PMC6342607_01
Supraventricular tachyarrhythmia (SVT). Sustained SVT was confirmed by Doppler and M-mode recordings at 30 weeks of gestation. A: Doppler recording of superior vena cava (SVC)-ascending aorta (aAo) flow showed short ventriculoatrial (VA) tachycardia (VA/atrioventricular [AV] ratio = 0.44) with a ventricular rate of 215 beats per minute (bpm). B: M-mode recording using a 4-chamber view showed 1:1 AV conduction with a ventricular rate of 215 bpm. C: Fetal baseline heart rate varied between 210 and 220 bpm on cardiotocography. A indicates the retrograde A wave in the SVC corresponding to atrial contraction. V indicates the aortic ejection wave (V wave). LV = left ventricle; RA = right atrium.
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Doppler recordings of superior vena cava (SVC)-ascending aorta (aAo) flows showed incessant short ventriculoatrial (VA) SVT (Figure 1A). M-mode recordings showed 1:1 atrioventricular (AV) conduction with a ventricular rate of 215 beats per minute (bpm) (Figure 1B). The fetal baseline heart rate was not constant, fluctuating between 210 and 220 bpm on cardiotocography (Figure 1C).
Paroxysmal atrial fibrillation (PAF). PAF was confirmed by M-mode recording at 30 weeks of gestation. A: Doppler recording of superior vena cava (SVC)-ascending aorta (aAo) flow showed irregular bradycardia with a ventricular rate of 70-90 beats per minute (bpm). The A wave frequently disappeared. B: M-mode recording using a 4-chamber view also showed irregular bradycardia. Atrioventricular dissociation was present, with a ventricular rate of 70-90 bpm and an atrial rate of 40-50 bpm. After a clear atrial contraction, the unique quivering of the atrial wall (*) was observed, suggesting PAF. C: Fetal baseline heart rate intermittently fluctuated between 70 and 215 bpm on cardiotocography. LV = left ventricle; RA = right atrium.
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Irregular bradycardia was intermittently detected by Doppler recording of SVC-aAo flow (Figure 2A). M-mode recording also showed irregular bradycardia; AV dissociation was present, with a ventricular rate of 70-90 bpm and an atrial rate of 40-50 bpm (Figure 2B). The fetal baseline heart rate intermittently fluctuated between 70 and 215 bpm on cardiotocography (Figure 2C).