The diagnosis and treatment of isolated diastolic failure is often a challenge, since the symptoms are so similar to systolic heart failure. It is important to distinguish between diastolic heart failure (caused by diastolic dysfunction) and systolic heart failure (caused by systolic dysfunction), as the treatment for one condition can aggravate the other condition.
Diastolic heart failure is caused by a fault in the organ’s filling mechanism, but the systolic function or contraction mechanism is preserved. Therefore, although the condition may be characterized by typical symptoms of heart failure, the ejection fraction is normal in patients with diastolic dysfunction. The ejection fraction refers to the percentage of blood that is pumped out of the heart with each heartbeat or cardiac cycle.
An outline of the steps taken to diagnose diastolic dysfunction is given below:
A detailed history of the patient’s symptoms is obtained and a clinical examination is performed. Long standing illnesses such as diabetes or hypertension can predispose to diastolic dysfunction Aortic stenosis is another condition that can lead to the condition and a doctor may listen to the chest using a stethoscope to check for the sound of an abnormal heart beat.
Echocardiography with Doppler can be used to diagnose diastolic dysfunction. This technique uses sound waves to provide real-time imaging of the heart’s structures and blood flow during a cardiac cycle. This is a routine and painless examination. Echocardiography can also be used to determine the heart’s ejection fraction.
Some of the parameters that are assessed during echocardiography to check for evidence of diastolic heart failure include:
- Pulmonary vein flow patterns
- Mitral inflow velocity patterns
- Tissue Doppler measurements
- M-mode echo measurements that are used to assess the size of the left atrium. The left atrium is often enlarged due to the backflow from the left ventricle when it fails to fill adequately.
Using Doppler echocardiography, diastolic heart failure can be classified into four grades, which include:
Grade I – The E/A ratio is reversed on the mitral inflow echocardiogram. This is the mildest form of diastolic heart failure and is referred to as an abnormal relaxation pattern. Patients are usually asymptomatic.
Grade II – This diastolic dysfunction is characterized by increased filling pressure in the atrium and is considered to be moderate stage disease. The left atrium may also increase in size due to the increased pressure.
Grade III – This is a severe form of diastolic dysfunction characterized by restrictive filling of the heart that leads to symptoms of advanced heart failure. When the patient is asked to perform the Valsalva manoeuvre during echocardiography, the diastolic abnormalities seem to reverse. This grade III dysfunction is therefore also called reversible restrictive diastolic dysfunction.
Grade IV – This is also a severe form diastolic dysfunction characterized by restrictive filling. However, at this stage, the abnormalities are not reversible and grade IV diastolic dysfunction is also called “fixed restrictive diastolic dysfunction”.
Reviewed by Sally Robertson, BSc