Learn about Heart Failure, its Prevention, and TreatmentHow is Heart Failure Diagnosed and Evaluated?
Diagnosis of Heart Failure
In order to assess the severity of heart failure, it is important to evaluate the degree to which the damaged heart is affecting the body as a whole, while at the same time evaluating any abnormalities in the functions and structure of the heart itself.
It is usually possible to evaluate structural and functional abnormality with an echocardiogram, but a BNP test or cardiac MRI may be performed for a more precise evaluation.
Also, in order to check how well the heart, lungs and muscles are working, a CPX (cardiopulmonary exercise test) may be carried out, which takes into account a patient's subjective symptoms and 6 minutes of walking to assess their tolerance for physical activity.
Evaluating the Severity of Heart Failure
The severity of heart failure is evaluated using NHYA classification (assessment based on the degree of subjective symptoms) or ACC/AHA classification (staging classification of heart failure such as that used in the evaluation of cancer).
This is the most effective test for causal diagnosis and assessment of the severity of heart failure. The information obtained through echocardiograms* varies widely.
- Left ventricular function/size, right ventricular function/size, left atrial volume, systolic/diastolic function, the presence or absence of pericardial disease/pericardial effusion, valve regurgitation/valve stenosis, estimated right atrial pressure, estimated pulmonary artery systolic pressure, estimated left atrial pressure, asynchronous heart failure
BNP is a hormone, discovered in Japan in 1988, which is secreted by the heart ventricles in order to protect the heart.
As the heart's function declines and the burden on the heart becomes greater, the amount of the secretion increases and its numerical value becomes higher.
A normal value for BNP is 18.4 pg/mL or less. If it is approximately 40 pg/mL or less, the possibility of heart failure requiring immediate treatment is considered to be low.
Treatment may be required if the BNP value increases above approximately 100 pg/mL.
Although NT-proBNP measurement is also used for the same purpose, be sure to check which test is being done, because the NT-proBNP will show a value that is 4 to 5 times higher than the BNP value.
What is the NHYA classification?
The classification of cardiac function based on the NYHA (New York Heart Association) Functional Classification system is widely used as an indicator of tolerance for physical activity.
This is assessed based on subjective symptoms caused by various physical activities.
The NYHA classification is "reversible". That is, the NYHA classification moves back and forth due to treatment.
Comparison of ACC/AHA Stages and NYHA Functional Classifications
ACC/AHA Stage Classification
This is a stage classification system that appeared in the heart failure guidelines of the ACC/AHA (American College of Cardiology/American Heart Association) in 2001.
The ACC/AHA classification is usually said to be "irreversible", once a patient progresses to a higher stage, they can never return to their original stage.
The stages progress as the heart failure becomes more severe.