The principal function of the heart is to propel oxygenated blood to the peripheral tissues to meet their metabolic demands. The systemic arterial and venous systems provide the conduits. The interaction of the left ventricle (LV) with the arterial and venous systems is therefore integral to the satisfactory performance of this vital function. It is important to understand how the normal heart functions and how it interacts with the systemic arterial and venous systems as a prelude to comprehending how it is affected by various pathologic conditions. This chapter provides a physiologic framework for understanding normal cardiac contraction and relaxation and the interaction of the LV with the systemic arterial and venous systems by developing seven basic concepts. Taken together, these concepts can be used to provide insight into abnormal cardiac mechanisms in pathophysiologic conditions.