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Circulatory Function

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sounds called crackles, which can be heard with a stethoscope on chest auscultation. As fluid moves into the larger airways, the crackles become louder and coarser. Diagnosis Diagnostic methods in heart failure are directed toward establishing the cause of the disorder and determin- ing the extent of the dysfunction. 1,2 Because heart fail- ure represents the failure of the heart as a pump and can occur in the course of a number of heart diseases or other systemic disorders, the diagnosis of heart fail- ure often is based on signs and symptoms related to the failing heart itself, such as dyspnea and fatigue. Functional classification systems from the New York Heart Association (NYHA) and the American College of Cardiology Foundation/American Heart Association (ACCF/AHA) provide important information about the presence and severity of HF (Table 20-1). The NYHA functional classification system is subjective, meaning the patient describes their level of activity and symp- toms. It is widely used in clinical practice and research settings. The ACCF/AHA classification system is more recent and emphasizes the progression of the disease along with risk factors associated with HF, such as hypertension (Stages A and B). The methods used in the diagnosis of heart failure include history and physical examination, laboratory studies,electrocardiography,chestradiography,andecho- cardiography. The history should include information

related to dyspnea, cough, nocturia, generalized fatigue, exercise intolerance and other signs and symptoms of heart failure. A complete physical examination includes assessment of heart rate and rhythm, heart sounds, blood pressure, jugular veins for venous congestion, lungs for signs of pulmonary congestion, and lower extremities for edema. Pulse oximetry can be used to measure the percentage of hemoglobin oxygen saturation. Laboratory tests are used in the diagnosis of ane- mia and electrolyte imbalances and to detect signs of chronic liver congestion. Measurements of BNP are recommended to confirm the diagnosis of heart fail- ure; to evaluate the severity of left ventricular com- promise, estimate the prognosis, and evaluate the effectiveness of treatment. BNP may not be as sensitive in persons with heart failure who are obese or have renal failure. 1,36 Echocardiography plays a key role in assessing ejec- tion fraction, right and left ventricular wall motion (nor- mal, akinesis, or hypokinesis), wall thickness, ventricular chamber size, valve function, heart defects and pericar- dial disease. Radionuclide ventriculography and cardiac angiography are recommended if there is reason to sus- pect coronary artery disease or ischemia as the underly- ing cause for heart failure. Chest radiographs provide information about the size and shape of the heart and pulmonary vasculature, and also can indicate the relative severity of the failure by revealing if pulmonary edema is predominantly vascular or interstitial or has advanced to the alveolar and bronchial stages. Cardiac magnetic resonance imaging and cardiac computed tomography

TABLE 20-1 Comparison of ACCF/AHA Stages of HF and NYHA Functional Classification

ACCF/AHA Stages of HF a

NYHA Functional Classification b

A

At high risk for HF but without structural heart disease or symptoms of HF Structural heart disease but without signs or symptoms of HF Structural heart disease with prior or current symptoms of HF

None

B

I

No limitation of physical activity. Ordinary physical activity does not cause symptoms of HF. No limitation of physical activity. Ordinary physical activity does not cause symptoms of HF. Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity causes symptoms of HF. Marked limitation of physical activity. Comfortable at rest, but less-than-ordinary physical activity causes symptoms of HF. Unable to carry on any physical activity without symptoms of HF, or symptoms of HF at rest.

C

I

II

III

IV

D

Refractory HF requiring specialized interventions

a From Hunt SA, AbrahamWT, Chin MH, et al. 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of heart failure in adults: A report of the American College of Cardiology Foundation/American Heart AssociationTask Force on Practice Guidelines. J Am Coll Cardiol. 2009;53:e1–e90. b The Criteria Committee of the NewYork Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. Boston, MA: Little & Brown; 1994. FromYancy CW, Jessup M, Bozkurt B, et al. 2013 ACCF/AHA guideline for the management of heart failure: a report of the American College of Cardiology Foundation/American Heart AssociationTask Force on Practice Guidelines. Circulation. 2013;128(16):e240–e319.