OBJECTIVES: Analysis of the left ventricular (LV) pressure-volume loop (P-V loop) to assess LV function. DESIGN: Retrospective study of clinical, hemodynamic and angiographic, data of 29 normal individuals and 115 patients with myocardial dysfunction, but no valvular or congenital heart disease. P-V loops were constructed, critically analyzed and compared with the clinical functional status of the patients. MAIN RESULTS: A number of theoretical new concepts was introduced and measured: end-systolic energy (ESE), total LV energy (TE) and potential maximal LV energy (PEmax). These variables were compared with the stroke work, which is neither sensitive nor specific, to separate different stages of cardiac function. ESE, TE and PEmax are sensitive variables, and inversely related to the cardiac reserve. CONCLUSIONS: P-V loops are easy to construct using well recorded hemodynamic and angiographic data. Analysis of P-V loops provides the cardiologist with an overall picture of the myocardial function and reserve.