Prenatal diagnosis of slow‐rate ventricular tachycardia using fetal electrocardiography

OBJECTIVES: We report a case in which fetal ventricular tachycardia (VT) could be diagnosed, in utero, using a transabdominal fetal electrocardiogram (fECG) with motion-mode (M-mode) echocardiography. METHODS: The fetus was referred at 32 weeks' gestation due to tricuspid atresia. The fetal cardiotocogram demonstrated paroxysmal tachycardia with a ventricular rate of 155 to 160 bpm within the confines of normal sinus rhythm. RESULTS: M-mode echocardiography showed atrioventricular dissociation with a rather slow ventricular rate. To identify the level of the ectopic focus for tachyarrhythmias, we attempted to detect the electrical signals of the fetal heart and succeeded in recording the fECG. Morphological assessment of the fECG allowed for the extraction of both the normal QRS complex and apparently dissimilar ectopic QRS beat, which has a different polarity despite a relatively similar width. CONCLUSION: Consequently, the case proved to have VT at a slow rate, probably originating from the focus near the atrioventricular junction inside the ventricle.