Objective To investigate the application value of late gadolinium enhancement(LEG)at cardiac MRI in predicting ventricular arrhythmia(VA)events in patients after implantation of ICD.Methods A retrospective analysis was performed on 16 patients at high risk of sudden cardi-ac death after ICD implantation and LEG examination in the First and the Sixth Medical Centers of Chinese PLA General Hospital from June 2020 to March 2024.According the occurrence of VA events receiving appropriate ICD therapy during the follow-up period,they were divided into post-operative VA group(7 cases)and non-VA group(9 cases).The correlation of clinical baseline fea-tures and LEG features with VA events was analyzed.Results The ratios of transmural enhance-ment and myocardial medium enhancement were obviously higher in the VA group than the non-VA group(71.4％vs 11.1％,P=0.035;85.7％vs 22.2％,P=0.041).Multivariate logistic regres-sionanalysis showed that transmural enhancement(OR=5.000,95％CI:0.150-166.589,P=0.368)and myocardial medium enhancement(OR=7.000,95％CI:0.217-226.005,P=0.272)were not independent factors influencing VA occurrence.ROC curve analysis indicated that the combined prediction of transmural enhancement and myocardial media enhancement and the pre-diction of transmural enhancement alone had better diagnostic efficacy(P＜0.05).Conclusion LEG has clinical value in predicting postoperative VA events in patients after ICD implantation.

Congenital long QT syndrome (LQTS) is a life-threatening ion channelopathy caused by mutations in genes encoding specific ion channels, which can result in malignant arrhythmia of the torsades de pointes type. LQTS type 4 represents less than 1% of inherited LQTS cases, in contrast to the 90% attributable to types 1-3, it is specifically caused by loss-of-function mutations in the membrane-binding domain of ANK2. Here, a novel ANK2 variant ( ANK2c 2245 A>C, resulting in p.Lys749Gln) associated with LQTS type 4 and Wolff-Parkinson-White syndrome was identified in a previously healthy 61-year-old male patient who suffered paroxysmal palpitations and pre-syncope due to recurrent torsades de pointes.

Congenital long QT syndrome (LQTS) is a life-threatening ion channelopathy caused by mutations in genes encoding specific ion channels, which can result in malignant arrhythmia of the torsades de pointes type. LQTS type 4 represents less than 1% of inherited LQTS cases, in contrast to the 90% attributable to types 1-3, it is specifically caused by loss-of-function mutations in the membrane-binding domain of ANK2. Here, a novel ANK2 variant ( ANK2c 2245 A>C, resulting in p.Lys749Gln) associated with LQTS type 4 and Wolff-Parkinson-White syndrome was identified in a previously healthy 61-year-old male patient who suffered paroxysmal palpitations and pre-syncope due to recurrent torsades de pointes.

Objective To summarize the results of different perioperative anticoagulation protocols for elderly patients with atrial fibrillation(AF)undergoing catheter radiofrequency ablation in our center.Methods A total of 197 elderly AF patients undergoing catheter radiofrequency ablation by a single operator in the First and Sixth Medical Centers of Chinese PLA General Hospital from January 2021 to December 2023 were retrospectively recruited,and the results of relevant exami-nations were collected.Based on the use of different direct oral anticoagulants,they were divided into dabigatran(n=125)and rivaroxaban(n=72)groups.During the procedure,the appropriate dose of unfractionated heparin was administered according to the initial activated clotting time(ACT)with a self-made formula.The time and rate of ACT were recorded,and perioperative ad-verse reactions such as bleeding and thrombosis were observed.Results There were no statistical differences between the two groups in baseline data,including age,gender,BMI,medical history,CHA2DS2-VASc score,HAS-BLED score,and left atrial anteroposterior diameter(P＞0.05).The baseline ACT value was obviously shorter(149.73+23.52 s vs 157.91±24.58 s,P=0.032),the initial heparin dose was significantly higher(0.71±0.12 mg/kg vs 0.65±0.13 mg/kg,P=0.031),and the rate of ACT reaching the target within 15 min was notably lower(60％vs 74％,P＜0.05)in the dabigatran group than the rivaroxaban group.But no significant difference was observed in the rate of ACT reaching the target in 45 min after additional heparin administration according to the formula(86％vs 88％,P＞0.05).The dabigatran group used higher dose of heparin during the procedure than the rivaroxaban group(0.99±0.30 mg/kg vs 0.85±0.31 mg/kg,P=0.009).Peri-cardial effusion was observed in one patient of the rivaroxaban group,and hematoma at the site of femoral vein puncture was seen in one patients of the dabigatran group in 1 d after procedure,which was treated surgically.No other severe complications occurred.Conclusion For elderly pa-tients with AF undergoing catheter ablation therapy,continuous perioperative anticoagulation and individualized application of unfractionated heparin based on initial ACT value can rapidly achieve ACT targets and improve anticoagulation efficacy.

Objective To summarize the results of different perioperative anticoagulation protocols for elderly patients with atrial fibrillation(AF)undergoing catheter radiofrequency ablation in our center.Methods A total of 197 elderly AF patients undergoing catheter radiofrequency ablation by a single operator in the First and Sixth Medical Centers of Chinese PLA General Hospital from January 2021 to December 2023 were retrospectively recruited,and the results of relevant exami-nations were collected.Based on the use of different direct oral anticoagulants,they were divided into dabigatran(n=125)and rivaroxaban(n=72)groups.During the procedure,the appropriate dose of unfractionated heparin was administered according to the initial activated clotting time(ACT)with a self-made formula.The time and rate of ACT were recorded,and perioperative ad-verse reactions such as bleeding and thrombosis were observed.Results There were no statistical differences between the two groups in baseline data,including age,gender,BMI,medical history,CHA2DS2-VASc score,HAS-BLED score,and left atrial anteroposterior diameter(P＞0.05).The baseline ACT value was obviously shorter(149.73+23.52 s vs 157.91±24.58 s,P=0.032),the initial heparin dose was significantly higher(0.71±0.12 mg/kg vs 0.65±0.13 mg/kg,P=0.031),and the rate of ACT reaching the target within 15 min was notably lower(60％vs 74％,P＜0.05)in the dabigatran group than the rivaroxaban group.But no significant difference was observed in the rate of ACT reaching the target in 45 min after additional heparin administration according to the formula(86％vs 88％,P＞0.05).The dabigatran group used higher dose of heparin during the procedure than the rivaroxaban group(0.99±0.30 mg/kg vs 0.85±0.31 mg/kg,P=0.009).Peri-cardial effusion was observed in one patient of the rivaroxaban group,and hematoma at the site of femoral vein puncture was seen in one patients of the dabigatran group in 1 d after procedure,which was treated surgically.No other severe complications occurred.Conclusion For elderly pa-tients with AF undergoing catheter ablation therapy,continuous perioperative anticoagulation and individualized application of unfractionated heparin based on initial ACT value can rapidly achieve ACT targets and improve anticoagulation efficacy.

Objective To investigate the application value of late gadolinium enhancement(LEG)at cardiac MRI in predicting ventricular arrhythmia(VA)events in patients after implantation of ICD.Methods A retrospective analysis was performed on 16 patients at high risk of sudden cardi-ac death after ICD implantation and LEG examination in the First and the Sixth Medical Centers of Chinese PLA General Hospital from June 2020 to March 2024.According the occurrence of VA events receiving appropriate ICD therapy during the follow-up period,they were divided into post-operative VA group(7 cases)and non-VA group(9 cases).The correlation of clinical baseline fea-tures and LEG features with VA events was analyzed.Results The ratios of transmural enhance-ment and myocardial medium enhancement were obviously higher in the VA group than the non-VA group(71.4％vs 11.1％,P=0.035;85.7％vs 22.2％,P=0.041).Multivariate logistic regres-sionanalysis showed that transmural enhancement(OR=5.000,95％CI:0.150-166.589,P=0.368)and myocardial medium enhancement(OR=7.000,95％CI:0.217-226.005,P=0.272)were not independent factors influencing VA occurrence.ROC curve analysis indicated that the combined prediction of transmural enhancement and myocardial media enhancement and the pre-diction of transmural enhancement alone had better diagnostic efficacy(P＜0.05).Conclusion LEG has clinical value in predicting postoperative VA events in patients after ICD implantation.

Objective To develop an intelligent model for differential diagnosis of atrioventricular nodal re-entrant tachycardia(AVNRT)and atrioventricular re-entrant tachycardia(AVRT)using 12-lead wearable electrocardiogram devices.Methods A total of 356 samples of 12-lead supraventricular tachycardia(SVT)electrocardiograms recorded by wearable devices were randomly divided into training and validation sets using 5-fold cross validation to establish the intelligent classification model,and 101 patients with the diagnosis of SVT undergoing electrophysiological studies and radiofrequency ablation from October,2021 to March,2023 were selected as the testing set.The changes in electrocardiogram parameters before and during induced tachycardia were compared.Based on multiscale deep neural network,an intelligent diagnosis model for classifying SVT mechanisms was constructed and validated.The 3-lead electrocardiogram signals from Ⅱ,Ⅲ,and V1 were extracted to build new classification models,whose diagnostic efficacy was compared with that of the 12-lead model.Results Of the 101 patients with SVT in the testing set,68 were diagnosed with AVNRT and 33 were diagnosed with AVRT by electrophysiological study.The pre-trained model achieved a high area under the precision-recall curve(0.9492)and F1 score(0.8195)for identifying AVNRT in the validation set.The total F1 scores of the lead Ⅱ,Ⅲ,V1,3-lead and 12-lead intelligent diagnostic models in the testing set were 0.5597,0.6061,0.3419,0.6003 and 0.6136,respectively.Compared with the 12-lead classification model,the lead-Ⅲ model had a net reclassification index improvement of-0.029(P=0.878)and an integrated discrimination index improvement of-0.005(P=0.965).Conclusion The intelligent diagnostic model based on multiscale deep neural network using wearable electrocardiogram devices has an acceptable accuracy for classifying SVT mechanisms.

Objective To analyze the outcomes of catheter ablation for persistent atrial fibrillation(AF)and the independent risk factors for its recurrence in the elderly.Methods A total of 194 patients with persistent AF who underwent catheter ablation at our department from January 2019 to December 2021 were enrolled in this study.They were divided into elderly group(≥60 years old,99 cases)and non-elderly group(＜60 years old,95 cases).Their surgical characteris-tics,postoperative complications and recurrence were compared between the two groups,and the independent risk factors for postoperative recurrence were analyzed in the elderly group.Results Advanced age,higher B-type natriuretic peptide,larger proportions of hypertension and coronary heart disease,and increased CHA2DS2-VASc and HAS-BLED scores,while lower male ratio and estimated glomerular filtration rate were observed in the elderly group than the non-elderly group(P＜0.05,P＜0.01).The elderly group had a higher proportion of left atrial fibrosis than the non-elderly group(30.3％vs 8.4％,P=0.001).Postoperative complications in the elderly group in-cluded 1 case of pericardial effusion and 2 cases of hematoma at the puncture site,and all of these were improved after treatment.There were no significant differences in the 1-year success rate(71.7％vs 69.5％,P=0.763)or recurrence rate during blanking period(21.2％vs 21.1％,P=0.981)between the elderly and non-elderly groups.AF duration(HR=1.020,95％CI:1.007-1.032,P=0.002)and recurrence during blanking period(HR=6.781,95％CI:3.078-14.935,P=0.001)were independent risk factors for postoperative recurrence in the elderly group.Conclu-sion Catheter ablation is safe and effective in the treatment of persistent AF in the elderly.The elderly patients with long duration of AF and recurrences during blanking period are more likely to experience recurrences within 1 year after ablation.

Objective To develop an intelligent model for differential diagnosis of atrioventricular nodal re-entrant tachycardia(AVNRT)and atrioventricular re-entrant tachycardia(AVRT)using 12-lead wearable electrocardiogram devices.Methods A total of 356 samples of 12-lead supraventricular tachycardia(SVT)electrocardiograms recorded by wearable devices were randomly divided into training and validation sets using 5-fold cross validation to establish the intelligent classification model,and 101 patients with the diagnosis of SVT undergoing electrophysiological studies and radiofrequency ablation from October,2021 to March,2023 were selected as the testing set.The changes in electrocardiogram parameters before and during induced tachycardia were compared.Based on multiscale deep neural network,an intelligent diagnosis model for classifying SVT mechanisms was constructed and validated.The 3-lead electrocardiogram signals from Ⅱ,Ⅲ,and V1 were extracted to build new classification models,whose diagnostic efficacy was compared with that of the 12-lead model.Results Of the 101 patients with SVT in the testing set,68 were diagnosed with AVNRT and 33 were diagnosed with AVRT by electrophysiological study.The pre-trained model achieved a high area under the precision-recall curve(0.9492)and F1 score(0.8195)for identifying AVNRT in the validation set.The total F1 scores of the lead Ⅱ,Ⅲ,V1,3-lead and 12-lead intelligent diagnostic models in the testing set were 0.5597,0.6061,0.3419,0.6003 and 0.6136,respectively.Compared with the 12-lead classification model,the lead-Ⅲ model had a net reclassification index improvement of-0.029(P=0.878)and an integrated discrimination index improvement of-0.005(P=0.965).Conclusion The intelligent diagnostic model based on multiscale deep neural network using wearable electrocardiogram devices has an acceptable accuracy for classifying SVT mechanisms.

Occasionally, incessant ventricular tachycardia (VT) exhibits a narrow QRS complex pattern that could be misdiagnosed as supraventricular tachycardia. In this case, a 66-year-old woman was referred to the emergency department due to the worsen hemodynamic and incessant VT manifesting as a narrow QRS complex pattern that was initially misdiagnosed as supraventricular tachycardia, which was unresponsive to antiarrhythmic drugs. The electrocardiogram manifestation of VT was characterized by an rS configuration in lead V 2 with Rs pattern in leads V 1 and V 3, and the R-wave amplitude of lead V 1 and V 3 was greater than that of lead V 2, which was different from the typical electrocardiogram features of right bundle branch block. The patient was subsequently found to have suspected acute myocarditis when the cause of the disease was investigated. A combination of high-dose methylprednisolone, immunoglobulin and intra-aortic balloon pump was given immediately. Hemodynamics gradually stabilized, and ventricular tachycardia did not recur. The rS change in the V 2 lead may be helpful to distinguish VT from supraventricular tachycardia.