Abstract
It is not easy to define the terms “invasive” and “non-invasive”, which are used very often recently. In the circulatory system, however, “non-invasive” examination may be regarded almost synonymous as “non-bloody” (nicht-blutig). A typical “bloody” examination of circulatory system is cardiac catheterization, which provides much important hemodynamic information. Among them, cardiac output, left ventricular ejection fraction, etc. can be determined in non-invasive ways using echocardiography, gamma camera or impedance plethysmography, but automation of measurement and calculation is required for their routine clinical use. Estimation of cardiac contractility by mechanocardiographic information can be applied only to limited situations. Noninvasive examination of coronary blood flow, detection of shunt and cardiac aneurysm and recording of His bundle electrogram are also discussed.
