The effects of the angiotensin II receptor (type I) antagonist irbesartan in patients with cardiac syndrome X

Blocking these ATII effects may thus be beneficial in cardiac syndrome X. To date, one small trial using the angiotensin-converting enzyme (ACE) inhibitor enalapril has shown a significant reduction in anginal chest pain and ECG evidence of ischaemia on exercise testing. 5 ACE inhibitors, however, only block ATII generation via the classical pathway, but by contrast ATII antagonists completely inhibit angiotensin effects and in addition are selective in blocking ATII effects. [...]if ATII is important in cardiac syndrome X, such drugs should be at least as effective as ACE inhibitors and possibly more effective due to more complete ATII blockade. The study duration was short and possibly not long enough to allow maximum potential effects of the medication. [...]the results of this small study do not support the use of the ATII blocker irbesartan in patients with cardiac syndrome X.