View clinical trials related to Arrhythmias, Cardiac.
Filter by:Background: End Stage Renal Disease (ESRD) patients have an extremely high mortality and the leading cause of death is cardiovascular disease which accounts for 50% of all deaths. It is estimated that about one third is due to arrhythmias. Previous studies reveal a higher risk of various arrhythmias in dialysis patients but the prevalence is uncertain. Atrial fibrillation is the most common arrhythmia among patients with ESRD. The arrhythmia is often asymptomatic, but the risk of stroke increases dramatically and the annual mortality doubles. Autonomic cardiac dysfunction is often seen in patients with ESRD, and this is expressed by attenuated Heart Rate Variability (HRV) which is a measure of the variation in the time interval between heart beats. Attenuated 24 hours HRV is associated with an increased risk of sudden cardiac death in the general population and among patients with ESRD. N-3 polyunsaturated fatty acids (PUFAs) in fish or fish oil supplements have been shown to increase HRV and reduce the risk of various ventricular and supraventricular arrhythmias in some but not all studies, but this effect has only been sparsely investigated in the high risk patients with ESRD, who has a very low intake of n-3 PUFAs. Objective: The purpose of this study is to investigate the effects of n-3 PUFA supplementation on HRV and arrhythmias in dialysis patients. Hypothesis: n-3 PUFA supplementation increases 24 hours HRV in dialysis patients. n-3 PUFA supplementation reduces the level of Supraventricular tachycardia, premature atrial complexes (PACs) and premature ventricular complexes (PVCs) in chronic dialysis patients. Design: Randomized double-blind, placebo controlled trial Study participants: 140 dialysis patients at Aalborg University Hospital and Vendsyssel Hospital, Hjørring in Denmark. Inclusion time: Summer 2014 to Fall 2015 Methods: The patients are allocated to 3 months treatment with supplements of 2 g n-3 PUFAs or placebo (olive oil). The following data are registered at baseline and after 3 months treatment: Demographics and medical history, Standard ECG-12, blood pressure, blood samples, 48 hours ambulatory ECG Holter recordings, Intake of n-3 PUFAs (assessed by questionnaires and blood measurements). Perspective: A positive result of this study might make it possible to achieve a reduction in arrhythmias and mortality in these high risk patients by a cheap and well tolerated nutritional supplement.
The objective of this study is to evaluate myocardial injury, if any, as quantified by cardiac markers (Troponin-T) in defibrillation threshold (DFT) testing during implantation of implantable cardioverter defibrillators (ICDs) using the upper limit of vulnerability (ULV) method vs. standard defibrillation threshold method.
If a surgical sponge is mistakenly left inside a patient's body after a surgical procedure, it can cause a serious infection. To prevent this from happening, a new device has been developed that uses radiofrequency (RF) signals to detect the presence of surgical sponges inside the body. The device is now being used routinely to make sure that no sponges are left inside a patient at the end of an operation. However, the RF device has not been implemented in procedures for patients with cardiac implantable electronic devices (CIEDs). While the device is FDA approved for use, there is a theoretical concern that the radiofrequency signals used to detect the sponges will change the settings on the pacemaker or the defibrillator. Changing the settings on a pacemaker might make it pace the heart too quickly or too slowly, while changing the settings on a defibrillator might cause unnecessary shocks or prevent it from shocking the heart if the patient were to have cardiac arrest. The purpose of this study is to test whether the radiofrequency device used to detect sponges can cause a clinically significant change to the settings on pacemakers and defibrillators. To minimize potential risk, the device will be tested only on patients who are having the pacemaker or defibrillator removed or replaced as part of their regular medical care, either because it is infected or because the battery has worn out. Before the pacemaker or defibrillator is removed, the settings will be carefully and completely recorded and the radiofrequency device will be used to scan the body for sponges as it would be done during normal operation. After the pacemaker or defibrillator is taken out, the settings will again be recorded and compared to the settings before the scan. In a standard device removal procedure, no clinically significant change in CIED settings would be expected. If a new pacemaker or defibrillator is implanted in the patient, it will not be exposed to the detection device at all. We will also test whether the RF device has any effect on temporary pacemakers that patients may receive after open heart surgery. We plan to perform testing in a total of 50 patients, 40 with permanent pacemakers or defibrillators and 10 with temporary pacemakers.
This is a PI-initiated study that aims to evaluate the efficacy of two different methods of paroxysmal atrial fibrillation (PAF) ablation. There are currently two strategies for PAF ablation that are routinely performed by electrophysiology clinicians: (1) circumferential pulmonary vein ablation (CPVA) and (2) segmental pulmonary vein isolation (SPVI). However, it is not known if one approach is better than the other. This randomized study will evaluate and compare the efficacy of CPVA versus SPVI in subjects undergoing ablation for paroxysmal atrial fibrillation only. Subjects will have a 50/50 chance of receiving either the CPVA or SPVI ablation method.
Approximately 2 million patients in North America are currently treated with the blood thinner warfarin. These patients have every year more than 200,000 invasive procedures, for which warfarin must be stopped to avoid bleeding complication. To protect the patient against blood clots and stroke while warfarin is stopped, most physicians today order "bridging" with low-molecular-weight heparin (LMWH). This is another blood thinner and it is injected under the skin during 3 days before the procedure. For implantation of pacemaker or defibrillator (27,000/year in Canada) the "bridging" routines vary a lot.The common "bridging" treatment with LMWH for 3 days before pacemaker surgery causes bleeding in the "pocket" where the pacemaker is placed in about 5%. For comparison, patients not on any blood thinners develop this bleeding in 2% after this surgery. "Pocket bleeding" may require evacuation of the blood collection and may cause infection. "Pocket bleeding" is thus a fairly common and clinically important but rarely a dangerous bleeding complication. It is a suitable safety endpoint in a study of "bridging" of blood thinners. LMWH costs $80-120, for which some patients are not covered. They have to be taught self-injection technique or have a nurse come to their home. The main hypothesis is if patients on blood thinners can be managed more conveniently before and after pacemaker surgery, without injections, without increased risk of pocket bleeding.
Successful radio frequency (RF) cardiac catheter ablation requires the creation of lesions by delivering energy while maintaining adequate catheter contact with the endocardium. Unfortunately, it is difficult to identify contact intraoperatively as a typical RF ablation catheter lacks clear indications of contact. We propose to use the Boston Scientific IntellaTip MiFi catheter to explore whether characteristics of the electrograms produced by the mini-electrodes on the ablation tip could help confirm tissue contact. Using an ultrasound catheter to define instances of clear contact and non-contact, we will determine whether the micro-electrodes produce sufficient information to confirm catheter contact. We propose that the MiFi catheter produces sufficient signal characteristics that can be used as an effective surrogate for adequate tissue contact.
This is a single center, non-randomized, unblinded study of patients who are followed at Essentia Health - St. Mary's Medical Center and who are referred for a clinically indicated diagnostic electrophysiology (EP) study with or without ablation. During the procedure, events of atrial fibrillation, sinus rhythm and bundle branch block that may occur during the course of the case will be saved electronically and analyzed offline. The stored data will be evaluated off-line for changes in activation timing of the near and far field ventricular signals of the stored events. This proof-of-concept study will attempt to assess whether atrial fibrillation, or bundle branch block can change activation timing compared to baseline sinus rhythm. If no significant activation change is seen, then this finding can be used as a basis to distinguish ventricular tachycardia from atrial fibrillation in future rhythm discrimination methods.
It is universally recognised that current methods for risk stratification of sudden cardiac death (SCD) are limited. A novel SCD risk marker, the Regional Restitution Instability Index (R2I2), measures the degree of heterogeneity in electrical restitution using data obtained from a standard 12 lead ECG acquired during an invasive electrophysiological study. In an ischaemic cardiomyopathy (ICM) cohort of 66 patients, an R2I2 of ≥1.03 identified subjects with a significantly higher risk of ventricular arrhythmia (VA) or death (43%) compared with those with an R2I2 <1.03 (11%) (P=0.004). This study will use non-invasive techniques to acquire electrical restitution data: exercise and pharmacological stress, and will incorporate body surface potential mapping to develop a non-invasive and high-resolution form of R2I2. Suitable patients will be recruited into a prospective, observational study. HYPOTHESES: PRIMARY: 1. R2I2 is predictive of ventricular arrhythmia (VA) / SCD in patients with ICM. 2. The exercise stress protocol will create a dynamic range of heart rates that allows ECG quantification of electrical restitution heterogeneity that correlates with invasive R2I2 and is predictive of VA/SCD. The pharmacological stress protocol will create a dynamic range of heart rates that allows ECG based quantification of electrical restitution heterogeneity that correlates with invasive R2I2 and is predictive of VA/SCD. SECONDARY: 1. A high-resolution electrical map acquired using body surface potential mapping will correlate with R2I2 and these data can be included in the R2I2 calculation to improve its prediction of SCD/VA. 2. Serial measurement of R2I2 will produce consistent values.
The objective of this study will be to evaluate the ability of IEGMs (Signal recorded from implanted pacing leads) and pseudo ECGs (derived from various IEGMs) to characterize various electrical conduction patterns. Electroanatomic mapping data and 12 Lead ECG will also be collected to characterize electrical conduction patterns during standard electrophysiology exam.
The purpose of this study is to validate a novel method of diagnosing arrhythmias using the NAVA catheter-positioning screen in patients who have a NAVA catheter in place.