Transplacental treatment of foetal ventricular tachycardia: a Japanese, nationwide survey

Foetal ventricular tachycardia (VT) carries a risk of sudden death and remains challenging to manage even after birth.1 Because foetal VT is an ultra-rare form of tachyarrhythmia, information on the condition is limited, with evidence largely restricted to case reports.2 Foetal VT with atrioventricular (AV) dissociation can be diagnosed when the ventricular rate exceeds the atrial rate or when the ventricular rhythm is irregular, as observed in torsades de pointes associated with long QT syndrome (LQTS).3 However, in foetal VT without AV dissociation, 1:1 ventriculoatrial conduction due to retrograde conduction makes it difficult to distinguish VT from supraventricular tachycardia (SVT) on foetal echocardiography. Although transplacental treatment for foetal VT has been recommended, supporting evidence remains limited to expert opinion and case studies.4–6 This study conducted a nationwide survey to validate the current diagnosis and management of foetal VT. Particularly, it focused on differences in the characteristics and prognosis of foetal VT in patients with and without LQTS and the efficacy and safety of transplacental treatment.