Management outcome and follow-up of fetal tachycardia

OBJECTIVES: The aim of this study was to evaluate fetal tachycardia and the efficacy of maternally administered antiarrhythmic agents and the effect of this therapy on delivery and postpartum management. BACKGROUND: Sustained fetal tachycardia is a potentially life-threatening condition in which pharmacologic therapy is reported to be effective. There is ongoing discussion about optimal management. METHODS: A group of 51 patients with M-mode echocardiographically documented fetal tachycardia was studied retrospectively. RESULTS: Thirty-three fetuses had supraventricular tachycardia; 15 had atrial flutter; 1 had two episodes of both; and 2 had ventricular tachycardia. Fetal hydrops was seen in 22 patients. Thirty-four fetuses received maternal therapy with either digoxin or flecainide as the first administered drug (additional drugs were given in 12). Drug treatment was successful in establishing acceptable rhythm control in 82% (84% without, 80% with hydrops). In the latter group the median number of drugs and number of days to conversion were higher. Three patients with fetal hydrops died. In 50% of cases, tachycardia reappeared at delivery: 9 neonates presented with atrial flutter, 14 with supraventricular tachycardia and 1 with ventricular tachycardia. Seventy-eight percent of the group had pharmacologic therapy by 1 month of age and 14% by 3 years. CONCLUSIONS: Fetal tachycardia can be treated adequately in the majority of patients, even in the presence of hydrops, and therefore emergency delivery might not be indicated. Digoxin and flecainide were drugs of first choice and produced no serious adverse effects in this series of patients. The majority of patients do not require prolonged therapy.