[Color-coded M-mode Doppler echocardiography in the diagnosis of fetal arrhythmia]

Colour-coded M-mode Doppler echocardiography is a simultaneous registration of the conventional M-mode echocardiogram and of the pulsed wave colour-coded Doppler echocardiogram with simultaneous analysis of several sample volumes along the ultrasound cursor with a high timely resolution, guided by the two-dimensional imaging. Within 9 months, 36 foetuses with arrhythmias were prospectively examined (24 foetuses with atrial premature beats, 9 foetuses with supraventricular tachycardia, and 3 foetuses with complete heart block). The classification of arrhythmia by the colour-coded M-mode Doppler echocardiography was always possible at first examination. The most important advantage of this method is the simultaneous registration of the information of conventional M-mode and Doppler echocardiography. Therefore, the intervals between atrial and ventricular contractions can also be analysed even when the angle of insonation to the foetal heart is unfavourable, since contractions cannot only be identified by wall movements but also by the flow velocities. Furthermore, the duration of regurgitation of atrioventricular valves can be exactly measured by colour-coded M-mode Doppler echocardiography. In foetal supraventricular tachycardia, it appears that severity of congestive heart failure is correlated with the duration of atrioventricular valve regurgitation up to a holosystolic insufficiency. Thus, it seems possible, that the duration of insufficiency of atrioventricular valves is a good parameter for evaluation of cardiac function and for modifying antiarrhythmic treatment in cases of supraventricular tachycardia.