View clinical trials related to Tachycardia.
Filter by:The drug-induced long QT syndrome (diLQTS) describes a clinical entity in which administration of a drug produces marked prolongation of the QT interval of the electrocardiogram, associated with the development of a polymorphic ventricular tachycardia, termed torsades de pointes (TdP). The heart rate is an important variable affecting the QT interval. The QT interval normally shortens as the heart rate accelerates; however, the adaptation of the QT interval to sudden heart rate acceleration is not instantaneous. Interestingly, Holter studies show that the speed of response of the QT interval to sudden changes in heart rate (that is, the time it takes the QT interval of a given person to reach a new steady-state QT/RR relation) in healthy persons is highly individual and independent of the basic QTc. The investigators and others recently proposed the "quick standing" test as a simple bedside test that facilitates the diagnosis of congenital LQTS. The test takes advantage of the fact that as one stands up, the heart rate acceleration is abrupt while the associated QT-interval shortening is gradual. As the R-R interval shortens faster than the QT interval, the QT appears to "stretch" toward the next P wave and the corrected QT interval (QTc) for heart rate actually increases momentarily. The phenomenon of "QT stretching" is universal but is exaggerated in patients with LQTS, allowing for a simple but accurate diagnostic test. There is no data on the effects of quick standing on drug-associated form of the long QT syndrome. The investigators therefore propose the present study to better understand who these patients with drug-associated form of the long QT syndrome are and what the significance of their abnormal QT-response is.
The objective of the study is to confirm safety and efficacy of the BioMonitor 2. The data is collected to support the regulatory approval of this product in countries outside the CE region.
Use of dipole density mapping to identify activation in complex supraventricular tachycardias.
Use of dipole density mapping to identify activation in complex supraventricular tachycardias
Use of dipole density mapping to identify activation in complex supraventricular tachycardias.
Tachycardia's (fast heart rhythms) can lead to troublesome palpitations, dizziness, blackouts and breathlessness. They are caused either by a cluster of abnormal cells within the heart, or an electrical short circuit which rotates rapidly around the heart. Sometimes these can be controlled with tablets, though owing to side effects many patients want something else. Many tachycardia's can be cured by a procedure known as an "ablation". In essence, either the focus of abnormal cells or the narrowest point of the short circuit causing the abnormal heart rhythm (the source) is electrically destroyed (burnt) resulting in restoration of the normal heart beat. One form of tachycardia is known is Atrial Tachycardia (AT). These arise from the top two chambers of the heart (the atrium). Interestingly, this problem is frequently seen in patients who have previously undergone an ablation or surgical procedure for a condition called Atrial Fibrillation. In others the reason for its occurrence is unknown. Current strategies to find the "source" during an ablation procedure are technically challenging resulting in long procedure times. Sometimes the wrong source is found resulting in ablation at the incorrect site. Ripple Mapping (RM) is a novel system that Investigators at Imperial College are looking to study. RM displays electrical information within the heart as a series of bars coming out of the chamber, with each bar representing signals travelling down the heart. By seeing the pattern of electrical information, they believe it will show the pattern of the tachycardia better than conventional techniques. In a previous retrospective study that they conducted, RM found the source of the tachycardia in 80% of the maps, compared to only 50% with the current system. Investigators at Imperial College have identified why they did not get 100% and they believe that, in future, RM will find the source of the tachycardia first time, and every time.
This study assesses the 18-month incidence of inappropriate shocks in subjects implanted with the EMBLEM Subcutaneous Implantable Defibrillator (S-ICD) for primary prevention of sudden cardiac death. Devices are to be programmed with zone cutoffs at 200 bpm and 250 bmp in order to mimic the programming settings for transvenous ICDs in the MADIT RIT study. The incidence of inappropriate S-ICD shocks will be compared to the incidence of inappropriate shocks observed in the MADIT RIT study.
This research study is being done to see whether general anesthesia (GA) affects our ability to start ventricular tachycardia (VT) during an VT ablation procedure. Data collected during this research study will help electrophysiologists and anesthesiologists to make the best decisions about the best anesthetic conditions to use to perform VT ablations. This research study is a "pilot" study. Pilot studies are done on a small group of subjects to learn if a larger study would be useful.
- The primary objective of this study is to assess the effect of an energy drink on ventricular repolarization as measured by the interval between the cardiac Q wave and the cardiac T wave (QT interval)obtained from the body surface ECG. - The secondary objective is to assess the effects of an energy drink on heart rate and blood pressure (hemodynamic effects). To place the observed changes in context, comparison will be made to a commonly consumed drink, coffee: Starbuck's K-cup Breakfast Blend.
This non-randomized study will examine the safety and efficacy of irrigated bipolar radiofrequency (RF) ablation in the treatment of ventricular tachycardia (VT) in patients for whom standard VT unipolar RF ablation has been unsuccessful. VT is a serious abnormality of the heart's electrical system. Ablation is a procedure that cauterizes heart tissue using catheters (long tubes that can be moved within or along the outside of the heart). Cauterizing the heart tissue is accomplished by using heat to damage the abnormal heart tissue that is not working well so that it can stop affecting the rest of the heart. Usually, heat is delivered using a unipolar catheter, in which energy travels from the catheter tip to a grounding pad. This research study seeks to find out if a bipolar ablation catheter, in which the energy travels between two catheter tips on either side of the heart muscle, can be used to eliminate the arrhythmia when the unipolar ablation is unsuccessful. The hypothesis is that the increased current density and improved rates of transmural lesion creation seen with bipolar RF ablation will lead to successful arrhythmia termination with minimal or no increased risk of complication.