Management of monomorphic ventricular tachycardia electrical storm in structural heart disease

Electrical storm (ES) is a life-threatening condition that is defined by three or more episodes of sustained ventricular tachycardia (VT), ventricular fibrillation (VF), or appropriate shocks from an implantable cardioverter defibrillator (ICD) within 24 hours. The most common form of ES is monomorphic VT. It carries poor outcome despite all available intervention therapies. The therapies include rapid recognition of the condition, treatment of the reversible causes, ICD-reprogramming, antiarrhythmic drugs, sedation, and catheter ablation (CA). The first line antiarrhythmic drugs are amiodarone and β-blockers with superiority of propranolol over the others. The long-term use of the antiarrhythmic drugs is limited due to their adverse effects and drug-related proarrhythmic effect. The basic mechanism of monomorphic VT is re-entry pathway which can be targeted by CA. CA should be considered in drug refractory ES and patients should be referred in early course of disease. There are reported studies which showed the superiority of CA over the medical treatment in reducing the arrythmia burden and ICD appropriate shock. The survival benefit has been reported after successful ablation of ES in case series but to date no randomized control trial shows mortality benefit.     

Incomplete bundle-branch block and st-segment elevation: Syndrome associated with sustained monomorphic ventricular tachycardia in patients with apparently normal heart

This paper reports on three cases of patients with an apparently normal heart admitted for sustained monomorphic ventricular tachycardia. The only abnormal finding showed in the electrocardiogram (ECG) in sinus rhythm that exhibited an entity associated with incomplete right bundle-branch block and persistent ST-segment elevation. The ECG entity was variable and disappeared transiently. Spontaneous ventricular tachycardia in one patient was inducible by programmed stimulation. There was no underlying heart disease. The origin of the ventricular tachycardia in one patient was located by pace mapping in the left ventricle at the left ventricular basal septum. The follow-up (from 6 months up to 6 years) demonstrated a good prognosis. This particular ECG entity associated with monomorphic ventricular tachycardia could have been missed because of the variations in the ECG in sinus rhythm and was associated with a favorable prognosis.     

起搏标测指导下射频消融器质性心脏病并发单形性室性心动过速

目的探讨起搏标测指导下射频消融器质性心脏病并发单形性室性心动过速(室速)的可行性和有效性。方法7例器质性心脏病患者,包括肥厚型心肌病4例,扩张型心肌病1例,冠心病、陈旧性心肌梗死1例,室间隔缺损修补术后1例。所有患者均为单形性室速。7例患者均在起搏标测下在室速折返环出口或病灶起源点行多靶点消融。以标测过程中出现与临床QRS波形态相同或相似的短阵室速或频发室性期前收缩为有效消融靶点。结果7例患者中4例为右室流入道室速,2例为左室流出道室速,1例为左室流入道室速。其中1例室速发生时血流动力学不稳定,1例程序刺激及药物不易诱发(术中仅记录到1次与临床发作相同的短阵室速)。7例患者分别完成消融3~10个靶点,其中2例手术失败。1例患者1周后再次行射频消融手术失败。所有患者术中、术后均无并发症发生。随访24~38(平均29.5)个月,其中6例患者在未服用抗心律失常药情况下(包括1例2次手术者)无室速复发。结论起搏标测指导下行多靶点消融能有效治疗器质性心脏病单形性室速;对于血流动力学不稳定性室速或程序刺激及药物不易诱发的室速起搏标测更有其应用价值。     

Is the time domain signal-averaged electrocardiogram helpful in patients with ventricular tachycardia without apparent structural heart disease?

The signal-averaged electrocardiogram (SAECG) has been a screening method for identifying patients at risk for ventricular tachycardia (VT) in the setting of coronary artery disease (CAD). Its significance in patients with VT unrelated to CAD or left ventricular dysfunction is undetermined. In order to define the value of SAECG in this patient population further, we compared the time domain SAECG at 25,40, and 80 Hz filters in 35 patients with clinically symptomatic VT in the absence of structural heart disease was compared with 10 normal controls and 10 patients with CAD and inducible VT. SAECG data in patients without structural heart disease were intermediate between normal controls and patients with CAD. No single or combined SAECG criterion helped to differentiate between patients with inducible and noninducible VT. There was no concordance to other arrhythmia testing. It was concluded that signal-averaged electrocardiography may have little screening value in VT unrelated to CAD or left ventricular dysfunction.     

Homozygous SCN5A mutation in Brugada syndrome with monomorphic ventricular tachycardia and structural heart abnormalities.

AIMS: To describe a patient showing monomorphic ventricular tachycardia, ECG aspect of Brugada syndrome, and structural heart abnormalities due to a homozygous missense mutation in SCN5A. METHODS AND RESULTS: Thirteen subjects (six males, seven females, mean age 46 +/- 22 years) belonging to the same family underwent physical examination, basal biochemical marker detection, 12-lead ECG, Holter ECG, signal-averaged ECG, echocardiogram and genetic analysis. The proband underwent a stress test together with left and right ventricular angiography and electrophysiological study. Three subjects (the proband, his mother, and one brother) showed on ECG an ST-segment elevation in the right precordial leads with coved type aspect. Moreover, the proband presented a sustained monomorphic ventricular tachycardia (left bundle branch block aspect with superior axis), whereas all other family members were asymptomatic. Imaging techniques documented right ventricular structural abnormalities only in the proband. Mutation screening in SCN5A gene was performed in the proband and in available family members. The proband carries a novel SCN5A mutation, R814Q, in homozygous, whereas the parents and four siblings were heterozygous carriers of the same mutation. CONCLUSION: This study provides the first evidence of a homozygous missense mutation in SCN5A associated with atypical ventricular arrhythmias and right structural abnormalities.     

Catheter ablation for hemodynamically unstable monomorphic ventricular tachycardia

INTRODUCTION: Hemodynamic collapse precludes extensive catheter mapping to identify focal target regions in many patients with ventricular tachycardia (VT) associated with heart disease. This study tested the feasibility of catheter ablation of poorly tolerated VTs by targeting a region identified during sinus rhythm. METHODS AND RESULTS: Ablation was attempted in five patients, ages 44 to 59 years, with left ventricular ejection fractions of 0.15 to 0.20 and poorly tolerated VT causing multiple implantable defibrillator therapies (6 to 30 episodes/month). VT was due to prior infarction in three patients and nonischemic cardiomyopathy in two. Target regions were sought that met the following criteria: (1) evidence of slow conduction from fractionated sinus rhythm electrograms and stimulus-QRS delays during pace mapping, and (2) evidence that the region contains the reentrant circuit exit from pace mapping. In 4 of 5 patients, a target region was identified and radiofrequency lesions applied. Ablation abolished all recurrences of VT in 3 of 4 patients during follow-up of 14 to 22 months. There were no complications. CONCLUSION: Ablation of poorly tolerated VT is feasible in some patients by mapping during sinus rhythm and performing ablation over a region of identifiable scar that contains abnormal conduction and a presumptive VT exit.     

Limited clinical utility of endomyocardial biopsy in patients presenting with ventricular tachycardia without apparent structural heart disease.

To determine the cardiac pathology underlying ventricular tachyarrhythmias, endomyocardial biopsy was performed in 14 patients, 10 men and 4 women, with a mean age of 40 years (range 17-63) and no apparent structural heart disease, presenting with high-density symptomatic nonsustained ventricular tachycardia (VT) (n = 4), sustained VT (n = 6), and ventricular fibrillation (n = 4). The absence of coronary or valvular heart disease was documented by cardiac catheterization. The mean left ventricular ejection fraction was 56 +/- 10%. Noninvasive assessment of the ventricular arrhythmia was made in all patients with Holter monitoring and/or exercise testing, while invasive evaluation with programmed electrical stimulation was performed in 13 patients. Biopsy findings included subendocardial and interstitial fibrosis in 7 patients, and monocytes containing periodic acid Schiff (PAS) positive vacuoles in 1 patient; biopsy was normal in 6 patients. There was no relationship between the presence or absence of pathologic abnormalities on biopsy and left ventricular ejection fraction, presenting or induced arrhythmias, or prognosis. Pathologic evidence supporting a specific treatable diagnosis was not present in any biopsy. Drugs to suppress spontaneous (3 patients) or induced (8 patients) VT were instituted, while 2 patients were not treated. In 1 patient who was resuscitated from out-of-hospital cardiac arrest an automatic defibrillator was implanted. In 24.6 months of mean follow-up there was 1 nonfatal arrhythmia recurrence, 1 noncardiac death, and 1 sudden death in a patient with fibrosis on biopsy, an ejection fraction of 45%, and both inducible and spontaneous sustained VT suppressed with an antiarrhythmic agent.(ABSTRACT TRUNCATED AT 250 WORDS)     

Initiation of monomorphic ventricular tachycardia: electrophysiological,clinical features,and drug therapy in patients with implantable defibrillators

At least 2 distinct patterns of sustained monomorphic ventricular tachycardia (MVT) have been ascribed during analysis of stored intracardiac electrograms retrieved from implantable cardioverter defibrillators and Holter recordings in patients with ventricular arrhythmia. We aimed to investigate the electrophysiological features of MVT with different initiation patterns in patients with implantable cardioverter defibrillators and to assess whether there is a relationship of the initiation patterns of sustained MVT with clinical characteristics and efficacy of antiarrhythmic therapy. Seventy-four stored intracardiac electrograms in 21 patients (mean age of 68.2 +/- 4.2 years) with MVT were evaluated. Cardiovascular diagnosis included coronary artery disease in 85.7% of the patients. All MVT episodes were classified as those initiating with ventricular premature beats (nonsudden onset MVT) and those without ventricular ectopy preceding tachycardia (sudden onset MVT). There was significant difference in left ventricular ejection fraction between MVTs with different initiation pattern, being the lower in those with nonsudden onset (33.6% +/- 38.4% vs. 38.4 +/- 7.0%, P <.04). Ventricular tachycardia cycle length was shorter in group of MVT with nonsudden onset as compared with sudden onset (338.5% +/- 48.1% vs. 376.8% +/- 57.0%, P <.02). Tachycardia with sudden onset was associated with shorter preceding RR interval than tachycardia with nonsudden onset (821.8 +/- 136.2% vs. 748.7 +/- 107.7%, P <.01). There were no significant differences in the type of antiarrhythmic drug therapy used between groups (P >.05). Monomorphic ventricular tachycardias with nonsudden onset occurred more frequently than with sudden onset, without precipitating RR cycles shortening, are faster in rate, associating with lower ejection fraction. Monomorphic ventricular tachycardias with sudden onset are characterized by preceding shortening of RR intervals, slower cycle length, and less worsening of ejection fraction.     

Are there gender differences in patients with coronary artery disease presenting with spontaneous sustained ventricular tachycardia and ventricular fibrillation?

The incidence of coronary artery disease (CAD) is greater in men than in women. The aim of the study was to analyze whether any gender-related differences in patients with CAD and documented spontaneous sustained ventricular tachyarrhythmias exist, and which parameters influence the induction of sustained ventricular tachyarrhythmias. The data of 250 patients [43 women (17.2%) and 207 men (82.8%)] with spontaneous sustained ventricular tachycardia [n = 190 (76%)] and fibrillation [n = 60 (24%)] who underwent coronary and left ventricular angiography, electrophysiological study, and signal-averaging electrocardiogram (ECG) form the basis of this analysis. No gender-related differences could be observed in age, number of diseased coronary arteries, history, location and number of myocardial infarctions, presence of left ventricular aneurysm, ejection fraction, type of spontaneous or induced arrhythmias, right ventricular effective refractory period, and signal-averaged ECG parameters. Age, presence of previous myocardial infarction, and ejection fraction were significant predictors (p<0.001) of inducibility of sustained ventricular tachyarrhythmias. Once CAD has begun, female and male patients present similar clinical and electrophysiologic characteristics. Thus, both genders should benefit similarly from diagnostic and therapeutic approaches if they are referred to the hospital or to invasive interventions at similar intervals in the course of their illness.     

Transition from purkinje fiber-related rapid polymorphic ventricular tachycardia to sustained monomorphic ventricular tachycardia in a patient with a structurally normal heart: a case report

We describe a 17-year-old woman with a structurally normal heart in which short-sustained rapid polymorphic ventricular tachycardias (VTs) were repetitively provoked by an antiarrhythmic agent, pilsicainide, and spontaneously changed into a sustained monomorphic VT. The latter was terminated by verapamil and was shown to be due to reentry by entrainment. Those two VTs originated from the Purkinje fibers in the left ventricular septum. Radiofrequency catheter ablation guided by the diastolic double potentials eliminated both VTs. Neither tachycardia recurred over a 5-month follow-up period or during antiarrhythmic drug challenge tests at 1 week, 1 month, and 3 months after the ablation.     

Apical hypertrophic cardiomyopathy presenting with sustained monomorphic ventricular tachycardia and electrocardiographic changes simulating coronary artery disease and left ventricular aneurysm

A 52-year-old male presented with sustained monomorphic ventricular tachycardia as the initial manifestation of apical hypertrophic cardiomyopathy. The electrocardiogram during normal sinus rhythm showed a pattern of an old anterior wall myocardial infarction with aneurysm formation. Cardiac catheterization documented angiographically normal coronary arteries. Apical hypertrophic cardiomyopathy was documented at cardiac catheterization and by echocardiogram and Doppler studies. Monomorphic ventricular tachycardia was reproducibly initiated and terminated during electrophysiological studies and antiarrhythmic drugs failed to control the tachycardia. At the time of implantation of a cardioverter defibrillator, left ventricular apical biopsy revealed pathologic findings characteristic of hypertrophic cardiomyopathy.     

Mapping and radiofrequency catheter ablation of the three types of sustained monomorphic ventricular tachycardia in nonischemic heart disease

INTRODUCTION: Sustained monomorphic ventricular tachycardia (VT) associated with nonischemic cardiomyopathy (CMP) is uncommon. Optimal approaches to catheter mapping and ablation are not well characterized, but they are likely to depend on the VT mechanism. The purpose of this study was to evaluate the mechanisms of sustained monomorphic VT encountered in nonischemic CMP and to assess the feasibility, safety, and efficacy of catheter radiofrequency ablation for treatment. METHODS AND RESULTS: Twenty-six consecutive patients with nonischemic CMP referred for management of recurrent VT were studied. In 16 (62%) patients, VT was related to a region of abnormal electrograms consistent with scar and the response to pacing suggested a reentrant mechanism. In 5 (19%) patients, VT was due to bundle branch or interfascicular reentry. In 7 (27%) patients, the VT mechanism was focal automaticity, 4 of whom had evidence of tachycardia-induced CMP. After catheter ablation targeting parts of reentrant circuits, VT was not inducible in 8 (53%) of 15 patients with scar-related reentry, was modified in 5 (33%) patients, and still was inducible in 2 (13%) patients. Ablation was successful in 5 of 5 patients with bundle branch reentry and in 6 of 7 patients with a focal automaticity mechanism. Overall, catheter ablation abolished clinical recurrence of VT in 20 (77%) of 26 patients during a follow-up of 15 +/- 12 months. CONCLUSION: Three different mechanisms of VT are encountered in patients with nonischemic CMP. The mapping and ablation approach varies with the type of VT. In this selected population, the overall efficacy was 77%.     

反复单形室性心动过速的导管射频消融治疗

目的对18例反复单形室性心动过速的消融情况进行分析,并对消融同形室性早搏根治反复单形室性心动过速的可行性、安全性及有效性进行分析.方法18例患者,男性4例,女性14例,年龄19～45岁.心电图及动态心电图均有频发室性早搏和非持续性室性心动过速.征得患者的知情同意书后,电生理检查和消融一次进行,标测和消融同形的室性早搏,采用起搏标测和激动标测相结合的方法,确定室性心动过速的起源处(消融靶点).靶点定位后进行射频消融,温度50～60度,能量30～40W.即刻成功标准为放电后10 s内同形室性早搏和非持续性室性心动过速消失,且静脉滴注异丙肾上腺素不能诱发,观察30 min窦性心律稳定.随访成功标准为术后动态心电图24h室性早搏少于100个,无室性心动过速发作.结果18例患者起源于右心室流出道17例,其中1例存在2种形态的室性心动过速,分别于肺动脉瓣上及瓣下消融成功.起源于左心室流出道1例,于主动脉瓣上左Valsalva窦内消融成功.即刻成功17例.随访平均(23±14)个月,无心动过速复发16例,复发2例,1例于术后3个月复发,再次消融成功,另1例于术后6个月复发,未接受第2次消融.1例术后出现少量心包积液,经放置引流管后好转,无其他并发症.结论消融同形室性早搏是根治反复单形室性心动过速安全和有效的方法.     

心肌缺血致室性心动过速的发生机制探讨

对冠心病患者心肌缺血（ＭＩ）时伴室性心动过速的１９例病人（Ｉ组）与无室速的４６例病人（Ⅱ组）进行对比分析。结果显示：２组每天ＭＩ总阵次和总时间有非常显著性差异（Ｐ均〈０．０１），Ｉ组全程持续性ＭＩ高于Ⅱ组（Ｐ〈０．０５）；Ｉ组中伴室速发作的ＭＩ持续时间、最大ＳＴ段压低幅度高于无室速的ＭＩ（Ｐ均〈０．０１）；Ｉ组心室晚电位阳性及３级以上室早总发生率均明显高于Ⅱ组（Ｐ均〈０．０１）。提示冠心病患者ＭＩ     

Prevalence and prognosis of ventricular tachycardia/ventricular fibrillation in patients with post-infarction left ventricular aneurysm: Analysis of 575 cases

Background

We investigated the prevalence of ventricular tachycardia/ventricular fibrillation (VT/VF) in Post-infarction left ventricular aneurysm (PI-LVA) patients and analyze clinical outcomes in patients presenting with VT/VF.

Implantable cardioverter defibrillator discharge rates in patients with unexplained syncope, structural heart disease, and inducible ventricular tachycardia at electrophysiologic study

BACKGROUND AND HYPOTHESIS: The implantable cardioverter defibrillator (ICD) is the best available strategy to protect patients from life-threatening ventricular arrhythmia. Although unproven, it is commonly utilized to treat subjects with syncope, a negative clinical workup, structural heart disease, and inducible sustained monomorphic ventricular tachycardia (VT) on programmed electrophysiologic stimulation (EPS). The purpose of this paper was to validate this approach. METHODS: We retrospectively identified 36 subjects who received primary ICD therapy for syncope in the setting of structural heart disease with inducible sustained monomorphic VT on EPS. The cohort was predominantly male (32/36) with underlying coronary artery disease (29/36). The mean left ventricular ejection fraction was 31 +/- 12%, and a third of the patients (12/36) had undergone bypass surgery. RESULTS: The study group was followed for a mean of 23 +/- 15 months (range 3-81 months) and experienced an ICD event rate of 22% at 3 months, which increased to 55% at 36 months. This event rate was comparable with the 66% event rate seen in a group of patients with primary ICD therapy for spontaneous life-threatening VT treated during the same time period. No future predictors of ICD events in the study group could be identified. CONCLUSION: Syncope patients with negative workup, structural heart disease, and sustained monomorphic VT at EPS are at high risk for future tachyarrhythmic events. Based on present evidence, primary ICD therapy in this group appears warranted and justified.