 grams vs 5,6 grams; HR 1.06; 95% CI (1.04-1-09), p <0.001), border zone mass (26,2 grams vs 15,9 grams; HR 1.05; 95% CI (1.04-1-09), p <0.001) and channel mass (3,0 grams vs 1,6 grams; HR 1.15 95% CI (1.06-1.25), p <0.001) were associated with appropriate therapies and SCD. A border zone mass >5.3 grams was independently associated with the primary endpoint (HR: 4.77; 95% CI (1.15-19.73), p = 0.03). Conclusions The amount of border zone, core and channel mass measured by LGE-MR and ADAS software are independent predictors of appropriate therapies and SCD in patients with ICD in primary prevention. Abstract Figure. Scar characterization
A new functional mapping strategy based on targeting deceleration zones (DZs) has become one of the most commonly used strategies within the armamentarium of substrate-based ablation methods for ventricular tachycardia (VT) in patients with structural heart disease. The classic conduction channels detected by voltage mapping can be accurately determined by cardiac magnetic resonance (CMR). The purpose of this study was to analyze the evolution of DZs during ablation and their correlation with CMR. Forty-two consecutive patients with scar-related VT undergoing ablation after CMR in Hospital Clinic (October 2018-December 2020) were included (median age 65.3 ± 11.8 years; 94.7% male; 73.7% ischemic heart disease). Baseline DZs and their evolution in isochronal late activation remaps were analyzed. A comparison between DZs and CMR conducting channels (CMR-CCs) was realized. Patients were prospectively followed for VT recurrence for 1 year. Overall, 95 DZs were analyzed, 93.68% of which were correlated with CMR-CCs: 44.8% located in the middle segment and 55.2% located in the entrance/exit of the channel. Remapping was performed in 91.7% of patients (1 remap: 33.3%, 2 remaps: 55.6%, and 3 remaps: 2.8%). Regarding the evolution of DZs, 72.2% disappeared after the first ablation set, with 14.13% not ablated at the end of the procedure. A total of 32.5% of DZs in remaps correlated with a CMR-CCs already detected, and 17.5% were associated with an unmasked CMR-CCs. One-year VT recurrence was 22.9%. DZs are highly correlated with CMR-CCs. In addition, remapping can lead to the identification of hidden substrate initially not identified by electroanatomic mapping but detected by CMR.
Neither the long-term development of ablation lesions nor the capability of late gadolinium enhancement (LGE)-MRI to detect ablation-induced fibrosis at late stages of scar formation have been defined. We sought to assess the development of atrial ablation lesions over time using LGE-MRI and invasive electroanatomical mapping (EAM).Ablation lesions and total atrial fibrosis were assessed in serial LGE-MRI scans 3 months and >12 months post pulmonary vein (PV) isolation. High-density EAM performed in subsequent repeat ablation procedures served as a reference. Serial LGE-MRI of 22 patients were analyzed retrospectively. The PV encircling ablation lines displayed an average LGE, indicative of ablation-induced fibrosis, of 91.7% ± 7.0% of the circumference at 3 months, but only 62.8% ± 25.0% at a median of 28 months post ablation (p < 0.0001). EAM performed in 18 patients undergoing a subsequent repeat procedure revealed that the consistent decrease in LGE over time was owed to a reduced detectability of ablation-induced fibrosis by LGE-MRI at time-points > 12 months post ablation. Accordingly, the agreement with EAM regarding detection of ablation-induced fibrosis and functional gaps was good for the LGE-MRI at 3 months (κ .74; p < .0001), but only weak for the LGE-MRI at 28 months post-ablation (κ .29; p < .0001).While non-invasive lesion assessment with LGE-MRI 3 months post ablation provides accurate guidance for future redo-procedures, detectability of atrial ablation lesions appears to decrease over time. Thus, it should be considered to perform LGE-MRI 3 months post-ablation rather than at later time-points > 12 months post ablation, like for example, prior to a planned redo-ablation procedure.
Abstract Background Novel concepts for pulmonary vein isolation (PVI) like pulsed field ablation (PFA) or high power-short duration ablation (HPSD) promise favourable profiles of safety and efficacy. However, clinical comparisons of ablation lesion quality are lacking. Purpose To systematically investigate lesion characteristics of novel ablation concepts, we performed a prospective head-to-head comparison between PFA, HPSD, conventional RF and latest generation cryoballoon ablation using late gadolinium enhancement (LGE)-MRI-based ablation lesion assessment. Methods This study included patients that underwent first-time PVI-only atrial fibrillation ablation - either by ablation index-guided RF ablation, cryoballoon ablation (Arctic Front Advance Pro), HPSD ablation (QDOT micro catheter, QMODE+, 90W, 4s) or PFA (Farapulse PFA system). All patients received an LGE-MRI 3 months post-ablation. LGE was quantified based on the signal intensity ratio of each voxel relative to the blood pool, applying a previously validated threshold of >1.2 to define LGE indicative of ablation-induced scarring using a dedicated software. LGE discontinuations of >3 mm were considered as gaps, and complete lesions were defined as LGE covering >90% of the peri-antral circumference of ipsilateral pulmonary vein (PV) pairs. Results Post-ablation LGE-MRIs from 120 patients were analysed (40 RF, 40 cryoballoon, 20 PFA, 20 HPSD). The proportion of complete PV-encircling LGE lesions was significantly higher with conventional RF than with cryoballoon ablation (50% vs. 34%; p=0.023). Importantly, HPSD ablation resulted in even more complete lesions than conventional RF (68%, p=0.004), whereas the proportion of complete LGE lesions was lowest with PFA (21%). Accordingly, the total number of gaps was lower with HPSD ablation (1.9 gaps/patient) compared to the other ablation concepts (conventional RF 2.7, cryoballoon 3.2, PFA 3.4 gaps/patient; p=0.034). As expected, large-area ablation with the cryoballoon (13.8 mm) and PFA (12.8 mm) single-shot devices resulted in the widest lesions. Of note, HPSD lesions were significantly wider than conventional RF lesions (11.1 mm vs. 8.9 mm; p=0.004). Conclusions HPSD ablation resulted in the most continuous lesions, translating in the lowest number of gaps. Of note, HPSD lesions were also significantly wider than conventional RF lesions, thus corroborating the concept of a shallower HPSD lesion geometry from experimental studies. Interestingly, conventional RF showed a higher proportion of complete PV-encircling lesions than cryoballoon ablation. While PFA lesions cover relatively large areas, comparable to cryoballoon ablation, lesions are more inhomogeneous. However, it remains to be determined, to what extent LGE discontinuities in PFA lesions indicate ineffective ablation or only reflect a different kind of remodeling compared to thermal ablation, which may be less detectable by LGE-MRI.
Abstract Background The scar and the amount of border zone measured by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) has been proposed as an independent predictor of ventricular arrhythmias in patients with ischemic and non-ischemic cardiomyopathy. However, at the present time, the guidelines are based only on the ejection fraction to recommend an implantable cardioverter defibrillator (ICD) in primary prevention, and only a minority of these patients receive appropriate therapies. So, prevention needs to be improved. Purpose To identify predictors of appropriate therapies in patients with a primary prevention ICD using cardiac magnetic resonance imaging and a dedicated software (ADAS-3D) to characterize the scar. Methods Patients who underwent a LGE-MR prior to ICD implantation in primary prevention were retrospectively included. Clinical and cardiac imaging characteristics were collected. The myocardium was segmented with ADAS-3D software in 10 layers (from endocardium to epicardium). The scar, border zone, core and conducting channels were automatically measured in grams by the software. Results Since 2008 to 2017, 206 patients were included. Mean age was 67±28 years, 80% men, mean ejection fraction 26%±9, 52% with ischemic cardiomyopathy and 48% non-ischemic. The primary endpoint was appropriate therapies and/or sudden cardiac death (SCD). Median follow-up was 46.33 months. 46 patients (22%) reached the primary endpoint. Greater scar mass (36.05 grams vs 21.5 grams; HR 1.04; 95% CI (1.03–1-05), p<0.001), core mass (9.8 grams vs 5.6 grams; HR 1.06; 95% CI (1.04–1-09), p<0.001), border zone mass (26.2 grams vs 15.9 grams; HR 1.05; 95% CI (1.04–1-09), p<0.001) and channel mass (3.0 grams vs 1.6 grams; HR 1.15 95% CI (1.06–1.25), p<0.001) were associated with appropriate therapies and SCD. A border zone mass >5.3 grams was independently associated with the primary endpoint (HR: 4.77; 95% CI (1.15–19.73), p=0.03). Conclusions The amount of border zone, core and channel mass measured by LGE-MR and ADAS software are independent predictors of appropriate therapies and SCD in patients with ICD in primary prevention. Scar characterization Funding Acknowledgement Type of funding source: None
Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Spanish Government, Madrid, Spain [FIS_PI16/00435 Background Late gadolinium enhancement MRI (LGE-MRI) is increasingly used to detect native as well as ablation-induced atrial fibrosis in the context of atrial fibrillation (AF). However, cardiac fibrotic tissue including ablation lesions is subject to sustained remodeling, and neither the development of ablation-induced fibrosis over time nor the capability of LGE-MRI to detect it at different stages of scar formation have been defined. We sought to define the long-term development of ablation-induced atrial fibrosis and to validate LGE-MRI for the assessment of ablation lesions at different time points. Methods Patients with first-time AF ablation and an early follow-up LGE-MRI (3 months post ablation) and a late follow-up LGE-MRI (>12 months post ablation) were included. LGE-MRI data were postprocessed for quantification of fibrotic tissue using the ADAS 3D software. In the majority of patients high-density electroanatomical mapping (EAM), performed in a repeat procedure served as a reference. Results 22 consecutive patients fulfilling the inclusion criteria were analysed retrospectively. In the LGE-MRI 3 months post ablation an average of 91.7 ± 7.0% of the ablation lines" circumference displayed late gadolinium enhancement (LGE) reflecting ablation-induced fibrosis, whereas in the late follow-up LGE-MRI, at a median of 28 months post ablation, only 62.8 ± 25.0% of the ablation lines" circumference was covered by LGE (p < 0.0001) (see figure for representative examples and individual development of LGE coverage over time). This decrease of LGE coverage of the ablation lines was also reflected by an increase in the median number of LGE-MRI-predicted gaps per circumferential ablation line from 4 (3 months) to 10 (28 months). These data may suggest a decrease of ablation-induced fibrosis over time. However, EAM subsequent to the late follow-up LGE-MRI, which was performed in 18 of the 22 patients, indicates that it was not ablation-induced fibrosis that decreased over time, but rather the capability of LGE-MRI to detect it. In 95% of the pulmonary vein segments in which the late follow-up LGE-MRI (28 months) indicated a disappearance of local ablation-induced fibrosis, EAM demonstrated durable lesions consistent with the 3-months LGE-MRI. In line with this observation, the overall agreement of EAM at the repeat procedures with the 3-months LGE-MRI regarding the prediction of ablation-induced fibrosis and functional gaps was good (K 0.74; p< 0.0001, positive predictive value 93%), whereas the agreement with the LGE-MRI at 28-months was only weak (K 0.29; p < 0.0001, positive predictive value 63%). Conclusions Our results indicate that while ablation-induced atrial fibrosis appears to remain rather constant over time, LGE-MRI loses some of its capability to detect it. Thus, LGE-MRI 3 months post ablation may be more accurate in the detection of durable ablation lesions than LGE-MRI at later time points more than 12 months after ablation. Abstract Figure
Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Catalan Society of Cardiology; Asociación del Ritmo Cardiaco (Spanish Society of Cardiology). Background Correction of dyssynchrony measured with echo strain, in conduction system pacing (CSP) vs biventricular pacing (BIVP) has not been reported. Objectives Our purpose was to compare echocardiographic dyssynchrony correction and strain improvement during follow-up between CSP and BIVP. Methods A treatment received analysis was performed in patients (n=29 CSP; BIVP 40). Patients were evaluated at baseline (ON and OFF programming) and at 6 and 12 months. All echocardiograms were completed by operators blinded to the type of device implanted. Intraventricular (septal flash), interventricular (difference between left and right ventricular outflow times), and auriculoventricular (diastolic filling time) dyssynchrony, as well as strain parameters (septal rebound, global longitudinal strain (GLS), and Risum pattern (typical left bundle branch block contraction pattern)) were analyzed. Results 32% (22/69) were women; baseline LVEF was 27.5% (7% SD) and left ventricular end-systolic volume (LVESV) 138ml (77ml SD) without differences between groups. At the 12-month follow-up, there were no differences in CSP vs. BIVP in LVEF (45.8% (10% SD) vs. 42.7% (12% SD), p=0.25) and LVESV (81.5 ml (41 ml SD) vs. 101.7 ml (56 ml SD), p=0.08). Longitudinal analyses showed that the improvement of all echocardiographic dyssynchrony parameters over time was similar between groups (p<0.001) (Table 1 and Fig 1A). GLS acute correction significantly correlated with LVEF and LVESV at the 12-month follow-up (Fig 1B). Conclusions CSP and BIVP provided a similar dyssynchrony and strain correction over time. Acute strain correction predicted ventricular remodeling at 12 months follow-up.