Download Diastolic Heart Failure

Diastolic Heart Failure
This is a controversial concept as there is no universally agreed definition, which means it is
hard to be definite about the diagnosis and even harder to undertake randomised controlled
trials of treatment. Nevertheless, it is an idea attracting a lot of attention and debate.
What is it?
The simplest way of conceiving of systolic and diastolic heart failure is to think of heart
failure due to:
a) weak ventricles (systolic- failure to contract strongly)
b) stiff ventricles (diastolic- failure to distend and hence fill effectively)
Many patients with weak ventricles also have a degree of ventricular stiffness; this is still
classified as systolic heart failure. What is attracting interest is the fact that a few patients
have isolated diastolic heart failure- stiff ventricles, which nevertheless have reasonable
contractile function. The main implication relates to prognosis, which is better in such
patients, rather than to any difference in treatment.
Is this the same as LVF vs CCF?
No. Most patients with LVF and CCF have systolic heart failure. However, a few patients
with CCF turn out to have problems with stiff ventricles but still have good systolic function.
Note that:
1) Most patients with heart failure have left ventricular failure
2) Some patients with heart failure have bi-ventricular failure with symptoms and signs
of right sided heart failure too (ankle oedema; raised JVP, pitting ankle and sacral
oedema).
3) Biventricluar failure is conventionally known as CCF. Many clinicians dislike the term
CCF as there is pulmonary CONGESTION with pure LVF; nevertheless, it is so
commonly used that this term is likely to persist.
4) Isolated right heart failure is rare
Most patients with left ventricular failure have impairment of systolic function, as assessed
by the ejection fraction on echocardiography or as assessed at cardiac catheterisation. Most
patients with biventricular failure have problems with systolic function, but affecting both
ventricles. Both groups of patients may well have some problems with ventricular stiffness
and will have a diastolic component to their heart failure too.
So what is diastolic heart failure?
A few patients with biventricular failure will have normal systolic function with good
ventricular contraction, but problems with ventricular filling due to stiffness. When this occurs
a diagnosis of diastolic heart failure can be made. Diastolic heart failure characteristically
affects both ventricles.
What causes myocardial stiffness?
The classical but rare form is restrictive cardiomyopathy, which is a primary heart muscle
disease, which can sometimes be associated with amyloidosis or an eosinophilic infiltrate.
Much more common is hypertensive heart disease with ventricular hypertrophy. In the
elderly, systolic hypertension is common and it is thought that some patients develop stiff
ventricles as a consequence- why this should affect the right as well as the left ventricle is
not clear. Perhaps a degree of chronic myocardial ischaemia is required- with stiff ventricles
resulting from a combination of hypertension and silent coronary disease (asymptomatic ie
no angina).
 Dr R Clarke
www.askdoctorclarke.com
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Making the diagnosis
Most cardiologists agree that there are three requirements:
1) A patient with symptoms and signs of biventricular failure (CCF)
2) Normal LV function on echo (ie ejection fraction >50%)
3) Abnormal diastolic function (see below)
Many would add a fourth requirement- exclusion of obesity, lung disease and coronary heart
disease- all of which frequently cause breathlessness with normal LV function and all of
which require specific treatment (Caruana et al. 2000).
So how do you assess diastolic function?
This is where it gets tricky and where there is no clear consensus (European Study Group
on Diastolic Heart Failure 1998). The simplest way is based on Doppler blood flow
velocities.
Heart sounds: lub dub
Atrial systole
Rapid filling phase
lub
dub
ventricular systole
diastole
Early in diastole is the rapid phase of ventricular filling, just after the mitral valve opens. Late
in ventricular diastole, the atria contract and the final phase of ventricular filling occurs.
Diastolic blood flow velocities can be assessed as the E:A ratio (early:atrial) and normally
the early phase is faster than the late atrial phase (E:A>1).
In diastolic heart failure, the stiff ventricle fails to fill properly, the early velocity is reduced
and the E:A ratio is <0.5. This is often manifest clinically as a third heart sound- just after the
second sound at the time of the normally rapid phase of ventricular filling.
 Dr R Clarke
www.askdoctorclarke.com
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Third heart sound: lub de dub
lub
de dub
ventricular systole
diastole
Note that there are many additional ways of assessing diastolic function and no clear
agreement about which is best (European Study Group on Diastolic Heart Failure 1998).
Treatment
Aim for superb BP control as this should prevent hypertensive heart disease from
worsening.
ACE inhibitors and diuretics are used for heart failure and will help BP control.
Beta blockers particularly useful if co-existent coronary heart disease.
Prognosis
The prognosis is better than the prognosis in systolic heart failure
Take home messages
All patients with suspected heart failure should have an echocardiogram.
If the ejection fraction (on echocardiography) is normal, consider alternative causes
of breathlessness- eg obesity, coronary heart disease and lung disease.
If BMI, exercise ECG and lung function tests are normal in a patient with CCF and
normal ejection fraction, the diagnosis may well be diastolic heart failure.
Isolated diastolic heart failure is less common than systolic heart failure, but may still
need to be considered particularly in the elderly with CCF.
It is commonest in the elderly with hypertensive heart disease, but also occurs
occasionally in younger patients with restrictive cardiomyopathy.
Further reading
Caruana, L., Petrie, M., Davie, A., & McMurray, J. (2000) "Do patients with suspected heart
failure and preserved left ventricular systolic function suffer from diastolic heart failure or
from misdiagnosis?", BMJ, vol. 321, pp. 215-219.
European Study Group on Diastolic Heart Failure (1998) "How to diagnose heart failure",
European Heart Journal, vol. 19, pp. 990-1003.
 Dr R Clarke
www.askdoctorclarke.com
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