Description
This comprehensive lecture on cardiac disease in pregnancy is authored by Dr. Andrew Kumwenda, a highly qualified specialist with a Bachelor of Science in Human Biology, a Bachelor of Medicine and Bachelor of Surgery from the University of Zambia, a Postgraduate Diploma, a Master of Philosophy from Stellenbosch, a Master of Public Health from the University of the Western Cape, a Master of Medicine in Obstetrics and Gynaecology from UNZA, and is a PhD candidate at the University of the Witwatersrand. Delivered to MBChB VII students at the School of Medicine, UNZA, on Friday 23rd September 2021, this tertiary-level material covers the physiological cardiovascular changes in pregnancy and their impact on pre-existing heart conditions. It details the classification, clinical evaluation, and predictors of adverse maternal and fetal outcomes, with a focus on the management principles from preconception counselling through antenatal care, intrapartum strategies, and the puerperium. The notes include specific guidance on anticoagulation, timing of hospital admission, and indications for therapeutic termination or surgical intervention, making it an indispensable resource for medical students and practitioners preparing for exams and clinical practice in obstetric medicine. This authoritative document provides essential revision material for understanding a significant cause of maternal morbidity. Review these detailed university notes to enhance your clinical knowledge.
What's inside
Cardiac disease in pregnancy Dr. Andrew Kumwenda BSc.(HB), MBChB (UNZA), Pg. Dip., MPhil.(Stellenbosch), MPH (UWC), MMed. (Obs-Gyn.) (UNZA), PhD candidate (Witwatersrand) MBChB VII lecture, School of Medicine, UNZA. Friday 23rd Sep., 2021 Objectives Be able to describe: Cardiovascular changes affecting cardiac disease Classification of cardiac disease Management of cardiac disease from conception to puerperium Case scenario Mrs Melody Kaluba is known to have pre-existing cardiac disease. i. What is the most common acquired cardiac lesion? ii. What are the effects of cardiac disease on pregnancy? iii. How should her labour be managed? Incidence: Cardiac disorders complicate about 1% of pregnancies They contribute significantly to maternal morbidity and mortality rates Commonest cardiac lesion is of rheumatic origin followed by the congenital ones Rheumatic valvular lesions predominantly include mitral stenosis (80%) Physiological considerations in pregnancy Pregnancy is a state of hypervolaemia Blood and plasma volume increase by 30-40% & 40-50% respectively However, RBCs and Hb increase by 20-30% and 18-20% respectively This disproportionate increase in plasma and RBC/Hb volume produces a state of hemodilution and an apparent fall in Hb Physiological considerations in pregnancy The marked pregnancy induced haemodynamic alterations can have a profound effect on underlying heart disease Primary event is probably peripheral vasodilatation (PV) PV leads to a fall in systemic vascular resistance (SVR) and to compensate for this the cardiac output is increased by as much as 50% Systemic vascular resistance decreases (20%) Physiological considerations in pregnancy CO starts to ↑from 5th wk, reaches its peak 40 – 50% at about 30 – 34 wks. Thereafter, CO remains static till term though minimal fall at term has been observed CO ↑is achieved mainly by an ↑in stroke volume and by a lesser increase in heart rate Intrapartum & postpartum haemodynamic changes Labour is associated with further ↑in CO (15% in 1st stage and 50% in 2nd stage) Uterine contractions lead to auto-transfusion of 300- 500mls of blood back into circulation Sympathetic response to pain and anxiety further elevate heart rate and BP Intrapartum & postpartum haemodynamic changes CO is ↑more during contractions and in between contractions Following delivery, there is an immediate rise in CO due to the relief of IVC obstruction and contraction of the uterus that empties blood into the circulation CO increases by 60% to 80% followed by a rapid decline to pre-labour values within 1 hour of delivery Intrapartum & postpartum haemodynamic changes Transfer of fluid from the extravascular space increases venous return and stroke volume further These women with cardiovascular compromise are therefore most at risk of pulmonary oedema during second stage of labour and immediate postpartum CO nearly returns to normal 2/52 after delivery although it may take longer in pts with PE Intrapartum & postpartum haemodynamic changes Women with underlying cardiac disease may not accommodate these changes and ventricular dysfunction leads to cardiogenic heart failure. In most women, heart failure develops peripartum Effect of cardiovascular physiology on pregnancy Normal heart has got enough reserve power to withstand the extra load Damaged heart may not withstand the extra load if reserve power is poor, cardiac failure may occur with such. Cardiac failure usually occurs around 30wks, during labour and mostly soon after delivery
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