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Fetal Atrial Flutter & Supraventricular Tachycardia (FAST) Therapy Trial

Although supraventricular tachycardia (SVT), including atrial flutter (AF), are the most common causes of intended in-utero fetal therapy, none of the medication used to date has been evaluated for their effects on the mother and her baby in a randomized controlled clinical trial (RCT). In the absence of such evidence, there is no consensus for the optimal management. The Fetal Atrial Flutter and Supraventricular Tachycardia (FAST) Therapy Trial is a prospective multi-center trial that addresses this knowledge gap to guide future fetal AF & SVT therapy to the best of care. 

Randomized Controlled Trials (RCTs) and Prospective Registry


Study components of the FAST Therapy Trial include three prospective sub-studies to determine the efficacy and safety of commonly used transplacental drug regimens in suppressing fetal AF without hydrops, SVT without hydrops, and SVT with hydrops. All RCTs are open label phase III trials of standard 1st line therapy, which either is started as monotherapy (no hydrops) or as dual therapy (hydrops).


The primary study aim is the probability of a normal pregnancy outcome after treatment with (A) Digoxin versus Sotalol  for AF without hydrops; (B) Digoxin versus Flecainide for SVT without hydrops; and (C) Digoxin plus Sotalol versus Digoxin plus Flecainide for SVT with hydrops. The study also includes the possibility to enroll non-randomized subjects into a prospective Registry to document the outcome of alternative management. This arm of the FAST Therapy Trial also includes atrial flutter with hydrops (excluded from RCTs due to low numbers) and aims to document the treatment and outcomes of the entire AF and SVT patient group in order to analyze and compare management options based on outcomes.


This study is only possible with the dedication and expertise contributed by many sites and Investigators around the world and with funding from the Canadian Institutes of Health Research (CIHR) in Canada supporting the study initiated by the Principal Investigator Dr. Edgar Jaeggi at the Sponsor institution The Hospital for Sick Children. For information about contributing sites and Investigators visit our study LOCATIONS page.

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