Fetal Bradycardia. A Practical Approach

Abstract

INTRODUCTIONFetal bradycardia may herald fetal demise. This article highlights arrhythmic fetal bradycardia rather than bradycardia caused by perinatal distress. We briefly examine the embryonic conduction system's development and physiology and we review the classification, aetiology, evaluation, and approach to fetal bradycardia. Our aim is to provide the clinician with practical information about fetal bradycardia that enlightens causative conditions and aids management.Utilizing careful observations and building upon previous work, 1 the late nineteenth-century physician, Wilhelm Preyer, quantified the average fetal heart rate at 140 beats per minute and determined a normal variance from 100 to 200. 2 In 1940, Ruben J Acherman is a Pediatric Cardiologist,

Fetal cardiac arrhythmia detection and in utero therapy

“…Acherman and colleagues described a number of fetal and maternal conditions that predispose to fetal bradycardia with 1:1 atrioventricular conduction 14. Fetal sinus bradycardia was defined as a heart rate <100 bpm, but in 2009 this threshold was revised to <110 bpm by the American College of Obstetrics and Gynecology in response to population data 15.…”

Systematic Appraisal of Diagnosis and Management of Arrhythmias in the Fetus

“…Further attention should be paid to the fetuses constantly exhi biting heart rates of between 110 and 125/min from 20 to 28 weeks of gestation. 10,11 This is because of the reported association between persistent fetal bradycardia and the long QT syndrome in pregnancies with multiple fetal losses. In such cases, a fetal rate of less than 5th centile for a given cohort is more reliable threshold for bradycardia prompting an investigation into the long QT syndrome than the rate of 110/min taken as the lower limit of fetal heart rate.…”