1. Unstable angina  (Trust Mark: Doctor-Reviewed)
Unstable angina is a condition in which your heart doesn't get enough blood flow and oxygen. It is a prelude to a heart attack. Most people experience a feeling of chest discomfort or shortness of breath. See also: Stable angina; Variant angina.• Reviewer: Steven Kang, MD, Division of Cardiac Pacing and Electrophysiology, East Bay Arrhythmia, Cardiovascular Consultants Medical Group, Oakland, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.