Prospective Observational Cohort Study of Fetal Atrial Flutter & Supraventricular Tachycardia (FAST Registry)

FAST Trial Registry: Prospective Observational Cohort Study of Fetal Atrial Flutter & Supraventricular Tachycardia

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.

Study Overview

• Status: Completed
• Conditions: Atrial Flutter; Tachycardia, Supraventricular; Tachycardia, Atrioventricular Nodal Reentry; Tachycardia Atrial; Tachycardia, Reciprocating; Tachycardia, Paroxysmal; Fetal Hydrops; Tachycardia, Atrial Ectopic
• Intervention / Treatment: Other: Prospective observational cohorts

Detailed Description

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:

1. A prospective Registry (FAST Registry; see this document) as well as
2. Three prospective Randomized Clinical Trials (FAST RCTs; see ClinicalTrials.gov #NCT02624765).

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.

• Study Type: Observational
• Enrollment (Actual): 330

Contacts and Locations

Study Locations

• Australia
  • Melbourne, Australia
    • The Royal Women's Hospital
• Brazil
  • São Paulo, Brazil, 04004- 030
    • Associação Beneficente Síria - Hospital do Coração
• Canada
  • Alberta
    • Edmonton, Alberta, Canada
      • University of Alberta
  • British Columbia
    • Vancouver, British Columbia, Canada
      • The U of British Columbia
  • Ontario
    • Calgary, Ontario, Canada, T3B 6A8
      • Alberta Children's Hospital
    • London, Ontario, Canada
      • London Health Sciences Centre
    • Toronto, Ontario, Canada, M5G1X8
      • The Hospital for Sick Children
    • Toronto, Ontario, Canada
      • Mount Sinai Hospital
  • Quebec
    • Montréal, Quebec, Canada, H3T 1C5
      • CHU Saine-Justine
• Czechia
  • Brno, Czechia
    • University Hospital Brno
• Finland
  • Helsinki, Finland
    • Pediatric Research Center
• France
  • Alpes
    • Grenoble, Alpes, France, 38043
      • Centre Hospitalier Universitaire
• Hong Kong
  • Hong Kong, Hong Kong
    • Queen Mary Hospital
• Netherlands
  • Leiden, Netherlands
    • Leiden University Medical Centre
• Russian Federation
  • Moscow, Russian Federation
    • National Medical Research Center for Obstetrics, Gynecology and Perinatology
• Spain
  • Barcelona, Spain
    • BCNatal - Hospital Sant Joan de Deu
  • Grenada, Spain
    • Hospital Virgen de las Nieves
• Sweden
  • Lund, Sweden
    • Lund University
  • Solna, Sweden
    • Karolinska University Hospital, Astrid Lindgen Childrens Hospital
  • Skåne County
    • Göteborg, Skåne County, Sweden, 416 85
      • Queen Silvia Children's Hospital
• Switzerland
  • Bern, Switzerland
    • Inselspital Universitatsspital Bern
• United Kingdom
  • Birmingham, United Kingdom
    • Birmingham Women's and Children's NHS Foundation Trust
  • London, United Kingdom
    • St George's University Hospital Foundation Trust
• United States
  • Arizona
    • Phoenix, Arizona, United States, 85016
      • Phoenix Children's Hospital
  • California
    • San Francisco, California, United States, 94158
      • University of California, San Francisco
  • Colorado
    • Denver, Colorado, United States, 80205
      • Children's Hospital Colorado
  • District of Columbia
    • Washington, District of Columbia, United States, 20010
      • Children's National Medical Center
  • Florida
    • St. Petersberg, Florida, United States, 33701-4804
      • Johns Hopkins All Children's Hospital
  • Louisiana
    • New Orleans, Louisiana, United States, 70121
      • John Ochsner Heart & Vascular Institute
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Boston Children's Hospital
  • Minnesota
    • Minnesota, Minnesota, United States, 55404
      • Children's Health Care
  • Missouri
    • Kansas City, Missouri, United States, 64108
      • Children's Mercy Kansas City
  • New York
    • Lake Success, New York, United States, 11040
      • Cohen Children's Medical Centre/Northwell Health - Lake Success
    • New York, New York, United States, 10032
      • Columbia University
  • Ohio
    • Cincinnati, Ohio, United States, 45229
      • Cincinnati Children's Hospital Medical Centre
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center
  • Texas
    • Austin, Texas, United States, 78722
      • Inc Pediatric Cardiology of Austin Practice
    • Houston, Texas, United States, 77030
      • Texas Children's Hospital
  • Utah
    • Salt Lake City, Utah, United States, 84113
      • University of Utah
  • West Virginia
    • Morgantown, West Virginia, United States, 26505
      • West Virginia University Research Corporation
  • Wisconsin
    • Milwaukee, Wisconsin, United States, 53226
      • Children's Hospital of Wisconsin

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 50 years (Child, Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

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.

Description

Inclusion Criteria:

1. Mother has provided written informed consent to participate
2. Fetal AF or SVT with or without hydrops

3. Tachyarrhythmia that is significant enough to justify immediate transplacental pharmacological treatment:

   • Tachycardia ≥ 180 bpm during at least 10% of observation time of 30 minutes or longer
   • Tachycardia ≥ 170 bpm during +100% of time (≤ 30 0/7 weeks of gestation)
   • Tachycardia ≥ 280 bpm (irrespective of SVA duration)
   • SVT with fetal hydrops (irrespective of duration)
4. Gestational age <36 0/7 weeks at time of enrollment
5. Singleton Pregnancy

6. Healthy mother with ± normal pre-treatment cardiovascular findings:

   • ECG within normal range (sinus rhythm; QTc ≤ 0.47; PR ≤ 0.2 sec; QRS: ≤ 0.12 sec; insignificant anomalies; isolated premature beats; isolated complete right bundle
   • Maternal resting heart rate ≥ 50 bpm
   • Maternal systolic BP ≥ 85 mmHg

Exclusion Criteria:

1. Primary delivery for postnatal cardioversion
2. Antiarrhythmic fetal treatment for more than 2 days at time of enrollment
3. Any maternal-fetal conditions associated with high odds of premature delivery and/or death
4. History of significant maternal heart condition (open heart surgery; sick sinus syndrome; long QT, Brugada syndrome; ventricular tachycardia; WPW syndrome; high-degree heart block; cardiomyopathy)

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Prospective observational cohorts; 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.; Other Names: Non-randomized antiarrhythmic fetal drug therapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Proportion of live-born children with a delivery at term and a normal cardiac rhythm	Term: 37 0/7 to 41 6/7 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average gestational age at birth		At birth
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	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.	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	From date of arrhythmia diagnosis or date of treatment start to 30 days of life
Birth weight (z-scores; centiles)		At birth
Total days of treatment related maternal and neonatal hospitalizations		From date of diagnosis or treatment begin to 30 days of life
Maternal prevalence of pregnancy/treatment-related AEs and outcomes		Diagnosis to birth
Maternal prevalence of adverse events and outcome		From date of treatment begin to 30 days of life

Collaborators and Investigators

• Sponsor: Edgar Jaeggi
• Collaborators: Labatt Family Heart Centre
• Investigators: Principal Investigator: Edgar Jaeggi, MD, FRCPC, The Hospital for Sick Children, Toronto, ON, Canada

Study record dates

Study Major Dates

• Study Start (Actual): June 8, 2017
• Primary Completion (Actual): March 31, 2025
• Study Completion (Actual): March 31, 2025

Study Registration Dates

• First Submitted: September 27, 2017
• First Submitted That Met QC Criteria: December 15, 2017
• First Posted (Actual): December 18, 2017

Study Record Updates

• Last Update Posted (Actual): May 31, 2025
• Last Update Submitted That Met QC Criteria: May 27, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Urogenital Diseases; Cardiovascular Diseases; Pathologic Processes; Female Urogenital Diseases and Pregnancy Complications; Heart Diseases; Genetic Diseases, Inborn; Immune System Diseases; Pregnancy Complications; Arrhythmias, Cardiac; Fetal Diseases; Hematologic Diseases; Hemoglobinopathies; Erythroblastosis, Fetal; alpha-Thalassemia; Thalassemia; Edema; Tachycardia; Tachycardia, Supraventricular; Atrial Flutter; Tachycardia, Atrioventricular Nodal Reentry; Hydrops Fetalis; Tachycardia, Reciprocating; Tachycardia, Paroxysmal; Tachycardia, Ectopic Atrial; Anti-Arrhythmia Agents
• Other Study ID Numbers: 1000048953

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No