Prospective evaluation of fetuses with autoimmune-associated congenital heart block followed in the PR Interval and Dexamethasone Evaluation (PRIDE) Study.

We evaluated the efficacy of dexamethasone (DEX) in anti-SSA/Ro-exposed fetuses newly diagnosed with congenital heart block. Previous use of DEX has been anecdotal with varying reports of therapeutic benefit. This was a multicenter, open-label, nonrandomized study involving 30 pregnancies treated with DEX (22 with third-degree block, 6 with second-degree block, 2 with first-degree block) and 10 untreated (9 with third-degree block, 1 with first-degree block). Initial median ventricular rates, age at diagnosis, and degree of cardiac dysfunction were similar between groups. Six deaths occurred in the DEX group. There was no reversal of third-degree block with therapy or spontaneously. In fetuses treated with DEX, 1/6 with second-degree block progressed to third-degree block and 3 remained in second-degree block (postnatally 1 paced, 2 progressed to third degree); 2 reverted to normal sinus rhythm (NSR; postnatally 1 progressed to second degree). DEX reversed the 2 fetuses with first-degree block to NSR by 7 days with no regression at discontinuation. Absent DEX, the 1 with first-degree block detected at 38 weeks had NSR at birth (overall stability or improvement in 4 of 8 in the DEX group vs 1 of 1 in the non-DEX group). Median gestational birth age was 37 weeks in the DEX group versus 38 weeks in the non-DEX group (p = 0.019). Prematurity and small size for gestational age were restricted to the DEX group. Pacemaker use and growth parameters at birth and 1 year were similar between groups. In conclusion, these data confirm the irreversibility of third-degree block and progression of second- to third-degree block despite DEX. A potential benefit of DEX in reversing first- or second-degree block was supported in rare cases but should be weighed against potential steroid side effects such as growth restriction.

Utility of cardiac monitoring in fetuses at risk for congenital heart block: the PR Interval and Dexamethasone Evaluation (PRIDE) prospective study.

BACKGROUND: Anti-SSA/Ro-associated third-degree congenital heart block is irreversible, prompting a search for early markers and effective therapy. METHODS AND RESULTS: One hundred twenty-seven pregnant women with anti-SSA/Ro antibodies were enrolled; 95 completed an evaluable course in 98 pregnancies. The protocol included fetal echocardiograms performed weekly from 16 to 26 weeks' gestation and biweekly from 26 to 34 weeks. PR intervals >150 ms were considered prolonged, consistent with first-degree block. Ninety-two fetuses had normal PR intervals. Neonatal lupus developed in 10 cases; 4 were neonatal lupus rash only. Three fetuses had third-degree block; none had a preceding abnormal PR interval, although in 2 fetuses >1 week elapsed between echocardiographic evaluations. Tricuspid regurgitation preceded third-degree block in 1 fetus, and an atrial echodensity preceded block in a second. Two fetuses had PR intervals >150 ms. Both were detected at or before 22 weeks, and each reversed within 1 week with 4 mg dexamethasone. The ECG of 1 additional newborn revealed a prolonged PR interval persistent at 3 years despite normal intervals throughout gestation. No first-degree block developed after a normal ECG at birth. Heart block occurred in 3 of 16 pregnancies (19%) in mothers with a previous child with congenital heart block and in 3 of 74 pregnancies (4%) in mothers without a previous child with congenital heart block or rash (P=0.067). CONCLUSIONS: Prolongation of the PR interval was uncommon and did not precede more advanced block. There was a trend toward more congenital heart block in fetuses of women with previously affected offspring than those without previously affected offspring. Advanced block and cardiomyopathy can occur within 1 week of a normal echocardiogram without initial first-degree block. Echodensities and moderate/severe tricuspid regurgitation merit attention as early signs of injury.