Instructions: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: Dual left coronary systems, one originating normally and the other anomalously from the right sinus of Valsalva, is described in a 53-year-old patient with atypical chest pain with exercise-induced ST-depression in the anteroseptal area (V2-4). Clinical consequences of this hitherto undescribed anomaly are discussed.
Output:
Angiography