The term "Syndrome X" was coined by Arbogast and Bourassa to describe patients with anginal symptoms but normal coronary angiography.
NOTE: The term "Syndrome X" has also been used to describe the metabolic syndrome associated with obesity and diabetes mellitus.
(1) presence of clinical angina, which may be typical or atypical
(2) most patients are women, often postmenopausal
(1) normal angiography or mild disease insufficient to explain symptoms
(2) exercise testing positive
The primary differential diagnosis is occult coronary artery arteriosclerotic disease. Other conditions to consider are coronary artery microspasm and noncardiac chest pain.
response to nitrates during exercise testing
worsening in exercise tolerance
improved exercise capacity
electron beam CT
very low score (see below)
may show a low score but typically significantly higher
response to rapid atrial pacing
normal, with improved left ventricular function
worsening in left ventricular function
Chen et al (page 1529)used age-based cutoffs for calcification scores from electron beam CT:
(1) For a patient <= 60 years of age, a score equal to 0 was 80% sensitive and 90% specific for syndrome X.
(1) For a patient > 60 years of age, a score <=45 was 92% sensitive and 77% specific for syndrome X.
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