Markers of myocardial ischaemia.

and the heart, ignoring the possibility that poor cardiac function leads to depression rather than the other way round. The study by van Melle et al. is very important because it shows that the severity of left ventricular dysfunction is significantly related to the severity of depressive symptoms in patients with myocardial infarction. This at least suggests the possibility that heart damage may be primary, and the mood disturbance follows. We agree with Kounis et al. that characterizing the mechanisms connecting the brain and the heart— as well as their direction—is critical, because the implication that left ventricular dysfunction might lead to depression is that if the former is treated appropriately, the latter may improve.