Comparison of the results of programmed ventricular stimulation from the right ventricular apex and outflow tract: a randomized, prospective study

Objective: The aim of this prospective study was to analysethe yield of programmed ventricular stimulation at the rightventricular apex compared with the outflow tract. Methods: A stepwise randomized cross-over protocol of programmedventricular stimulation with alternating stimulation at bothsites was used in 66 patients who were studied because of sustainedventricular tachycardia (n = 30), ventricular fibrillation (n= 7), or non-sustained ventricular tachycardia and/or syncope(n = 29). Results: There were no significant differences between the resultsof stimulation from either right ventricular site with regardto the presence or absence of structural heart disease, spontaneousarrhythmia, ejection fraction or effective refractory periods.Overall, monomorphic ventricular tachycardia was inducible in33 patients (50%); in 25 patients (75.8%), this arrhythmia wasinduced from both sites. However, in only 17 of these 25 patients(68%) did the induced monomorphic ventricular tachycardias havethe same morphologies and similar (± 50 ms) cycle lengths.Ventricular fibrillation was inducible in 11 patients (17%),mostly by three extrastimuli (n=8; 73%). Conclusions: (1) stimulation from at least two right ventricularsites is desirable because of their independent contributionto the induction of ventricular tachyarrythmias, (2) the non-inducibilityor inducibility at one ventricular site does not predict theeffect at another stimulation site, (3) the effective refractoryperiod at the right ventricular apex and outflow tract do notdiffer, (4) the inducibility of multiple ventricular tachycardiamorphologies emphasizes the importance of documenting the causeof spontaneous arrhythmias with multiple electrocardiographicleads to ensure the correct interpretation of arrhythmias inducedby programmed stimulation, (5) clinical or haemodynamic featurescannot predict whether one or more stimulation sites will berequired for induction of ventricular tachycardia. These resultsare important for the diagnostic evaluation and assessment ofpharmacological or non-pharmacological interventions.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

Idiopathic Left Ventricular Aneurysm: An Unusual Substrate of Ventricular Fibrillation and Ventricular Tachycardia

Idiopathic left ventricular aneurysm (LVA) is a very rare clinical condition. This article describes a patient with idiopathic LVA associated with episodes of ventricular tachycardia and ventricular fibrillation. Clinical and instrumental examinations did not reveal the pathogenesis of the aneurysm. The malignant clinical course suggests that an aggressive antiarrhythmic treatment, including ICD implantation, may be warranted.     

The “Short‐Coupled” Variant of Right Ventricular Outflow Ventricular Tachycardia: A Not‐So‐Benign Form of Benign Ventricular Tachycardia?

Idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT-VT) and idiopathic RVOT-extrasystoles are generally considered benign arrhythmias. We described three cases who originally presented with typical "benign looking" RVOT-extrasystoles or RVOT-VT but developed malignant polymorphic VT during follow-up. The unusual aspect of their RVOT-extrasystoles was their coupling interval, which appears to be intermediate between the ultra-short coupling interval of idiopathic VF and the long coupling interval seen in the truly benign RVOT-VT.     

Effect of Basic Drive Train Cycle Length on Induction of Ventricular Tachycardia by a Single Extrastimulus

This study determined the effects of a wide range of basic drive cycle lengths on the induction of ventricular tachycardia (VT) by a single extrastimulus (S₂). Seventy-one patients with coronary artery disease and inducible sustained monomorphic VT underwent 121 electrophysiology tests either in the control state or during treatment with an antiarrhythmic drug. Ventricular basic drive trains were eight beats in duration and the intertrain interval was three seconds. Programmed ventricular stimulation was performed with S₂ using the longest possible basic drive cycle length rounded off to the nearest multiple of 100 msec, then using basic drive train cycle lengths that decreased in 100 msec steps to 400 msec, and finally using a basic drive cycle length of 350 msec. At each drive cycle length, an interval of > 50 msec beyond the effective refractory period (ERP) was scanned with S₂. Monomorphic VT was induced by S₂ in 52/121 studies (43%). The drive cycle length had a significant linear effect on the log odds of inducing VT (P < 0.0001). The highest yield of VT occurred with a drive cycle length of 350 msec (42/121, 34%), and with each increment in drive cycle length, the expected odds of inducing VT decreased by a factor of 1.7. In 88% of cases in which VT was induced at a particular drive cycle length but not at longer drive cycle lengths, the coupling intervals that induced VT exceeded the ERP measured at one or more of the longer basic drive cycle lengths. In conclusion, there is an inverse relationship between the basic drive cycle length and the yield of monomorphic VT induced by S₂. The use of shorter basic drive cycle lengths often facilitates the induction of VT by some effect other than critical shortening of the S₂ coupling interval.     

Hoffmayer心电图积分识别ARVC室早／室速

目的探讨应用Hoffmayer心电图积分鉴别致心律失常性右室心肌病（arrhvthmogenic right ventricular cardiomyopathy,ARVC）和特发f生右室流出道室早／室速的临床意义。方法收集2009年9月至2013年5月就诊于北京大学人民医院患者中,心电图表现为右室流出道起源室早／室速患者57例。其中明确诊断为ARVC患者4例,经电生理检查及射频消融治疗成功的特发性右室流出道室早／室速患者53例。由两位电生理医生在不知道确切诊断的情况下,依据Hoffmayer心电图积分对上述患者的心电图进行分析,计算总积分≥5分,各单项积分诊断ARVC伴发的室早／室速的敏感度、特异度、阳性预测值、阴性预测值及诊断符合率。结果Hoffmayer心电图积分≥5分诊断ARVC伴发室早／室速的敏感度75％,特异度96．23％,阳性预测值60％,阴性预测值98％、诊断符合率94．7％。结论Hoffmayer积分≥5可有效鉴别右室流出道室早／室速是ARVC伴发的还是特发性的。应用此项积分具有简单、快速、敏感度及特异度均较高的优点,具较高的临床应用价值。     

Selective right ventricular angiography in apparently idiopathic ventricular fibrillation

Summary The definition of underlying heart disease in apparently idiopathic ventricular fibrillation seems to be important in regard to prognosis and choice of therapy. From October 1989, until August 1993, cardiac arrest due to the documented ventricular fibrillation occurred in eight consecutive patients with normal results on clinical examination, normal echocardiography, and normal or apparently nonspecific electrocardiogram (ECG) findings. Complete invasive investigations, including selective right ventricular angiography, were done; regional hypokinesia and segmental bulging of the right ventricle were found in seven patients (88%). Arrhythmogenic right ventricular dysplasia was suspected in these patients, although endomyocardial biopsy was not performed. After the finding of localized right precordial QRS prolongation of more than 110 ms in November 1993 in five patients, a retrospective, a more precise approach to QRS duration in standard ECG supported this diagnosis. Selective right ventricular angiography is of great help in identifying underlying heart disease in patients with apparently idiopathic ventricular fibrillation, and confirms ECG findings.     

Vulnerability of the right ventricle to cathodal,anodal, and bipolar stimulation at double diastolic threshold strength

Summary The repetitive ventricular response (RVR) to three stimulation techniques (bipolar, cathodal and anodal) was investigated in 35 patients. 26 patients suffered from coronary heart disease and 9 patients from dilative cardiomyopathy. The stimulation study was performed at a ventricular driving rate of 120/min with one and two premature ventricular extrastimuli. We used rectangular impulses of 1.8 ms duration at duable diastolic threshold strength. RVR was scored as follows: 0: no RVR, 1: one nonstimulated RVR, 2: two nonstimulated RVR, 3: three nonstimulated RVR, 4: four to ten nonstimulated RVR, 5: more than ten nonstimulated RVR lasting less than 2 minutes, 6: sustained ventricular tachycardia or ventricular fibrillation. We found that with unipolar anodal stimulation the diastolic threshold was significantly greater and the effective refractory period of the right ventricle was significantly shorter as compared to the other stimulation techniques. Between the three different electrode configurations there were no significant differences concerning the number of consecutive ventricular depolarizations following premature stimulation. Conclusion: the phenomenon of RVR is not influenced by the stimulation technique (bipolar, cathodal and anodal) at double diastolic threshold.Supported by the Robert-Müller-Stiftung     

Cryosurgery for ventricular bigeminy using a transaortic closed ventricular approach

Disabling monomorphic ventricular bigeminy has not been describedas an indication for surgery. Three young patients with thisarrhythmia sometimes deteriorating into ventricular tachyarrhythmiasand in whom drug therapy failed completely were accepted forsurgical ablation of the arrhythmogenic area. The earliest endocardialsite of origin was located preoperatively by catheter mappingof the spontaneously occuring ventricular bigeminy in the leftand right ventricles. For maximum preservation of myocardialmuscle and function, the peroperative mapping and surgical procedurewere preformed through the aortic root; mapping by transaorticmultipolar balloon was done during normothermic coronary perfusionand cryocoagulation was done during cardioplegic arrest. Cryocoagulationof the endocardial site was performed using the transaorticapproach and epicardial cryocoagulation at the opposite sitewas done afterwards. In the two patients in whom the peroperativemapping results were consistent with those of preoperative cathetermapping, the arrhythmia could be abolished, as documented duringlong-term follow-up. In the only patient in whom the mappingresults were not in agreement, the ventricular arrhythmia reoccurredand was the cause of death at five months after surgery. Postoperativewall-motion studies performed in the two surviving patientsshowed limited scars in the area of cryocogulation and minordamage to the coronary arteries in that area. The transaorticapproach can be considered as a new and important surgical optionfor endocardial mapping and cryocoagulation which prevents thedamaging effects of a left ventriculotomy.     

左心室质量及几何模式对左心室功能的影响

目的 探讨左心室质量(LVM)及几何模式对左心室功能的影响。方法 根据相对室壁厚度(RWT)>0.43和≤0.43将170例高血压患者分为向心性模式组和离心性模式组,分别作超声心动图检测。结果 向心性模式组的EF明显高于离心性模式组,而前者E、E/A明显低于后者。单变量及多变量回归分析均显示EF与LVM及RWT相关,E/A在单变量分析时与RWT呈非常显著负相关,但在多变量分析时被剔出。结论 LVM及几何模式的改变均对左心室收缩功能产生明显的损害,几何模式的变化可能对左心室舒张功能也会产生不利影响。     

右室流出道间隔部与心尖部起搏对心功能的影响

目的了解右室流出道间隔部起搏和右室心尖部起搏参数的差异及对心功能的影响。方法65例安装DDD起搏器的患者随机分为右室心尖部（RVA）与右室流出道间隔部（RVS）起搏进行置入时及术后3个月起搏参数、左室射血分数的分析。结果两组基线资料无显著差异，术后15min及3个月两组的起搏阂值、感知、阻抗均无差异，术后3个月右室流出道间隔部组左室射血分数显著高于右室心尖部组（0．57±0．04vs0．50±0．03，p〈0．05）。结论右室流出道间隔部起搏安全可行，且对心功能的影响优于右室心尖部起搏。     

Ventricular parasystole and ventricular couplets: A re-entry within the parasystolic focus?

We report a 62-year-old man with a persistent ventricular rhythm originating in a parasystolic focus associated with frequent ventricular couplets with fixed coupling. Both intravenous (IV) procainamide (1 g) and propafenone (70 mg IV) promptly suppressed only the second component of ventricular couplets, suggesting that re-entry rather than enhanced automaticity was the mechanism of ventricular couplets. On the contrary, the nonresponse of ventricular rhythm and ventricular couplets to verapamil (10 mg IV) suggested that triggered activity should not play a role in the genesis of this ventricular rhythm. The mechanisms of the ventricular couplets (rapidly discharging parasystolic focus vs. re-entry) are discussed.     

Case Report: Adenosine Induced Ventricular Fibrillation in a Patient with Stable Ventricular Tachycardia

Adenosine is frequently used in emergency departments and intensive care units for the termination of narrow complex tachycardias. Recently its utility in terminating wide complex tachycardias has been reported in the literature. Adenosine is generally felt to be a safe medication even though its proarrhythmic effects in the setting of narrow complex or supraventricular tachycardias have been well documented. Herein, we describe the first case to our knowledge of adenosine inducing ventricular fibrillation in a patient with a stable wide complex tachycardia that was subsequently proven to be ventricular tachycardia at electrophysiologic study.     

室早指数及临床意义的探讨

目的探讨室早指数对器质性病变患者发生恶性室性心律失常的预测价值。方法106例经动态心电图诊断为窦性心律伴发室性心律失常的患者,分为器质性与非器质性病变两组,统计室早个数、室速和室颤的发作阵次及诱发室速、室颤的室早联律间期、室早前次心搏的QT间期。结果106例患者中,平均24h室早总数12066±1105个;阵发室速662±79次,53例由RonT室早诱发,其中器质性病变46例(86.85%);阵发室颤39±5次,均发生于器质性病变者,其中11例(68.8%)由快速多形性室速诱发;器质性与非器质性病患者中诱发室速和(或)室颤的室早联律间期分别为340±15ms和420±20ms,室早前次心搏的QT间期分别为420±10ms和410±25ms,室早指数分别为0.90±0.10和1.00±0.15,两组比较有显著性差异(p<0.05)。结论当室早指数在0.78～0.83之间时,易诱发阵发性室速和室颤,尤其是器质性病变者,临床应给予足够的重视和治疗。     

Isolated noncompaction left ventricular myocardium and polymorphic ventricular tachycardia

A 57-year-old woman with syncope was admitted. She had a family history of sudden death: two brothers had died suddenly at the age of 47. Transesophageal echocardiography showed numerous prominent trabeculations and deep intertrabecular recesses in the anterior and lateroapical zones. Isotopic left ventricular ejection fraction was 46%. Cardiac catheterization showed coronary arteries with no angiographic lesions. A prominent trabecular zone and deep intertrabecular recesses were seen in the anterior wall on left ventriculography. Right ventriculography was normal. The diagnosis of isolated noncompaction left ventricular myocardium was established. Continuous 24-h electrocardiographic registry showed episodes of polymorphic ventricular tachycardia. Programmed ventricular stimulation performed at the right ventricular apex with up to three extrastimuli failed to induce ventricular arrhythmias. Treatment with beta blockers was initiated, but short runs of polymorphic ventricular tachycardia persisted. A dual-chamber automatic implantable defibrillator was implanted. We discuss the physiopathology of the arrhythmia. It appears that several factors could be responsible for the malignant arrhythmias in this entity.     

The mechanisms of ventricular tachycardia in humans determined by intraoperative recording of the electrical activation sequence

We recorded ventricular activation sequence during ventricular tachycardia in 76 patients who underwent surgical therapy of refractory ventricular tachycardia. Ventricular tachycardia arose from a discrete site (focal origination) in 28 patients (37%) or resulted from reentry around scar (macroreentry) in 22 patients (29%). The mechanism responsible for ventricular tachycardia was not discernable in the remaining 26 patients (34%), usually because of inadequacy of activation data. We conclude: (1) although focal originating of ventricular tachycardia is common, more frequently the mechanism is either macroreentry or uncertain, as assessed by conventional recording techniques; thus, a search for the "site of earliest activation" during ventricular tachycardia frequently may fail to direct rationally the operative procedure; (2) conventional techniques for intraoperative study of electrical activation during ventricular tachycardia are inadequate.