BACKGROUND: Persistent junctional reciprocating tachycardia (PJRT) tends to be a persistent arrhythmia and requires aggressive therapeutic management. Diagnosis and management of this infrequently occurring tachycardia in the fetus at an early stage is of importance for the prevention of congestive heart failure (CHF). METHODS: A retrospective study of four fetuses with supraventricular tachycardia (SVT) of the PJRT type was performed. RESULTS: All had sustained SVT (mean of 228 beats/min) at a mean gestational age of 34 + 5 weeks, with CHF present in two. Three fetuses had prenatal characteristics of PJRT on M-mode echocardiography with a ventriculoatrial (VA)/atrioventricular ratio of > 1 on M-mode echocardiography suggesting a slow conducting accessory pathway. All four fetuses had postnatal confirmation of the diagnosis. Transplacental treatment with flecainide was effective in one patient; sotalol as a single drug or in combination with digoxin was partially effective in the remaining three. Two developed sinus rhythm, with short intermittent periods of tachycardia and decreasing signs of CHF; one case showed a minimal decrease in heart rate. Oral propranolol therapy converted two patients postnatally; in the remaining two patients radiofrequency ablation was performed at the age of 5 months and 6 years. CONCLUSIONS: The characteristics of our prenatal PJRT cases included a sustained heart rate not exceeding 240 beats/min with a long VA interval, the presence of CHF and therapy resistance. Transplacental treatment should be initiated, possibly with a combination of sotalol and digoxin in non-hydropic cases, or flecainide, especially in case of fetal hydrops. Pharmacological therapy is to be preferred postnatally, but radiofrequency ablation seems to be indicated in therapy-resistant cases with CHF, even in the first months of life.