Patient with known repaired Tetralogy of Fallot (ToF) suffers new-onset, regular, narrow complex tachycardia which is unresponsive to medical management requiring DC cardioversion under general anaesthesia.

Stage 1: Initial assessment of narrow complex tachycardia in labouring parturient with adult congenital heart disease (ACHD).

Stage 2: Correction of electrolytes, perform vagal manoeuvres, administer adenosine for continued tachyarrhythmia.

Stage 3: Medical management for tachyarrhythmia unsuccessful, adverse features now present.

Stage 4: DC cardioversion and caesarean section.

29-year-old 36-week primipara woman, with history of repaired Tetralogy of Fallot, attends delivery suite in spontaneous labour. She has been complaining of sudden onset of palpitations and feels her heart is racing. She has a confirmed narrow complex tachyarrhythmia on the monitor.

Her past surgical history is repaired TOF with Waterston shunt, followed by a repair of pulmonary valve and closure of VSD. Recent echo shows signs of moderate pulmonary regurgitation and mild RV dysfunction. She attended the joint obstetric, cardiac, anaesthetic clinic 6 weeks ago. (For the Anaesthetic letter see Figure 33.1. For the echocardiogram report see Figure 33.2.)

Figure 33.1 Anaesthetic Clinic Letter.

Figure 33.2 Patient’s echocardiogram report.

On arrival on the delivery suite, she is reviewed by the team. All investigations performed and bloods taken. Potassium and magnesium corrected.

Although initially stable with tachyarrhythmia, it does not respond to vagal manoeuvres, adenosine or beta blockers.

Patient then becomes hypotensive and complains of chest pain. Decision made for DC cardioversion in theatre.

The patient is intubated and cardioverted successfully.

CTG remains suspicious, the obstetric team proceed to perform an emergency LSCS.