Heart failure can be diagnosed when the patient has one major criterion and two minor criteria or two major criteria not attributed to another medical condition. Major criteria are paroxysmal nocturnal dyspnea, orthopnea, elevated jugular venous pressure, pulmonary rales, third heart sound, cardiomegaly on chest x-ray, pulmonary edema on chest x-ray, weight loss ≥4.5 kg in five days in response to treatment of presumed heart failure. Minor criteria are bilateral leg edema, nocturnal cough, dyspnea on ordinary exertion, hepatomegaly, pleural effusion, tachycardia (heart rate ≥120 beats/min).