View clinical trials related to Tachycardia.
Filter by:With the increasing use of implantable cardioverter defibrillators (ICD) for primary prevention in patients with structural heart disease, an increasing number of patients are expected to develop their first episode of monomorphic ventricular tachycardia (VT) after an ICD is in place and the only documentation of the clinical arrhythmia will be the ICD electrogram (EG). The absence of a 12-lead ECG in patients with an ICD and sustained monomorphic VT represents a limitation when performing treatment with radiofrequency (RF) ablation. The analysis of ICD-EG during a RF ablation procedure is expected to provide a reference "model" of VT with clinical expression consisting of the electrical signal of the ICD during VT (which otherwise is not generally possible to obtain in ICD patients). This will allow for a more targeted approach to the substrate of the VT with clinical expression because: 1) if VT is induced by programmed stimulation, one can tell whether it is with clinical expression or not, and 2) if VT is not induced, ventricular pacing could be performed based on the comparative analysis of morphology and activation times of ICD-EG. These approaches will result in improved outcomes of the ablation procedure.
The purpose of this post approval study is to characterize the chronic performance of the SJM Optisure family of HV leads in patients.
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.
Supraventricular tachycardia (SVT) is a term describing any rhythm coming from the top half of the heart. Although atrial fibrillation is the commonest cardiac arrhythmia, regular SVT's are also common. The two commonest regular SVT's are atrioventricular (nodal) reentry tachycardias (AV(N)RT) and atrial flutter (AFL). Atrioventricular (nodal) reentry tachycardias (AV(N)RT) are common but benign forms of fast heart rhythm. Although AV(N)RT can cause unpleasant symptoms and are frightening it is not dangerous. If patients present with AV(N)RT the accepted and normal treatment for most is to have the fast heart rhythm stopped by either taking a deep breath and straining or by the use of drugs. Patients can then be discharged home and have further investigation and treatment as an outpatient. SVT can be frightening for the patient but is easy to diagnose and treat. There is high success rate post treatment for this benign condition. This is traditionally done in the local accident and emergency, although patients can sometimes be unnecessarily admitted to hospital overnight. We propose to investigate the safety and efficacy of training paramedics to treat safe forms of AV(N)RT at the scene and then giving the patient an information pack which includes a request for a GP referral to a heart rhythm specialist. Patients will be randomly allocated after consenting to take part in the study to either get paramedic or accident and emergency department treatment. We will compare these two approaches by telephone follow up of the patients. The costs of the different approaches will be compared by assessing the rate of appropriate investigation and the information given to patients and how they rated their experiences.
We are investigating ways to help patients with heart failure, which is caused by damaged hearts which function less well, and cause symptoms of breathlessness, fatigue, lack of energy and swelling. Cardiac Resynchronisation Therapy (CRT) pacemakers are used to improve the pumping function of the main heart chamber in certain suitable people with heart failure. CRT requires a pacemaker with 2 wires, one placed inside the right heart chamber and one normally placed on the outside of the left heart chamber. These two wires act together to re-time the coordination of the heartbeat, which is known to improve heart function. The investigators are assessing whether they might be able to improve heart function even more by placing two wires on the inside of the left heart chamber, rather than one around the outside. The investigators wish to assess whether: 1. Using two wires within the left side of the heart gives a greater increase in heart function than one. 2. It is possible to choose the best spot inside of the heart by measuring the pattern of the heart beat. 3. Is it possible to use a different type of heart monitor placed outside the body instead of a monitor wire inside the heart to assess improvement in heart function? They are investigating this in people with hearts that beat less effectively than normal.
Septic shock is a condition that is marked by severe infection causing hypotension requiring vasopressors to maintain adequate perfusion to vital organs. The Surviving Sepsis campaign, an international organization formed for the purpose of guiding the management of sepsis and septic shock, currently recommends norepinephrine as the first-choice vasopressor for septic shock. Phenylephrine, a vasopressor FDA-approved for use in septic shock, is recommended as an alternative vasopressor when septic shock is complicated by tachyarrhythmia to mitigate cardiac complications. This recommendation is based solely on experience with no scientific evidence to support this recommendation. The investigators will conduct an open-label randomized controlled trial (RCT) directly comparing phenylephrine and norepinephrine, two FDA-approved vasopressors that are both used in clinical practice for the management of septic shock. The investigators will perform this study with a population of patients that have septic shock to complete the following aims: Aim 1: Determine the incidence of tachyarrhythmias. Aim 2: Determine which vasopressor, phenylephrine or norepinephrine, is associated with a lower heart rate. Aim 3: Determine which vasopressor, phenylephrine or norepinephrine, is associated with a higher incidence of new tachyarrhythmias. Aim 4: Determine which vasopressor, phenylephrine or norepinephrine, is associated with less time in tachyarrhythmia. Aim 5: Determine which vasopressor, phenylephrine or norepinephrine, is associated with fewer complications, including cardiac complications. The investigators hypothesize that in this setting, phenylephrine will improve the management of septic shock when used as a "first choice" vasopressor by: 1. Decreasing the mean heart rate 2. Decreasing the incidence of new tachyarrhythmias 3. Decreasing the amount of time spent in tachyarrhythmia for patients who develop new onset and recurrent tachyarrhythmias 4. Decreasing the number of cardiac complications
In this pilot study, the investigators will test the hypothesis that patients with postural tachycardia syndrome will have an elevated percentage of functional antibodies to adrenergic receptors compared with control subjects without POTS. The investigators further hypothesize that the percentage of POTS patients with antibodies will be higher in those patients with a viral infection at the onset of their illness than in those patients with other or undefined illness onsets.
Clinical study suggests that beta-blockers by decreasing heart rate together with an increase in stroke volume do not negatively affect cardiac output allowing an economization of cardiac work and oxygen consumption in patients with septic shock. Whether this hemodynamic profile leads to an amelioration of myocardial performance is still unclear. The objective of the present study is therefore to elucidate whether a reduction in heart rate with esmolol is associated to an improvement of cardiac efficiency in patients with septic shock who remained tachycardic after hemodynamic optimization.
The purpose of the study is to investigate effect of medical treatment and prognosis of Postural Orthostatic Tachycardia Syndrome (POTS)
Orthostatic intolerance refers to symptoms that occur with standing and improve or resolve with recumbency. Few studies have evaluated orthostatic intolerance symptoms by electroencephalography (EEG), and none of those studies have focused on the adolescent-aged patient. This study will compare EEG characteristics and sweat rate during head-upright tilt (HUT) testing among patients with postural tachycardia syndrome (POTS) and patients with syncope without POTS. Patients with POTS will also undergo a separate HUT with abdominal and lower extremity compression. The primary aim of this study is to characterize video EEG changes that correspond with orthostatic intolerance in youth during HUT testing. The investigators hypothesize that the clinical encephalopathy related to POTS and referred to as 'brain fog' will have an electrographic correlate. Secondary aims include (1) EEG comparisons of POTS symptoms with and without abdominal and lower extremity compression during HUT, (2) correlation between sweat rate and EEG changes during HUT, and (3) analysis of EEG characteristics that distinguish syncope with POTS from syncope without POTS. The investigators hypothesize that POTS patients have prolonged syncopal prodromes (compared to syncope patients without POTS) which are protective of syncope during daily activities.