The diagnosis of heart failure is difficult because the presentation of heart failure can change from patients with no symptoms to those with pulmonary edema and cardiogenic shock. Only 50% of patients with heart failure are diagnosed initially. Dr. Ventura discussed a systematic approach to improve the diagnosis of heart failure. This approach consists of clinical history, physical exam and laboratory tests.

A complete clinical history includes asking patients about the cardinal signs of heart failure: dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, fatigue and weakness. As heart failure progresses, patients may present with gastrointestinal problems such as abdominal pain and distention. In late stages of heart failure, neurological symptoms are present including anxiety or panic attacks, syncope, decreased mental activity or confusion. Patients should be asked about their history of hypertension, coronary artery disease, myocardial infarctions and familial history of heart failure.

The second step in diagnosing heart failure is a complete physical examination. Particular attention is given to venous pressure, the lungs and heart. Venous pressure is checked by the hepatojugular reflex. Breathing disorders, such as apnea/hypopnea and central sleep apnea, are common in patients with heart failure. The heart responds to the valsalva manuver in a characteristic manner in heart failure.

Laboratory tests used to diagnose heart failure are electrocardiogram, chest x-ray, echocardiography, exercise testing, levels of B-type natriuretic peptide and complete blood chemistries. The chest x-ray is used to see the size of the heart and the pulmonary vasculature. Echocardiography provides information on the structure and function of the heart. Exercise or a cardiopulmonary stress test is used because patients with heart failure have a decreased cardiac output, pulmonary capillary wedge pressure, maximal oxygen consumption and anaerobic threshold. B-type natriuretic peptide is an indicator of the severity of heart failure.

Prognosis can be predicted from physical signs, B-type natriuretic peptide and maximal oxygen consumption. Poor prognosis is indicated by elevated venous pressure, third heart sounds, B-type natriuretic peptide levels more than 73 pg/mL and maximal oxygen consumption less than 14 mL/kg/min.