Acute heart failure has recently become a very common syndrome. Therefore, even if you are not a cardiologist, you should know how to diagnose and treat it. A basic technique is here summarized. Diagnosis of heart failure can be performed from a simple criteria including coarse crackles, an extra-sound (S3), a distention of the cervical vein, cardiomegaly, pulmonary edema, and serum levels of B-type natriuretic peptide (100 pg/ml<). After diagnosis, the severity should be assessed by the degrees of both pulmonary edema and cardiac output. For these evaluations, a Swan-Ganz catheter might not be needed, since we can evaluate them clinically, i.e., physical examinations and auscultation. We can then treat the patient with heart failure with a vasodilator and/or diuretics. If the blood pressure is low, we can administer a low dose of an inotropic agent. But an inotropic agent should be withdrawn as early as possible, because they can occasionally have deleterious effects. Finally, please bear in mind that the elimination of several triggers, e.g., infection, transient cessation of medication, and physical or metal stress, and also the detection of early symptoms of heart failure, e.g., shortness of breath on exertion, fatigue, increase in body weight, and appetite loss, are very important for the prevention of acute heart failure.