What is the relationship between cardiac ischemia and shortness of breath?

Uncertain: The exact mechanism by which cardiac ischemia causes dyspnea is unknown. There are a number of possible reasons including 1) increased pulmonary edema from poor heart function during ischemia (ie systolic dysfunction) 2) weakening of filling of the heart during relaxation (ie diastolic dysfunction) and 3) increased sensation of shortness of breath due to chest pain (angina).

Symptoms: Cardiac ischemia (lack of enough blood supply to a part of the heart muscle) can manifest as shorteness of breath (second most common symptom after chest pain).