Active clinical trials for "Tachycardia"

A common complaint among patients with Postural Tachycardia Syndrome (POTS) is "brain fog" or difficulty concentrating. This problem is poorly understood. The purpose of this study is to better understand the cognitive dysfunction associated POTS, and to determine optimal treatment strategies for this condition. In this study, the investigators will test the hypothesis that acute administration of the psychostimulant drug modafinil can improve seated measures of cognitive function in patients with POTS.

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.

DanICD is a randomized, controlled study to with the aim to assess whether there is a benefit of ICD-implantation in patients with coronary artery disease (including acute myocardial infarction), who survive cardiac arrest due to ventricular fibrillation/sustained ventricular tachycardia and undergo revascularization and with an LVEF above 35%.

POTS patients seem to experience orthostasis-dependent muscle weakness and pain as well as increased muscle fatigue upon physical activity, which can be improved by regular aerobic exercise. However, reduced sweat production of the extremities with limited control of the body temperature leads to exercise intolerance, so that sticking to a training program becomes a challenge for most patients. Recordings of MVRCs provide a new tool to assess muscle membrane dysfunction, depending on ischemia, surface temperature and training. As muscle dysfunction is assumed to be present in the majority of POTS patients but has not yet been scientifically studied the present study aims at understanding the muscular and cutaneous functioning in POTS using MVRC recordings, dependent both on orthostatic stress and exercise training as well as body temperature regulation. Our main hypothesis is that POTS patients experience functional muscle dysfunction that may be linked to altered muscle perfusion or body temperature regulation. The purpose of this study is to examine muscular and cutaneous dysfunction in POTS in order to i) better understand the underlying pathology for symptoms and to ii) ultimately improve treatment options.

Individuals with repaired Tetralogy of Fallot (rTOF) remain at risk for sudden cardiac death from ventricular tachycardia (VT). Transcatheter pulmonary valve replacement (TPVR) indications continue to broaden, yet its capability to reduce the risk of VT and sudden cardiac death remains unknown. Thus, in a cohort of participants with rTOF who are presenting for TPVR the investigators intend to: (1) quantify and localize right ventricular (RV) isthmuses with abnormal voltage and/or conduction velocity; (2) identify which RV isthmuses are at risk of being "jailed" by TPV prostheses; and (3) explore the feasibility of omnipolar technology to characterize wavefront directionality and differentiate slow conduction from conduction block.

Sympathetic tone is important in cardiac arrhythmogenesis. The simultaneous recording of sympathetic nerve activity (SNA) and electrocardiogram (ECG) was obtained by invasive method. The purpose of this protocol is to further develop this recording method to turn it into a new non-invasive tool for arrhythmia prediction and detection. This method may also be useful in validating the results of surgical procedures aimed at sympathetic denervation

The investigators will test whether an intravenous infusion of saline (salt water) will improve the exercise capacity in patients with postural tachycardia syndrome (POTS).

The purpose of this study is to describe the mechanism of orthostatic intolerance, relying on cardiovascular physiological studies. The syndrome is of undetermined etiology, but the syndrome causes impairment of a number of young adults, females more than males, with symptoms of tachycardia, fatigue, lightheadedness, palpitations, blurred vision, chest discomfort, difficulty concentrating, and dizziness with the upright posture. It is believed that many different pathophysiological processes can give rise to this disorder.

The purpose of this study is to see if some people with postural tachycardia syndrome (POTS) have higher levels of immune proteins (autoantibodies) directed against receptors of the autonomic nervous system, and if these autoantibodies make a difference in their POTS symptoms. The investigators also want to see if the levels of these autoantibodies stay the same over time.

Medtronic is sponsoring Enlighten: The EV-ICD Post Approval Registry, to further confirm safety and effectiveness of EV-ICD in routine clinical practice, following commercial release of EV-ICD devices.