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.


Clinical features:

(1) presence of clinical angina, which may be typical or atypical

(2) most patients are women, often postmenopausal


Diagnostic features:

(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.


Clinical Finding

Syndrome X

Coronary Arteriosclerosis

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.


To read more or access our algorithms and calculators, please log in or register.