BACKGROUND: While the guidelines acknowledge the anticipated benefits of using an implantable cardioverter defibrillator (ICD) in individuals with catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the potential adverse effects have received less attention.
METHODS: To address this issue comprehensively, we will explore various databases such as the Cochrane Library, Web of Science, EMBASE and PubMed. Our study will include CPVT patients, both with and without ICD implantation. Two researchers will evaluate the eligible studies independently and gather pertinent data. The quality of the studies included will be assessed using either the Newcastle-Ottawa Scale or the Cochrane Risk of Bias Tool. Data analysis will be conducted using RevMan.
BACKGROUND: Because this research depends exclusively on existing studies, obtaining patient informed consent and ethics approval is unnecessary. The results of this meta-analysis will be shared at conferences or in peer-reviewed journals.
UNASSIGNED: CRD42022370824.

BACKGROUND: Idiopathic ventricular arrhythmias (IVAs) arising from different portions of the communicating vein of the left ventricular summit (summit-CV) are not a rare phenomenon. Whereas its electrocardiographic (ECG) and electrophysiological characteristics are not fully investigated.
OBJECTIVE: This study aimed to identify distinct ECG and electrophysiological features of IVAs originating from different portions of summit-CV.
METHODS: Nineteen patients confirmed arising from summit-CV were included in this study.
RESULTS: The 19 patients were divided into proximal and distal portion groups based on their target sites in summit-CV. In the proximal portion group, 100% (11/11) VAs showed dominant negative (rs or QS) waves in lead I, while in the distal portion group, 87.5% (7/8) showed dominant positive waves (R, Rs or r) (p < 0.000). In lead V1, 100% (11/11) of the proximal portion group showed dominant positive waves (R or Rs), while 62.50% (5/8) of the distal portion group showed positive and negative bidirectional or negative waves (RS or rS) (p < 0.005). RI>4mV, SI<3.5mV, RV1<13mV, SV1>3.5mV, RI/SI>0.83, and RV1/SV1< 2.6 indicated a distal portion of summit-CV with the predictive value of 0.909, 1.000, 0.653, 0.972, 0.903, 0.966, respectively. A more positive wave in lead I and a more negative wave in lead V1 indicated more distal origin in summit-CV. Target sites in proximal and distal summit-CV groups showed similar electrophysiological characteristics during mapping.
CONCLUSIONS: There were significant differences in ECG characteristics of VAs at different portions of summit-CV, which could aid pre-procedure planning and facilitate radiofrequency catheter ablation (RFCA) procedures.

This article describes the case of a 40-year-old individual who presented with fulminant myocarditis. Initial ECG displayed sinus tachycardia with a heart rate of 117 bpm, QS complexes in leads V1-V3, ST-segment depression in leads II, III, aVF, V5-V6, and ST-segment elevation >0.2 mV in leads V1 through V3. The initial clinical assessment suggested an acute anteroseptal myocardial infarction. However, subsequent diagnostic evaluation through coronary angiography disclosed that the coronary arteries were normal. Therefore, clinicians should carefully consider the differential diagnosis between these conditions, as their management strategies differ markedly. Two hours after admission, the patient unexpectedly developed syncope. The ECG findings were consistent with the typical characteristics of bidirectional ventricular tachycardia. Our report described the appearance and morphology as well as mechanism of bidirectional ventricular tachycardia in detail. Additionally, we delineate differential diagnoses for disease that can cause bidirectional ventricular tachycardia, such as aconite poisoning, digoxin overdose, immune checkpoint inhibitor (ICI), myocardial ischemia, and hereditary channelopathies, such as catecholaminergic polymorphic ventricular tachycardia (CPVT) and Andersen-Tawil syndrome. Therefore, clinicians should recognize this ECG finding immediately and initiate appropriate treatment promptly as these measures may be vital in saving the patient\'s life.

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Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.
目的： 探讨循环辅助支持在血流动力学不稳定的室性心动过速患者的标测及导管消融治疗中的作用，对该类患者的单中心经验进行总结分析，为临床提供循证医学证据。 方法： 该研究为回顾性队列研究。纳入2021年8月至2023年12月于首都医科大学附属北京安贞医院在循环辅助支持下接受导管消融手术的血流动力学不稳定的室性心动过速患者，根据治疗目的分为挽救性治疗组和预防性治疗组，对两组患者的人口学资料、围术期管理、导管消融情况及临床结局进行总结。 结果： 共纳入15例血流动力学不稳定的室性心动过速患者（挽救性治疗组8例，预防性治疗组7例），所有患者手术均获得即刻成功。1例患者（挽救性治疗组）植入左心室辅助装置，其余14例患者均采用体外膜肺氧合进行循环支持。术后在院期间，12例患者临床和血流动力学稳定，进行了体外膜肺氧合撤机，其中6例术后即刻撤机，其余在术后2.0（2.5）d撤机。挽救性治疗组中2例患者在院期间分别因顽固性心力衰竭和脑出血死亡。在30 d（1 d至12个月）的随访中，植入左心室辅助装置的1例患者在出院后第6个月出现1次心室颤动，经抗心律失常药物治疗后未再出现心室颤动和（或）室性心动过速。其余12例患者术后均未发生恶性室性心律失常事件。 结论： 循环辅助支持有助于血流动力学不稳定的室性心动过速患者完成激动标测及精准消融；尤其是急诊条件下，循环辅助支持是药物治疗无效的血流动力学不稳定的室性心动过速患者得以行急诊导管消融的唯一支持手段。.

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BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an infrequent hereditary disorder distinguished by fibrofatty replacement of the myocardium in the right ventricular, which predisposes individuals to life-threatening arrhythmias. This case delineates an ARVC patient who suffered recurrent bouts of sustained ventricular tachycardia (VT). In this case, we mainly discuss the application of myocardial contrast echocardiography (MCE) in displaying myocardial fibrosis in patients with ARVC.
METHODS: A 43-year-old male experienced three episodes of unexplained VT over an eight-year period, accompanied by symptoms of chest discomfort, palpitations and dizziness. Coronary angiography revealed no significant coronary stenosis. The electrocardiogram (ECG) results indicated characteristic epsilon waves in right precordial leads, and subsequent echocardiography identified right ventricular enlargement and right ventricular systolic dysfunction. MCE further disclosed regional myocardial ischemia at the epicardium of the left ventricular apex. Ultimately, cardiovascular magnetic resonance imaging (CMR) corroborated the ARVC diagnosis, highlighting linear intensification in the right ventricle during the delayed enhancement.
CONCLUSIONS: Prompt identification of ARVC is crucial for timely intervention and management. MCE may offer an effective and valuable technique for the detection of myocardial involvement in ARVC patient.

BACKGROUND: The accuracy of surface ECG algorithms for predicting the origin of outflow tract ventricular arrhythmias (OT-VAs) might be questioned. Intracardiac electrograms recorded at anatomic landmarks could provide new predictive insights. We aim to evaluate the efficacy of a novel criterion utilizing the activation pattern of the coronary sinus (CS) in localizing OT-VAs, including VAs originating from the right ventricular outflow tract (RVOT), endocardial left ventricular outflow tract (Endo-LVOT), and epicardial left ventricular outflow tract (Epi-LVOT).
METHODS: We measured the ventricular activation time of the mitral annulus (MA) from the onset of the earliest QRS complex of VAs to the initial deflection over the isoelectric line at local signals, namely the QRS-MA interval. The activation at 3 and 12 o\'clock of the MA was recorded as the QRS-MA3 and QRS-MA12 intervals, respectively. Their predictive values were compared to previous ECG algorithms.
RESULTS: A total of 68 patients with OT-VAs were enrolled (51 for development and 17 for validation). From early to late, the ventricular activation sequences at MA12 were as follows: Epi-LVOT, Endo-LVOT, and RVOT. In LBBB morphology OT-VAs, the QRS-MA12 interval was significantly earlier for LVOT origins than RVOT origins. In the combined cohort of development and validation cohort, a cut-off value of ≤10 ms predicted the LVOT origin with a sensitivity of 100% and specificity of 78%. The QRS-MA12 interval ≤ -24 ms additionally predicted epicardial LVOT sites of origin.
CONCLUSIONS: The QRS-MA interval could accurately differentiate the OT-VAs localization.

BACKGROUND: Ventricular tachycardia (VT) is the primary cause of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, the strategy for VT treatment in HCM patients remains unclear. This study is aimed to compare the effectiveness of catheter ablation versus antiarrhythmic drug (AAD) therapy for sustained VT in patients with HCM.
METHODS: A total of 28 HCM patients with sustained VT at 4 different centers between December 2012 and December 2021 were enrolled. Twelve underwent catheter ablation (ablation group) and sixteen received AAD therapy (AAD group). The primary outcome was VT recurrence during follow-up.
RESULTS: Baseline characteristics were comparable between two groups. After a mean follow-up of 31.4 ± 17.5 months, the primary outcome occurred in 35.7% of the ablation group and 90.6% of the AAD group (hazard ratio [HR], 0.29 [95%CI, 0.10-0.89]; P = 0.021). No differences in hospital admission due to cardiovascular cause (25.0% vs. 71.0%; P = 0.138) and cardiovascular cause-related mortality/heart transplantation (9.1% vs. 50.6%; P = 0.551) were observed. However, there was a significant reduction in the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation in ablation group as compared to that of AAD group (42.9% vs. 93.7%; HR, 0.34 [95% CI, 0.12-0.95]; P = 0.029).
CONCLUSIONS: In HCM patients with sustained VT, catheter ablation reduced the VT recurrence, and the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation as compared to AAD.