Taquicardia ventricular en la enfermedad coronaria

Ventricular arrhythmias are important contributors to morbidity and mortality in patients with coronary artery disease. Ventricular fibrillation accounts for the majority of deaths occurring in the acute phase of ischemia, whereas sustained, monomorphic ventricular tachycardia due to reentry generated in the scar tissue develops most often in the setting of healed myocardial infarction, especially in patients with lower left ventricular ejection fraction. Despite determinant advances in population education and myocardial infarction management, the ventricular tachycardia risk in the overall population with coronary artery disease continues to be a major problem in clinical practice. The initial evaluation of a patient presenting with ventricular tachycardia requires a 12-lead electrocardiogram, which can be helpful to confirm the diagnosis, suggest the presence of potential underlying heart disease, and identify the location of the ventricular tachycardia circuit. An invasive electrophysiologic study is usually crucial to determine the mechanism of the arrhythmia once induced and to provide guidance for ablation. The approach for ventricular tachycardia ablation depends on several factors, including inducibility, sustainability, and clinical tolerance of ventricular tachycardia. The paper also reviews other therapeutic options for patients with ventricular tachycardia associated with coronary artery disease, including antiarrhythmic drug therapy, surgical ablation, and current implantable cardioverter-defibrillator indications.     

A Comparative Study of Intracoronary Iced Saline Versus Intracoronary Antiarrhythmic Drugs to Identify the Ventricular Tachycardia-Related Artery

Identifying the Tachycardia-Related Coronary Artery. Introduction: Transcatheter chemical ablation is a new treatment option for patients with ventricular tachycardia. Availability of a safe, simple, and sensitive method to identify the ventricular tachycardia-related artery is required for successful intracoronary chemical ablation for ventricular tachycardia. The purpose of this study was to compare bolus intracoronary iced saline injection to bolus intracoronary antiarrhythmic drug injection as methods for identifying the ventricular tachycardia-related coronary artery. Methods and Results: Patient selection was limited to eight individuals with recurrent sustained monomorphic ventricular tachycardia, coronary artery disease, remote myocardial infarction, and in whom programmed stimulation could reproducihiy induce the clinical arrhythmia. An infusion catheter was positioned in the putative ventricular tachycardia-related artery and ventricular tachycardia was provoked hy programmed stimulation. In four patients the putative ventricular tachycardia-related artery was a patent infarct-related vessel and in the other four patients was a vessel supplying collateral flow to an occluded infarct-related artery. The effects of selective intracoronary iced saline bolus injection (10 mL), and then of selective intracoronary bolus antiarrhythmic drug injection (2.5 mg lidocaine in one patient, procainamide 1.0–9.0 mg in seven patients) were observed. Bolus intracoronary iced saline injection did not alter ventricular tachycardia in any patient. Bolus intracoronary antiarrhythmic drug injection, however, led to ventricular tachycardia cycle length prolongation in two patients and arrhythmia termination in four patients. In two of these individuals, infusion of ethanol into the tachycardia-related vessel previously identified by intracoronary drug injection resulted in ablation of the ventricular tachycardia. Conclusions: In the present study, selective intracoronary antiarrhythmic drug injection appeared to be more effective than intracoronary iced saline for identifying the ventricular Uchycardia-related coronary artery, (J Cardiovasc Electrophysiol, Vol. 3, pp. 199–208 June 1992)     

Antidromic atrioventricular reentrant tachycardia mimicking ventricular tachycardia in the setting of previous myocardial infarction

The differentiation between ventricular tachycardia and broad-complex supraventricular tachycardia can be extremely difficult, particularly in emergency situations. We report a case of hemodynamically compromising broad-complex tachycardia in a 63-year-old man. The patient had previously sustained an anteroseptal myocardial infarction and had subsequently undergone coronary artery bypass surgery because of triple-vessel coronary artery disease. Intravenous treatment with ajmalin terminated the tachycardia and revealed preexcited QRS complexes compatible with the presence of a left-sided atrioventricular accessory pathway. An antidromic atrioventricular reentrant tachycardia (identical to the clinical tachycardia) was induced during an electrophysiologic study. In conclusion, there are several causes of broad-complex tachycardia, even in patients with previous myocardial infarction, and, where doubt exists, electrophysiologic studies should be performed.     

Epicardial idiopathic ventricular tachycardia originating within the left main coronary artery ostium area: identification using the LocaLisa nonfluoroscopic catheter navigation system

Idiopathic ventricular tachycardia (IVT) in patients without structural heart disease commonly arises from the right or left outflow tracts, but there remain arrhythmias that can only be ablated by an epicardial approach. We report a case of an epicardial ventricular tachycardia originating within the left main coronary artery ostium area, as identified using the LocaLisa nonfluoroscopic catheter navigation system. Due to the high risk of coronary artery thrombosis, ventricular tachycardia was successfully ablated by a transthoracic surgical approach using cryoenergy. Ventricular ectopy disappeared and ventricular tachycardia did not recur during long-term follow-up.     

Ventricular Tachycardia After Myocardial Infarction: From Arrhythmia Surgery to Catheter Ablation

Ablation of Ventricular Tachycardia. Ventricular tachycardia due to prior myocardial infarction is caused by reentry. Intraoperative mapping at the time of arrhythmia surgery has shown that the reentry circuits arc diverse in size and location. Many circuits are large, extending over several square centimeters. Endocardial excision guided by activation sequence mapping, fractionated sinus rhythm electrograms, or visual identification of scarred subendo-cardium renders 69% to 95% of patients free from inducible ventricular tachycardia, but with an operative mortality that exceeds 8%, at most centers. Catheter ablation is difficult due to limitations of catheter mapping, relatively small size of lesions produced with current techniques, and limited access to intramural and epicardial portions of the reentry circuits. Many problems need to be overcome for catheter ablation to achieve success comparable to that of surgery. At present, only hemodynamically tolerated ventricular tachycardias can he mapped. Progress is being made, and it is likely that catheter ablation will become a viable therapy for subgroups of patients with postmyocardial infarction ventricular tachycardia.     

Ventricular arrhythmias in ischemic heart disease

Ventricular arrhythmias remain the leading cause of death from coronary artery disease. This review summarizes current thinking in several areas relating to the pathophysiology, prognosis, and therapy of ventricular arrhythmias associated with acute and chronic coronary artery disease syndromes. The experimental basis of arrhythmias in the setting of acute myocardial ischemia and chronic myocardial infarction is described, stressing the important pathophysiologic differences between these two conditions. The effects of the autonomic nervous system as a key modulator of ischemic arrhythmogenesis are discussed. Insights, derived from endocardial mapping studies, into the nature of ventricular tachycardia in humans with chronic myocardial infarction are described, including implications for risk stratification and therapy to prevent arrhythmia recurrence. Current therapeutic principles are discussed in the management of ventricular arrhythmias associated with coronary artery disease, including pharmacologic approaches, surgical and catheter ablation, and automatic implantable cardioverting and defibrillating devices.     

Catheter ablation and antiarrhythmic drugs for haemodynamically tolerated post-infarction ventricular tachycardia; long-term outcome in relation to acute electrophysiological findings.

AIMS: Radiofrequency catheter ablation is effective at terminating ventricular tachycardia, but the overall clinical role of the technique in patients with a prior myocardial infarction is still debated, due to the uncertainties of the long-term reliability of the procedure. The purpose of this study was to prospectively investigate the relationship between acute results obtained by catheter ablation and long-term outcome in a homogeneous population of patients with post-myocardial infarction ventricular tachycardia. METHODS AND RESULTS: One hundred and twenty-four consecutive patients with recurrent, drug-refractory, haemodynamically tolerated ventricular tachycardia were included in the study. This population accounted for 30% of the patients with post-myocardial infarction ventricular tachycardia admitted between April 1992 and September 1997 to the investigating centres. The ablation was successful in eliminating sustained ventricular tachycardia in 91 of them (73%); a partial result was obtained in 21 (17%) and failure in 12 (10%). Low dose amiodarone and/or beta-blockers were maintained in 86% of the patients. Over a median follow-up of 41.5 months (interquartile range 30.5-59.5 months), there were 15 deaths (12%), three of which were sudden (2.4%); the 12 remaining patients died of heart failure. Event-free survival analysis showed a significantly lower ventricular tachycardia recurrence rate in patients with a successful procedure as compared to those with failure or a partial result (19% vs 53% at one year and 27% vs 60% at 3 years, P=0.003). A repeat procedure was performed in 15 patients with early recurrences and was followed in all by long-term success. Of those who submitted to a second procedure, 93/124 patients (75%) are free of ventricular tachycardia recurrences. An implantable cardioverter-defibrillator (ICD), following procedure failure, was implanted in 13 patients (11%) of the study population. CONCLUSIONS: Radiofrequency catheter ablation is effective in a wide population of patients with recurrent tolerated ventricular tachycardia, with very low sudden death and cardiac mortality rates over the long-term. Persistent ventricular tachycardia inducibility after catheter ablation requires an ICD implant and/or repeat ablation.     

Inducible ventricular flutter and fibrillation predict for arrhythmia occurrence in coronary artery disease patients presenting with syncope of unknown origin

INTRODUCTION: Ventricular fibrillation and ventricular flutter (cycle length < or = 230 msec) induced at electrophysiologic studies are thought to be nonspecific findings in patients presenting with syncope of unknown origin. However, there are limited data on the prognosis of these patients in long-term follow-up. METHODS AND RESULTS: We followed 274 consecutive patients with coronary artery disease presenting with syncope or presyncope who underwent electrophysiologic studies from January 1992 to June 1999 and assessed the risk of subsequent arrhythmias stratified by the electrophysiologic result at the time of their presentation with syncope. Ventricular fibrillation was induced in 23 patients (8%); ventricular flutter in 24 (9%), sustained ventricular tachycardia in 41 (15%); and nonsustained ventricular tachycardia 42 (15%). In 37 +/- 25 months of follow-up, there have been ventricular arrhythmias in 34 patients, including 3 (13%) of 23 who had induced ventricular fibrillation, and 7 (30%) of 24 with induced ventricular flutter, compared to 13 (32%) of 41 with sustained ventricular tachycardia, 7 (17%) of 42 with nonsustained ventricular tachycardia, and only 4 (3%) of 144 noninducible patients (P < 0.001 for induced ventricular fibrillation and ventricular flutter vs noninducible patients). The inducibility of ventricular fibrillation and ventricular flutter were independent risk factors for arrhythmia occurrence in follow-up. CONCLUSION: Ventricular fibrillation and ventricular flutter induced at electrophysiologic studies have prognostic significance for arrhythmia occurrence in patients presenting with syncope. These induced arrhythmias may not be as nonspecific as previously thought and treatment should be considered for these patients.     

经皮穿刺心外膜电-解剖标测及射频消融心肌梗死后室性心动过速的实验研究

目的探讨经心外膜途径在电-解剖标测系统指导下行射频消融治疗心肌梗死后室性心动过速的可行性和安全性。方法成年中华小型猪共7只,采用经皮穿刺的方法将球囊置于左前降支中下部,封堵150 min建立心肌梗死模型。3～5周后将心肌梗死模型猪,行电生理检查诱发室性心动过速。经胸穿刺进入心包腔,采用电-解剖标测系统在窦性心律下进行心外膜电压标测和线性消融。射频消融后再次行电生理检查,不能再诱发室性心动过速为消融成功。结果存活的心肌梗死模型的猪7只,3～5周后行电生理检查,共诱发出单形性室性心动过速共8种,7种表现为右束支阻滞图形,1种表现为左束支阻滞图形,室性心动过速(VT)周长平均在(338±66)ms。1只猪同时诱发心室颤动,电除颤转复窦性心律。7只猪心包穿刺均成功,完成心外膜电压标测,沿瘢痕区到二尖瓣环或正常心肌区逐点进行线性消融。射频消融后再次行电生理检查,6只猪不能再诱发室性心动过速。结论经胸穿刺进入心包腔行心外膜标测和消融治疗心肌梗死后室速的方法是安全可行的,心外膜标测消融心肌梗死后室速的方法可以作为心内膜消融的一种有效补充方法。     

Left ventricular aneurysm without coronary artery disease, incidence and clinical features: clinical analysis of 11 cases

OBJECTIVE: To examine the incidence, underlying disease and clinical features of left ventricular aneurysm (LVA) not related to coronary artery occlusion. METHODS: Retrospective review of consecutive patients who underwent both left ventriculography and coronary angiography. PATIENTS: LVA was confirmed in 11 of 2,348 consecutive patients (0.47%). RESULTS: The location of LVA was mainly in the apical region (81.8%). In five of the 11 patients (45.5%), the underlying heart disease was hypertrophic cardiomyopathy (HCM), including 4 patients of dilated phase and one patient of midventricular type. The serial ECG changes from left ventricular hypertrophy to abnormal Q wave and endomyocardial biopsy were useful for the differential diagnosis of these cases against myocardial infarction. The underlying disease of the remaining patients was: myocarditis (2 patients), arrhythmogenic right ventricular dysplasia (1 patient), Chagas' disease (1 patient), glycogen storage disease (1 patient), and sarcoidosis (1 patient). Ventricular tachycardia appeared in 9 of 11 cases (81.8%) including 2 patients with sustained ventricular tachycardia. CONCLUSION: LVA formation without coronary artery disease was a rare phenomenon. The underlying disease was varied but the incidence of hypertrophic cardiomyopathy in the dilated phase was comparatively high. Ventricular tachycardia was a significant complication in these patients.     

Catheter Ablation with Radiofrequency Energy: Biophysical Aspects and Clinical Applications

Radiofrequency Catheter Ablation. Radiofrequency catheter ablation techniques are becoming increasingly accepted as the therapy of choice for selected patients with symptomatic arrhythmias. The ability to titrate the power output using radiofrequency current has allowed these ablative techniques to be applied safely in a variety of arrhythmias. In many institutions, radiofrequency catheter ablation has now become standard therapy for controlling medically refractory atrial arrhythmias using atrioventricular (AV) junction ablation and for curing AV nodal reentrant tachycardia and supra ventricular tachycardia due to accessory AV connections. This technology is also being used to treat some forms of ventricular tachycardia such as bundle branch reentry ventricular tachycardia, ventricular tachycardia in structurally normal hearts, and with limited success in patients with ventricular tachycardia and coronary artery disease. Advancements in catheter design and energy delivery systems may further expand the use of this form of therapy. (J Cardiovasc Electrophysiol, Vol. 3, pp. 173–186, April 1992)     

Clinical significance and characteristics of exercise-induced ventricular tachycardia

Forty-seven patients (0.08%) from a total of 5,730 consecutive patients undergoing treadmill stress tests developed one or more episodes of ventricular tachycardia. Forty patients had heart disease, coronary artery disease being the leading cause. Rest ECG was normal in 12 patients and showed long QT (>440 msec) in 16 patients. Ventricular tachycardia was brief and self-terminating, requiring D/C cardloverston In only one patient. “Exertional hypotension” preceded ventricular tachycardia In 16 of 34 patients. There was poor correlation (r=0.16) between the rate of ventricular tachycardia (VT) and the underlying heart rate. Only four episodes of VT were Initiated by R on T premature ventricular beats. In summary, exercise-Induced ventricular tachycardia 1) Is a rare complication of treadmill stress test and occurs In patients with heart disease; 2) is frequently preceded by “exertional hypotension;” and 3) Is not related to the R on T phenomenon. The high incidence of prolonged QT may indicate a role for the autonomic nervous system in its pathogenesis.     

Catheter Ablation of Recurrent Scar-Related Ventricular Tachycardia Using Electroanatomical Mapping and Irrigated Ablation Technology: Results of the Prospective Multicenter Euro-VT-Study

Catheter Ablation of Ventricular Tachycardia.   Introduction: Ventricular tachycardia (VT) late after myocardial infarction is an important contributor to morbidity and mortality. This prospective multicenter study assessed the efficacy and safety of electroanatomical mapping in combination with open-saline irrigated ablation technology for ablation of chronic recurrent mappable and unmappable VT in remote myocardial infarction.
Methods and Results: In 8 European institutions, 63 patients (89% males) were enrolled in the study. All patients had remote myocardial infarction and presented with a median number of 17 (range 1–380) VTs in the preceding 6 months. Incessant VT was present in 14 patients (22%). Left ventricular ejection fraction measured 30 ± 13%. A mean of 3 VTs were targeted per patient and 22% of all patients had only unmappable VT. The mean follow-up period was 12 ± 3 months. A total of 164 VTs were targeted during catheter ablation. Ablation was acutely successful in 51 patients (81%). One patient (1.5%) experienced a major complication with degeneration of VT into ventricular fibrillation necessitating cardiopulmonary resuscitation maneuvers. However, no death occurred acutely or within the first 30 days after catheter ablation. During the follow-up, 19 of the initially successful ablated patients (37%) and 31 of all ablated patients (49%) developed some type of VT recurrence.
Conclusions: The results of this multicenter study demonstrate the high acute success rate and a low complication rate of irrigated tip catheter ablation of all clinical relevant VTs in remote myocardial infarction. However, during the follow-up a relevant number of recurrences occurred. (J Cardiovasc Electrophysiol, Vol. 21, pp. 47–53, January 2010)     

微伏级T波电交替与室性心动过速的临床研究

目的室性心动过速（室速）是器质性心脏病猝死的主要机制.微伏级T波电交替（microvolt T wave alternans,MTWA）是近年来无创评价和预测室速/心室颤动（室颤）及心脏性猝死的新方法.本研究的目的是探讨MTWA与室速的关系及其临床意义.方法用system剑桥心脏诊断系统（Cambridge Heart.Heartwave^TM）,以频谱法检测45例健康志愿者及82例可疑室性心律失常者（其中有资料记载的室速48例）的MTWA.结果MTWA阳性主要见于陈旧性心肌梗死、冠心病、心肌病等,它与室速有一定的相关性（r=0.37,P＜0.01）.器质性心脏病室速组MTWA阳性率高于非器质性心脏病室速组（P＜0.01）,非器质性心脏病室速组MTWA阳性率与健康人组差异无统计学意义（P＞0.05）.MTWA诊断器质性心脏病室速的敏感性75.00%,特异性92.10%,诊断符合率87.03%.结论MTWA与器质性心脏病室速相关,可用于室速患者的危险分层.     

Catheter Ablation of Ventricular Tachycardia Induced by Injection of Acetylcholine in the Right Coronary Artery

Ventricular Tachycardia Induced by Acetylcholine. We report the case of a patient who suffered from early morning nonsustained ventricular tachycardia. Clinical ventricular tachycardia without coronary spasm was reproducibly induced only by injection of acetylcholine in the right coronary artery. A good pace mapping site with 30 ms early ventricular activity was present in the right ventricular free wall. After radiofrequency ablation based on electroanatomical mapping, the tachycardia could no longer be induced by intracoronary injection of acetylcholine. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1410‐1412, December 2010)     

The role of collateral blood supply in ventricular tachycardia after myocardial infarcation

The hypothesis that collateral or anterograde blood supply toan infarcted area maintains blood supply to cells responsiblefor ventricular tachycardia after myocardial infarction wasstudied in six patients. All patients had suffered a myocardialinfarction and developed spontaneous episodes of sustained monomorphicventricular tachycardia. The arrhythmia was paroxysmal in threepatients and incessant in the other three. During ventriculartachycardia iced isotonic saline (10 ml in approximately 4 s)was injected first in the coronary artery ostia and thereaftersuperselectively in the coronary artery providing collateralor anterograde blood supply to the infarcted area. A 2.5-F catheterwas used superselectively to catheterize coronary arteries ofapproximately 2–3 mm lumen for that purpose. Three patientshad anterograde blood supply to the infarcted area through areperfused infarct-related vessel. Two patients had only collateralretrograde blood supply to the infarcted region. One patienthad both anterograde and retrograde collateral blood supplyto the area of infarction. Ventricular tachycardia was not terminatedin any patient during non-selective injection of iced salinein the coronary ostia. In five of the six patients ventriculartachycardia was terminated by the super-selective administrationof iced saline. The morphology of ventricular tachycardia waschanged many times, but did not terminate, in the remainingpatient. Termination or change in morphology was achieved duringadministration of iced saline through collateral vessels intwo patients through the coronary artery supplying anterogradeflow in three patients and both through collaterals and anterogradeflow in the remaining patient. It is concluded that collaterolvessels or anterograde flow through the infarct-related vesselmaintain the viability of electrically normal, but electricallybadly coupled, cells responsible for ventricular tachycardiaafter myocardial infarction.     

Induction of transient third degree atrioventricular block during radiofrequency catheter ablation in a patient with ventricular tachycardia and remote myocardial infarction

INTRODUCTION: Radiofrequency catheter ablation has been demonstrated to bean effective and safe therapy in patients with so-called idiopathicventricular tachycardia, whereas the benefit/risk profile forablation of ventricular tachycardia in patients with chronicmyocardial infarction and severely compromised left ventricularfunction still needs to be determined. The present report describesthe unintended induction of transient third-degree atrioventricularblock in a patient with remote myocardial infarction who underwentradiofrequency catheter ablation of ventricular tachycardia. METHODS AND RESULTS: Endocardial catheter mapping and radiofrequency ablation wereperformed in a 57-year-old patient with chronic recurrent ventriculartachycardia, who had previously suffered from anterior and posteriorwall myocardial infarction. Additionally, the patient presentedwith complete right bundle branch block during sinus rhythm.Radiofrequency energy applied to a critical site of the reentranttachycardia at the left ventricular basal septum during sinusrhythm induced third-degree atrioventricular block after 20s of current delivery, which lasted for 24 h. At this site,a presumable left bundle branch potential was recorded duringsinus rhythm. CONCLUSIONS: Radiofrequency current application for ablation of ventriculartachycardia may induce third-degree atrioventricular block inpatients with remote myocardial infarction. When current isdelivered to target sites at the left ventricular basal septum,radiofrequency energy should be applied during sinus rhythmto allow continuous monitoring of atrioventricular conduction.Special caution should be given to patients with right bundlebranch block during sinus rhythm.     

Clinical Results with Catheter Ablation: AV Junction, Atrial Fibrillation and Ventricular Tachycardia

With the limitations of pharmacologic and device therapies for atrial fibrillation and ventricular tachycardia, catheter ablation is assuming a larger role in the management of patients with these common arrhythmias. Multiple case series and clinical trials have helped to define the evolving role of these techniques for ablation of the atrioventricular node, atrial fibrillation, and ischemic ventricular tachycardia. Based on very low complication rates, excellent efficacy and proven outcomes with radiofrequency ablation of the atrioventricular node, this approach with permanent pacing should play a larger role in the treatment of symptomatic patients with permanent atrial fibrillation. While linear ablation of atrial fibrillation has limited clinical utility for the treatment of this common arrhythmia, the results of multiple case series of focal atrial fibrillation ablation indicate the potential for an expanding role of this curative technique. Catheter ablation techniques for ventricular tachycardia in the setting of coronary artery disease have a role as supplemental therapy to the implantable cardioverter defibrillator in patients with recurrent pharmacologically refractory ventricular arrhythmias requiring frequent device interventions.     

Serial ambulatory monitoring in patients with unstable angina pectoris

We performed a prospective study by dual-channel ambulatory monitoring performed for 24 to 72 hours immediately after hospitalization for unstable angina. The incidence of ST-segment depression or elevation or ventricular tachycardia or complex premature ventricular complexes (PVCs) in 42 consecutive patients with unstable angina due to coronary artery disease (39 by coronary arteriography) was investigated. During ambulatory monitoring, 28 of 42 patients (67%) exhibited ST-segment depression or elevation, 13 of 42 patients (31%) had ventricular tachycardia or complex PVCs, and 31 of 42 patients (74%) had either ST-segment depression or elevation, ventricular tachycardia, or complex PVCs. Ventricular tachycardia or complex PVCs occurred in 10 of 20 patients (50%) with abnormal left ventricular function and in 3 of 22 patients (14%) with normal left ventricular function (p less than 0.025). We found that 72 hours of ambulatory monitoring was not more useful than 48 hours in detecting the incidence of ST-segment depression or elevation, ventricular tachycardia, or complex PVCs. Ambulatory monitoring did not help in clinically differentiating patients with left main or 3-vessel disease from 1-vessel or 2-vessel disease. In addition, ambulatory monitoring did not help in predicting which patients with unstable angina would require coronary artery surgery.     

Focal right ventricular tachycardia originating from the subtricuspid septum.

Ventricular tachycardia originating from the right ventricular septum is very uncommon. In a 54-year-old male patient with right ventricular tachycardia, the focus of the ventricular tachycardia was localized to the subtricuspid septum of the right ventricle, which could be successfully eliminated with radiofrequency catheter ablation. The patient's echocardiogram and coronary angiogram were normal. The available literature on idiopathic right ventricular tachycardia is reviewed.