An observational study in Atrial Flutter, Tachycardia, Supraventricular and Tachycardia, Atrial Ectopic, sponsored by Edgar Jaeggi. Completed at 41 sites in 14 countries. Open to female participants aged 16 Years to 50 Years. Per ClinicalTrials.gov, last updated 2025-05-31.
Sponsored by Edgar Jaeggi · Observational
The FAST Trial Registry is a prospective observational cohort study of fetuses with a new diagnosis of atrial flutter (AF) or supraventricular tachycardia (SVT) that is severe enough to consider prenatal treatment (see eligibility criteria below). Aims of the Registry include to establish a large clinical database to determine and compare the efficacy and safety of different prenatal treatment strategies including observation without immediate treatment, transplacental antiarrhythmic fetal treatment and direct fetal treatment from the time of tachycardia diagnosis to death, neonatal hospital discharge or to a maximum of 30 days after birth.
Few studies are specifically designed to address health concerns 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 fast heart rate up to 300 beats per minute due to supraventricular tachyarrhythmia (SVA) in the unborn baby (fetus). Although fetal SVA, including AF and other forms of SVT, is the most common cause of intended in-utero fetal therapy, our knowledge of drug effects on the baby and the co-treated mother is still limited. The Fetal Atrial Flutter and Supraventricular Tachycardia (FAST) Therapy Trial is a prospective multi-center trial to address this knowledge gap in order to guide future patient management to the best of care.
FAST Trial components include:
The FAST Registry is a prospective observational cohort study to determine the impact of different prenatal treatment strategies on patients diagnosed with fetal AF without hydrops, AF with hydrops, SVT without hydrops, and SVT with hydrops. All management decisions including the choice of antiarrhythmic medication or the decision to observe without treatment are at the discretion of the treating physician. The primary outcome measure will be the proportion of term deliveries of live-born children with a normal cardiac rhythm. Secondary outcome measures include the efficacy of 1st line, 2nd line, 3rd line, and maintenance drug therapy in controlling the different arrhythmias prior to birth and patient safety.
Participation of a site in the FAST Registry requires experience with the perinatal management of fetal AF and SVT, local REB/IRB approval and an executed legal contract with the Hospital for Sick Children, Toronto.
Participation of a patient in the FAST Registry requires that all inclusion and none of the exclusion criteria are fulfilled (see below). Enrollment is possible within 2 days of the arrhythmia diagnosis and the initial management decision.
223 studies on the registry are indexed under Atrial Flutter; 51 are open to participants now.
This study's enrollment of 330 is close to the median of 300 across 59 observational studies indexed under Atrial Flutter.
Browse Atrial Flutter studies →Edgar Jaeggi is the lead sponsor of 2 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Enrollment into the Registry is possible within maximally 2 days of the fetal SVA diagnosis and management decision to treat or not to treat. If a mother elects participation in the Registry, her treating physician will continue to provide care in accordance with clinical practice at the site and will decide all therapy including close observation without or with immediate prenatal treatment.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Tachyarrhythmia that is significant enough to justify immediate transplacental pharmacological treatment:
Healthy mother with ± normal pre-treatment cardiovascular findings:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
1\) Atrial flutter without fetal hydrops; 2) Atrial flutter with fetal hydrops; 3) Supraventricular tachycardia without fetal hydrops; and 4) Supraventricular tachycardia with fetal hydrops
Other: Prospective observational cohorts
Patients with AF or SVT that is significant enough to consider prenatal treatment are eligible for enrollment. Management decisions are made at each patient encounter by the primary physician based on clinical findings and may include: 1) no antiarrhythmic treatment; 2) transplacental antiarrhythmic treatment; 3) direct fetal antiarrhythmic treatment; 4) delivery. Patients enrolled in the FAST Registry will be followed from the time of enrollment until the baby is discharged after birth.
Also known as: Non-randomized antiarrhythmic fetal drug therapy
Proportion of live-born children with a delivery at term and a normal cardiac rhythm
Time frame: Term: 37 0/7 to 41 6/7 weeks
Proportion of patients with cardioversion over time
Number of participants with persistent tachycardia compared to number of participants with cardioversion to a normal rhythm over time
Time frame: From date of SVA dignosis until the date of first documented cardioversion or until the date of delivery/fetal death without cardioversion, whichever comes first, assessed up to 30 gestational weeks
Proportion of participants with treatment failure
Number of participants with treatment failure compared to number of participants with successful treatment. Treatment failure is defined as one of the following: 1) cross-over to another drug; 2) SVT/AF that persists to birth; 3) preterm birth; 4) death.
Time frame: From date of treatment start until the date of first documented fetal cardioversion or until the date of treatment failure, whichever comes first, assessed up to 30 gestational weeks
Proportion of participants with arrhythmia-related death
Number of participants with arrhythmia-related death compared to other outcomes
Time frame: From date of arrhythmia diagnosis or date of treatment start to 30 days of life
Average gestational age at birth
Time frame: At birth
Birth weight (z-scores; centiles)
Time frame: At birth
Total days of treatment related maternal and neonatal hospitalizations
Time frame: From date of diagnosis or treatment begin to 30 days of life
Maternal prevalence of pregnancy/treatment-related AEs and outcomes
Time frame: Diagnosis to birth
Maternal prevalence of adverse events and outcome
Time frame: From date of treatment begin to 30 days of life
Plan to share: No
No publications or documents are linked to this record.
Ran from Jun 2017 to primary completion in Mar 2025, 93 months.
Of 37 observational studies under Atrial Flutter, half reached primary completion within 47 months of starting (the median), counting those still running; a quarter within 26 and three quarters within 93. This study's 93 months is above that.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Apr 2025. You cannot join it, but the record below documents what was studied.
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Edgar Jaeggi