Prospective Randomized Clinical Trial of Fetal Atrial Flutter & Supraventricular Tachycardia Therapy (FAST RCT)
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ClinicalTrials.gov Identifier: NCT02624765 |
Recruitment Status :
Recruiting
First Posted : December 8, 2015
Last Update Posted : August 27, 2020
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Condition or disease | Intervention/treatment | Phase |
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Fetal Atrial Flutter Without Hydrops Fetal Supraventricular Tachycardia Without Hydrops Fetal Supraventricular Tachycardia With Hydrops | Drug: Digoxin (monotherapy) Drug: Sotalol (monotherapy) Drug: Flecainide (monotherapy) Drug: Digoxin (dual therapy) Drug: Sotalol (dual therapy) Drug: Flecainide (dual therapy) | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 600 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | FAST RCT: Prospective Randomized Clinical Trial of Fetal Atrial Flutter & Supraventricular Tachycardia Therapy |
Actual Study Start Date : | February 2016 |
Estimated Primary Completion Date : | March 31, 2023 |
Estimated Study Completion Date : | March 31, 2023 |
Arm | Intervention/treatment |
---|---|
Active Comparator: RCT A (1st arm): AF without hydrops
Atrial Flutter (AF) without hydrops: Treatment with Digoxin as monotherapy.
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Drug: Digoxin (monotherapy)
Oral or IV loading dose: 0.5 mg q 12 h (total 4 doses over 48 hours) followed by Oral maintenance dose: 0.25 mg-1mg/day |
Active Comparator: RCT A (2nd arm): AF without hydrops
Atrial Flutter (AF) without hydrops: Treatment with Sotalol as monotherapy.
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Drug: Sotalol (monotherapy)
Oral dose: 80 mg TID or 120 mg BID (240 mg/day) |
Active Comparator: RCT B (1st arm): SVT without hydrops
Supraventricular Tachycardia (SVT) without hydrops: Treatment with Digoxin as monotherapy.
|
Drug: Digoxin (monotherapy)
Oral or IV loading dose: 0.5 mg q 12 h (total 4 doses over 48 hours) followed by Oral maintenance dose: 0.25 mg-1mg/day |
Active Comparator: RCT B (2nd arm): SVT without hydrops
Supraventricular Tachycardia (SVT) without hydrops: Treatment with Flecainide as monotherapy.
|
Drug: Flecainide (monotherapy)
Oral dose: 100 mg TID (300 mg/day) |
Active Comparator: RCT C (1st arm): SVT with hydrops
Supraventricular Tachycardia (SVT) with hydrops: Treatment with Digoxin and Sotalol.
|
Drug: Digoxin (dual therapy)
Oral or IV loading dose: 0.5 mg q 8 h (total 4 doses over 32 hours) followed by oral maintenance dose: 0.25 mg-1mg/day Drug: Sotalol (dual therapy) Oral dose: 160 mg BID (320 mg/day) |
Active Comparator: RCT C (2nd arm): SVT with hydrops
Supraventricular Tachycardia (SVT) with hydrops: Treatment with Digoxin and Flecainide.
|
Drug: Digoxin (dual therapy)
Oral or IV loading dose: 0.5 mg q 8 h (total 4 doses over 32 hours) followed by oral maintenance dose: 0.25 mg-1mg/day Drug: Flecainide (dual therapy) Oral dose:100 mg TID (300 mg/day) |
- 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 [ Time Frame: From date of randomization 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 ]Number of participants with persistent tachycardia compared to number of participants with cardioversion to a normal rhythm over time
- Proportion of participants with treatment failure [ Time Frame: From date of randomization until the date of first documented fetal cardioversion or until the date of treatment failure, whichever comes first, assessed up to 30 gestational weeks ]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.
- Proportion of participants with arrhythmia-related death [ Time Frame: From date of randomization to 30 days of life ]Number of participants with arrhythmia-related death compared to other outcomes
- Average gestational age at birth [ Time Frame: At birth ]
- Birth weight z-scores [ Time Frame: At birth ]
- Total days of treatment related maternal and neonatal hospitalizations [ Time Frame: From date of randomization to 30 days of life ]
- Maternal prevalence of adverse events and outcome [ Time Frame: From date of randomization to 30 days of life ]

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Ages Eligible for Study: | 16 Years to 50 Years (Child, Adult) |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Mother has provided written informed consent to participate
- Either fetal AF without hydrops, SVT without hydrops or SVT with hydrops
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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)
- Gestational age > 12 0/7 weeks and <36 0/7 weeks at time of enrollment
- Untreated tachycardia at time of enrollment
- Singleton Pregnancy
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Healthy mother with ± normal pre-treatment cardiovascular findings:
- ECG without significant abnormalities (sinus rhythm; QTc ≤ 0.47; PR ≤ 0.2 sec; QRS: ≤ 0.12 sec; isolated PACs or PVCs or isolated complete right bundle branch block allowed)
- Resting heart rate ≥ 50 bpm
- Systolic BP ≥ 85 bpm
Exclusion Criteria:
- AF with hydrops (eligible for FAST Registry only)
- Any maternal-fetal conditions associated with high odds of premature delivery or death other than tachycardia (e.g. severe IUGR; premature rupture of membrane; life-threatening maternal disease (incl. pre-eclampsia; HELLP syndrome); severe congenital fetal abnormalities (T 13 or 18; surgery or death expected < 1 month)
- History of significant maternal heart condition (open heart surgery; sick sinus syndrome; channelopathy (long QT, Brugada syndrome); ventricular tachycardia; WPW syndrome; high-degree heart block; cardiomyopathy)
- Relevant preexisting maternal obstructive airway disease including asthma
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Current therapy with the following medications:
- Antiarrhythmic drugs
- Pentamidine
- Maternal serum potassium level <3.3 mmol/L / <3.3 mEq/L (at start of treatment)
- Maternal ionized serum calcium level of <1 mmol/L / <4 mg/dL) or total serum calcium level <2 mmol/L / <8mg/dL (at start of treatment)
- Maternal serum creatinine level > 97.2 µmol/L (>1.1 mg/dl)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02624765
Contact: Prachi Sharma, MSc, CCRA | 1-416-813-7654 ext 309423 | fast.trial@sickkids.ca | |
Contact: Alliya Remtulla Tharani, M.Sc, BScKin | 1-416-813-7654 ext 309423 | fast.trial@sickkids.ca |

Principal Investigator: | Edgar Jaeggi, MD | The Hospital for Sick Children, Toronto |
Documents provided by Edgar Jaeggi, The Hospital for Sick Children:
Responsible Party: | Edgar Jaeggi, Edgar Jaeggi, MD FRCP (C), Section Head, Fetal Cardiac Program, The Hospital for Sick Children |
ClinicalTrials.gov Identifier: | NCT02624765 |
Other Study ID Numbers: |
1000039945 |
First Posted: | December 8, 2015 Key Record Dates |
Last Update Posted: | August 27, 2020 |
Last Verified: | August 2020 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
RCT A: Fetal Atrial Flutter without Hydrops RCT B: Fetal Supraventricular Tachycardia without Hydrops RCT C: Fetal Supraventricular Tachycardia with Hydrops |
Tachycardia Atrial Flutter Tachycardia, Supraventricular Edema Arrhythmias, Cardiac Heart Diseases Cardiovascular Diseases Cardiac Conduction System Disease Pathologic Processes Digoxin Sotalol Flecainide Anti-Arrhythmia Agents Cardiotonic Agents |
Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action Protective Agents Physiological Effects of Drugs Adrenergic beta-Antagonists Adrenergic Antagonists Adrenergic Agents Neurotransmitter Agents Sympatholytics Autonomic Agents Peripheral Nervous System Agents Voltage-Gated Sodium Channel Blockers Sodium Channel Blockers Membrane Transport Modulators |