Chronic Heart Failure — Bowditch Revisited: Defining the Optimum Heart Rate Range in Chronic Heart Failure
Citation(s)
Al-Najjar Y, Witte KK, Clark AL Chronotropic incompetence and survival in chronic heart failure. Int J Cardiol. 2012 May 17;157(1):48-52. doi: 10.1016/j.ijcard.2010.11.018. Epub 2010 Dec 23.
Shelton RJ, Ingle L, Rigby AS, Witte KK, Cleland JG, Clark AL Cardiac output does not limit submaximal exercise capacity in patients with chronic heart failure. Eur J Heart Fail. 2010 Sep;12(9):983-9. doi: 10.1093/eurjhf/hfq086. Epub 2010 Jun 4.
Witte KK, Clark AL Chronotropic incompetence does not contribute to submaximal exercise limitation in patients with chronic heart failure. Int J Cardiol. 2009 May 29;134(3):342-4. doi: 10.1016/j.ijcard.2008.02.014. Epub 2008 Jun 20.
Witte KK, Clark AL Chronotropic incompetence in heart failure. J Am Coll Cardiol. 2006 Aug 1;48(3):595; author reply 595-6. Epub 2006 Jul 12.
Witte KK, Clark AL Resting left ventricular function, however measured, is poorly related to exercise capacity in chronic heart failure. Am J Cardiol. 2006 Sep 1;98(5):709-10. Epub 2006 Jul 5.
Witte KK, Cleland JG, Clark AL Chronic heart failure, chronotropic incompetence, and the effects of beta blockade. Heart. 2006 Apr;92(4):481-6. Epub 2005 Sep 13.
Bowditch Revisited: Defining the Optimum Heart Rate Range in Chronic Heart Failure
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.
