Apparatus and methods are described including identifying a subject as suffering from a condition selected from the group consisting of congestive heart failure, diastolic heart failure, acute myocardial infarction, and hypertension. In response to the identifying, an electrode is placed on the subject's aorta at an aortic site that is between a bifurcation of the aorta with the subject's left subclavian artery and a bifurcation of the aorta with the subject's fifth intercostal artery. The subject is treated by electrically stimulating the aortic site by driving a current into the aortic site, via the electrode. Other applications are also described.