FIGURE 49-2 Normal electrocardiograph (ECG) adaptations durPersistent tachycardia and/or arrhythmia ing pregnancy, including a reduced mean PR interval, increased Persistent split second sound heart rate, left axis deviation, inverted or flattened T waves and a
With radiography, anteroposterior (AP) and lateral chest radiographs are useful, and when a lead apron shield is used, fetal radiation exposure is minimal. Gross cardiomegaly can usually be excluded, but slight heart enlargement cannot be detected accurately because the heart silhouette normally is larger in pregnancy. his is accentuated further with a portable
AP chest radiograph.
Echocardiography is now widely used and permits accurate diagnosis of most heart diseases during pregnancy. Some nor the dimensions of all cardiac chambers, a slight but signii cant growth in left ventricular mass, and greater tricuspid and mitral valve regurgitation (Grewal, 2014). Of note, systolic function normally does not change. Savu (2012) and Vitarelli diographic parameters for pregnancy, which are listed in the
Appendix (p. 1261). In some situations, such as complex con genital heart disease, transesophageal echo cardiography may be useful.
Cardiovascular MR imaging, compared with echocardiography, is associated with higher reproducibility and is less hindered by ventricular geometry and body habitus. The right ventricle can also be assessed (Nelson, 2017). Ducas and associates (2014) have published normal reference values for pregnancy.
Of other studies, albumin or red cells tagged with technetium-99m are rarely needed during pregnancy to evaluate ventricular function. That said, the estimated fetal radiation exposure from nuclear medicine studies of myocardial perfusion is negligible. It is safe to perform cardiac catheterization with limited fluoroscopy time. During coronary angiography, the mean radiation exposure to the unshielded abdomen is 1.5 mGy, and less than 20 percent of this reaches the fetus (European Society of Cardiology, 2011). Shortening the fluoroscopic time may help to minimize radiation exposure (Raman, 2015; Tuzcu, 2015). In women with clear indications, any minimal theoretical fetal risk is outweighed by maternal beneits (Chap. 46, p. 906).
• Classification of Functional Heart Disease
No clinically applicable test accurately measures functional cardiac capacity. The clinical classification of the New York Heart Association (NYHA) is based on past and present disability and is uninfluenced by physical signs: • Class I. Uncompromised-no limitation of physical activiy:
These women do not have symptoms of cardiac insuiciency or experience anginal pain.
Class II. Slight limitation of physical activiy: These women are comfortable at rest, but if ordinary physical activity is undertaken, discomfort in the form of excessive fatigue, palpitation, dyspnea, or anginal pain results.
Class III. Marked limitation of physical activiy: These women are comfortable at rest, but less than ordinary activity causes excessive fatigue, palpitation, dyspnea, or anginal pain.
Class IV. Severey compromised-inabiliy to peorm any physical activity without discomort: Symptoms of cardiac insufficiency or angina may develop even at rest. If any physical activity is undertaken, discomfort is increased.
Cardiovascular Disorders 95.1