High-Grade Atrioventricular Block and Ventricular Standstill in a Pregnant Patient.

Heart block during pregnancy is a rare and understudied condition that poses considerable mortality risks to both the mother and foetus. The severity of atrioventricular block (AVB) tends to worsen throughout pregnancy but may resolve postpartum in some patients, suggesting that its aetiology is linked to the haemodynamic changes of pregnancy. Management of this condition necessitates a multidisciplinary approach across cardiology, obstetrics, and anaesthetics. Pacemaker indications remain consistent with those for non-pregnant patients and can be inserted safely, particularly after the first trimester. Anaesthetists must consider the potential impacts of the Valsalva manoeuvre and neuraxial anaesthesia on maternal haemodynamics during delivery. Decisions regarding the method of delivery should be based solely on obstetric indication. This report details the case of a pregnant woman who presented with pre-syncope attributed to intermittent high-grade AVB with ventricular standstill. Transthoracic echocardiogram and cardiac magnetic resonance imaging performed during and after pregnancy, respectively, revealed a structurally normal heart. The patient was successfully treated with a leadless pacemaker, had an uncomplicated vaginal delivery and experienced no recurrence of symptoms.