With advances in diagnosis and treatment, breast cancer has become an increasingly survivable disease with a growing population of long-term survivors. As an essential component of breast conservation therapy, radiotherapy is a standard treatment for many women with stage I/II breast cancer. Cardiac radiation exposure has been associated with an increased risk of cardiovascular diseases. Among these are coronary artery disease, cardiomyopathy, valvular heart disease, and pericardial disease. Microvascular changes and accelerated atherosclerosis are likely the primary underlying mechanisms of radiation induced cardiovascular damage. A simple and highly effective technique, deep inspiration breath-hold (DIBH), has been shown to decrease cardiac radiation exposure without compromising target coverage. This brief review focuses on the effects of radiation therapy on the heart, radiation-induced cardiovascular diseases in breast cancer survivors, and the DIBH technique as a means for reducing cardiac radiation exposure.