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Aims Bi-atrial remodelling in patients with atrial fibrillation (AF) is rarely assessed and data on the presence of right atrial (RA) fibrosis, the relationship between RA and left atrial (LA) fibrosis, and possible association of RA remodelling with AF recurrence after ablation in patients with AF is limited. Methods and results A total of 110 patients with AF undergoing initial pulmonary vein isolation (PVI) were included in the present study. All patients were in sinus rhythm during cardiac magnetic resonance (CMR) imaging performed prior to ablation. LA and RA volumes and function (volumetric and feature tracking strain) were derived from cine CMR images. The extent of LA and RA fibrosis was assessed from 3D late gadolinium enhancement images. AF recurrence was followed up for 12 months after PVI using either 12-lead electrocardiograms or Holter monitoring. Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (interquartile range: 122–286) days. RA remodelling parameters were not significantly different between patients with and without AF recurrence after ablation, whereas LA remodelling parameters were different (volume, emptying fraction, and strain indices). LA fibrosis had a strong correlation with RA fibrosis (r = 0.88, P < 0.001). Both LA and RA fibrosis were not different between patients with and without AF recurrence. Conclusions This study shows that RA remodelling parameters were not predictive of AF recurrence after AF ablation. Bi-atrial fibrotic remodelling is present in patients with AF and moreover, the amount of LA fibrosis had a strong correlation with the amount of RA fibrosis.

Objectives: This prospective pilot study assessed the feasibility of cardiovascular magnetic resonance (CMR) imaging during biventricular (BIV) pacing in patients with a CMR conditional cardiac resynchronization therapy defibrillator (CRT-D) and compared the results with invasive volume measurements. Methods: Ten CRT-D patients underwent CMR imaging prior to device implantation (baseline) and six weeks after device implantation, including CRT-on and CRT-off modes. Left ventricular (LV) function, volumes, and strain measurements of LV dyssynchrony and dyscoordination were assessed. Invasive pressure–volume measurements were performed, matching the CRT settings used during CMR. Results: Post-implantation imaging enabled reliable cine assessment, but showed artefacts on late gadolinium enhancement images. After six weeks of CRT, significant reverse remodeling was observed, with a 22.7 ± 11% reduction in LV end-systolic volume during intrinsic rhythm (CRT-off). During CRT-on, the LV ejection fraction significantly improved from 27.4 ± 5.9% to 32.2 ± 8.7% (p < 0.01), and the strain assessment showed the abolition of the left bundle branch block contraction pattern. Invasively measured and CMR-assessed LV hemodynamics during BIV pacing were significantly associated. Conclusions: Post-CRT implantation CMR assessing acute LV pump function is feasible and provides important insights into the effects of BIV pacing on cardiac function and contraction patterns. LV assessment during CMR may constitute a future CRT optimization strategy.

Pulmonary vein isolation (PVI) by radiofrequency (RF) ablation is an important alternative to antiarrhythmic drugs in the treatment of symptomatic atrial fibrillation. However, the inability to consistently achieve durable isolation of the pulmonary veins hampers the long-term efficacy of PVI procedures. The large number of factors involved in RF lesion formation and the complex interplay of these factors complicate reliable creation of durable and transmural ablation lesions. Various surrogate markers of ablation lesion formation have been proposed that may provide information on RF lesion completeness. Real-time assessment of these surrogates may aid in the creation of transmural ablation lesions, and therefore, holds potential to decrease the risk of PV reconnection and consequent post-PVI arrhythmia recurrence. Moreover, titration of energy delivery until lesions is transmural may prevent unnecessary ablation and subsequent adverse events. Whereas several surrogate markers of ablation lesion formation have been described over the past decades, a ‘gold standard’ is currently lacking. This review provides a state-of-the-art overview of ablation strategies that aim to enhance durability of RF-PVI, with special focus on real-time available surrogates of RF lesion formation in light of the biophysical basis of RF ablation.

Introduction: Approximately 18% of patients with atrial fibrillation (AF) undergo a repeat ablation within 12 months after their index ablation. Despite the high prevalence, comparative studies on nonpulmonary vein (PV) target strategies in repeat AF ablation are scarce. Here, we describe 12 months efficacy of non-PV and PV target ablations as a repeat ablation strategy. Methods: A multicentre retrospective, descriptive study was conducted with data of 280 patients who underwent repeat AF ablation. The ablation strategy for repeat ablation was at the operators' discretion. Non-PV target ablation (n = 140) included PV reisolation, posterior wall isolation, mitral line, roofline, and/or complex fractionated atrial electrogram ablation. PV target ablation (n = 140), included reisolation and/or wide atrium circumferential ablation. Patients' demographics and rhythm outcomes during 12 months follow-up were analyzed. Results: At 12 months, more atrial tachyarrhythmias were observed in the non-PV target group (48.6%) compared to the PV target group (29.3%, p =.001). Similarly, a significantly higher AF and atrial tachycardia (AT) recurrence rate was observed after non-PV target ablation compared to PV target ablation (36.4% vs. 22.1% and 22.9% vs. 10.7%). After adjustment, a significantly higher risk of AT recurrence remained in the non-PV target group. Both groups significantly de-escalated antiarrhythmic drug use; de-escalation was more profound after PV target ablation. Patients with isolated PVs during non-PV target ablation had a significantly higher risk for AF recurrence than those with reconnected PVs. Conclusion: Compared to PV target ablation, non-PV target repeat ablation did not improve outcomes after 12 months and was independently associated with an increased risk for AT recurrences.

Purpose: The present study assesses different left atrial (LA) strain approaches in relation to atrial fibrillation (AF) recurrence after ablation and compares LA feature tracking (FT) strain to novel rapid LA strain approaches in AF patients. Methods: This retrospective single-center study comprised of 110 prospectively recruited AF patients who underwent cardiac magnetic resonance (CMR) imaging in sinus rhythm prior to their first pulmonary vein isolation ablation. LA rapid strain (long axis strain and atrioventricular (AV)-junction strain), LA FT strain, and LA volumes were derived from 2-chamber and 4-chamber cine images. AF recurrence was followed up for 12 months using either 12‑lead ECGs or rhythm Holter monitoring. Results: Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (122–286) days. LA long axis strain, AV-junction strain, and FT strain were all more impaired in patients with AF recurrence compared to patients without AF recurrence (long axis strain: P < 0.01; AV-junction strain: P < 0.001; FT strain: P < 0.01, respectively). Area under the curve (AUC) values for LA remodeling parameters in association with AF recurrence were 0.68 for long axis strain, 0.68 for AV-junction strain, 0.66 for FT strain, 0.66 for LA volume index. Phasic FT LA strain demonstrated that contractile strain had the highest AUC (0.70). Conclusion: Both LA rapid strain and LA FT strain are associated with arrhythmia recurrence after ablation in AF patients. LA rapid strain can be a convenient and reproducible alternative for LA FT strain to assess LA function in clinical practice.

Background: A significant number of patients experience recurrent atrial fibrillation (AF) after ablation. Various risk scores have been described that may predict outcomes after AF ablation. In this study, we aimed to compare ten previously described risk scores with regard to their predictive value for post-ablation AF recurrence and procedural complications. Methods: A total of 482 AF patients (63% paroxysmal AF, 66% male, mean age 62 ± 9 years) undergoing initial radiofrequency pulmonary vein isolation (PVI) were included in the present analysis. Prior to ablation, all patients underwent both transthoracic echocardiography (TTE) and either cardiac CT imaging or CMR imaging. The following risk scores were calculated for each patient: APPLE, ATLAS, BASE-AF 2, CAAP-AF, CHADS 2, CHA 2DS 2-VASc, DR-FLASH, HATCH, LAGO and MB-LATER. Results: Median follow-up was 16 (12–31) months. AF recurrence after a 90-day blanking period was observed in 199 patients (41%), occurring after a median of 183 (124–360) days. AF recurrence was less frequent in paroxysmal AF patients compared to non-paroxysmal AF patients (34% vs. 54%, p < 0.001). Overall periprocedural complication rate was 6%. All scores, except the HATCH score, demonstrated statistically significant but poor predictive value for recurrent AF after ablation (area under curve [AUC] 0.553–0.669). CHA 2DS 2-VASc and CAAP-AF were the only risk scores with predictive value for procedural complications (AUC 0.616, p = 0.043; AUC 0.615, p = 0.044; respectively). Conclusions: Currently available risk scores perform poorly in predicting outcomes after AF ablation. These data suggest that the utility of these scores for clinical decision-making is limited.

Aims Various methods and post-processing software packages have been developed to quantify left atrial (LA) fibrosis using 3D late gadolinium-enhancement cardiac magnetic resonance (LGE-CMR) images. Currently, it remains unclear how the results of these methods and software packages interrelate. Methods and results Forty-seven atrial fibrillation (AF) patients underwent 3D-LGE-CMR imaging prior to their AF ablation. LA fibrotic burden was derived from the images using open-source CEMRG software and commercially available ADAS 3D-LA software. Both packages were used to calculate fibrosis based on the image intensity ratio (IIR)-method. Additionally, CEMRG was used to quantify LA fibrosis using three standard deviations (3SD) above the mean blood pool signal intensity. Intraclass correlation coefficients were calculated to compare LA fibrosis quantification methods and different post-processing software outputs. The percentage of LA fibrosis assessed using IIR threshold 1.2 was significantly different from the 3SD-method (29.80 ± 14.15% vs. 8.43 ± 5.42%; P < 0.001). Correlation between the IIR-and SD-method was good (r = 0.85, P < 0.001) although agreement was poor [intraclass correlation coefficient (ICC) = 0.19; P < 0.001]. One-third of the patients were allocated to a different fibrosis category dependent on the used quantification method. Fibrosis assessment using CEMRG and ADAS 3D-LA showed good agreement for the IIR-method (ICC = 0.93; P < 0.001). Conclusions Both, the IIR1.2 and 3SD-method quantify atrial fibrotic burden based on atrial wall signal intensity differences. The discrepancy in the amount of LA fibrosis between these methods may have clinical implications when patients are classified according to their fibrotic burden. There was no difference in results between post-processing software packages to quantify LA fibrosis if an identical quantification method including the threshold was used.

PURPOSE: To determine whether the distance between the descending aorta and left atrial (LA) wall correlates with the amount of fibrosis quantified in the posterior left inferior pulmonary vein (LIPV) area of the LA in patients with atrial fibrillation (AF). MATERIALS AND METHODS: In this retrospective study, patients with AF underwent cardiac MRI in sinus rhythm prior to a pulmonary vein isolation procedure (July 2018 to February 2020). The mean distance (distance(mean)) and shortest distance (distance(short)) between the descending aorta and the LA wall were measured on three-dimensional (3D) contrast-enhanced MR angiograms; distance(mean) was defined as the average of five measurements at different levels between the descending aorta and the LA wall. The extent of LA fibrosis, both global fibrosis and regional fibrosis within the LIPV area, was derived from postprocessed, 3D, late gadolinium–enhanced images. Associations between the extent of fibrosis and the proximity of the descending aorta were analyzed by using correlative and multivariable analyses. RESULTS: A total of 47 (mean age, 60 years ± 8 [standard deviation]; 31 men) patients were included for analysis. The extent of fibrosis in the posterior LIPV area was correlated with the distance(mean) (r(s) = −0.48; P < .01) and distance(short) (r(s) = −0.49; P < .01). Patients with a short distance between the descending aorta and LA wall (defined as a distance(short) < 2 mm) had a higher percentage of fibrosis in the posterior LIPV area than patients with a distance(short) greater than 2 mm (38.7% ± 22.7 vs 21.2% ± 17.8; P < .01). CONCLUSION: The distance between the descending aorta and LA was correlated with the extent of quantified fibrosis within the posterior LIPV area. Keywords: MRI, Cardiac, Left Atrium Supplemental material is available for this article. © RSNA, 2022

Introduction: Global left atrial (LA) strain is a predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). Recently, novel rapid LA long axis strain has been introduced. Currently, it is unknown whether this fast and simple strain approach can predict AF recurrence after PVI and hence may be a simple alternative for the cumbersome LA feature tracking (FT) strain analysis. Hypothesis: Rapid LA strain is a fast and simple alternative for predicting AF recurrence after PVI as compared to LA FT strain. Methods: A total of 58 AF patients (78% paroxysmal AF, 64% male, mean age 61±7 years) undergoing first PVI ablation were included. Prior to PVI, all patients were in sinus rhythm during cardiac magnetic resonance imaging. LA rapid strain, LA FT strain and LA volumes were derived from 2-chamber and 4-chamber cine CMR images (Figure A). All patients were routinely followed up for arrhythmia recurrence. Results: At one year follow-up, arrhythmia recurrence was observed in 21 patients (36%). Both, rapid LA strain and FT strain were significantly reduced in patients with AF recurrence compared to patients without AF recurrence (rapid strain: -19.96 ± 11.03% vs. -28.18 ± 9.93%, P=0.005; FT strain: -12.54 ± 4.16% vs. -15.94 ± 3.50%, P=0.002, Figure B, and C) while maximal LA volume index (LAVImax) was not different between both groups (16.98 ± 3.70ml/m2 vs. 15.04 ± 2.47ml/m2, P=0.11, Figure D). ROC analysis identified LA FT strain as having the highest area under the curve (AUC) for predicting AF recurrence after PVI (AUC: 0.75 for LA FT strain, 0.71 for LA rapid strain, 0.62 for LAVImax, figure E). Conclusions: Both rapid LA strain and LA FT strain are predictive of AF recurrence after index PVI in AF patients. Moreover, LA mechanical function (strain) may be a more useful marker for predicting AF recurrence than LA volume. Therefore, LA rapid strain can be a more convenient and reproducible parameter for the assessment of LA performance in clinical practice.

Introduction: Radiofrequency (RF) atrial fibrillation (AF) ablation using a catheter dragging technique may shorten procedural duration and improve durability of pulmonary vein isolation (PVI) by creating uninterrupted linear ablation lesions. We compared a novel AF ablation approach guided by Grid annotation allowing for “drag lesions” with a standard point-by-point ablation approach in a single-center randomized study. Methods: Eighty-eight paroxysmal or persistent AF patients were randomized 1:1 to undergo RF-PVI with either a catheter dragging ablation technique guided by Grid annotation or point-by-point ablation guided by Ablation Index (AI) annotation. In the Grid annotation arm, ablation was visualized using 1 mm³ grid points coloring red after meeting predefined stability and contact force criteria. In the AI annotation arm, ablation lesions were created in a point-by-point fashion with AI target values set at 380 and 500 for posterior/inferior and anterior/roof segments, respectively. Patients were followed up for 12 months after PVI using ECGs, 24-h Holter monitoring and a mobile-based one-lead ECG device. Results: Procedure time was not different between the two randomization arms (Grid annotation 71 ± 19 min, AI annotation 72 ± 26 min, p =.765). RF time was significantly longer in the Grid annotation arm compared with the AI annotation arm (49 ± 8 min vs. 37 ± 8 min, respectively, p

Background During pulmonary vein isolation (PVI), nonisolation after initial encircling of the pulmonary veins (PVs) may be due to gaps in the initial ablation line, or alternatively, earliest PV activation may occur on the intervenous carina and ablation within the wide‐area circumferential ablation (WACA) circle is needed to eliminate residual conduction. This study investigated prognostic implications and predictors of gap‐related persistent conduction (gap‐RPC) and carina‐related persistent conduction (carina‐RPC) during PVI. Methods and Results Two hundred fourteen atrial fibrillation (AF) patients (57% paroxysmal, 61% male, mean age 62 ± 9 years) undergoing first contact force‐guided radiofrequency PVI were studied. Preprocedural cardiac computed tomography imaging was used to assess left atrial and PV anatomy. PVI was assessed directly after initial WACA circle creation, after a minimum waiting period of 30 minutes, and after adenosine infusion. Persistent conduction was targeted for additional ablation and classified as gap‐RPC or carina‐RPC, depending on the earliest activation site. The 1‐year AF recurrence rate was higher in patients with gap‐RPC (47%) compared to patients without gap‐RPC (28%; P = .003). No significant difference in 1‐year recurrence rate was found between patients with carina‐RPC (37%) and patients without carina‐RPC (31%; P = .379). Multivariate analyses identified paroxysmal AF and WACA circumference as independent predictors of gap‐RPC, whereas carina width and WACA circumference correlated with carina‐RPC. Conclusions Gap‐RPC is associated with increased AF recurrence risk after PVI, whereas carina‐RPC does not predict AF recurrence. Moreover, gap‐RPC and carina‐RPC have different correlates and may thus have different underlying mechanisms.

BACKGROUND: Left atrial (LA) sphericity has been proposed as a more sensitive marker of atrial fibrillation (AF)-associated atrial remodeling compared to traditional markers such as LA size. However, mechanisms that underlie changes in LA sphericity are not fully understood and studies investigating the predictive value of LA sphericity for AF ablation outcome have yielded conflicting results. The present study aimed to assess correlates of LA sphericity and to compare LA sphericity in subjects with and without AF.METHODS: Measures of LA size (LA diameter, LA volume, LA volume index), LA sphericity and thoracic anteroposterior diameter (APd) at the level of the LA were determined using computed tomography (CT) imaging data in 293 AF patients (62% paroxysmal AF) and 110 controls.RESULTS: LA diameter (40.1 ± 6.8 mm vs. 35.2 ± 5.1 mm; p < 0.001), LA volume (116.0 ± 33.0 ml vs. 80.3 ± 22.6 ml; p < 0.001) and LA volume index (56.1 ± 15.3 ml/m2 vs. 41.6 ± 11.1 ml/m2; p < 0.001) were significantly larger in AF patients compared to controls, also after adjustment for covariates. LA sphericity did not differ between AF patients and controls (83.7 ± 2.9 vs. 83.9 ± 2.4; p = 0.642). Multivariable linear regression analysis demonstrated that LA diameter, LA volume, female sex, body length and thoracic APd were independently associated with LA sphericity.CONCLUSIONS: The present study suggests that thoracic constraints rather than the presence of AF determine LA sphericity, implying LA sphericity to be unsuitable as a marker of AF-related atrial remodeling.

Background Pulmonary vein isolation (PVI) is not always achieved after initial encircling of the pulmonary veins (PVs). Additional touch-up lesions are frequently required to close residual gaps, which may occur both in the initial ablation line and on the intervenous carina. Purpose We aimed to identify determinants and prognostic implications of residual gaps during index radiofrequency PVI. Methods Two hundred fourteen AF (atrial fibrillation) patients (57% paroxysmal, 61% male, mean age 62±9 years) undergoing contact force-guided PVI were studied. Residual gaps after initial encircling of the PVs were targeted for additional ablation and were classified as either gap ablation in the initial WACA (wide-area circumferential ablation) circle or carina ablation, depending on the site of earliest activation. After a waiting period of at least 30 minutes, persistence of PVI was tested through administration of 9–18 mg intravenous adenosine. Pre-procedural cardiac computed tomography imaging was used to assess left atrial and PV anatomy. Carina width was defined as the distance between ipsilateral superior and inferior PV ostia. Ablation procedures were analyzed to define the perimeter of the WACA circle. Results One hundred thirty-three patients (62%) required additional ablation lesions beyond the initial WACA circles to achieve complete PVI. Gap ablation was required in the left WACA circle in 34 patients (16%) and in the right WACA circle in 49 patients (23%). Left and right carina ablation were required in 50 (23%) and 83 (39%) patients, respectively. Multivariate analyses identified carina width and perimeter of the WACA circle as independent predictors of requirement for ipsilateral carina ablation, whereas paroxysmal AF and the perimeter of the WACA circle were associated with requirement of gap ablation in the initial WACA circle. Recurrence of atrial tachyarrhythmias was documented in 73 patients (34%) at 12 months follow-up. Kaplan–Meier survival analyses demonstrated a significantly higher rate of recurrence in patients with one or more residual gaps in the ablation line (43% vs. 30%, p=0.019, figure A), whereas no significant difference between patients with and without requirement of carina ablation was found (38% and 29%, respectively; p=0.111, figure B). Kaplan-Meier survival analyses Conclusion Residual gaps in the initial WACA circle were associated with increased AF recurrence rate after PVI, whereas residual gaps on the intervenous carina had no statistically significant impact on AF recurrence. Consequently, gaps occurring in the ablation line and gaps on the intervenous carina may represent different mechanisms and may have different prognostic implications.

Transradial intervention (TRI) may impair digital perfusion with hand dysfunction as a result. However, the effect of TRI on digital perfusion has never been investigated, including the influence of variations of the collateral arterial network and the effect on hand dysfunction.We investigated the effect of TRI on digital perfusion by laser Doppler perfusion imaging. Laser Doppler perfusion imaging was performed at baseline, during radial access, TR band application, and at discharge. We compared tissue perfusion of the homolateral thumb (access site) with the contralateral thumb (comparator) during radial access as primary outcome. The hand circulation was assessed with angiography. Upper extremity function was evaluated with the validated QuickDASH questionnaire at baseline and follow-up. A significant reduction of tissue perfusion was observed during radial access and TR band application in the homolateral thumb (-32%, -32%, respectively) and contralateral thumb (-34%, -21%, respectively). We detected no perfusion difference between the homolateral and contralateral thumb during radial access (217; interquartile range, 112-364 versus 209; interquartile range, 99-369 arbitrary flux units; P=0.59). Reduced perfusion of the thumb during radial access was not associated with incompleteness of the superficial palmar arch ( P=0.13). Digital perfusion improved at discharge, though it remained below baseline levels (homolateral -11% and contralateral -14%). Hand dysfunction at 18 months was not associated with TRI-induced perfusion reduction ( P=0.54).TRI is safe. Digital perfusion is reduced in both hands during radial access and TR band application but is not associated with future loss of hand function and variations of the arterial hand supply.

Background: Transradial intervention (TRI) may impair digital perfusion with hand dysfunction as a result. However, the effect of TRI on digital perfusion has never been investigated, including the influence of variations of the collateral arterial network and the effect on hand dysfunction. Methods and Results: We investigated the effect of TRI on digital perfusion by laser Doppler perfusion imaging. Laser Doppler perfusion imaging was performed at baseline, during radial access, TR band application, and at discharge. We compared tissue perfusion of the homolateral thumb (access site) with the contralateral thumb (comparator) during radial access as primary outcome. The hand circulation was assessed with angiography. Upper extremity function was evaluated with the validated QuickDASH questionnaire at baseline and follow-up. A significant reduction of tissue perfusion was observed during radial access and TR band application in the homolateral thumb (−32%, −32%, respectively) and contralateral thumb (−34%, −21%, respectively). We detected no perfusion difference between the homolateral and contralateral thumb during radial access (217; interquartile range, 112–364 versus 209; interquartile range, 99–369 arbitrary flux units; P =0.59). Reduced perfusion of the thumb during radial access was not associated with incompleteness of the superficial palmar arch ( P =0.13). Digital perfusion improved at discharge, though it remained below baseline levels (homolateral −11% and contralateral −14%). Hand dysfunction at 18 months was not associated with TRI-induced perfusion reduction ( P =0.54). Conclusions: TRI is safe. Digital perfusion is reduced in both hands during radial access and TR band application but is not associated with future loss of hand function and variations of the arterial hand supply.