View clinical trials related to Tachycardia.
Filter by:Background: Patients at increased risk for sudden cardiac death (SCD) may receive an implantable cardioverter defibrillator (ICD). The primary criterion for a primary prevention ICD implantation is a left ventricular ejection fraction (LVEF) below 35%, but refinement of ICD criteria is important since only a small proportion of ICD patients receives appropriate device therapy (ATP or a shock) during follow-up. Post-extrasystolic potentiation (PESP) may be a new risk marker for SCD. PESP is defined as a temporary increase in contractility that follows an extrasystolic beat (ESB) and is associated with myocardial calcium handling. In heart failure, changes in calcium homeostasis may lead to afterdepolarisations and thus predispose for SCD. PESP can be measured indirectly and non-invasively as post-extrasystolic blood pressure potentiation (PESP-BP). Abnormal PESP-BP was previously found to be an independent predictor of increased mortality in post-myocardial infarction patients with a reduced LVEF. However, it is unknown if this increased mortality in heart failure patients with abnormal PESP-BP is caused by an increased risk of SCD. Hypothesis: The investigators hypothesize that PESP-BP might be a new predictor of the occurrence of SCD, and can be used to enhance patient selection for primary prevention ICD therapy. Design: During scheduled device replacement ESB with various extrasystolic and post-extrasystolic coupling intervals will be evoked by electrical stimulation via the right atrial and ventricular device leads of the patient. Throughout the stimulation study blood pressure will be measured non-invasively a continuous electrocardiogram will be recorded. Either before or after the procedure, patients will undergo a 30-minutes assessment of spontaneous ESB, again with blood pressure and ECG recordings. Study population: 30 patients who are scheduled for device replacement or reposition, are eligible for this study; (1) 10 ICD patients who previously received appropriate device therapy (ADT); (2) 10 ICD patients who are free from ADT and (3) 10 dual-chamber pacemaker patients (control group). Outcomes: (1) Evoked PESP-BP (i.e. blood pressure differences between baseline, ESB and post-ESB); (2) Spontaneous PESP-BP (i.e. blood pressure differences between baseline, ESB and post-ESB); (3) Timing parameters (in ms): the basic cycle length interval; Extra-systolic interval (ESI); Post-extrasystolic interval (PESI).
Aim of this study is to collect data from pace mapping performed in three groups of patients : patients presenting ventricular tachycardia and infarction history, patients presenting infarction history without presenting ventricular tachycardia, and in patients without structural heart disease.
The PROTECT-ICD trial is a physician-led, multi-centre randomised controlled trial targeting prevention of sudden cardiac death in patients who have poor cardiac function following a myocardial infarct (MI). The trial aims to assess the role of electrophysiology study (EPS) in guiding implantable cardioverter-defibrillator (ICD) implantation, in patients early following MI (first 40 days). The secondary aim is to assess the utility of cardiac MRI (CMR) in analysing cardiac function and viability as well as predicting inducible and spontaneous ventricular tachyarrhythmia when performed early post MI. Following a MI patients are at high risk of sudden cardiac death (SCD). The risk is highest in the first 40 days; however, current guidelines exclude patients from receiving an ICD during this time. This limitation is based largely on a single study, The Defibrillator in Acute Myocardial Infarction Trial (DINAMIT), which failed to demonstrate a benefit of early ICD implantation. However, this study was underpowered and used non-invasive tests to identify patients at high risk. EPS identifies patients with the substrate for re-entrant tachyarrhythmia, and has been found in multiple studies to predict patients at risk of SCD. Contrast-enhanced CMR is a non-invasive test without radiation exposure which can be used to assess left ventricular function. In addition, it provides information on myocardial viability, scar size and tissue heterogeneity. It has an emerging role as a predictor of mortality and spontaneous ventricular arrhythmia in patients with a previous MI. A total of 1,058 patients who are at high risk of SCD based on poor cardiac function (left ventricular ejection fraction (LVEF) ≤40%) following a ST-elevation or non-STE myocardial infarct will be enrolled in the trial. Patients will be randomised 1:1 to either the intervention or control arm. In the intervention arm all patients undergo early EPS. Patients with a positive study (inducible ventricular tachycardia cycle length ≥200ms) receive an ICD, while patients with a negative study (inducible ventricular fibrillation or no inducible VT) are discharged without an ICD, regardless of the LVEF. In the control arm patients are treated according to standard local practice. This involves early discharge and repeat assessment of cardiac function after 40 days or after 90 days following revascularisation (PCI or CABG). ICD implantation after 40 days according to current guidelines (LVEF≤30%, or ≤35% with New York Heart Association (NYHA) class II/III symptoms) could be considered, if part of local standard practice, however the ICD is not funded by the trial. A proportion of trial patients from both the intervention and control arms at >48 hours following MI will undergo CMR to enable correlation with (1) inducible VT at EPS and (2) SCD and non-fatal arrhythmia on follow up. It will be used to simultaneously assess left ventricular function, ventricular strain, myocardial infarction size, and peri-infarction injury. The size of the infarct core, infarct gray zone (as a measure of tissue heterogeneity) and total infarct size will be quantified for each patient. All patients will be followed for 2 years with a combined primary endpoint of non-fatal arrhythmia and SCD. Non-fatal arrhythmia includes resuscitated cardiac arrest, sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) in participants without an ICD. Secondary endpoints will include all-cause mortality, non-sudden cardiovascular death, non-fatal repeat MI, heart failure and inappropriate ICD denial. Secondary endpoints for CMR correlation will include (1) the presence or absence of inducible VT at EP study, and (2) combined endpoint of appropriate ICD activation or SCD at follow up. It is anticipated that the intervention arm will reduce the primary endpoint as a result of prevention of a) early sudden cardiac deaths/cardiac arrest, and b) sudden cardiac death/cardiac arrest in patients with a LVEF of 31-40%. It is expected that the 2-year primary endpoint rate will be reduced from 6.7% in the control arm to 2.8% in the intervention arm with a relative risk reduction (RRR) of 68%. A two-group chi-squared test with a 0.05 two-sided significance level will have 80% power to detect the difference between a Group 1 proportion of 0.028 experiencing the primary endpoint and a Group 2 proportion of 0.067 experiencing the primary endpoint when the sample size in each group is 470. Assuming 1% crossover and 10% loss to follow up the required sample size is 1,058 (n=529 patients per arm). To test the hypothesis that tissue heterogeneity at CMR predicts both inducible and spontaneous ventricular tachyarrhythmias will require a sample size of 400 patients to undergo CMR. It is anticipated that the use of EPS will select a group of patients who will benefit from an ICD soon after a MI. This has the potential to change clinical guidelines and save a large number of lives.
Carvedilol is known to be effective in reducing ventricular arrhythmias and mortality in patients with heart failure. It is suggested that one of the mechanisms is its ability to block store overload-induced Calcium release which activates spontaneous calcium release by Ryanodine receptors. Ventricular outflow tract tachyarrhythmia is known to be associated with calcium overload due to activation of Ryanodine receptors. The aim of this study is to evaluate the efficacy of Carvedilol on premature ventricular complex(PVC)/ventricular tachycardia(VT) originating from outflow tract.
The goal of this study is to test the efficacy of the new imaging/simulation ("virtual heart") approach for determining the optimal ablation sites in patients with VT, which render post-infarction VT non-inducible. The study will test both the acute outcome of the ablation procedure, and the effect the use of the predicted targets has upon procedure time.
Sudden cardiac death is a frequent cause of cardiovascular mortality. Numerous rhythmic risk assessment criterion have been described targeting the substratum, the cardiac nervous tone or the trigger of arrhythmias. Development of ventricular tachycardia ablation in the past few years show interesting results preventing the recurrence of ventricular arrhythmias.
Cardiac pacing which involved stimulating the heart electrically with electrical wires that go into the heart is routine practice in the diagnosis and treatment of heart rhythm problems. Clinically this involved the fields of cardiac pacing and electrophysiology. Patients who are at risk of sudden death because of serious heart rhythms that are a result of malfunction of the electrical system of the pumping chambers of the heart (ventricles) are generally implanted with specialised pacemakers that can defibrillate (shock) the heart if a nasty life threatening rhythm should result. Shocks are painful and in order to try and treat these rhythms without shocks, anti tachycardia pacing is performed (this is routine part of the device), which aims to interrupt the rhythm by stimulating the heart electrically. This does not always work and can destabilise the rhythm leading to a shock. REVRAMP is a novel modification of anti tachycardia pacing which involved stimulating the heart through the defibrillator wires in a different way. It appears to work better and seems less likely to destabilise the heart rhythm, hence can reduce painful shocks.
This is a randomized, double blind, single center trial to study of the effects of Ivabradine vs. Placebo on patients hospitalized for Stage D heart failure (HF)/ and cardiogenic shock (CS) who will require continuous infusion of Dobutamine and have developed sinus tachycardia (ST) (heart rate >100 beats/min). The aim of the study will be to assess the potential of Ivabradine to slow ST and improve hemodynamics in patients with stage D HF/CS on Dobutamine treatment.
The FAST Trial Registry is a prospective observational cohort study of fetuses with a new diagnosis of atrial flutter (AF) or supraventricular tachycardia (SVT) that is severe enough to consider prenatal treatment (see eligibility criteria below). Aims of the Registry include to establish a large clinical database to determine and compare the efficacy and safety of different prenatal treatment strategies including observation without immediate treatment, transplacental antiarrhythmic fetal treatment and direct fetal treatment from the time of tachycardia diagnosis to death, neonatal hospital discharge or to a maximum of 30 days after birth.
The implantable device therapy for cardiac arrhythmias has been an established therapy, and one of the common standard procedures in cardiac clinical practice. Pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy have been developed since 1960s, and the technologies in this field are still progressively developing. Not only these "traditional" implantable devices, there are multiple new devices for cardiac diseases, such as implantable loop recorder, vagal nerve stimulator and barostimulator. The aim of this registry is to demonstrate the efficacy and the safety of standard device implantation procedures and to evaluate/ identify specific factors, including clinical characteristics, laboratory data and procedural data, which predict the prognosis/complication of the patients. These identification will result in further improvement of patients' care.