Active clinical trials for "Tachycardia, Ventricular"

The MADIT-II trial has shown that patients with severely reduced left ventricular ejection fraction (LVEF) post myocardial infarction benefit from the implantable cardioverter-defibrillator (ICD). However, retrospective analyses of the MADIT-II data have revealed a significantly increased morbidity and mortality in patients with appropriate ICD therapy: Appropriate ICD therapy is associated with 3.3-fold increased all-cause mortality, and the risk of a first heart failure hospitalization is 90% higher after 1st appropriate ICD therapy. Hence, the 1st appropriate therapy might indicate the necessity and utility of further clinical diagnostics and therapy in these patients. This trial is designed to (i) improve the knowledge of the group characteristics of patients suffering from 1st appropriate ICD therapy, (ii) but moreover to take additional therapeutic steps to reduce the mortality of this patient population.

The purpose of this study is to evaluate the clinical efficacy and safety of stereotactic ablative radiotherapy (SAbR), also known as stereotactic body radiation therapy (SBRT), for treatment of ventricular tachycardia (VT) requiring implantable cardioverter defibrillator (ICD) treatments in patients with VT refractory to standard invasive ablation techniques. We hypothesized that SAbR is effective in suppressing sustained VT and reducing ICD treatments in this group of patients and is associated with acceptably low risk of serious complications.

There is an increasing evidence regarding the efficacy of a substrate-based ablation approach to ventricular tachycardia (VT). This approach involves identifying regions of scar and also areas displaying late potentials and fractionated activity. Automated mapping systems are now available which may be able to generate high density maps displaying regions containing both late potentials and ventricular scar. Such an automated approach has not been validated. Furthermore, most patients presenting for VT ablation have pacing devices in situ. It is not known how the pacing modality affect the substrate maps generated for these procedures. Once an area felt to be important to ablate has been identified, the next key step is to perform effective ablation. An algorithm has now been made available (Ablation index - Biosense Webster Inc.,) which in preclinical studies is an effective predictor of radiofrequency lesion depth. This algorithm has been studied extensively in the atrium but not in the ventricle. This study would also seek to collect ablation index data during ablation to assess the algorithm during ventricular ablation.

The heart beat is controlled by electrical signals. Following a heart attack, part of the heart muscle dies and is later replaced by scar tissue. Within this area of scar, there often remain "channels" of surviving tissue still able to transmit electrical signals. However, it is well established that these "conduction channels" (CC) can form a short circuit around the scar, leading to electrical disturbances (arrhythmias) that are potentially life threatening. The commonest of these is ventricular tachycardia (VT), and is estimated to cause 300,000 deaths per year. One recognised treatment option of VT involves burning (ablation) these "conduction channels" (CC) within the scar. However, at present, the procedure is long and is far off 100% effective. Consequently, current best practice does not rely on treating the VT, but rather preventing it from causing sudden death - this is achieved with an Implantable Cardioverter Defibrillator (ICD), a device which can recognise when a patient is in VT and deliver an internal shock to restore the normal electrical conduction. Patients with defibrillators subsequently are subject to recurrent painful and debilitating shocks which, although lifesaving, significantly reduce their quality of life. The limitation with ablation at present is due to the difficulty in visualising these CC's. Investigators at Imperial College have created a novel electrogram visualisation program, Ripple Mapping (RM), which they have already found to be superior to currently used programmes in cases of arrhythmias in the upper chambers of the heart (the atria). During a retrospective study in patients with scar related VT following a heart attack, when ablation was delivered in areas associated with identified Ripple Mapping Conduction Channels, these patients remained free of VT recurrence for >2 year follow up interval. The study hypothesis is that Ripple Mapping can identify all conduction channels within scar tissue critical to the VT circuit, ablation of which will lead to long-term freedom from VT and ICD therapies. The investigators now aim to perform a prospective randomised study comparing Ripple Mapping guided VT ablation against conventional VT ablation.

To determine the antiarrhythmic effects of dietary N-3 fatty acids in patients with implanted defibrillators.

To determine if the dietary N-3 class of polyunsaturated fatty acids (PUFAs) provided in the diet largely from marine fish oils would prevent fatal ventricular tachycardia (VT) or ventricular fibrillation (VF).

Subjects will be consented to wear the CoVa-2 monitoring system prior to (baseline), during, and after an Electrophysiology Procedure (EP). During this time, the system will measure the following parameters from subjects: heart rate (HR), Heart Rate Variability (HRV), respiration rate (RR), and Cardiac Output (CO). Data will be retrospectively analyzed to determine if the system effectively operates under these conditions, and can effectively monitor subjects and allow them to be discharged early from the hospital. Subjects will not be measured while transferred in and out of the operating room. Approximate sample size is 20 subjects.

The purpose of this clinical study is to collect safety and performance data to support a demonstration of substantial equivalence of the Catheter Robotics Remote Catheter System to predicate devices when used to perform EP mapping of the right heart (atrium and ventricle).

Ventricular tachycardia (VT) is a morbid arrhythmia responsible for many sudden deaths and ICD shocks. Despite much progress in the treatment of arrhythmia, VT remains a therapeutic challenge. Most patients with VT have an implantable cardioverter defibrillator (ICD) for secondary prevention of sudden cardiac death, however, an ICD merely treats VT, it does not prevent VT. In patients with recurrent VT and ICD shocks, two strategies are available to decrease the burden of VT. The first is antiarrhythmic drugs, and the second is VT ablation. The aim of this study is to compare the efficacy of antiarrhythmic drugs and VT ablation guided by MRI. VT can sometimes be suppressed with antiarrhythmic medications, however, these are often ineffective, and carry a high burden of side effects. Many forms of VT can be cured by selective destruction of critical electrical pathways with catheter ablation. A major limitation in the ablation of VT, however, is the time required to localize scar tissue and important pathways for targeting of lesions. Magnetic resonance imaging can now obtain reliable images of scar location within the ventricles. Recent advances in electroanatomical mapping systems allow operators to import pre-acquired images into the mapping system. The aim of this study is to examine the feasibility of importing historic MRI scar maps of the ventricles into the electroanatomical system and using such images to guide catheter ablation, as compared to antiarrhythmic drug suppression of VT. We suspect that MRI guidance will be especially useful in patients with "unstable" VT, i.e. VT that causes an abrupt drop in blood pressure, and thus cannot be maintained in the electrophysiology (EP) lab for mapping and entertainment purposes. Patients referred for VT ablation have ICDs. Through previously completed animal work (Circulation 2004; 110(5): 475-82) and a human trial (2006 Sep 19;114(12):1277-84) we have demonstrated the safety of MRI in the setting of pacemakers and implantable defibrillators using appropriate precautions. Through careful device programming and using MRI sequences with limited energy exposure (specific absorption rate < 2 W/kg) we will study the pre procedural myocardial anatomy of patients enrolled into this study. The primary endpoint will be lack of VT documented by implantable defibrillator (when present) interrogation or Holter monitoring 6 months post ablation. The secondary endpoints will be comparison of inducible arrhythmia at the end of the procedure, procedure time, comparison of endocardial voltage mapping to scar on delayed enhancement MRI images, and complications in each study arm.

To assess potential link between unrecognized myocardial inflammation (myocarditis) and premature ventricular contractions (PVCs) associated with and without reduced Left ventricular ejection fraction (LVEF) through comprehensive diagnostic work up.