Hassanpour Dehkordi A, Khaledi Far A Effect of exercise training on the quality of life and echocardiography parameter of systolic function in patients with chronic heart failure: a randomized trial. Asian J Sports Med. 2015 Mar;6(1):e22643. doi: 10.5812/asjsm.22643. Epub 2015 Mar 20.
Maldonado-Martín S, Brubaker PH, Eggebeen J, Stewart KP, Kitzman DW Association Between 6-Minute Walk Test Distance and Objective Variables of Functional Capacity After Exercise Training in Elderly Heart Failure Patients With Preserved Ejection Fraction: A Randomized Exercise Trial. Arch Phys Med Rehabil. 2017 Mar;98(3):600-603. doi: 10.1016/j.apmr.2016.08.481. Epub 2016 Sep 28.
Teng HC, Yeh ML, Wang MH Walking with controlled breathing improves exercise tolerance, anxiety, and quality of life in heart failure patients: A randomized controlled trial. Eur J Cardiovasc Nurs. 2018 Dec;17(8):717-727. doi: 10.1177/1474515118778453. Epub 2018 May 18.
van Tol BA, Huijsmans RJ, Kroon DW, Schothorst M, Kwakkel G Effects of exercise training on cardiac performance, exercise capacity and quality of life in patients with heart failure: a meta-analysis. Eur J Heart Fail. 2006 Dec;8(8):841-50. Epub 2006 May 18.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
