22. Miscellanea: 22.1 Arrhythmias in Fetal Life: Echocardiographic Diagnosis and Complex Therapeutic Approach

Fetal arrhythmia occurs in ∼1-2% of all pregnancies. Compared with the general population, fetuses with a cardiac arrhythmia (CA) have high perinatal and neonatal mortality rates. Diagnosis and management of CA in the fetal age is crucial for the prevention of heart failure.

To evaluate the management protocol of fetal CA based on prior identification of the underlying mechanism of the arrhythmias.

In the last two years 566 fetuses with suspicious cardiac malformation were evaluated with echocardiography in our centre. Rhythm diagnosis was done by performing M mode, pulsed and continuous Doppler and tissue Doppler through the fetal heart so that both the ventricular and atrial activity were recorded.

Thirty-three out of 566 fetuses showed cardiac arrhythmias (mean weeks of gestation at diagnosis: 24,3±4,5). Two out of 33 had fetal hydrops and one, despite medical therapy, died at 28 weeks. The weight at birth of survived 32 was 2920±320 gr. One fetus with tachycardia had a congenital heart disease (Ebstein anomaly). The supposed prenatal diagnosis was confirmed at the birth in 29/33 fetuses. Nineteen fetuses had tachycardia with a 1:1 AV conduction during fetal life (HR 225±25 bpm). Ten out of 19 showing a 1:1 AV conduction, had a long VA' interval; the diagnosis at the birth were: 1 inappropriate sinus tachycardia, 5 persistent junctional reciprocating tachycardia (PJRT) and 4 atrial ectopic tachycardia (AET). Nine out of 19 fetuses showing a 1:1 AV conduction had a short VA' interval; the diagnosis at the birth was atrioventricular re-entrant tachycardia (AVRT). One fetus had atrial tachycardia with a 2:1 AV conduction (atrial flutter). Six fetuses showed isolated ectopic beats. Four fetuses showed AV dissociation with a low ventricular rate (HR 42±18 bpm); in all at the birth the diagnosis of complete AV block was confirmed and two underwent epicardial pacemaker implanting (at 3 and 7 months). One, with a familiarity for long QT syndrome (LQTS), showed a fetal tachycardia with AV dissociation; at the birth it was confirmed the diagnosis of LQTS and recurrent ventricular tachycardia. In fetal life therapeutical approach (maternal administration of digoxin, sotalol or flecainide for fetuses with sustained supraventricular tachycardia) was decided according to the supposed electrophysiological mechanism.

Fetal echocardiography could clarify the electrophysiological mechanism of fetal cardiac arrhythmias and guide the therapeutic approach.