Aims Corticosteroids are widely used in patients with cardiac sarcoidosis (CS). In addition, upgrading to cardiac resynchronization therapy (CRT) is sometimes needed. This study aimed to investigate the impact of corticosteroid use on the clinical outcomes following CRT upgrades. Methods A total of 48 consecutive patients with non-ischemic cardiomyopathies who underwent CRT upgrades were retrospectively reviewed and divided into three groups: group 1 included CS patients taking corticosteroids before the CRT upgrade (n = 7), group 2, CS patients not taking corticosteroids before the CRT upgrade (n = 10), and group 3, non-CS patients (n = 31). The echocardiographic response, heart failure hospitalizations, and cardiovascular deaths were evaluated. Results The baseline characteristics during CRT upgrades exhibited no significant differences in the echocardiographic data between the three groups. After the CRT upgrade, responses regarding the ejection fraction (EF) and end-systolic volume (ESV) were significantly lower in CS patients than non-CS patients (ΔEF: group 1, 6.7% vs. group 2, 7.7% vs. group 3, 13.6%; p=0.039, ΔESV: 3.0 mL vs. -12.7 mL vs. -37.2 mL; p = 0.008). The rate of an echocardiographic response was lowest in group 1 (29%). There were, however, no significant differences in the cumulative freedom from a composite outcome among the three groups (p = 0.19). No cardiovascular deaths occurred in group 1. Conclusion CS patients taking corticosteroids before the CRT upgrade had lower echocardiographic responses but higher freedom rates from a composite endpoint. The timing of corticosteroid use would affect the clinical course following a CRT upgrade.

Introduction: In the COVID-19 era, demand is growing for remote ECG monitoring systems with less or no in-person contact. However, the practical usage of wearable ECG devices has been little studied in Japan. This study aimed to report our initial experience of using the postal system in the delivery of the self-wearable ECG device (Duranta) and long-term ECG monitoring in outpatient care. Methods:　　 The Duranta is small, light (35 g), and easy to attach to the chest with two patch electrodes. Real-time ECG data were automatically transmitted to a cloud server via iPhones. The devices were packed in prepaid envelopes that could be put in any postbox for delivery between the hospital and patients’ homes. Results: Twenty-five patients (61 ± 17 years) were enrolled. The median distance to the hospital from the patients’ homes was 10 km (range: 1.1–183). The patients had no difficulties with either the postal delivery or wearing the ECG devices. A total of 57 hours (range: 20–179) of ECG monitoring per patient was performed, and the data were successfully transmitted to the hospital. The median percentage of noise/artifact burden during the ECG monitoring was 0.9%. Arrhythmic events were observed in 8 patients. Most patients were satisfied with the ECG system and delivery via the postal service. Conclusion: The use of a postal delivery of a wearable ECG device could work in clinical practice with to achieve less or no in-person contact. This system can be applicable for telehealth, home care, and arrhythmia screening.

Background: Some of atrial fibrillation (AF) drivers are found in lesser late-gadolinium enhancement (LGE) areas, as well as heterogenous ones. The atrial wall thickness (AWT) has been reported to be important as a possible AF substrate. However, the AWT and degree of LGEs as an AF substrate has not been fully validated in humans. Objective: The purpose of this study was to evaluate the impact of the AWT in lesser LGE areas on AF drivers. Methods: A total of 287 segments in 15 persistent AF patients were assessed. AF drivers were defined as non-passively activated areas (NPAs), where rotational activation was frequently observed, and were detected by the novel real-time phase mapping (ExTRa Mapping). Lesser LGE areas were defined as areas with a volume ratio of the enhancement voxel of <10%. The AWT was defined as the minimum distance from the manually determined endocardium to the epicardial border on the LGE-MRI. Results: NPAs were found in 20 (18.0%) of 131 lesser LGE areas where the AWT was significantly thicker than that in the passively activated areas (PAs) (2.46±0.26 vs. 2.20±0.25 mm, p<0.001). However, NPAs were found in 61 (21.3%) of 287 LGE areas where the AWT was similar to that of the PAs (2.24±0.24 vs. 2.22±0.25 mm, p=0.58). An ROC curve analysis yielded an optimal cutoff value of 2.24 mm for predicting the presence of an NPA in lesser LGE areas. Conclusion: The location of AF drivers in lesser LGE areas might be more accurately identified by evaluating the AWT.

Atrial tachycardia (AT) in the right atrium often occurs following open-heart surgery. Catheter ablation for these AT is challenging and can lead to unintended conduction block. We performed late-gadolinium enhancement magnetic resonance imaging prior to catheter ablation and predicted wavefront propagation during SR as well as the slow conduction zone

A 61-year-old female with 50000 ventricular premature contractions and reduced left ventricular ejection fraction of 35% referred to our center. Although the origin was considered to be originated from the junction between the left and right coronary cusp, a single radiofrequency application above the aortic sinus cusp could eliminate it.

Atrial tachycardia (AT) in the right atrium often occurs following open-heart surgery. Catheter ablation for these AT is challenging and can lead to unintended conduction block. We performed late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) prior to catheter ablation and predicted wavefront propagation during SR as well as the slow conduction zone during tachycardia. LGE-MRI may assist predicting the conduction disturbance and reducing the risk of unexpected sinus exit block.

Background: A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy fibrotic tissue and play an important role in AF drivers. However, this was not validated in humans. Objective: The purpose of this study was to evaluate the fibrotic tissue properties of AF rotors in patients with persistent AF. Methods: A total of 287 segments in 15 patients with persistent AF (longstanding persistent AF in 9 patients) that underwent AF ablation were assessed. Non-passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real-time phase mapping (ExTRa Mapping). Atrial fibrosis was detected by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI), and the fibrotic heterogeneity and density were assessed by the entropy (LGE-entropy) and volume ratio of the enhancement voxel (LGE-volume ratio), respectively. Results: NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7 and 10% for the LGE-entropy and LGE-volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE-entropy of >5.7 and LGE-volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments, p = 0.001). No NPAs were found at segments with an LGE-volume ratio of >50% regardless of the LGE-entropy. Conclusion: AF rotors are mostly distributed in relatively weak and much more heterogenous fibrotic tissue.

Background: Computer simulation model demonstrated that atrial fibrillation (AF) driver attached to the patchy fibrosis assessed by late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, it has not been well elucidated in patients with persistent AF. The aim of this study is to investigate whether radiofrequency (RF) application on the patchy LGE site (PLS) could terminate AF or convert to atrial tachycardia (AT) and improve the rhythm outcome. Methods: A total of 31consecutive persistent AF patients with PLS were enrolled (PLS ablation group, mean age: 69 ± 8 years, mean left atrial diameter: 42 ± 6 mm). AF direct termination or AT conversion during RF application on the PLS were defined as favorable response. The rhythm outcome was compared between the PLS ablation group and the propensity matched conventional ablation group. Results: Favorable response was found in 15 (48%) of 31 patients (AF termination in 7, AT conversion in 8 patients). AF recurrence at 12 months follow-up was significantly less in the PLS group as compared to the control group (4 (13%) of 31 patients vs. 11 (35%) of 31 patients, log-rank p = 0.019). In patients with favorable response, AT recurred in 1 (7%) of 15 patients but AF. Conclusions: The PLS ablation could terminate AF or convert to AT in half of the patients and improve the rhythm outcome as compared to the conventional ablation. No AF recurrence was documented in patients with a favorable response.

RESPONSE FOR THE LETTER TO THE EDITORDon’t miss a chance taking the best shot!!Kunihiko KiuchiDivision of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of MedicineAddress for correspondence:Kunihiko Kiuchi, MD, FHRSSection of Arrhythmia, Division of Cardiovascular Medicine,Department of Internal Medicine, Kobe University Graduate School of Medicine7-5-2 Kusunoki-chou chuou-ku, Kobe, Hyogo, JapanTelephone: (81)-78-382-5846Fax: (81)-78-382-5859E-mail: kunihikokiuchi@yahoo.co.jpDisclosures:The Section of Arrhythmia was supported by an endowment from Medtronic JAPAN and Abbott JAPAN. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.Funding: NoneTo the Editor,We thank Dr. Althoff and Mont for their interest, comments, and suggestions related to our paper.1 In our study, as they suggested, LGE-MRI was acquired 1-3 months after the ablation. An animal study reported that ablation lesions are fully formed by 3 weeks and are dense with collagen and fat deposition by 6 weeks.2 In our pilot study, the ablation lesion area dramatically diminished from 1 week to 6 weeks after the procedure in most of the patients. Furthermore, the ablation lesion area was comparable between 6 weeks and just 3 months after the ablation. Of interest, the ablation lesion disappeared after 5-6 months following the procedure in some patients without AF recurrence. We speculated that the shrinkage of the ablation lesion might have occurred during the pathophysiological healing process and reverse remodeling of the left atrium. Therefore, we considered that the time point of taking the “best shot” might have been earlier than we expected. Furthermore, the dose of the contrast agent was important for determining the time point. Our dose of the contrast agent was 0.1mmol/kg, which was relatively lower than that of the other groups. To address this issue, further study will be needed.As for an internal reference for normalization, the threshold of the signal intensity was initially determined according to the signal intensity histogram on the “whole LA wall” in our previous studies.3,4 However, as the authors suggested, neither the ablation lesion nor atrial fibrosis could be accurately visualized in some patients with advanced atrial remodeling. Therefore, the internal reference was changed from the “whole LA wall” to the “healthy LA wall” in our recent studies.1,5 We believed that this simple but important tip might make it possible to sensitively identify pre-existing atrial fibrosis, particularly interstitial fibrosis. The signal intensity of ablation lesion was significantly higher than that of the pre-existing atrial fibrosis. Our question is whether the ablation lesion characteristics dramatically differed between the different references in patients without atrial remodeling. Although we re-analyzed the LGE-MRI with two different references (“whole LA wall” and “healthy LA wall”), no significant difference in the lesion characteristics could be found. Cryoballoon ablation and RF ablation with contact-force sensing catheter induced intensive inflammation which followed by the artificial fibrosis.6 In this study, we focused on the visualization of the ablation lesion not the pre-existing atrial fibrosis, and patients without atrial remodeling were enrolled. We considered that the impact of the difference in the reference could be less than we expected, when we focused on the ablation lesions in patients without atrial remodeling.To visualize the atrial fibrosis and the ablation lesion, different visualization methods were developed. However, very few histological validations could be found. Furthermore, the dose of the contrast agents, MRI system, and visualization software completely differed due to the regulations in each institution. Therefore, it is not surprising that the image differed between each visualization technique. It is important to note the reproducibility of the visualization method and clinical implication of the best shot. The authors had already reported the reproducibility of their method.7 However, this issue is still in debate.8 We would like to challenge to improve the quality of our “best shot” and strengthen both reproducibility and clinical implication in a further study.References1. Kurose J, Kiuchi K, Fukuzawa K, et al. Lesion characteristics between cryoballoon ablation and radiofrequency ablation with a contact-force sensing catheter: late-gadolinium enhancement magnetic resonance imaging assessment. J Cardiovasc Electrophysiol. 2020.2. Avitall B, Kalinski A. Cryotherapy of cardiac arrhythmia: From basic science to the bedside. Heart Rhythm. 2015;12(10):2195-2203.3. Shigenaga Y, Kiuchi K, Ikeuchi K, et al. Fusion of Delayed-enhancement MR Imaging and Contrast-enhanced MR Angiography to Visualize Radiofrequency Ablation Scar on the Pulmonary Vein. Magn Reson Med Sci. 2015;14(4):367-372.4. Kiuchi K, Okajima K, Shimane A, et al. Visualization of the radiofrequency lesion after pulmonary vein isolation using delayed enhancement magnetic resonance imaging fused with magnetic resonance angiography. J Arrhythm. 2015;31(3):152-158.5. Akita T, Kiuchi K, Fukuzawa K, et al. Lesion distribution after cryoballoon ablation and hotballoon ablation: Late-gadolinium enhancement magnetic resonance imaging analysis. J Cardiovasc Electrophysiol. 2019.6. Kiuchi K, Fukuzawa K, Mori S, Watanabe Y, Hirata KI. Feasibility of Imaging Inflammation in the Left Atrium Post AF Ablation Using PET Technology. JACC Clin Electrophysiol. 2017;3(12):1466-1467.7. Benito EM, Carlosena-Remirez A, Guasch E, et al. Left atrial fibrosis quantification by late gadolinium-enhanced magnetic resonance: a new method to standardize the thresholds for reproducibility.Europace. 2017;19(8):1272-1279.8. Kamali R, Schroeder J, DiBella E, et al. Reproducibility of Clinical Late Gadolinium Enhancement Magnetic Resonance Imaging in Detecting Left Atrial Scar after Atrial Fibrillation Ablation. J Cardiovasc Electrophysiol. 2020 in press.