Cardiac toxicity is damage to the heart by harmful chemicals. As part of the treatment patients are given toxins drugs to kill cancer cells. Chemotherapy can cause mild or severe damage to the heart. If severe, congestive heart failure or other life-threatening problems can occur. A side effect is that the normal cells in and around your heart can also be killed. Besides cell death, other types of cardiac toxicity from cancer treatment include cardiomyopathy in which heart muscle is weakened, enlarged, thickened, or stiff; Myocarditis, inflammation or swelling of the heart; pericarditis is inflammation or swelling of the sac surrounding the heart; acute coronary syndromes caused by blood vessel damage; congestive heart failure, when the heart is unable to pump enough blood throughout the body. A heart transplant may even be needed.