Maternal cardiac arrhythmias during pregnancy and lactation

Abstract

Arrhythmias occurring during pregnancy can cause significant symptoms and even death in mother and fetus. The management of these arrhythmias is complicated by the need to avoid harm to the fetus and neonate. It is useful to classify patients with arrhythmias into those with and without structural heart disease. Those with a primary electrical problem, but an otherwise normal heart, often tolerate rapid heart rates without compromise whereas patients with problems such as rheumatic heart disease, congenital heart disease or cardiomyopathy may quickly decompensate during an arrhythmia.

Management of palpitations and cardiac arrhythmias in pregnancy

“…A resting 12‐lead electrocardiogram (ECG) in pregnancy will demonstrate an increase in heart rate. There may be a slight left axis deviation, within the normal range, in part due to the rotation of the heart from the gravid uterus . Inverted or flattened T waves in leads III, V1–V3 and a Q wave in leads II, III and aVF, are also commonly seen…”

“…Cardiac output increases by approximately 50% during pregnancy . This is largely due to an increase in stroke volume as a result of reduced vascular resistance and an increase in blood volume.…”

“…In these circumstances, palpitations are considered physiological rather than pathological. During pregnancy, women may experience the sensation of a ‘pounding heartbeat’, originating from a heightened awareness of the physiological increase in heart rate and accompanying increased stroke volume . Atrial and ventricular ectopic beats are often experienced as a ‘missed’ or ‘skipping’ heartbeat.…”

“…Most commonly, paroxysmal supraventricular tachycardia (PSVT) is caused by an atrioventricular nodal re‐entrant tachycardia (AVNRT) . In this arrhythmia, a re‐entry circuit occurs via the atrioventricular (AV) node and surrounding perinodal atrial tissue . Another common cause of PSVT is the presence of an overt or concealed accessory pathway, which allows conduction to bypass the AV node.…”

Cardiac disease in pregnancy

“…The arrhythmia encountered most commonly in pregnancy is supraventricular tachycardia (SVT). 19 First-onset of SVT (accessory pathway mediated or atrioventricular nodal re-entrant) is rare in pregnancy, but exacerbation of symptoms is common in pregnancy. Propranolol, verapamil and adenosine (preferred) can be used for acute termination of SVT or for those who do not respond to vagal manoeuvres (50%).…”