Diastolic Function of the Heart in Clinical Cardiology

During the last six years, there has been increased interest in the detection of abnormalities of left ventricular diastolic function in patients with heart disease. Before 1981, most studies on diastolic function were performed in the catheter laboratory using invasive techniques and complex methods. Recently, radionuclide angiograms and Doppler echocardiography have been employed to measure the dynamics of filling in normal individuals and in patients with heart disease. These methods are noninvasive, easy to perform, accurate, and reproducible. It is now clear that diastolic function may be altered globally and regionally, at rest and perhaps during exercise, in many patients with ischemic heart disease, hypertension, and hypertrophic cardiomyopathy. Interestingly, these diastolic abnormalities may even appear before systolic abnormalities are identified in these patients. Thus, diastolic abnormalities may permit assessment of presence of disease early in its evolution. Whether detection and quantitation of diastolic abnormalities will permit grading of disease severity or evaluation of therapeutic efficacy remains an important research question. At the present time, it appears that the decision to employ either radionuclide angiography or Doppler echocardiography for the assessment of diastolic abnormalities will depend on the local expertise to carry out the investigation. Both diagnostic modalities require standardization of accuracy and reproducibility with proper selection of control values from the appropriate populations of normal individuals. It is also important to remember that left ventricular diastolic abnormalities have to be identified after the elimination of the confounding influence of variables such as ejection fraction, heart rate, age, and preload (end-diastolic volume). Automation of the derivation of indexes of diastolic filling should provide an objective assessment of the dynamics of left ventricular filling. Although the value of measurement of diastolic filling in the individual patient remains controversial, we believe that the practice of cardiology is incomplete without consideration of the second half of cardiac function.