Evaluation of left ventricular function: does the imaging technique matter?

Measurement of left ventricular ejection fraction is a common procedure in cardiology. This is not without reason. Left ventricular ejection fraction has proven to be an important predictor of mortality in patients with heart failure and after myocardial infarction [1, 2]. It is also frequently used to monitor left ventricular remodelling after myocardial infarction and to select patients for ICD therapy and biventricular pacing [3, 4]. Next to this, measurement of left ventricular ejection fraction is used to detect cardiac toxicity in cancer treatment, especially chemotherapy with anthracyclines and related compounds (doxorubicin, daunorubicin, idarubicin, epirubicin, anthraquinone mitoxantrone) and trastuzumab [5, 6]. Therefore determination of left ventricular ejection fraction has to be correct and reproducible. Fortunately, several techniques are available to measure left ventricular ejection fraction: echocardiography, nuclear imaging, magnetic resonance imaging, CT of the heart and contrast angiography. Echocardiography is the most commonly used technique, particularly because it is a cheap and easy to perform technique, gives no irradiation gives no patient discomfort and can be used anywhere. In addition, the technique can be used in settings where MRI cannot be used and in patient with irregular heart rhythm, which makes radionuclide angiography inaccurate. Unfortunately the technique is highly operator dependent and patient dependent. Left ventricular function is frequently measured with 2D techniques with extrapolation to a 3D structure, assuming, that the four chamber view and two chamber view give a correct display of this 3D structure. In this setting, visual assessment may not always be accurate [7, 8]. Intra observer and inter observer variability improves if quantitative assessment with the Simpson’s rule is used. In some patients echocardiography is technically cumbersome (Patients with pulmonary disease, women with large breasts and patients with deformations of the thorax). Contrast enhancement can improve estimates of left ventricular ejection fraction significantly in this setting [9]. Magnetic resonance imaging gives also no radiation exposure, but is more difficult to perform and more expensive. Because of the high resolution of the images, the high endocardial intrinsic contrast, the absence of foreshortening, the absence of user-dependence, the high reproducibility, the ability to perform 3D images and the moderate to high temporal resolution, MRI has become the gold standard for the last two decades [10]. Nuclear imaging, CT of the heart and contrast angiography give radiation exposure, and are therefore contraindicated in pregnant women, are relative expensive and require contrast agents (CT and contrast angiography) with possible adverse effects. Radionuclide ventriculography was introduced three decades ago and soon became an accepted technique for measurement of left ventricular ejection fraction. This L. H. B. Baur (&) Department of Cardiology, Atrium Medical Centre Parkstad and University of Maastricht, Henri Dunantstreet 5, 6401CX Heerlen, The Netherlands e-mail: l.baur@atriummc.nl