05 July 2007
Eur Heart J 2007; 28: 1554–1558
A small clinical study has failed to detect subendocardial ischemia in patients with "cardiac syndrome X," a term used to describe individuals with chest pain but normal coronary angiograms.
The study, which appears in the European Heart Journal, conflicts with recent research and appears to rule out the possibility that subendocardial hypoperfusion explains angina in patients with this syndrome.
Ilse Vermeltfoort (VU University Medical Center, Amsterdam, The Netherlands) and team used magnetic resonance imaging (MRI) to assess visually and semi-quantitatively coronary perfusion in 20 patients with angina pectoris and normal angiograms.
Just 1.1% of the MRI segments displayed visual signs of ischemia, the authors report. Furthermore, myocardial perfusion increased significantly during adenosine infusion in both the subendocardium and the subepicardium.
Next the team calculated an index for myocardial perfusion reserve (MPRI) based on myocardial perfusion at rest and during maximal vasodilation. Again, this index increased significantly in both areas of the heart, and the mean subendocardium-to- subepicardium MPRI was well above the cutoff used to define hypoperfusion.
"We found no evidence for subendocardial ischemia in our group of patients," the authors state.
"The exact mechanism of chest pain in syndrome X patients remains unclear."