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Pulsed Doppler echocardiographic assessment of the fetal PR interval

2000; Elsevier BV; Volume: 86; Issue: 2 Linguagem: Inglês

10.1016/s0002-9149(00)00867-5

1879-1913

Julie S. Glickstein, Jill P. Buyon, Deborah Friedman,

ECG Monitoring and Analysis

Arrhythmias and conduction abnormalities are commonly observed in the fetus. Fetal echocardiograms have become the most useful noninvasive means for detection, diagnosis, and monitoring of fetal arrhythmias. By placing M-mode sampling cursors through both the fetal atrium and ventricle imaged by 2-dimensional echocardiography, the relative timing of atrial and ventricular contractions can be determined. Hence, electrical activity can be inferred from the timing of the mechanical events. However, fetal echocardiographic M-mode tracings are limited in their ability to detect and distinguish between milder levels of atrioventricular block, specifically first- and second-degree (Wenkebach) atrioventricular block. Gated-pulsed Doppler studies of the atrioventricular and semilunar valves have been described in helping identify rhythm disturbances in fetal hearts. By using the gated-pulsed Doppler technique, we measured time intervals from the onset of the mitral A wave (atrial systole) to the onset of the aortic pulsed Doppler tracing (ventricular systole) within the same left ventricular cardiac cycle. This time interval represents the "mechanical" PR interval. We hypothesized that the mechanical PR interval obtained by fetal pulsed Doppler were technically feasible to obtain and could be dependent on gestational age. Its validity can be confirmed by neonatal electrocardiographic correlation to the pulsed Doppler mechanical PR interval.