Wellens' syndrome is an electrocardiographic manifestation of critical proximal left anterior descending (LAD) coronary artery stenosis in people with unstable angina.

[1] First described by Hein J. J. Wellens and colleagues in 1982 in a subgroup of people with unstable angina,[2] it does not seem to be rare, appearing in 18% of patients in his original study.

[3] The presence of Wellens' syndrome carries significant diagnostic and prognostic value.

In the original Wellens' study group, 75% of those with the typical syndrome manifestations had an anterior myocardial infarction.

Sensitivity and specificity for significant (more or equal to 70%) stenosis of the LAD artery was found to be 69% and 89%, respectively, with a positive predictive value of 86%.