Isoproterenol infusion for treatment of refractory symptomatic bradycardia in parturients with congenital complete heart block

Genetic Complexity of Sinoatrial Node Dysfunction

The pacemaker cells of the cardiac sinoatrial node (SAN) are essential for normal cardiac automaticity. Dysfunction in cardiac pacemaking results in human sinoatrial node dysfunction (SND). SND more generally occurs in the elderly population and is associated with impaired pacemaker function causing abnormal heart rhythm. Individuals with SND have a variety of symptoms including sinus bradycardia, sinus arrest, SAN block, bradycardia/tachycardia syndrome, and syncope. Importantly, individuals with SND report chronotropic incompetence in response to stress and/or exercise. SND may be genetic or secondary to systemic or cardiovascular conditions. Current management of patients with SND is limited to the relief of arrhythmia symptoms and pacemaker implantation if indicated. Lack of effective therapeutic measures that target the underlying causes of SND renders management of these patients challenging due to its progressive nature and has highlighted a critical need to improve our understanding of its underlying mechanistic basis of SND. This review focuses on current information on the genetics underlying SND, followed by future implications of this knowledge in the management of individuals with SND.

Heart Disease and Pregnancy

Cardiac disease remains a major cause of morbidity and mortality in pregnant and post-partum women, although progress has been made, with specialist joint obstetric-cardiology clinics providing an integrated, safe and personalised service to these women. As a result, fewer non-specialist cardiologists are managing women in pregnancy with cardiovascular disease. The aim of this review is to provide a brief overview of current knowledge and practice in the field, with an emphasis on the major physiological changes which occur during pregnancy, focussing on progress through the trimesters, clinical assessment in pregnancy, management of delivery (concentrating on managed vaginal delivery), drug treatment, key conditions and risk assessment. The latter factor is particularly important in terms of being able to identify high-risk women earlier and to counsel them appropriately. Pregnant women with cardiovascular conditions can, with appropriate knowledge and counselling, be managed safely in specialist multidisciplinary services, but there is a need for cardiologists to understand the key changes and risks involved in pregnancy, delivery and the post-partum period.