Millions of people die every year due to cardiovascular diseases. The objective against these diseases is primary prevention, but secondary prevention is the major goal in those individuals who already suffered an event. The order of the cardiovascular complication is the next one: arrhythmia, heart failure, myocardial infarction or stroke, and death. Approximately between 1 and 2 % of adults present heart failure, but this percentage rises to more than 10 % in adults over 70 years. Therefore, it is necessary to diagnose and to treat this complication. Left ventricular ejection fraction is the most important prognosis factor in these patients, because it decreases in 50 % of them. Almost 50 % of patients with heart failure have a conserved systolic function, but a decreased diastolic function. Treatment must improve the structural and functional heart abnormalities. Echocardiography is a useful tool in these patients due to its exactitude, accessibility, safety, and low cost. It provides information about the characteristics of the cardiac chambers and its volumes, the diameter in the walls, and about the diastolic, systolic and valvular function. Recently, echocardiography evolved to third dimension techniques, which seem to be more exact. In the next years, we will have more evidence about this diagnostic modality.