Heart Failure: Diagnosis

The New York Heart Association classification system¹ describes the functional limitations of heart failure:

Class I: Symptoms (eg, fatigue, dyspnea, and palpitations) are experienced on heavy exertion.

Class II: Symptoms occur with mild-to-moderate levels of exertion.

Class III: Symptoms occur with less-than-ordinary exertion.

Class IV: Symptoms occur at rest.

Diagnostic Tools

2-D and Doppler echocardiogram is the most common imaging modality for assessing cardiac function. Echocardiography can evaluate left and right ventricular systolic function, diastolic function, valvular function, and cardiac chamber sizes. It also identifies possible heart failure etiologies, such as MI, valvular disease, and cardiomyopathies.

Chest x-ray can identify intrinsic pulmonary disease, pulmonary edema, and pleural effusions. It can also estimate the degree of cardiac enlargement, but is much less accurate than echocardiography. 

Electrocardiogram may reveal MI, dysrhythmias, conduction abnormalities, or left ventricular hypertrophy.             

Pulmonary artery catheterization may identify increased pulmonary capillary wedge pressure, decreased cardiac output, and increased systemic vascular resistance in low-output failure. However, this procedure entails some risk and usually adds little to a careful clinical assessment and echocardiogram.
Measurement of circulating concentrations of brain natriuretic peptide (BNP), which is produced by the heart, is increasingly used to assess the degree of heart failure and monitor treatment effects.