Long-term follow-up after sustained monomorphic ventricular tachycardia: Causes, pump failure, and empiric antiarrhythmic therapy that modify survival

Catheter ablation of well tolerated ventricular tachycardia in patients with structural heart disease and without automatic defibrillator implantation: long term follow-up

BACKGROUND

The occurrence of a sustained monomorphic ventricular tachycardias (SMVT) in patients with underlying structural heart disease (SHD) is considered related to poor prognosis. The purpose of our work was to evaluate if these patients could benefit from radiofrequency (RF) ablation, and the defibrillator (ICD) implantation could be deferred during follow-up.

METHODS

We reviewed consecutive patients with well-tolerated SMVT, SHD and left ventricular ejection fraction over 30%. These patients were treated by RF ablation and were discharged without ICD. The primary outcome was a composite of all-cause death and recurrence of SMVT; the secondary outcome was death from all causes.

RESULTS

62 patients were selected. After a median follow-up of 38.8 months, the primary outcome occurred in 24 (38.7%) and the secondary in 11 (17.7%) patients. The annual mortality rate was 4.3% and no patient died from sudden death.

CONCLUSIONS

RF ablation as a first-choice therapy seems to represent an effective and beneficial therapeutic approach.

Risk Stratification in Arrhythmic Right Ventricular Cardiomyopathy Without Implantable Cardioverter-Defibrillators

OBJECTIVES

The primary objective of this study is risk stratification of patients with arrhythmic right ventricular cardiomyopathy (ARVC).

BACKGROUND

There is a need to identify those who need an automatic implantable defibrillator (ICD) to prevent sudden death.

METHODS

This is an analysis of 88 patients with ARVC from three centers who were not treated with an ICD.

RESULTS

Risk factors for subsequent arrhythmic deaths were pre-enrollment sustained or nonsustained ventricular tachycardia (VT) and decreased left ventricular function.

CONCLUSION

These factors serve as proposed guidelines for implantation of an ICD in patients with ARVC to prevent sudden death.

Prophylactic implantable defibrillator in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia and no prior ventricular fibrillation or sustained ventricular tachycardia

BACKGROUND

The role of implantable cardioverter-defibrillator (ICD) in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia and no prior ventricular fibrillation (VF) or sustained ventricular tachycardia is an unsolved issue.

METHODS AND RESULTS

We studied 106 consecutive patients (62 men and 44 women; age, 35.6±18 years) with arrhythmogenic right ventricular cardiomyopathy/dysplasia who received an ICD based on 1 or more arrhythmic risk factors such as syncope, nonsustained ventricular tachycardia, familial sudden death, and inducibility at programmed ventricular stimulation. During follow-up of 58±35 months, 25 patients (24%) had appropriate ICD interventions and 17 (16%) had shocks for life-threatening VF or ventricular flutter. At 48 months, the actual survival rate was 100% compared with the VF/ventricular flutter-free survival rate of 77% (log-rank P=0.01). Syncope significantly predicted any appropriate ICD interventions (hazard ratio, 2.94; 95% confidence interval, 1.83 to 4.67; P=0.013) and shocks for VF/ventricular flutter (hazard ratio, 3.16; 95% confidence interval, 1.39 to 5.63; P=0.005). The positive predictive value of programmed ventricular stimulation was 35% for any appropriate ICD intervention and 20% for shocks for VF/ventricular flutter, with a negative predictive value of 70% and 74%. None of the 27 asymptomatic patients with isolated familial sudden death had appropriate ICD therapy. Twenty patients (19%) had inappropriate ICD interventions, and 18 (17%) had device-related complications.

CONCLUSIONS

One fourth of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia and no prior sustained ventricular tachycardia or VF had appropriate ICD interventions. Syncope was an important predictor of life-saving ICD intervention and is an indication for ICD. Prophylactic ICD may not be indicated in asymptomatic patients because of their low arrhythmic risk regardless of familial sudden death and programmed ventricular stimulation findings. Programmed ventricular stimulation had a low predictive accuracy for ICD therapy.

Amiodarone therapy for sustained ventricular tachycardia after myocardial infarction: long-term follow-up, risk assessment and predictive value of programmed ventricular stimulation

We determine the value of the programmed ventricular stimulation (PVS) and of clinical, angiographic and electrophysiologic variables in assessing the long-term risk of arrhythmia recurrence in a group of coronary artery diseased patients presenting with a first episode of monomorphic sustained ventricular tachycardia (VT) treated with amiodarone. Mortality and arrhythmia recurrence rates were retrospectively assessed in 55 consecutive patients with previous myocardial infarction presenting with a first VT episode. Results of left heart catheterization, echocardiography and time-domain signal-averaging were collected. Patients underwent PVS after amiodarone oral loading and were classified according to inducibility before being all discharged on amiodarone (200 mg daily). The mean follow-up was 42+/-31 months. Total and cardiac mortality rates were 29% (16 patients) and 23% (13 patients) respectively. Sudden death (SD) occurred in nine patients (16%). VT recurred in 13 patients (23%). Sustained monomorphic VT was inducible in 40 patients (72%) after amiodarone loading. Neither total mortality (10/40 vs. 6/15) nor cardiac mortality (3/40 vs. 1/15) were significantly different between inducible and non-inducible patients. Recurrent VT rate was 27% (11/40 patients) for the inducible group and 13% (2/15 patients) for the non-inducible group (NS). SD occurred in 6/40 inducible patients (15%) and in 2/15 non-inducible patients (13%) (NS). Arrhythmic events occurred in 42% (17/40) inducible patients vs. 26% (4/15) non-inducible patients (P=0.07). Parameters correlated with outcome were ejection fraction (EF) (5 SD/11 patients with EF <0.3 vs. 4/44 with EF >0.3, P=0.003), mitral insufficiency (MI) (4 SD/10 patients with MI vs. 4/44 patients without MI, P=0.004) and age (65+/-9 years for patients with VT recurrence vs. 58+/-9, P=0.02). Although the risk stratification can be improved, reliable and safe long-term prediction of recurrence of malignant ventricular arrhythmia in individual patients cannot be made. Consequently, the systematic implantation of a cardioverter-defibrillator in case of a first episode of sustained VT occurring in coronary artery disease patients should be further debated.

Drug therapy of sustained ventricular tachyarrhythmias. Is there still a role?

This article provides a review of the risks faced by patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) in the absence of a reversible or transient cause so that the goals of therapy can be clearly defined. The therapeutic approaches that have been proposed to achieve these goals are outlined and evidence comparing these various approaches to therapy is then summarized in order to propose an algorithm for the optimal use of antiarrhythmic drug therapies as primary therapy for selected VT/VF patients. Options for the ancillary uses of antiarrhythmic drug therapies in ICD patients are considered.

Prognosis of patients with a first episode of sustained monomorphic ventricular tachycardia

AIMS

To evaluate the cardiac mortality in patients suffering from a first episode of sustained monomorphic ventricular tachycardia (SMVT).

METHODS

100 patients less than 75 years old were evaluated during a 50-month follow-up period. Patients were classified into four groups: myocardial infarction, dilated cardiomyopathy, normal heart and miscellany. Seventeen patients underwent a cardioverter-defibrillator implantation, two heart transplant, three aneurysmectomy and 10 other types of cardiac surgical proceedings.

RESULTS

Patients with a left ventricle ejection fraction (EF)> or =50% presented a cardiac mortality of 5% compared with 38% of those with EF<50%. Etiology of underlying cardiomyopathy with an EF> or =50% was associated with a cardiac mortality of 5% (normal heart), 5% (myocardial infarction) and 9% (miscellany) compared to those with EF<50%: 33% (dilated cardiomyopathy) and 40% (myocardial infarction). Patients who experienced syncope during the first episode of SMVT showed a cardiac mortality of 31% compared to those 14% (P < 0.05) who did not experience. Patients with syncope, myocardial infarction and EF<50% showed a cardiac mortality of 68%.

CONCLUSION

The present study shows that survival after the first episode of SMVT is closely related to EF and the existence of syncope. Patients with myocardial infarction and EF<50% had a worse prognosis when the site was the inferior wall.

Mechanisms and management of ventricular dysrhythmias in heart failure

Despite recent pharmacologic and surgical advances in the management of heart failure, the morbidity and mortality rates of this chronic illness remain high. Ventricular dysrhythmias are common in heart failure and may be independently associated with increased mortality rates. Although the risks of sudden cardiac death leading to the patient's death are increased by the presence of complex ventricular dysrhythmias, the management of dysrhythmias is subject to controversy. The purpose of this article is to review the normal electrophysiologic properties of the heart and to examine the likely mechanisms, diagnostic approaches, and proposed treatments for ventricular dysrhythmias in heart failure.

Management of patients with life-threatening ventricular tachyarrhythmias in the defibrillator era: the need to differentiate

Patients with a history of sustained ventricular tachyarrhythmias form an extremely inhomogeneous group with respect to presenting arrhythmia, underlying cardiac disease, and therefore, risk of dying suddenly. For subgroups such as ventricular tachycardia in the absence of underlying cardiac disease, radiofrequency catheter ablation offers cure. In others, implantation of a cardioverter defibrillator already appears to have gained the therapy of first choice, leaving only a secondary role to antiarrhythmic drugs. It must be emphasized however, that these new therapeutic strategies have their pros and cons like the older, seemingly out-fashioned approaches of noninvasively or invasively guided antiarrhythmic drug therapy or empiric amiodarone treatment. Until the advent of controlled randomized trials comparing the implantable cardioverter defibrillator (ICD) with the best other, usually medical form of treatment, physicians must continue to base their individual therapeutic decisions on circumstantial published and personal experience. In doing so, the recent achievements of catheter ablation and defibrillator implantation have definitely improved patient care, but have not made antiarrhythmic drugs jobless. With all the alternatives at hand, it remains a challenging task to weigh the benefits and risks of the various approaches against each other in an attempt to tailor the antiarrhythmic intervention to the very individual need of the patient.

Beta adrenergic blockade in the treatment of sustained ventricular tachycardia or ventricular fibrillation

The value of beta-blockers as antiarrhythmic drugs in patients with sustained VT or VF has received only little attention. This article summarizes the current state of knowledge regarding the identification of patients with sustained VT or VF with the highest benefit of beta-blockade. The antiarrhythmic mechanisms of beta-blockade and its efficacy as single or adjuvant therapy in patients with sustained VT or VF are reviewed. Current insights into the effects of beta-blockade in patients suffering from VT, in particular in the setting of heart failure, are discussed and future directions are considered.

Predictors of mortality in patients with sustained ventricular tachycardias or ventricular fibrillation and depressed left ventricular function: importance of beta-blockade

To study prognostic factors in patients with sustained ventricular tachycardias (VT) or ventricular fibrillation (VF) complicated by left ventricular dysfunction, we evaluated the predictive value of demographic, clinical, and hemodynamic parameters for cardiac mortality and sudden cardiac death in 85 patients with VT or VF and left ventricular ejection fraction < 0.45 (mean 0.27 +/- 0.10). Patients underwent serial drug testing and received appropriate antiarrhythmic treatment, with amiodarone given as last-resort therapy. During a follow-up of 24 +/- 13 months, 23 patients died of cardiac causes, and 18 of them died suddenly. Left ventricular ejection fraction < or = 0.27 and amiodarone treatment were related to greater cardiac mortality and increased risk of sudden cardiac death, whereas beta-blockade was associated with improved survival. In the multivariate model cardiac mortality was best predicted by a left ventricular ejection fraction < or = 0.27, and absence of beta-blockade and severe left ventricular dysfunction were the strongest predictors of sudden cardiac death. We conclude that severe left ventricular dysfunction predicts increased cardiac mortality and high risk of sudden cardiac death. Moreover, beta-blocking treatment is associated with lower cardiac mortality and a reduced risk of sudden cardiac death in patients with sustained VT or VF and depressed left ventricular function. beta-Blocking agents may therefore be an important addition to conventional antiarrhythmic treatment in patients with VT or VF and left ventricular dysfunction.

Implantable cardioverter defibrillator therapy in patients with arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, or no structural heart disease

Recent technical developments in implantable cardioverter defibrillator (ICD) systems and reduced operative mortality and morbidity rates associated with ICD implantation have expanded the indications for ICD treatment of ventricular tachyarrhythmias. This review summarizes data regarding ICD therapy in patients with arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, and idiopathic ventricular fibrillation and presents preliminary concepts for identification of patients who will benefit more from ICD therapy than from pharmacologic and other nonpharmacologic approaches. Recent studies suggest that ICD therapy may improve long-term prognosis by reliably terminating recurrences of life-threatening arrhythmias. Appropriate ICD therapies during mean follow-up periods of 12 to 36 months occurred in 30% of patients with idiopathic ventricular fibrillation to 50% of patients with arrhythmogenic right ventricular cardiomyopathy and long QT syndrome. At present no strict recommendations can be given for ICD implantation in these patients. However, at least in cardiac arrest survivors in whom the clinical arrhythmia is not reproducibly inducible during electrophysiologic study, ICD therapy appears to be superior to other treatment options with regard to long-term survival and thus should be considered as a first-line treatment. We are hopeful that continued study of long-term follow-up with and without ICD treatment and improved risk stratification will lead to better criteria for selection of treatment options.

Amiodarone. An overview of its pharmacological properties, and review of its therapeutic use in cardiac arrhythmias

Amiodarone, originally developed over 20 years ago, is a potent antiarrhythmic drug with the actions of all antiarrhythmic drug classes. It has been successfully used in the treatment of symptomatic and life-threatening ventricular arrhythmias and symptomatic supraventricular arrhythmias. In patients with left ventricular dysfunction amiodarone does not usually produce any clinically significant cardiodepression and the drug has relatively high antiarrhythmic efficacy. Preliminary studies indicate that amiodarone may have a beneficial effect on mortality and survival in certain groups of patients with ventricular arrhythmias, an action probably related to both its antiarrhythmic and antifibrillatory effects. The adverse effect profile of amiodarone is diverse, involving the cardiac, thyroid, pulmonary, hepatic, gastrointestinal, ocular, neurological and dermatological systems. Interstitial pneumonitis and hepatitis are potentially fatal, but the vast majority of adverse events are less serious, and some may be dose dependent. Pretreatment monitoring, regular assessments and the use of minimum effective doses are, therefore, necessary. Thus, with appropriate monitoring to control its well recognised adverse effects amiodarone has an important place as an effective 'broad spectrum' antiarrhythmic drug which has, so far, been used when other treatments have proved ineffective. More recent preliminary data also suggest that it may also have a beneficial effect in the prevention of sudden death in some patients.