Active clinical trials for "Atrial Fibrillation"

Atrial fibrillation (AF), the most common sustained heart rhythm disorder, is becoming increasingly prevalent in the Western world. The number of people with AF in the United States is projected to roughly double by the year 2050, to an estimated 6-12 million. For many patients with AF, rate control with atrioventricular (AV) node blockers is a widely accepted therapeutic strategy. These agents control heart rate, thus preventing symptoms and systolic heart failure associated with tachycardia due to a rapid ventricular response to AF. Beta-blockers are widely accepted as first line agents for rate control in AF, especially when patients have concomitant hypertension (HTN), coronary artery disease, cardiomyopathies, or heart failure (HF). As a class, beta-blockers are among the most commonly prescribed cardiovascular medications. Among patients with AF treated with beta-blockers, the heart rate (HR) response varies substantially. Sometimes, adequate rate control can be achieved by titration of the beta-blocker dose; but frequently, additional AV nodal blockers and/or digoxin are necessary. In some cases, adequate rate control cannot be achieved even with the simultaneous use of multiple AV nodal blockers, necessitating mechanical ablation of the AV node and permanent pacemaker implantation. Patient-specific variables that influence the response to beta-blockers include comorbid conditions, weight, age, and level of physical activity. Ethnic differences in the response to beta-blockers for the treatment of HTN and HF are well-described. However, the contribution of genetic variants to beta-blocker efficacy in AF is unknown. We propose to study whether the ADRB1 Gly389Asp SNP reduces response to beta-blockade in subjects with permanent AF.

The purpose of this study is to assess the efficacy of F373280 on the maintenance of normal cardiac rhythm after direct electric cardioversion in patients with persistent atrial fibrillation and cardiac failure.

Atrial fibrillation is a condition in which the heart's upper chambers, the atria, contract at an abnormally rapid rate. It is a common type of arrhythmia, and occurs in 1-2% of the general population. The prevalence of atrial fibrillation increases with age. Between 50 and 70% of patients with atrial fibrillation lasting <48 hours spontaneously convert to normal sinus rhythm, and drug therapy increases the likelihood of conversion to sinus rhythm. Another treatment option for conversion of atrial fibrillation and atrial flutter is electrical conversion. This is an effective treatment but requires anesthesia. Current treatment strategy for medical conversion of atrial fibrillation and atrial flutter is to employ drugs that affect ion channel activity in atrial cardiomyocytes. However, such converting drugs all have potentially serious side effects and are expensive. Potassium, sodium, calcium, and magnesium molecules are the most important ions causing electric current in the heart tissue. Our hypothesis is that hypokalemia promotes atrial fibrillation/atrial flutter by a direct effect on cardiomyocytes. Accordingly, we also hypothesize that potassium infusion may convert atrial fibrillation/atrial flutter to normal sinus rhythm. If so, this would be an inexpensive treatment with potentially very few side effects.

The purpose of this study is to determine whether vitamin K supplementation will improve anticoagulation control in patients on hemodialysis taking warfarin for atrial fibrillation. Patients who participate will receive vitamin K1 three times a week on dialysis days for a period of four months. INR levels collected during this period will be compared to the four month period prior to receiving the vitamin K1 to determine if vitamin K improves the standard deviation of INRs and time in therapeutic range.

This is a feasibility study to assess the safety and efficacy of the AtriCure AtriClip when placed via Minimally Invasive Surgical Deployment to the Left Atrial Appendage. The purpose is for evaluation of Stroke Prevention in Patients with Non-Valvular Atrial Fibrillation who are unable to take Oral Anticoagulants.

Cryoballoon based therapy is an established therapy for the treatment of (paroxysmal) atrial fibrillation. However, with the rapid evolution in cryoablation technique and its increased effectiveness, the risk of complications increases. Therefore it is of utmost importance to define the optimal duration of cryoballoon ablation time.The objective of the study is to assess the optimal ablation duration using the second generation cryoballoon for isolation of pulmonary veins in the treatment of atrial fibrillation.

Atrial fibrillation is an abnormal heart rhythm in which the top chambers of the heart (the atrial chambers) beat very fast. Electrical cardioversion is a technique to convert heart rhythm from AF to normal rhythm. The technique sends out a brief electric shock to the heart through electrodes (paddles or skin patches) applied to the outside of the chest wall. The shock resets the heart rhythm back to its normal pattern. This technique is practiced at many hospitals, including the Heart Institute, and is not experimental. However no detailed national or international guidelines exist to assist physicians in performing cardioversion. Physicians use a variety of methods. Electrical cardioversion does not always restore normal rhythm. Adjusting the electrical energy dose, changing the electrode position and applying pressure to the electrodes may improve the success rate. This study will look at the safety and efficacy of a protocol (step by step method) for electrical cardioversion. The protocol prescribes the electrical energy dose, the electrode position and the application of pressure to the electrodes the physician will use. The individual elements of the protocol (energy dose, electrode position and pressure application) are often used by physician in clinical practice but not necessarily in the step by step order. The purpose of this study is to get all doctors to follow a standard protocol 'the Ottawa AF cardioversion protocol'. We think that using this protocol will improve overall cardioversion success rates. The results of this study may change usual practice in Canada and in other countries. All supplies, equipment and medications used in the protocol cardioversion are approved by Health Canada. We estimate that 389 participants from the University of Ottawa Heart Institute will be enrolled in the study over the next 2 years. The results will be compared with a group of previous patients.

The FIRM Study Oslo will in two sequential within-patient trials investigate the efficacy of focal impulse and rotor modulation (FIRM) as a stand-alone procedure in the treatment of paroxysmal and persistent atrial fibrillation, evaluated by continuous pre- and post-procedural heart rhythm monitoring.

Radiofrequency catheter ablation is highly effective in the treatment of patients with persistent atrial fibrillation. In order to decrease the recurrence rate after catheter ablation, the investigators propose to apply 'virtual' ablation on patient-specific atria by simulating 3D atrial computer model. The investigators will test with five different set of ablation methods and find successful methods for a specific patient. Then, this result will be compared to empirical catheter ablation result by randomly controlled trial.

Comparing efficacy and safety of isolation of the pulmonary veins (PV) using a Cryoballoon catheter versus a radiofrequency ablation with a ThermoCool catheter in patients with paroxysmal atrial fibrillation.