Patients presenting to the critical care specialist with respiratory insufficiency commonly have cardiac disease that contributes to or complicates their management. Following the acute stabilization of these patients, ischemia, cardiac dysrhythmias, heart failure, and circulatory failure may prevent further stabilization or precipitate subsequent clinical deterioration. The functional capacity and ultimate fate of the heart and the lungs are closely intertwined; acute failure of one organ immediately challenges the function of the other. Chronic disease of the heart or the lungs is associated with compensatory changes in the other organ that initially are salutatory but, eventually, persistent dysfunction of the heart or lungs may lead to the failure of both and the death of the patient. In this article, the authors review the common cardiac conditions that lead to or complicate the management of the chronically critically ill patient.