Megaloblastic anemia may cause heart disease such as panic, myocardial ischemia, and heart failure. 1. Panic: Megaloblastic anemia may cause panic, chest tightness, shortness of breath and other symptoms. 2. Myocardial ischemia: Prolonged megaloblastic anemia may lead to abnormal diastolic function of the myocardium, which in turn causes myocardial ischemia. 3. Heart failure: Myocardial ischemia caused by megaloblastic anemia may lead to heart failure if the anemia is severe or the duration of ischemia is long. In addition, the lack of vitamin B12 in megaloblastic anemia affects the activation of myocardial energy, which may further induce the occurrence of heart failure. Megaloblastic anemia may also have other effects on the heart, once the occurrence of megaloblastic anemia should go to the hospital in a timely manner, under the guidance of the doctor for standardized treatment.