Rate Control in Atrial Fibrillation II
Overview
- Phase
- Phase 4
- Intervention
- Metoprolol
- Conditions
- Atrial Fibrillation
- Sponsor
- Asker & Baerum Hospital
- Enrollment
- 122
- Locations
- 1
- Primary Endpoint
- Levels of NT-proBNP
- Status
- Completed
- Last Updated
- 4 years ago
Overview
Brief Summary
The RATAF II study is a randomized, prospective, parallel group study, designed to compare the effects of two different drug regimens for rate control in permanent AF (atrial fibrillation). We will investigate on the difference in effects on exercise capacity, biomarkers (NT-proBNP (N-terminal pro-brain natriuretic peptide), troponins, hs-CRP), heart rate, echocardiographic measurements and symptoms.
Our main hypothesis is that six months' treatment with the calcium channel blocker diltiazem will lower NT-proBNP and increase exercise capacity (peak VO2) compared to treatment with the beta blocker metoprolol in permanent AF.
Detailed Description
Atrial fibrillation is a common cardiac disease, with increasing incidence and prevalence. There are two main treatment strategies for this arrhythmia, rhythm control and rate control. As rate control is easier to achieve and no major difference in outcome has been found between these two strategies, it is considered a reasonable initial treatment for the majority of AF patients. Reduced exercise capacity is the most prevalent symptom in patients with permanent AF. In the first Rate control in Atrial Fibrillation (RATAF) study, we demonstrated that calcium channel blockers preserved exercise capacity, reduced arrhythmia-related symptoms and lowered levels of NT-proBNP - whereas the beta blockers reduced the exercise capacity, did not reduce arrhythmia-related symptoms and increased NT-proBNP. These findings are relevant to a large proportion of patients with permanent AF, suggesting that calcium channel blockers should be the first drug of choice for rate control in patients without heart failure or coronary heart disease. Our results challenge the current widespread use of beta blockers in this setting. However, as the follow up time in the RATAF study was only 3 weeks, it is not clear if these effects are sustained over time. Furthermore, we do not know the mechanisms for the differential effects on exercise capacity, arrhythmia related symptoms and NT-proBNP levels. In the RATAF II study we will investigate whether the effects on NT-proBNP levels, exercise capacity and symptoms are sustained over time, and explore potential mechanisms that may explain the difference in these effects. The study will provide new insights and results relevant for everyday clinical practice and be of importance for a large and growing group of patients. A total of 240 patients will be included. Eligible patients will be recruited from the out-patient clinics at the participation hospitals and through advertisements in local newspapers. After inclusion and a wash-out period of 14 days free from drugs affecting the heart rate, patients will be examined by echocardiography, 12-lead ECG (electrocardiography), 24h Holter monitoring, maximal cardiopulmonary exercise test and venous blood sampling at rest, at maximal exercise and after recovery. Perceived arrhythmia related symptoms, quality of life and level of physical activity will be assessed using self-administered questionnaires. Participants will be randomized through a computer-generated randomization list, to receive one of the study drug regimens; metoprolol 100 mg o.d. or diltiazem 360 mg o.d. The investigators and study personnel will be blinded with regard to allocated study drug. The participants themselves will know what study drug they are assigned. Also, study personnel not involved in examinations will also be able to acquire knowledge concerning assigned study drug, to ensure the process of dosage in the startup phase, assess adverse events (AE) and side effects throughout the study. Examinations will be repeated after four weeks and six months. All examinations will be performed at the Department of Medical Research, Baerum Hospital to ensure standardized procedures.
Investigators
Sara Reinvik Ulimoen
MD PhD postdoc fellow
Asker & Baerum Hospital
Eligibility Criteria
Inclusion Criteria
- •Above 18 years of age
- •Symptomatic, permanent AF of at least three months duration
- •Resting heart rate ≥80 bpm
- •Signed informed consent
Exclusion Criteria
- •Congestive heart failure
- •Ischemic heart disease
- •Hypotension (Systolic blood pressure \<100 mmHg)
- •Treatment with class I or III antiarrhythmic drugs
- •Severe hepatic or renal failure
- •Pregnancy or lactation
- •Hypersensitivity or contradictions to study drugs
- •Atrio-ventricular conduction disturbances
- •Thyrotoxicosis
- •Life limiting disease or substance abuse which may affect participation
Arms & Interventions
Metoprolol
Metoprolol, extended release tablets. 100 mg daily
Intervention: Metoprolol
Diltiazem
Diltiazem, extended release tablets. 360 mg daily
Intervention: Diltiazem
Outcomes
Primary Outcomes
Levels of NT-proBNP
Time Frame: 6 months
Levels of NT-proBNP will be measured after 6 months
Secondary Outcomes
- Echocardiographic measures - Standard parasternal long axis and three apical views recordings.(6 months)
- Ventricular heart rate(6 months)
- Quality of life in SF-36(6 months)
- Exercise capacity defined as peak VO2(6 months)
- Echocardiographic measures - Left ventricular mass.(6 months)
- Echocardiographic measures - Left ventricular ejection fraction will also be calculated.(6 months)
- Symptoms(6 months)
- Other biomarkers(6 months)
- Echocardiographic measures - Left ventricular and left atrial maximal and minimal volumes.(6 months)
- Echocardiographic measures - Transmitral flow and pulmonary venous flow.(6 months)
- Echocardiographic measures - Left ventricular dimension, septal and posterior wall thickness.(6 months)
- Echocardiographic measures - Global and regional longitudinal left ventricular strain.(6 months)
- Echocardiographic measures - Left atrial deformation for assessment of global as well as regional left atrial strain.(6 months)