Simple treatment options exist for supraventricular tachycardia in pregnancy

Dear Editor,

Köşüş et al. (2011) show that cardiac arrhythmias are common during pregnancy and demonstrate, in their study, they post no risk to mother or fetus in those with no cardiovascular pathology. Supraventricular tachycardia (SVT) however, has been associated with increased morbidity including the risk of emergency caesarean section (Robins and Lyons 2004).

In our institution, a 40-year-old woman, G₁P₀ was admitted for induction of labour. She was an ex-smoker with gestational diabetes mellitus and denied any previous history of cardiorespiratory disease.

Induction of labour was achieved with topical prostaglandins, artificial rupture of membranes and oxytocin. Several hours later she complained of severe palpitations associated with chest tightness persisting for several hours. She was haemodynamically stable. A 12-lead ECG showed a narrow complex tachycardia consistent with AV nodal reentry tachycardia (AVNRT). Vagal manoeuvres were ineffective. After counselling, adenosine was administered, which restored sinus rhythm. Follow-up revealed failure-to-progress to augmented labour with delivery of a healthy baby via caesarean section under epidural anaesthesia without recurrence of the arrhythmia.

Pregnancy is proarrhythmic due to a combination of increased circulating oestrogen and β-human chorionic gonadotropin which effect the expression of cardiac ion channels; increased circulating volume and cardiac output which results in myocardial stretch and an increase in cardiac end diastolic volumes; and increase sympathetic tone resulting in high plasma catecholamine concentrations and adrenergic receptor sensitivity.

The majority of palpitations are due to sinus tachycardia. SVT is the commonest arrhythmia in pregnancy (AVNRT and WPW account for the majority). Treatment may affect the fetus, therefore, drug therapy should only be used in the presence of severe symptoms, haemodynamic instability or prolonged episodes. Adenosine, beta blockers, verapamil and digoxin have all been safely used in pregnancy, as well as DC cardioversion in cases of resistant arrhythmias or hypotension. This case highlights that SVTs occur during pregnancy and simple treatment options exist.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.