Noninvasive programmed stimulation in the setting of ventricular tachycardia catheter ablation

In the setting of catheter ablation of ventricular tachycardia (VT), invasive programmed ventricular stimulation (PVS) is considered an important tool to assess the (residual) inducibility of ventricular arrhythmias and determine the acute success of the procedure. In patients with cardiovascular implantable electronic devices, noninvasive programmed stimulation via implantable cardioverter‐defibrillator (ICD) leads can be an alternative to the invasive PVS with intracardiac catheters. The advantages of noninvasive programmed stimulation include preprocedure planning of the electrophysiology procedure to ensure optimal conditions for successful catheter ablation of VT. Following the procedure, noninvasive programmed stimulation has been shown to be used as a guide for repeat early ablation, to offer better programming of ICD, to offer prognostic value regarding the VT recurrence, and to guide antiarrhythmic drug therapy. The noninvasive nature of noninvasive programmed stimulation makes it an attractive alternative to PVS in patients with ICD who have not undergone catheter ablation of VT to obtain prognostic value regarding the occurrence of VT.     

Devices for the management of ventricular arrhythmias in cardiac failure

Heart failure is a common clinical syndrome with a high morbidity and mortality. Despite advances in medical treatment, death from dangerous ventricular arrhythmias is frequently implicated. Emerging evidence supports the use of the implantable cardioverter defibrillator for selected patients. This includes secondary prevention indications for patients who have survived life-threatening ventricular arrhythmias. In addition, patients who have not suffered spontaneous sustained ventricular arrhythmias, but who are at high risk for sudden arrhythmic death are starting to be recognized as candidates for ICD therapy. At present the only primary prevention indication with a good evidence base is the presence of inducible ventricular arrhythmias at electrophysiologic testing in patients with prior myocardial infarction, impaired left ventricular systolic function and non-sustained ventricular tachycardia on Holter monitoring. Studies planned or in progress are likely to expand further the role of device therapy in the treatment of patients with cardiac failure.     

Programmed ventricular stimulation after myocardial infarction does not help reduce the risk of ventricular events

Summary Programmed ventricular stimulation could be a useful technique to detect patients at high risk for ventricular arrhythmias and sudden death after acute myocardial infarction. However, prevention of arrhythmic events using this technique has never been demonstrated. To determine whether prophylactic antiarrhythmic therapy influences prognosis after acute myocardial infarction, 196 patients without spontaneous ventricular tachycardia (VT) but with inducible sustained monomorphic VT were followed for 3±1 years. Ninety-seven patients were not treated (control group). In 99 patients (study group), the antiarrhythmic therapy was guided by electrophysiologic study: One to four trials using class I, II, and III antiarrhythmic drugs were performed until the VT was not inducible or the induced VT was slower and was associated with hemodynamic stability. An effective antiarrhythmic drug prevented VT induction in 34 patients (34%; group I). Sixty-five patients (group II) still had inducible VT with the antiarrhythmic drug. Group II differed from group I in having a higher incidence of an inferior myocardial infarction location (57% vs. 47%; NS), a lower left ventricular ejection fraction (36.5% vs. 41%; NS), a slower rate of induced VT in the control state (227 vs. 255 beats/min; p<0.05), and a higher number of drug trials (1.9 vs. 1.3; p<0.001). During the follow-up in the control group and in groups I and II, the incidence of total cardiac events was 25%, 15%, and 16% (NS), respectively, and the incidence of total arrhythmic events (VT, sudden death) was 18.5%, 9%, and 12% (NS). Only the risk of VT was reduced (14%, 0%, and 4%; p<0.05). In conclusion, guided-antiarrhythmic therapy, including class III agents after acute myocardial infarction, was successful in only 34% of patients, and the incidence of arrhythmic events was not significantly decreased. Therefore, programmed ventricular stimulation does not help in managing patients at risk of ventricular arrhythmia after myocardial infarction but could help to indicate the need for nonmedical treatment, such as device therapy.     

室性心律失常的治疗进展

Ventricular arrhythmias(VA)include premature ventricular contractions(PVC),ventricular tachycardia(VT),ventricular flutter or defibrillation(VFL/VF).Although commonly related to structural heart disease,a significant percentage of VA are idiopathic(occurring in patients with otherwise normal hearts).Classic antiarrhythmic drugs(AADs)for VA have limited effectiveness,and pose the risk of life-threatening VT/VF.Very few AADs have been successful in the last few decades,due to safety concerns or limited benefits in comparison to existing therapy.Amiodarone has emerged as the leading antiarrhythmic therapy for termination and prevention of VA in different clinical settings because of its proven efficacy and safety.For VT/VF,implantable cardioverter defibrillator(ICD)appear to be the unique,yet unsatisfactory,solution.Indications for ICD have evolved considerably from initial implantation exclusively in patients who had survived one or more cardiac arrests and failed pharmacological therapy.Multipie clinical trials have established that ICD use results in improved survival compared with antiarrhythmic agents for secondary prevention of sudden cardiac death(SCD).Large prospective,randomized,multicenter studies have also demonstrated that ICD therapy is effective for primary prevention of sudden death and improves total survival in selected patient populations who have not previously had a cardiac arrest or sustained VT.Catheter ablation is now an important option to control recurrent VT.The field has evolved rapidly and is a work in progress.Ablation is often a sole therapy of VT in patients without structural heart disease and is commonly combined with an ICD and/or antiarrhythmic therapy for scar-related VT associated with structural heart disense.     

Dofetilide reduces the frequency of ventricular arrhythmias and implantable cardioverter defibrillator therapies

Dofetilide Reduces VT/VF and ICD Therapies . Background: Patients with an implanted cardioverter defibrillator (ICD) and ventricular arrhythmias leading to ICD therapies have poor clinical outcomes and quality of life. Antiarrhythmic agents and catheter ablation are needed to control these arrhythmias. Dofetilide has only been approved for the treatment of atrial fibrillation. The role of dofetilide in the control of ventricular arrhythmias in patients with an ICD has not been established. Objective: Evaluate the safety and efficacy of dofetilide in a consecutive group of patients with an ICD and recurrent ventricular tachycardia (VT) and/ or ventricular fibrillation (VF) after other antiarrhythmic drugs have failed to suppress these arrhythmias. Methods: We studied 30 patients (age 59 ± 11; 5 women) with symptomatic VT or VF and ICDs for secondary prevention of sudden cardiac death. These patients had an average of 1.8 ± 4.5 episodes of VT/VF per month despite antiarrhymic therapy. Twenty‐one patients (70%) had recurrent appropriate ICD therapies prior to initiation of dofetilide, and 9 (30%) VTs below the programmed detection rate of the ICD. Twenty‐three patients (77%) had coronary artery disease. Mean ejection fraction was 30 ± 14% and 26/30 (87%) had congestive heart failure. All patients had previously failed 2 ± 1 antiarrhythmic drugs including amiodarone (n = 19) and sotalol (n = 10). Results: During the first month of treatment, 25 patients (83%) had complete suppression of VT/VF and of the 21 patients with ICD therapies 16 (76%) had no therapies during the first month of treatment. During a follow‐up period of 32 ± 32 months, dofetilide reduced the monthly episodes of VT/VF from 1.8 ± 4.5 to 1.0 ± 3.5 (P = 0.006). Monthly ICD therapies decreased from 0.9 ± 1.4 to 0.4 ± 1.7 (P = 0.037). In 9 patients that presented with slow VTs under the ICD detection zone, dofetilide reduced monthly VT/VF episodes from 0.7 ± 0.6 to 0.1 ± 0.1 (P = 0.01) and 6 (67%) had no further ICD therapies. Dofetilide was discontinued in 13 patients (43%) after 24 ± 30 months due to failure to control VT/VF (n = 7), placement of a left ventricular assist device (n = 3), catheter ablation (n = 1), heart transplantation (n = 1), and left ventricular restoration surgery (n = 1). There were 7 documented deaths (2 patients died suddenly; 3 patients of progressive heart failure; and 2 of non‐cardiac causes). Conclusions: In patients with an ICD and ventricular arrhythmias, dofetilide decreases the frequency of VT/VF and ICD therapies even when other antiarrhythmic agents, including amiodarone, have previously been ineffective. Recurrences still occur in some patients requiring catheter ablation, mechanical support, or heart transplantation. (J Cardiovasc Electrophysiol, Vol. 23 p. 296‐301, March 2012.)     

Importance of the atrial channel for ventricular arrhythmia therapy in the dual chamber implantable cardioverter defibrillator

INTRODUCTION: Performance of dual chamber implantable cardioverter defibrillator (ICD) systems has been judged based on functioning of the ventricular tachycardia:supraventricular tachycardia (VT:SVT) discrimination criteria and DDD pacing. The purpose of this study was to evaluate the use of dual chamber diagnostics to improve the electrical and antiarrhythmic therapy of ventricular arrhythmias. METHODS AND RESULTS: Information about atrial and ventricular rhythm in relation to ventricular arrhythmia occurrence and therapy was evaluated in 724 spontaneous arrhythmia episodes detected and treated by three types of dual chamber ICDs in 41 patients with structural heart disease. Device programming was based on clinically documented and induced ventricular arrhythmias. In ambulatory patients, sinus tachycardia preceded ventricular arrhythmias more often than in the hospital during exercise testing. The incidence of these VTs could be reduced by increasing the dose of a beta-blocking agent in only two patients. In five patients in whom sinus tachycardia developed after onset of hemodynamic stable VT, propranolol was more effective than Class III antiarrhythmics combined with another beta-blocking agent with regard to the incidence of VT and pace termination. In all but three cases, atrial arrhythmias were present for a longer time before the onset of ventricular arrhythmias. During atrial arrhythmias, fast ventricular rates before the onset of ventricular rate were observed more often than RR irregularities and short-long RR sequences. Dual chamber diagnostics allowed proper interpretation of detection and therapy outcome in patients with different types of ventricular arrhythmia. CONCLUSION: The advantages of the dual chamber ICD system go further than avoiding the shortcomings of the single chamber system. Information from the atrial chamber allows better device programming and individualization of drug therapy for ventricular arrhythmia.     

Analysis of implantable cardioverter defibrillator therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial

INTRODUCTION: The implantable cardioverter defibrillator (ICD) is commonly used to treat patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia recurrence rates in these patients are high, but which patients will receive a therapy and the forms of arrhythmia recurrence (VT or VF) are poorly understood. METHODS AND RESULTS: The therapy delivered by the ICD was examined in 449 patients randomized to ICD therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. Events triggering ICD shocks or antitachycardia pacing (ATP) were reviewed for arrhythmia diagnosis, clinical symptoms, activity at the onset of the arrhythmia, and appropriateness and results of therapy. Both shock and ATP therapies were frequent by 2 years, with 68% of patients receiving some therapy or having an arrhythmic death. An appropriate shock was delivered in 53% of patients, and ATP was delivered in 68% of patients who had ATP activated. The first arrhythmia treated in follow-up was diagnosed as VT (63%), VF (13%), supraventricular tachycardia (18%), unknown arrhythmia (3%), or due to ICD malfunction or inappropriate sensing (3%). Acceleration of an arrhythmia by the ICD occurred in 8% of patients who received any therapy. No physical activity consistently preceded arrhythmias, nor did any single clinical factor predict the symptoms of the arrhythmia. CONCLUSION: Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided.     

Implantable cardioverter defibrillator shocks from ventricular tachyarrhythmias in patients with ischemic heart disease: Preventative measures,shortcomings, cost-effectiveness,and global practice perspectives

Implantable cardioverter defibrillators (ICDs) have proven to be life-saving devices in patients with ischemic cardiomyopathy (ICM) who are prone to develop ventricular tachycardia (VT) and fibrillation (VF). Antiarrhythmic drugs (AADs) are commonly prescribed in many such patients with ICDs to treat and prevent different forms of arrhythmias in clinical practice. When these patients experience recurrent monomorphic VT despite chronic AADs therapy, or when AAD therapy is contraindicated or not tolerated, and VT storm is refractory to AAD therapy, catheter ablation constitute guideline-based class I indication of treatment. However, what should be the most appropriate strategy to prevent first ICD shock or subsequent multiple shocks from VT/VF in patients with ICM who undergo ICD implantation without prior incidence of cardiac arrest, remains debatable. The purpose of this review is to discuss preventative aspects of ICD shocks for VT and the shortcomings of these measures along with the cost-effectiveness and global perspectives based on the current knowledge of the topic.     

Combining Antiarrhythmic Drugs and Implantable Devices Therapy: Benefits and Outcome

At least 50% of patients who received an ICD have been treated with antiarrhythmic drugs (AAD). The potential indications for combining antiarrhythmic drugs and ICD are generally the following: reduction of the number of episodes of ventricular tachycardia or ventricular fibrillation and therefore of the number of shocks, improving patient's quality of life and extending the battery life of the ICD, prevention of supraventricular arrhythmias and/or control of their rate, lengthening of the tachycardia cycle length to allow ventricular tachycardia conversion by antitachycardia pacing and reduction of the number of episodes of syncope.Although previous papers reported conflicting results about pharmacologic therapy in reducing the frequency of iCD shocks, some recent randomized prospective studies showed the efficacy of pharmacologic therapy in reducing the frequency of ICD shocks.The use of antiarrhythmic drugs can have also adverse effect: an increase in the defibrillation threshold, an increase in the pacing threshold and an increase in the VT cycle length leading to detection failure. We have also to consider that some advantages derived from antiarrhythmic drugs can be reached by the new devices with atrial sensing and pacing and/or the possibility of atrial defibrillation or by using catheter ablation as adjunctive therapy to ICD.For these reasons, the concomitant use of antiarrhythmic drugs and ICD should be evaluated in each patient in relation to specific clinical and electrophysiologic features including: the frequency, the rate and the clinical presentation of the ventricular arrhythmia, the effect of the selected drug on the defibrillation threshold, the defibrillation threshold at the implant, the effect of the selected drug on the ventricular function and the likelihood of proarrhythmic events.     

第四代埋藏式自动复律除颤器的临床应用

2例冠心病,陈旧心肌梗塞并持续室性心动过速的病人,服用2～3种抗心律失常药无效而考虑埋藏式自动复律除颤器(ICD)治疗.术前电生理检查均诱发了持续室速,并了解了诱发和终止条件.经锁骨下静脉穿刺安装了第四代ICD.术后随访7～12个月中,2例均有室速发作而正确放电,但1例有窦性心动过速被误感知现象,经程序调整而消失.本文强调了适应症选择,术前电生理检查和术后随访的重要性.     

Comparison of arrhythmia recurrence in patients presenting with ventricular fibrillation versus ventricular tachycardia in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial

Because many episodes of ventricular fibrillation (VF) are believed to be triggered by ventricular tachycardia (VT), patients who present with VT or VF are usually grouped together in discussions of natural history and treatment. However, there are significant differences in the clinical profiles of these 2 patient groups, and some studies have suggested differences in their response to therapy. We examined arrhythmias occurring spontaneously in 449 patients assigned to implantable cardioverter-defibrillator (ICD) therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial to determine whether patients who receive an ICD after VT have arrhythmias during follow-up that are different from patients who present with VF. ICD printouts were analyzed both by a committee blinded to the patients' original presenting arrhythmia and by the local investigator. During 31 +/- 14 months of follow-up, 2,673 therapies were reported. Patients who were enrolled in the AVID trial after an episode of VT were more likely to have an episode of VT (73.5% vs 30.1%, p <0.001), and were less likely to have an episode of VF (18.3% vs 28.0%, p = 0.013) than patients enrolled after an episode of VF. Adjustment for differences in ejection fraction, previous infarction, and beta-blocker and antiarrhythmic therapy did not appreciably change the results. Ventricular arrhythmia recurrence during follow-up is different in patients who originally present with VT than in those who originally present with VF. These findings suggest there are important differences in the electrophysiologic characteristics of these 2 patient populations.     

Prevalence, predictors, and mortality significance of the causative arrhythmia in patients with electrical storm

INTRODUCTION: Electrical storm (ES) is characterized by either refractory ventricular tachycardia (VT) or ventricular fibrillation (VF). However, little is known about the prevalence, predictors, and mortality implications of the causative arrhythmia in ES. We sought to assess the prevalence, predictors, and survival significance of VT and VF as the causative arrhythmia of ES in implantable cardioverter defibrillator (ICD) patients. METHODS AND RESULTS: Consecutive patients from January 2000 to December 2002 who presented to the ICD clinic with > or = 2 separate ventricular arrhythmic episodes requiring shock within 24 hours were included in the study. ICD interrogation confirmed the number of shocks and provided electrograms for interpretation of the causative arrhythmia. Patients were grouped as VF or VT according to the causative arrhythmia. Their prevalence, predictors, and mortality rates were compared. Of 2,028 patients assessed in the ICD clinic, 208 (10%) presented with ES. VF was the cause of ES in 99 of 208 patients, for an overall prevalence of 48%. Original ICD indication, coronary artery disease, and amiodarone therapy were predictive for the causative arrhythmia. There was no mortality difference between the VT and VF groups; however, both groups had significantly increased mortality compared to a control ICD population without ES. CONCLUSION: VF is the causative arrhythmia for a sizable proportion of patients with ES. The initial ICD indication, coronary artery disease, and amiodarone therapy are predictors of the causative arrhythmias in ES. There does not appear to be any mortality difference between ES patients with VT and VF, but mortality is increased in patients with ES versus control ICD patients without ES.     

Predictors of appropriate implantable defibrillator therapies in patients with arrhythmogenic right ventricular dysplasia

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden cardiac death. The risk factors for sudden death and indications for implantable cardioverter-defibrillator (ICD) placement in patients with ARVD are not well defined. OBJECTIVES: The purpose of this study was to determine which clinical and electrophysiologic variables best predict appropriate ICD therapies in patients with ARVD. Particular attention focused on whether the ICD was implanted for primary or second prevention. METHODS: We enrolled 67 patients (mean age 36 +/- 14 years) with definite or probable ARVD who had undergone ICD placement. Appropriate ICD therapies were recorded, and Kaplan-Meier analysis was used to compare the event-free survival time between patients based upon the indication for ICD placement (primary vs secondary prevention), results of electrophysiologic testing, and whether the patient had probable or definite ARVD. RESULTS: Over a mean follow-up of 4.4 +/- 2.9 years, 40 (73%) of 55 patients who met task force criteria for ARVD and 4 (33%) of 12 patients with probable ARVD had appropriate ICD therapies for ventricular tachycardia/ventricular fibrillation (VT/VF; P = .027). Mean time to ICD therapy was 1.1 +/- 1.4 years. Eleven of 28 patients who received an ICD for primary prevention (39%) and 33 of 35 patients who received an ICD for secondary prevention (85%) experienced appropriate ICD therapies (P = .001). Electrophysiologic testing did not predict appropriate ICD interventions in patients who received an ICD for primary prevention. Fourteen patients (21%) received ICD therapy for life-threatening (VT/VF >240 bpm) arrhythmias. There was no difference in the incidence of life-threatening arrhythmias in the primary and secondary prevention groups (P = .29). CONCLUSION: Patients who meet task force criteria for ARVD are at high risk for sudden cardiac death and should undergo ICD placement for primary and secondary prevention, regardless of electrophysiologic testing results. Further research is needed to confirm that a low-risk subset of patients who may not require ICD placement can be identified.     

Implantable cardioverter defibrillator utilization based on discharge diagnoses from Medicare and managed care patients

INTRODUCTION: Implantable cardioverter defibrillators (ICDs) have become an accepted therapy for patients at high risk of sudden cardiac death. To assess the current utilization of this therapy, we estimated the number of patients at risk of sudden death using an historical claims-based study and compared these results to current ICD usage volumes. METHODS AND RESULTS: Managed care and Medicare databases (claims related to 4.6 million covered U.S. lives during a 12-month period) were analyzed to identify patients who had either a primary or secondary diagnosis of ventricular tachycardia, ventricular fibrillation, ventricular flutter, or cardiac arrest. These patients were further required to have a diagnosis code indicating a previous myocardial infarction or congestive heart failure. Patients who died during the study period or did not have medical insurance were excluded. In the base case scenario, 1,226 patients per million population were identified as potential ICD candidates. Sensitivity analyses reduced that value to a range from 736 to 1,140 ICD candidates per million population. Sensitivity factors considered included acute myocardial infarction, comorbidities, age, secondary ventricular tachycardia/ventricular fibrillation diagnosis, and varying degrees of left ventricular dysfunction. These results contrast with an ICD usage rate of 416 per million population in the United States and lower rates in other countries. CONCLUSION: This study suggests that, based on discharge diagnoses, many patients who could benefit from ICDs are not receiving this therapy. Diverse reasons for this underutilization should be addressed to improve access to, and appropriate use of, this therapy.     

The Role of EP-Guided Therapy in Ventricular Arrhythmias: Beta-Blockers,Sotalol, and ICD's

Arrhythmic death can be reduced by antiarrhythmic drugs to a range of 2—4%. Electrophysiologic study by testing noninducibility of ventricular arrhythmia represents the classic method for evaluating the effectiveness of drug therapy.Several clinical studies have shown thaat sotalol suppresses VT induction and prevents arrhythmias recurrences at long term follow-up in 23% to 67% of patients. The efficacy of sotalol EP guided therapy in preventing VT/VF is not necessarily related to prevention of sudden death. In the ESVEM study the superiority of d,l-sotalol to other antiarrhythmic drugs was confirmed. The response to programmed ventricular stimulation was found to be strongly predictive for arrhythmia free state while the failure of sotalol therapy to suppress VT at the EP study was associated with an high recurrence rate (40%). However, EP study failes to predict freedom from sudden death. The beta-blocking activity of racemic sotalol may account for some of the observed survival benefit.Beta-blockers therapy reduces mortality in patients after myocardial infarction primarily by a reduction of sudden death. A reduction of death, worsening heart failure and life threatening ventricular arrhythmias was shown in a recent study on carvedilol. In the prospective study of Steinbeck the EP guided-therapy did not improve the overall outcome when compared to metoprolol. Suppression of inducible arrhythmias by antiarrhythmic drugs was associated with a better outcome. The effectiveness of defibrillator therapy in reducing overall mortality, has been uncertain since great clinical trials have been concluded. MADIT, AVID and CASH trials confirmed the superiority of ICD therapy over antiarrhythmic drugs therapy: ICD should be considered the first choice therapy in post-cardiac arrest patients.The ongoing BEST Trial will give us further responses about the interaction between EP study and metoprolol effect compared to ICD in patients post myocardial infarction also focusing on tolerability and compliance of the beta-blocking therapy in patients with low ejection fraction. In this study will be useful to optimize therapy in patients at high risk of sudden death     

Obesity as a risk factor for sustained ventricular tachyarrhythmias in MADIT II patients

Background: Obesity, as defined by body mass index ≥30 kg/m², has been shown to be a risk factor for cardiovascular disease. However, data on the relationship between body mass index (BMI) and the risk of ventricular arrhythmias and sudden cardiac death are limited. The aim of this study was to evaluate the risk of ventricular tachyarrhythmias and sudden death by BMI in patients after myocardial infarction with severe left ventricular dysfunction.
Methods : The risk of appropriate defibrillator therapy for ventricular tachycardia or ventricular fibrillation (VT/VF) by BMI status was analyzed in 476 nondiabetic patients with left ventricular dysfunction who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II (MADIT II).
Results : Mean BMI was 27 ± 5 kg/m². Obese patients comprised 25% of the study population. After 2 years of follow-up, the cumulative rates of appropriate ICD therapy for VT/VF were 39% in obese and 24% in nonobese patients, respectively (P = 0.014). In multivariate analysis, there was a significant 64% increase in the risk for appropriate ICD therapy among obese patients as compared with nonobese patients, which was attributed mainly to an 86% increase in the risk of appropriate ICD shocks (P = 0.006). Consistent with these results, the risk of the combined endpoint of appropriate VT/VF therapy or sudden cardiac death (SCD) was also significantly increased among obese patients (Hazard Ratio 1.59; P = 0.01).
Conclusions : Our findings suggest that in nondiabetic patients with ischemic left ventricular dysfunction, a BMI ≥30 kg/m² is an independent risk factor for ventricular tachyarrhythmias.     

Renal Sympathetic Denervation as an Adjunct to Catheter Ablation for the Treatment of Ventricular Electrical Storm in the Setting of Acute Myocardial Infarction

We present a case of ventricular storm (VS) in a patient with acute ST‐elevation myocardial infarction (STEMI). After initial successful thrombus extraction and percutaneous coronary intervention (PCI) of the proximal left anterior descending (LAD) coronary artery, a 63‐year‐old male patient showed recurrent monomorphic ventricular tachycardia (VT) and fibrillation (VF) episodes refractory to antiarrhythmic drug therapy. After initial successful VT ablation, fast VT and VF episodes remained an evident problem despite maximum antiarrhythmic drug therapy. Due to an increasing instability, renal sympathetic denervation (RDN) was performed. ICD interrogation and 24‐hour Holter monitoring excluded recurrent episodes of VT or VF at a 6‐month follow‐up (FU) after discharge. This case highlights that RDN was effective and safely performed in a hemodynamically unstable patient with VS after STEMI and adjunct catheter ablation. RDN may open a new avenue for an adjunctive interventional bailout treatment of such highly challenging patients.     

Stellate ganglion blockade and bilateral cardiac sympathetic denervation in patients with life‐threatening ventricular arrhythmias

Autonomic modulation is being increasingly employed as a strategy to treat ventricular arrhythmias refractory to beta‐blockers, antiarrhythmic drugs, and catheter‐based ablation procedures. We report 6 patients with refractory ventricular tachycardia (VT) or ventricular fibrillation (VF) treated with stellate ganglion blockade (SGB) and/or bilateral cardiac sympathetic denervation (CSD). Our case series emphasizes the concept that the cardiac sympathetic nerves are important targets in the management of ventricular arrhythmias. SGB and CSD can be effective in suppressing VT/VF and can be offered to patients with refractory ventricular arrhythmias as an adjunct to conventional therapy.     

Primary prevention of sudden cardiac death: indications for cardioverter-defibrillator implantation.

Sudden cardiac death accounts for 400,000 to 450,000 deaths annually in Europe and in the United States. In patients with previous life-threatening arrhythmia, several perspective, randomized, controlled studies have demonstrated that implantable cardioverter-defibrillator (ICD) therapy is superior to the best antiarrhythmic therapy in prolonging survival. Furthermore, in a stratified-risk population with coronary artery disease, left ventricular ejection fraction < or = 35%, non-sustained ventricular arrhythmias, and inducible ventricular tachycardia, the ICD supports the class I level of recommendation by the guidelines published in 1998. The American College of Cardiology, American Heart Association, and North American Society of Pacing and Electrophysiology have updated the 1998 guidelines on the implantation of arrhythmia devices including in a class IIa level of recommendation also patients with a previous Q wave myocardial infarction and left ventricular ejection fraction < or = 30%, independently of their arrhythmic risk profile. In the recent years several randomized studies assessed the role of ICD treatment for primary prevention of sudden cardiac death and total mortality reduction in high-risk groups of patients with ischemic and non-ischemic dilated cardiomyopathy, with special reference to those with heart failure and ventricular dysfunction. This article reviews those trials that have resulted in defining indications for ICD, and that will expand its use in the future.     

Relationship between signal-averaged electrocardiography and dangerous ventricular arrhythmias in patients with left ventricular aneurysm after myocardial infarction.

We performed signal-averaged electrocardiography (SAECG) and Holter monitoring, and subsequently followed-up 53 ambulatory patients with left ventricular aneurysm (LVA) after myocardial infarction (MI). A history of spontaneous episodes of sustained ventricular tachycardia (VT) was also analysed. Out of 53 patients, 25 (47%) had an abnormal SAECG. Abnormal SAECG correctly identified nine out of 10 cases with a history of sustained VT. Complex ventricular arrhythmias were detected on Holter monitoring in 23 patients: in five out of 28 with normal SAECG (18%) and in 18 out of 25 with abnormal SAECG (72%) (P less than 0.001). During follow-up (mean 19 months) sustained VT and/or sudden cardiac death (SCD) occurred in eight cases, out of which seven had an abnormal SAECG. The negative predictive value of SAECG (no VT or SCD during follow-up) was very high, 96%, similar to the negative predictive value of a history of sustained VT (93%). Using multivariate analysis only a history of sustained VT was an independent factor in predicting the outcome of patients in this study. We conclude that an abnormal SAECG identifies those post infarction patients with LVA who are prone to complex ventricular arrhythmias. A normal SAECG and an absence of a history of sustained VT strongly indicate that the risk of developing arrhythmic events is very low.