Slow Heart Registry of Fetal Immune-mediated High Degree Heart Block

The Hospital for Sick Children

Status

Enrolling

Conditions

Heart Block Second Degree

Heart Block Complete

Treatments

Other: No Dexamethasone

Drug: Dexamethasone

Study type

Observational

Funder types

Other

Identifiers

NCT04559425

1000065121

Details and patient eligibility

About

Few studies are specifically designed to address health concerns that are already relevant during pregnancy. The consequence is a lack of evidence on best clinical practice. This includes mothers and their babies when pregnancy is complicated by an abnormally slow heart rate due to maternal antibody-mediated heart disease in the unborn baby (fetus). Since the late seventies, it has been possible to detect and monitor fetal disease by ultrasound images and to treat selected conditions with pharmaceuticals administered via the mother. To this day, physicians need to make decisions about the management of such pregnancies without evidence from prospective clinical trials on drug efficacy and safety. The SLOW HEART REGISTRY is a multi-centered prospective observational study that will address the knowledge gap to guide future management of high-degree immune-mediated heart block to the best of care. The study seeks to establish an international database of the management and outcome of affected fetuses, to be used to publish information on the results of currently available prenatal care and to evaluate the need for additional research.

Full description

The SLOW HEART REGISTRY is a multi-centered prospective observational study of fetuses diagnosed with high-degree immune-mediated atrio-ventricular heart block (AVB). The study seeks to establish an international database of the management and outcome of affected fetuses, to be used to publish information on the results of currently available prenatal care and to evaluate the need for additional research.

The study aims are to document the outcome of patients diagnosed prenatally with immune-mediated 2nd or 3rd degree AVB irrespective of the primary choice of prenatal care.

The primary objective will be to determine the rate of transplant-free survival to 1 year of life of fetuses with AVB based on the prenatal management decision:

Cohort 1: Fetuses not treated with fluorinated glucocorticoids
Cohort 2: Fetuses treated with fluorinated glucocorticoids from the time of immune-mediated AVB diagnosis.

Secondary objectives will be to determine:

the evolution of clinical findings from AVB diagnosis to birth (AV conduction; fetal heart rate; other NL manifestations; fetal growth; effusions/hydrops) between cohorts;
the need of new/additional treatment (steroids; beta-mimetics; IVIG) to birth;
gestational age and weight at birth;
postnatal management (pacing; steroids; IVIG); and
clinical evolution from birth to 1-3 years of life (cardiac function; developmental milestones; infant growth; health).

Prevalence of relevant fetal-maternal events and complications (death; IUGR; morbidity) between the study cohorts will also be determined.

All management is decided by the treating center and physicians in accordance to institutional guidelines and clinical findings. Patient enrollment in the SLOW HEART REGISTRY is possible within up to 8 days of the initial management decision.

Participation in this prospective observational cohort study requires site REB approval and an executed legal contract with the primary investigator/SickKids Hospital, Toronto.

Enrollment

350 estimated patients

Sex

Female

Ages

16 to 50 years old

Volunteers

No Healthy Volunteers

Inclusion criteria

Written informed maternal consent to participate in the Slow Heart Registry
High-degree (2nd; 2:1; 2nd-3rd or 3rd degree) AVB diagnosed ≤ 32+0 weeks with or without hydrops
Enrollment within maximally 8 days of high-degree AVB diagnosis
Positive or pending anti-Ro/La antibody test results at the time of enrollment

Exclusion criteria

AVB associated with major CHD (e.g. left atrial isomerism, cc-TGA)
AVB with known negative anti-Ro and/or La antibody test result at enrollment
1st degree AVB
Sinus bradycardia with normal 1:1 AV conduction
Blocked atrial bigeminy (irregular atrial rate with failure of AV conduction of the premature atrial beat)
Primary delivery for postnatal treatment
Maternal-fetal conditions (other than cardiac NL) associated with high odds of premature delivery or death (e.g. renal failure, significant infectious diseases, major extracardiac anomalies, PROM, etc.)
Preexisting maternal mental disorder (e.g. bipolar, mania, severe depression, substance abuse)
Poorly controlled insulin-dependent diabetes (HbA1c >7%) at CAVB diagnosis
Oligohydramnios (deepest/maximal vertical pocket <2 cm)
Severe IUGR (estimated fetal weight <3rd percentile)