Malignant entity of idiopathic ventricular fibrillation and polymorphic ventricular tachycardia initiated by premature extrasystoles originating from the right ventricular outflow tract.

OBJECTIVES: The aim of this study was to assess the clinical characteristics and the efficacy of radiofrequency catheter ablation (RFCA) for idiopathic ventricular fibrillation (VF) and/or polymorphic ventricular tachycardia initiated by ventricular extrasystoles originating from the right ventricular outflow tract (RVOT). BACKGROUND: Ventricular fibrillation and/or polymorphic ventricular tachycardia are occasionally initiated by ventricular extrasystoles originating from the RVOT in patients without structural heart disease. METHODS: Among 101 patients without structural heart disease in whom RFCA was conducted for idiopathic ventricular tachyarrhythmias arising from the RVOT, we examined the clinical characteristics and the efficacy of RFCA in 16 patients with spontaneous VF and/or polymorphic ventricular tachycardia initiated by the ventricular extrasystoles originating from the RVOT. RESULTS: Among 16 patients, spontaneous episodes of VF were documented in 5 patients, and 11 patients had prior episodes of syncope. Holter recordings showed frequent isolated ventricular extrasystoles with the same morphology as that of initiating ventricular extrasystoles, and non-sustained polymorphic ventricular tachycardia with short cycle length (mean of 245 +/- 28 ms) in all 16 patients. Radiofrequency catheter ablation by targeting the initiating ventricular extrasystoles eliminated episodes of syncope, VF, and cardiac arrest in all patients during follow-up periods of 54 +/- 39 months. CONCLUSIONS: Our data suggest that the malignant entity of idiopathic VF and/or polymorphic ventricular tachycardia was occasionally present in patients with idiopathic ventricular arrhythmias arising from the RVOT. Radiofrequency catheter ablation was effective as a treatment option for this entity.     

Successful catheter ablation in a patient with polymorphic ventricular tachycardia

We describe a patient with polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) without organic heart disease who was cured by radiofrequency catheter ablation. The patient was a 65-year-old woman with a 10-year history of recurrent syncope. There was no evidence of organic heart disease, and the QT interval during sinus rhythm was borderline normal (corrected QT interval = 0.45 sec1/2). ECG recording during syncope showed PVT. On one occasion, PVT degenerated into VF. This PVT was always induced by a premature ventricular complex (PVC) originating from the right ventricular (RV) outflow tract. Rapid pacing (220 beats/min) at the site of PVC origin reproduced polymorphic change of the QRS wave on surface ECG that was similar to PVT. This suggests that the PVT originated from a single focus in the RV outflow tract. Catheter ablation was performed at the site of PVC origin. During 18-month follow-up, PVT/VF was not documented.     

体表心电图特征对特发性右心室流出道室性心动过速和室性早搏起源点的定位价值

目的 起源于右心室流出道(RVOT)不同位点的室性心动过速(VT)具有相应的心电图表现,本研究旨在摸索一种相对简单的根据体表心电图进行定位的方法 .方法 将RVOT分为游离壁和间隔而两大区,其中间隔面又分为9个区域.共320例RVOT-VT患者中,对213例既往消融成功患者的靶点与体表12导联心电图中QRS波形态之间的关系进行分析,并在消融前前瞻性地对另外107例患者的消融靶点进行预测,以检验其定位价值.结果 I导联对RVOT起源的VT有特殊的定位价值.在间隔面前部起源时,I导联以负向波为主,多为QS、Qr及rS型,随着起源点从前向后、从上向下,R波逐渐升高,其中起源于间隔侧中带(2、5、8区)时,以"M"型居多,在后壁时则表现为R波且有切迹.游离壁起源者的QRS时限明显延长,I和aVL导联的R波较间隔起源者高,而下壁导联的R波均较间隔的低(P<0.05).在前瞻性分析中,这些参数的敏感度、特异度、阳性和阴性预测值均较高.结论 RV-OT不同部位起源的VT有相应的心电图特征,其中I导联形态尤其具有定位价值,为RVOT心律失常起源提供了简便的定位标准.     

低能量放电下标测无室性早搏的流出道室性心动过速

目的 本文报道11例非频发室性早搏(室早)的流出道室性心动过速(室速)伴反复晕厥病例经导管射频消融成功的体会,并由此介绍一种新的针对这类患者的标测方法.方法 11例患者,全部为女性,年龄(39.9±13.7)岁,全部曾使用2种以上抗心律失常药物治疗,治疗期间均有晕厥或黑矇病史1～3年.结果 (1)所有11例患者在术中经过各种方法均可记录到至少1次室早、室速发作心电图,其中6例经程序刺激不能诱发的通过静脉滴注异丙肾上腺素能诱发室早、室速.(2)所有患者先在右心室流出道预测起源区以15～20 W低能量放电下微调消融电极导管位置和方向,在诱发出与所记录、冻结的室早完全一致的位点时,加大能量至35～50 W,反复巩固2～3次,直至室早、室速不再出现.然后以此点为中心,向周围微移动电极导管约5 mm,最终消融出大约1 cm2的面积.所有11例患者,采用这种方法全部都诱发出与记录室早12/12导联完全一致的室速.(3)11例患者中有10例达到消融终点,其中9例在右心室流出道间隔部及后壁,1例在右冠窦基底部.另1例未达到消融终点的患者,在消融开始时用异丙肾上腺素仅可诱发极少的室早,但在低能量消融后诱发频发的短阵室速,激动标测提示最早激动点位于左冠窦中下部,该处放电诱发出与自发室早一致的图,但反复放电室早、室速不能完全消除,考虑为靠外膜区室早而放弃.(4)术后所有患者经电话、预约门诊随访3～14个月,没有1例主诉再发黑矇和晕厥者.结论 低能量放电标测完全可作为一种新的标测手段在实际工作中配合使用,尤其对那些反复黑矇、晕厥但室早、室速发作较少的患者,常规标测方法几乎无用,此时低能量放电标测就显得更加实用.     

特发性右室流出道室性早搏触发多形性室性心动过速或心室颤动四例的临床特点

目的报道4例特发性右室流出道(RVOT)室性早搏(PVC)触发多形性室性心动过速/心室颤动(PVT/VF)的临床特点。方法 76例起源于RVOT的VT患者,其中4例为PVC触发PVT/VF,总结4例的临床资料并与另72例有关资料相比较。结果所有4例触发PVT/VF时的PVC与孤立PVC的形态一致,但2种PVC的联律间期发生了明显改变,其改变幅度均≥70 ms,其中2例缩短,2例延长。1例孤立PVC时的联律间期亦不恒定。72例PVC触发的单形VT患者每天PVC次数为15 427±1 109,QT间期为404±15 ms,孤立PVC联律间期为419±22ms。4例PVC触发PVT/VF患者中3例1天的PVC次数与72例PVC触发的单形VT患者平均PVC次数相当。4例患者的QT间期及孤立PVC联律间期与另72例患者相当。而4例PVT/VF的周长均小于280 ms,明显短于72例VT的平均周长(324±59 ms)。72例单形VT患者发生晕厥比率4.1%;4例PVT/VF患者中发生晕厥者2例。采用激动标测和起搏标测证实4例患者PVC均起源于RVOT间隔侧,经射频导管消融PVC取得成功。结论起源于RVOT的PVC触发PVT/VF具有PVC联律间期不恒定及PVT/VF的周长短的临床特征,射频导管消融治疗有效。     

起源于左右心室流出道心动过速和早搏的射频导管消融治疗

目的 探讨射频导管消融（RFCA）治疗心室流出道特发性室性心动过速（室速）和室性早搏（室早）的临床效果、心电图及电生理特征。方法 58例患者中室速10例,室早48例。起源于右室流出道（RVOT）43例,左室流出道（LVOT）15例,其中起源于主动脉瓣上Valsalva左冠窦（LSV）12例。5例RVOT室速是在非接触标测系统Ensite3000指导下进行消融的。结果 （1）58例患者中55例成功,3例失败,9例复发。（2）其中1例患者术中出现急性心包压塞。（3）起源心室流出道的室速和室早具有典型的心电图特征,其中Ⅱ、Ⅲ、aVF导联单向R波是流出道室性心律失常的共同特点。（4）V1或V2导联的R波时限指数与R／S波幅指数可作为区别LSV与RVOT室速和室早的有效指标。结论 射频导管消融治疗心室流出道特发性室性心律失常是一种安全、有效的方法。非接触标测系统对于血流动力学不稳定的复杂性室性心律失常的标测与治疗具有重要的意义。     

射频导管消融治疗的特发性室性心律失常心电图特征分析

目的：探讨不同起源的特发性室性期前收缩（PVCs）和（或）室性心动过速（VT）的心电图特征,提出鉴别流程。方法根据射频导管消融PVCs/VT有效靶点或心室最早激动点的X线胸片进行定位,分析不同起源PVCs/VT的12导联心电图QRS波群。结果828例接受导管消融,580例起源于右心室,248例起源于左心室,左、右心室起源者胸导联移行指数＜0的分别占97.58%及7.24%;左和右心室流出道起源者下壁导联多数呈R型,V1上,多数右心室流出道起源者呈rS型,右室间隔起源呈QS型,主动脉瓣上起源者常呈rS或RS型;下壁导联上,左前分支起源者常呈qR型,左后分支起源者常呈rS型。结论结合体表心电图胸导联移行指数、下壁导联和V1上的QRS波群特征可初步判断特发性PVCs/VT的起源部位。     

特发性室性心动过速及室性期前收缩的射频消融治疗

目的探讨射频导管消融(radiofrequency catheter ablation,RFCA)治疗特发性室性心动过速(idiopathic ventricular tachycardia,IVT)和室性期前收缩(premature ventricualr contraction,PVC)可行性、必要性和疗效。方法回顾性分析16例IVT、PVC患者采用激动顺序标测和起搏标测法确定室性心动过速(ventricular tachycardia,VT)、PVC的起源部位并行RFCA治疗的资料。结果 3例IVT中2例起源于左室间隔部左后分支的蒲肯野系统,1例起源于右心室流出道(right ventricular outflow tract,RVOT)游离壁,同时合并另一种游离壁起源的PVC,3例消融均成功,1例复发。13例PVC中7例起源RVOT间隔部,3例起源于RVOT游离壁,1例同时存在两种形态PVC(分别起源于ROVT间隔部和游离壁),2例起源于左心室流出道,13例消融成功,1例复发。结论 RFCA治疗IVT及特定部位的PVC是安全、有效且成功率高的一种方法。     

右室流出道室性心律失常的射频导管消融体会

目的报道右室流出道(RVOT)室性心律失常的射频导管消融(RFCA)体会。方法43例RVOT室性心律失常患者男18例、女25例,年龄39.2±15.1(13～67)岁。经血液生化、胸片、心脏彩超等检查证实无器质性心脏病证据。其中室性心动过速(VT)8例,室性早搏(PVC)35例。38例采用传统的起搏与激动标测。5例VT是在非接触标测系统EnSite3000指导下进行消融治疗的。结果①间隔部起源40例,游离壁起源3例。42例成功,1例失败,成功率97.7%,9例复发,再次标测消融后成功。②RVOT起源的VT和PVC具有典型的心电图特征,表现为典型的左束支传导阻滞型伴电轴右偏。RVOT的起源点不同,其12导联心电图特征不同,Ⅰ、Ⅱ、Ⅲ和aVF导联呈RR′型,V1～V3具有深S波是游离壁起源的特征。③1例术中出现急性心包压塞,其心电图虽具有RVOT起源的特征,但Ⅱ、Ⅲ和aVF导联R波振幅异常增高。结论RVOT室性心律失常具有典型的心电图和电生理特征,RFCA是一种安全、有效的治疗方法。EnSite3000非接触标测系统定位快速准确,适用于血流动力学不稳定的复杂性心律失常的标测。     

The Use of Fontaine Leads in the Diagnosis of Arrhythmogenic Right Ventricular Dysplasia

We report a case of a 68‐year‐old man admitted to the emergency department with syncope preceded by rapid palpitations. His admission ECG demonstrated a sustained ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). This report highlights the importance of distinguishing ventricular tachycardia caused by arrhythmogenic right ventricular dysplasia (ARVD) from the more benign idiopathic RVOT‐VT. Furthermore, we demonstrate the utility of the Fontaine leads placement in increasing the sensitivity for uncovering epsilon waves, a highly specific electrocardiographic feature that increases diagnostic accuracy in patients with ARVD.     

Left ventricular outflow tract tachycardia originating from the right coronary cusp: identification of location of origin by endocardial noncontact activation mapping from the right ventricular outflow tract

Idiopathic left ventricular outflow tract (LVOT) tachycardia has been shown to originate from a supravalvular site in some patients. Considerable attention recently has focused on identifying this variant of LVOT tachycardia on 12-lead ECG. We report the case of 15-year-old boy in whom a noncontact three-dimensional mapping electrode deployed in the right ventricular outflow tract (RVOT) assisted in identifying a supravalvular LVOT tachycardia. Observation of two early breakthrough sites in the RVOT and right ventricular septum suggested a right aortic cusp origin of the tachycardia. Pace mapping in the right aortic cusp identified a successful ablation site.     

Catecholaminergic ventricular tachycardia initially diagnosed as right ventricular outflow tract arrhythmia. Differential diagnosis of CPVT, LQTS and RVOT arrhythmia

We described a case of 33 year-old woman with catecholaminergic polymorphic ventricular tachycardia (VT) with first presentation as syncope in age of 14. In subsequent ECGs premature ventricular contractions (PVC) with morphology of left bundle branch block-like pattern with positive R wave in leads: II, III and aVF what suggested PVC arising from right ventricular outflow tract were observed. Nonsustained VT was observed. No ventricular arrhythmias were induced during EPS. The 2 unsuccessful sessions of ablation were performed in the right ventricular outflow area. The exercise test provoked bidirectional VT. The adrenaline infusion provoked bidirectional nonsustained VT and the U wave amplitude augmentation. Betablocker was initiated (bisoprolol). The patient is free of symptoms, only single PVC is observed.     

A case of short-coupled variant of torsade de pointes characterized by spatial heterogeneity of action potential duration and its restitution kinetics

A 21-year-old male experienced frequent episodes of polymorphic ventricular tachycardia (PVT) initiated by a closely coupled premature ventricular complex (PVC) in the absence of QT prolongation and structural heart disease. Programmed stimulation at right ventricular apex (RVA), but not at the outflow tract (RVOT), provoked PVT degenerating into ventricular fibrillation (VF). Monophasic action potential duration (MAPD) was significantly shorter at RVA than RVOT. The maximum slope of MAPD restitution was much steeper at RVA than RVOT (1.91 versus 0.50). Such spatial heterogeneities of MAPD and its restitution may facilitate wavebreak and functional reentry predisposing to PVT and VF.     

Use of the signal-averaged electrocardiogram for predicting inducible ventricular tachycardia in patients with unexplained syncope: Relation to clinical variables in a multivariate analysis

Objectives. The purpose of this study was to determine the predictors of electrically induced ventricular tachycardia in a large sample of patients with unexplained syncope and to examine the value of the signal-averaged electrocardiogram (ECG) in those patient subsets with varying pretest probability of ventricular tachycardia.Background. In patients with unexplained syncope, electrophysiologic study can provide important diagnostic information, such as inducibility of ventricular tachycardia. The signal-averaged ECG can predict inducible ventricular tachycardia, but its utility has not been prospectively studied in a large group of patients with unexplained syncope.Methods. At six hospitals, 189 consecutive patients with unexplained syncope underwent signal-averaged ECG and electrophysiologic studies.Results. Ventricular tachycardia was induced in 28 patients (15%). Univariate predictors of ventricular tachycardia included history of previous myocardial infarction, reduced left ventricular ejection fraction and abnormal signal-averaged ECG results. The signal-averaged ECG was the most sensitive test but had poor specificity. By multivariate analysis, the signal-averaged ECG and history of previous myocardial infarction were independently predictive. The risk of ventricular tachycardia increased 17-fold in patients with a previous myocardial infarction who also had an abnormal signal-averaged ECG. In patients with no history of previous myocardial infarction, no additional testing was useful in identifying those at risk for inducible ventricular tachycardia. Conclusions. The signal-averaged ECG was the most sensitive noninvasive test available to predict sustained ventricular tachy-cardia at electrophysiologic study but was false positive in many patients. A history of previous myocardial infarction followed by the signal-averaged ECG was the most efficient screening process for predicting electrically induced ventricular tachycardia.     

Catecholaminergic polymorphic ventricular tachycardia with associated sinus node dysfunction

An 11-year-old Nepalese male child presented with history of recurrent abrupt episodes of syncope for the last one year. There was no family history of sudden death at a young age in his family. ECG at base-line revealed an isorhythmic AV dissociation with a heart rate of 50 bpm and a normal QTc. Echocardiography of the heart was normal. His 24 hour holter study revealed frequent VPC's and episodes of polymorphic ventricular tachycardia. Exercise stress test provoked a polymorphic VT. On EP study, sinus node recovery time (SNRT) was prolonged and ventricular tachycardia (VT) was induced on Isoproterenol infusion. He was treated with a permanent pacemaker and beta-blocker.     

Acute coronary artery occlusion and ischemia-related ventricular tachycardia during catheter ablation in the right ventricular outflow tract

Coronary artery injury is a rare complication of catheter ablation in the right ventricular outflow tract (RVOT). Furthermore, acute myocardial ischemia usually causes polymorphic ventricular tachycardia (VT) or ventricular fibrillation. We herein describe a case in which catheter ablation for VT originating from the RVOT provoked ischemia-related VTs due to acute occlusion of the left anterior descending artery.     

Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle

INTRODUCTION: Most idiopathic nonreentrant ventricular tachycardia (VT) and ventricular premature contractions (VPCs) arise from the right or left ventricular outflow tract (OT). However, some right ventricular (RV) VT/VPCs originate near the His-bundle region. The aim of this study was to investigate ECG characteristics of VT/VPCs originating near the His-bundle in comparison with right ventricular outflow tract (RVOT)-VT/VPCs. METHODS AND RESULTS: Ninety RV-VT/VPC patients underwent catheter mapping and radiofrequency ablation. ECG variables were compared between VT/VPCs originating from the RVOT and near the His-bundle. Ten patients had foci near the His-bundle (HIS group), with the His-bundle local ventricular electrogram preceding the QRS onset by 15-35 msec (mean: 22 msec) and His-bundle pacing produced a nearly identical ECG to clinical VT/VPCs. The HIS group R wave amplitude in the inferior leads (lead III: 1.0 +/- 0.6 mV) was significantly lower than that of the RVOT group (1.7 +/- 0.4 mV, P < 0.05). An R wave in aVL was present in 6 of 10 HIS group patients, while almost all RVOT group patients had a QS pattern in aVL. Lead I in HIS group exhibited significantly taller R wave amplitudes than RVOT group. HIS group QRS duration in the inferior leads was shorter than that of the RVOT group. Eight of 10 HIS group patients exhibited a QS pattern in lead V1 compared to 14 of 81 RVOT group patients. HIS group had larger R wave amplitudes in leads V5 and V6 than RVOT group. CONCLUSION: VT/VPCs originating near the His-bundle have distinctive ECG characteristics. Knowledge of the characteristic QRS morphology may facilitate catheter mapping and successful ablation.     

Electrocardiographic determinants of the polymorphic QRS morphology in idiopathic right ventricular outflow tract tachycardia

Coupling Intervals and Polymorphic QRS Morphologies . Introduction: Premature ventricular contractions (PVCs) arising from the right ventricular outflow tract (RVOT) can trigger polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) in patients with no structural heart disease. We aimed to clarify the ECG determinants of the polymorphic QRS morphology in idiopathic RVOT PVT/VF. Methods and Results: The ECG parameters were compared between 18 patients with idiopathic PVT/VF (PVT‐group) and 21 with monomorphic VT arising from the RVOT (MVT‐group). The coupling interval (CI) of the first VT beat was comparable between the 2 groups. However, the prematurity index (PI) of the first VT beat was smaller in the PVT‐group than in the MVT‐group (P < 0.001). Furthermore, the QT index, defined as the ratio of the CI to the QT interval of the preceding sinus complex, was also smaller for the PVT/VF in the PVT‐group than that for the VT in the MVT‐group (P < 0.01). In the PVT‐group, the CI of the first VT beat was comparable between that of VT and isolated PVCs, but the PI of the first VT beat was shorter for VT than isolated PVCs (P < 0.05). The PI was the only independent determinant of the polymorphic QRS morphology (odd ratio = 2.198; 95% confidence interval = 1.321–3.659; P = 0.002). Conclusion: The smaller PIs of the first VT beat may result in a polymorphic QRS morphology. (Cardiovasc Electrophysiol, Vol. 23, pp. 521‐526, May 2012)     

Correlation of the standard electrocardiogram and continuous ambulatory monitoring in the detection of ventricular arrhythmias in coronary patients

To evaluate the efficacy of ventricular arrhythmia detection in ambulatory patients with stable coronary artery disease, 101 coronary patients documented by arteriography or remote myocardial infarction underwent concurrent evaluation by 10-hour portable ambulatory ECG monitoring and standard 12-lead electrocardiograms (ECGs) obtained serially over 24 months. Portable ECG recorded premature ventricular contractions (PVCs) in 77 patients: 50% serious PVCs (multifocal, paired, >5/minute, R on T) and 9% patients with ventricular tachycardia. Standard ECG was insensitive (p<.001) in arrhythmia detection both by one tracing (PVC prevalence 17%) obtained within 12 hours of portable ECG or by four serial standard ECGs during the subsequent two weeks (PVC prevalence 18%). Although a total of 1,414 standard ECGs during 24 months recorded PVCs in 49% of patients, serious PVCs were limited (p<.001) to 25% and ventricular tachycardia to 1% of patients. However, ventricular ectopy present by any standard ECG (10 per patient) within three months of ambulatory monitoring was associated with high prevalence of hazardous ectopics by portable ECG (p<.05): serious PVC 92%; ventricular tachycardia 17% patients. Even in patients free of ventricular ectopy by 24-month serial standard ECG, portable ECG detected serious PVCs in 62% and ventricular tachycardia in 6% of patients. Thus stable coronary patients manifested frequent ventricular ectopics by portable ECG which were usually undetected by even multiple serial standard ECGs. Importantly, presence of PVCs by standard ECG was related to increased risk of hazardous ventricular arrhythmias by portable ECG.     

Successful radiofrequency catheter ablation of the symptomatic ventricular tachycardia in structurally normal heart. Case report

Radiofrequency catheter ablation (RFA) in structurally normal heart ventricular arrhythmias has been found to be promising direction of develop. Authors presented the case of successful RFA of symptomatic ventricular tachycardia originating from right ventricle outflow tract (RVOT). Arrhythmogenic locus was localised basing on ECG pattern, analyze of endocardial potentials and pace mapping method. In two-year follow up she was free of symptoms and ventricular arrhythmia, no medication needed. RFA is an effective and safe therapy in ventricular tachycardia in structurally normal heart.