Diastolic heart failure is usually diagnosed by the combination of clinical heart failure and preserved left ventricular systolic function, ie, a left ventricular ejection fraction exceeding 40% to 45%. Such patients account for one third of those in clinical heart failure. However, the diagnostic entity is ambiguous. Describing heart failure as diastolic suggests that diastolic mechanisms are responsible for cardiac pump dysfunction, whereas in fact the diagnosis is usually based on the absence of systolic dysfunction. A preferable term is heart failure with preserved systolic function, although this is empirical and somewhat crude, being based on largely nonspecific clinical indicators such as dyspnea, fatigue, and edema (isolated dyspnea on exertion is rather more specific) and an instrumental indicator such as the ejection fraction, which has a measurement error >5%. Because an ejection fraction of 40% to 45% is in the higher part of the distribution curve of ejection fraction values, a 5% measurement error can include or exclude a fair number of patients.
Apart from measurement error, the ejection fraction, even if accurate, may not represent ventricular functional status. Many situations are characterized by transient reductions of left ventricular function, eg, uncontrolled hypertension, myocardial ischemia, atrial fibrillation, alcoholism. These states may produce clinical failure in a context of preserved systolic function, if ventricular function is assessed outside the acute episode, after functional recovery. Another cause of possible confusion is mitral insufficiency. In this case an accurate ejection fraction may remain inside the range considered normal because ejection into the aorta and regurgitation into the left atrium both help to reduce end-systolic volume, even if systolic function is severely compromised.
Table I lists the possible causes of heart failure with preserved systolic function. Table 71 lists clinical presentations suggestive of diastolic heart failure.
Inaccurate diagnosis of heart failure (chronic obstructive airways disease)
Inaccurate measurement of left ventricular ejection fraction
Overestimation of left ventricular systolic function (mitral insufficiency)
Transient left ventricular diastolic dysfunction, improved at assessment (severe hypertension, ischemia, tachycardia, volume overload, peripartum cardiomyopathy, alcoholic cardiomyopathy, infection, medication)
Left ventricular inflow obstruction (mitral stenosis, left atrial myxoma)
Abnormal left ventricular relaxation
– Hypertrophy (hypertension, hypertrophic cardiomyopathy, aortic stenosis)
– Elevated cardiac output (infection, anemia, thyrotoxicosis, beri-beri, arteriovenous fistula)
– Pressure overload (hypertension, aortic stenosis, hypertrophic cardiomyopathy)
– Advanced age
Altered passive elasticity
– Abnormal collagen composition
– Infiltrating myocardial disease (amyloidosis, sarcoidosis)
– Myocardial storage disease (hemochromatosis)
– Endomyocardial disease (endomyocardial fibrosis, radiation, anthracyclines)
– Pericardial disease (constrictive pericarditis, tamponade)
Table I. Causes of heart failure with preserved systolic function.
Signs or symptoms of congestive heart failure (Framingham criteria)
Left ventricular ejection fraction >45% in an asymptomatic patient or on starting treatment
Absence of uncorrected valvulopathy
Coherent clinical scenario
Elderly patient (especially if female)
History of hypertension
Hypertension at first encounter
Recent development of tachyarrhythmia concomitant with the episode of destabilization
Coronary artery disease with no history of myocardial infarction or Q waves
Clinical presentations suggestive of diastolic heart failure.
In summary, the pathophysiology of clinically relevant diastolic abnormalities falls into two general categories: abnormal myocardial relaxation, and decreased ventricular compliance. Abnormal myocardial relaxation may be due to the slow reuptake of the calcium massively released from sarcoplasmic reticulum during systole and which has to be rapidly reintroduced into the sarcoplasmic tubules at the end of systole. Being energy-dependent, this process is rapidly compromised by situations that threaten the energy supply, such as ischemia. Decreased ventricular compliance (or increased passive ventricular stiffness) can be due to increased ventricular mass and/or ventricular connective tissue abnormalities (fibrosis or qualitatively abnormal collagen composition). Hypertension and diabetes, infiltrating diseases such as amyloidosis and sarcoidosis, and storage diseases such as hemochromatosis, can all markedly impair ventricular compliance. Pericardial disease can depress ventricular compliance by exerting extramyocardial constriction.
Having excluded pericardial disease and restrictive or hypertrophic cardiomyopathy, most cases of heart failure with preserved systolic function will be found due to multiple, often nonspecific causes. Many patients are elderly: advanced age has been associated with left ventricular hypertrophy. Many have coronary artery disease, and many have diabetes and variable degrees of renal dysfunction. In the acute phase, a single factor may cause ventricular dysfunction. Over the longer term, more than one factor is usually involved.
Based on the definition proposed by the European Study Group on Diastolic Heart Failure (Table III), the diagnosis of diastolic heart failure must be reserved for cases with evidence not only of failure and preserved left ventricular systolic function (ejection fraction >45%), but also of abnormalities of relaxation, filling, distensibility, and/or left ventricular compliance. In other words, the diagnosis requires evidence of left ventricular diastolic dysfunction.
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