title: Comparison of transplacental treatment of fetal supraventricular tachyarrhythmias with digoxin, flecainide, and sotalol: results of a nonrandomized multicenter study.
abstract: BACKGROUND
  Fetal tachyarrhythmia may result in low cardiac output and death. Consequently, antiarrhythmic treatment is offered in most affected pregnancies. We compared 3 drugs commonly used to control supraventricular tachycardia (SVT) and atrial flutter (AF).
  
  
  RESULTS
  We reviewed 159 consecutive referrals with fetal SVT (n=114) and AF (n=45). Of these, 75 fetuses with SVT and 36 with AF were treated nonrandomly with transplacental flecainide (n=35), sotalol (n=52), or digoxin (n=24) as a first-line agent. Prenatal treatment failure was associated with an incessant versus intermittent arrhythmia pattern (n=85; hazard ratio [HR]=3.1; P<0.001) and, for SVT, with fetal hydrops (n=28; HR=1.8; P=0.04). Atrial flutter had a lower rate of conversion to sinus rhythm before delivery than SVT (HR=2.0; P=0.005). Cardioversion at 5 and 10 days occurred in 50% and 63% of treated SVT cases, respectively, but in only 25% and 41% of treated AF cases. Sotalol was associated with higher rates of prenatal AF termination than digoxin (HR=5.4; P=0.05) or flecainide (HR=7.4; P=0.03). If incessant AF/SVT persisted to day 5 (n=45), median ventricular rates declined more with flecainide (-22%) and digoxin (-13%) than with sotalol (-5%; P<0.001). Flecainide (HR=2.1; P=0.02) and digoxin (HR=2.9; P=0.01) were also associated with a higher rate of conversion of fetal SVT to a normal rhythm over time. No serious drug-related adverse events were observed, but arrhythmia-related mortality was 5%.
  
  
  CONCLUSIONS
  Flecainide and digoxin were superior to sotalol in converting SVT to a normal rhythm and in slowing both AF and SVT to better-tolerated ventricular rates and therefore might be considered first to treat significant fetal tachyarrhythmia.
authors.affiliation: Labatt Family Heart Center, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada. edgar.jaeggi@sickkids.ca
authors.forename: Edgar T
authors.initials: ET
authors.lastname: Jaeggi
authors.forename: Julene S
authors.initials: JS
authors.lastname: Carvalho
authors.forename: Ernestine
authors.initials: E
authors.lastname: De Groot
authors.forename: Olus
authors.initials: O
authors.lastname: Api
authors.forename: Sally-Ann B
authors.initials: SA
authors.lastname: Clur
authors.forename: Lukas
authors.initials: L
authors.lastname: Rammeloo
authors.forename: Brian W
authors.initials: BW
authors.lastname: McCrindle
authors.forename: Greg
authors.initials: G
authors.lastname: Ryan
authors.forename: Cedric
authors.initials: C
authors.lastname: Manlhiot
authors.forename: Nico A
authors.initials: NA
authors.lastname: Blom
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004077:Digoxin / Q000627:therapeutic use; D004341:Drug Evaluation; D005260:Female; D005315:Fetal Diseases / Q000188:drug therapy*; D046128:Fetal Therapies / Q000379:methods*; D005424:Flecainide / Q000627:therapeutic use; D006801:Humans; D011247:Pregnancy; D012189:Retrospective Studies; D013015:Sotalol / Q000627:therapeutic use; D013617:Tachycardia, Supraventricular / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D004077:Digoxin; D013015:Sotalol; D005424:Flecainide