It is possible for leukemia to cause an increased heart rate. Common symptoms of leukemia include anemia, infection and fever, and bleeding. Most patients present with anemia at the time of diagnosis, which can lead to chest tightness, fatigue, and increased heart rate. This is due to the inhibition of normal hematopoiesis in leukemia patients, which results in fewer oxygen-carrying red blood cells and reduced oxygen supply. As the lack of oxygen causes sympathetic excitation, the heart rate is increased to enhance the blood supply from the heart to the tissues and organs throughout the body in order to relieve the hypoxia. In severe cases, heart failure may occur. In addition to anemia, infections and fever can also increase metabolism, which makes the heart rate increase. When leukemia patients experience increased heart rate, they should consult a doctor for standardized diagnosis and treatment.