Primary diastolic failure is typically seen in patients with hypertensive or valvular
heart disease as well as in hypertrophic or restrictive cardiomyopathy but can also
occur in a variety of clinical disorders, especially tachycardia and ischemia. Diastolic
dysfunction has a particularly high prevalence in elderly patients and is generally
associated, with low mortality but high morbidity. The pathophysiology of diastolic
dysfunction includes delayed relaxation, impaired LV filling and/or increased stiffness.
These conditions result typically in an upward displacement of the diastolic pressure-volume
relationship with increased end-diastolic, left atrial and pulmo-capillary wedge pressure
leading to symptoms of pulmonary congestion. Diagnosis of diastolic heart failure
requires three conditions: (1) presence of signs or symptoms of heart failure; (2)
presence of normal or slightly reduced LV ejection fraction (EF > 50%) and (3) presence
of increased diastolic filling pressure. Assessment of diastolic function can be performed
with several non-invasive (2D- and Doppler-echocardiography, color Doppler M-mode,
Doppler tissue imaging, MR-myocardial tagging, radionuclide ventriculography) and
invasive techniques (micromanometry, angiography, conductance method). Doppler-echocardiography
is the most useful tool to routinely measure diastolic function. Different techniques
can be used alone or in combination to assess LV diastolic function, but most of them
are dependent on heart rate, pre- and afterload. The transmitral flow pattern remains
the starting point, since it is easy to acquire and rapidly categorizes patients into
normal (E > A), delayed relaxation (E < A), and restrictive (E > A) filling patterns.
Invasive assessment of diastolic function allows determination of the time constant
of relaxation from the exponential pressure decay during isovolumic relaxation, and
the evaluation of the passive elastic properties from the slope of the diastolic pressure-volume
(= constant of chamber stiffness) and stress-strain relationship (= constant of myocardial
stiffness). The prognosis of diastolic heart failure is usually better than for systolic
dysfunction. Diastolic heart failure is associated with a lower annual mortality rate
of approximately 8% as compared to annual mortality of 19% in heart failure with systolic
dysfunction, however, morbidity rate can be substantial. Thus, diastolic heart failure
is an important clinical disorder mainly seen in the elderly patients with hypertensive
heart disease. Early recognition and appropriate therapy of diastolic dysfunction
is advisable to prevent further progression to diastolic heart failure and death.
There is no specific therapy to improve LV diastolic function directly. Medical therapy
of diastolic dysfunction is often empirical and lacks clear-cut pathophysiologic concepts.
Nevertheless, there is growing evidence that calcium channel blockers, beta-blockers,
ACE-inhibitors and AT2-blockers as well as nitric oxide donors can be beneficial.
Treatment of the underlying disease is currently the most important therapeutic approach.