A rare tumour that randomly secretes stress hormones – historically leading some doctors to diagnose sufferers with a psychiatric disorder – does more damage to the heart than previously thought, University of Oxford research reports today.
In the largest study of its kind, researchers said phaeochromocytoma tumours in the adrenal glands, which sit above the kidneys, are likely to suffer inflammation and small areas of scarring of the heart as a result of their condition.
After analysing more than 60 patients at Oxford’s John Radcliffe Hospital using sophisticated cardiac MRI scans, researchers found persistent problems with the heart contracting and relaxing in some patients, even when the heart looks like it is pumping normally.
This goes against previous research which said the heart would return to normal as long as the tumour is removed.
The new research also proposes that it is stress hormones and not the associated high blood pressure as previously thought that have a direct toxic effect on the heart.
The findings were made possible by the use of MRI machines at the University of Oxford Centre for Clinical Magnetic Resonance Research at the JR hospital. It is the first large scale study to use MRI in phaeochromocytoma tumours.
The adrenal glands secrete stress hormones to produce a “fight or flight” response to control heart rate, metabolism and blood pressure so the person can function when stressed.
Phaeochromocytomas can cause the glands to produce too much of these hormones at random times, resulting in heart palpitations, sweating, headaches and high blood pressure when not stressed.
The study scanned 29 people with newly diagnosed phaeochromocytoma before and after surgery, 31 who had had the tumour removed as well as healthy volunteers and people with high blood pressure.
It found those with high blood pressure did not have as much scarring and inflammation of the heart as those with phaeochromocytoma.
The study also reported that patients with pheochromocytoma typically do not have thickened hearts like those with uncontrolled high blood pressure, leading to the conclusion that the hormones, and not high blood pressure, causes this damage.
The study was funded by the NIHR Oxford Biomedical Research Centre and supported by the Alberta Innovates Health Solutions Clinical Fellowship, the University of Oxford Clarendon Fund Scholarship and British Heart Foundation Centre of Research Excellence, Oxford.