RHYTHM (RHeumatoid Arthritis studY of THe Myocardium): How Rheumatoid Arthritis (RA) and Tumor Necrosis Factor (TNF) Inhibitors Affect the Myocardial Structure and Function.

Patients with Rheumatoid Arthritis (RA) have a shortened life expectancy compared to the general population. Cardiovascular disease (CVD), including heart failure (HF), is the primary cause of the extra deaths in RA. HF, in general, results from failure of the heart muscle to pump adequately. In other words the heart muscle in HF becomes "weak". In patients without RA, the heart muscle gets larger before symptoms of HF appear. Contrary to that, patients with RA have reduced heart size and reduced heart strength. This may mean that in RA the pathway to heart failure may be different compared to what happens in patients without RA. It is possible - for example - that in RA the heart muscle becomes smaller before it becomes weak (while in non-RA patients the heart muscle becomes larger before it becomes weak). It is possible that cells that create inflammation in the joints may also do the same in the heart muscle making it smaller, thinner and eventually weaker.

Patients with RA nowadays can be treated with a variety of medications for their joint inflammation. These medications are powerful and have reduced the risk of permanent joint damage and disability. However it is unknown what is the effect of these medications on the heart size and strength and whether they increase or decrease the risk for cardiovascular disease and heart failure.

Among the medications used for RA are medications called TNF inhibitors. They are usually prescribed to patients who have joint inflammation that has not responded to treatment with the first line medication Methotrexate. Data in non-RA patients with advanced heart failure suggest that anti-TNF agents may not help heart failure and may even be harmful. However, the effect of these agents on the hearts of RA patients has never been directly studied. Some observational studies suggest that RA patients treated with TNF inhibitors have a lower risk of developing heart disease. Overall the knowledge regarding the effect of TNF inhibitors on RA patients heart function is limited.