Systolic heart failure is characterized by ventricular dilation and reduced ejection fraction, and this syndrome may be either chronic or acute. Left ventricular remodeling is the principal cause of progression of systolic heart failure. Acute heart failure resulting from cardiomyopathy has similar functional and morphologic abnormalities. This review discusses remodeling, initial therapy based on neurohormonal modulation, and treatment of decompensated and refractory heart failure. Diagnosis, prognosis, and management of acute myocarditis are also discussed.