When during routine prenatal care, the auscultation++ of the fetal heart beat reveals an abnormal rate or rhythm, two things are needed: 1) the accurate diagnosis of the arrhythmia, and 2) the hemodynamic impact of the rhythm disturbance on the fetus. In Poland, external cardiotocography is the most widely Supported in part by the American Heart Association, Delaware Affiliate, Grant = 41161 available diagnostic system used by obstetricians, but it records only the mean heart rate or the instantaneous heart rate. Cardiotocography is therefore useful only in identifying tachycardia or bradycardia. The most frequent tape of fetal arrhythmia is an irregular rhythm, especially premature contractions (1, 15, 18). We believe that any disturbance in fetal cardiac condition should be evaluated more fully by fetal echocardiography.