heart disease in pregnancy

Cardiac disease in pregnancy
An increased prevalence of cardiovascular disease (CVD) has been found in women of childbearing age, [with the presence of CVD in pregnant women posing a difficult clinical scenario in which the responsibility of the treating physician extends to the unborn fetus. Profound changes occur in the maternal circulation that have the potential to adversely affect maternal and fetal health, especially in the presence of underlying heart conditions. Up to 4% of pregnancies may have cardiovascular complications despite no known prior disease.
The European Society of Cardiology has published guidelines on the management of cardiovascular disease during pregnancy.
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Physiological Changes During Pregnancy and Puerperium
Pregnancy has a profound effect on the circulatory system. Most of these hemodynamic changes start in the first trimester, peak during the second trimester, and plateau during the third trimester. Cardiac output increases 30-50% secondary to increase in blood volume and heart rate. [Blood pressure decreases by 10-15 mm Hg owing to a decrease in systemic vascular resistance caused by the creation of a low resistance circuit by the placenta and vasodilatation] Additionally, heart rate normally increases by 10-15 beats per minute.
The hematocrit level decreases due to a disproportionate increase in plasma volume that exceeds the rise in red cell mass.
During the third trimester, cardiac output is further influenced by body position, where the supine position causes caval compression by the gravid uterus. This leads to a decrease in venous return, which can cause supine hypotension of pregnancy. Stroke volume normally increases in the first and second trimester and decreases in the third trimester. This decrease is due to partial vena cava obstruction.
The delivery and immediate postpartum period is associated with further profound and rapid changes in the circulatory system. During delivery, cardiac output, heart rate, blood pressure, and systemic vascular resistance increase with each uterine contraction. ] Delivery-related pain and anxiety aggravate the increase in heart rate and blood pressure.
Immediately postpartum, the delivery of the placenta increases afterload by removing the low resistance circulation and increases the preload by returning placental blood to the maternal circulation. This increase in preload is accentuated by the elimination of the mechanical compression of the inferior vena cava. Blood loss is typically 300-400 mL during vaginal delivery and 500-800 mL during cesarean delivery. These changes can place an intolerable strain on an abnormal heart, necessitating invasive hemodynamic monitoring and aggressive medical management. [Postpartum, the cardiac output is typically reduced for 2-6 weeks.

Cardiovascular Evaluation During Pregnancy
The patient s history is an essential part of the initial risk assessment and should include information on the baseline functional status and previous cardiac events because these are strong predictors of peripartum cardiac events. The strongest predictors include the following:
• Any prior cardiac event
• Cyanosis or poor functional class
• Left-sided heart obstruction
• Ventricular dysfunction
Left-sided heart obstruction includes;

valve disease or hypertrophic cardiomyopathy(aortic valve area < 1.5 cm2, mitral valve area < 2 cm2, or left ventricular outflow tract peak gradient >30 mm Hg). Impaired ventricular function is significant when the ejection fraction is below 40%. [Prior events of interest also include treatment for heart failure, TIA or stroke, or arrhythmia.
The 2011 update to the American Heart Association guideline for the prevention of cardiovascular disease (CVD) in women recommends that risk assessment at any stage of life include a detailed history of pregnancy complications. Gestational diabetes, preeclampsia, preterm birth, and birth of an infant small for gestational age are ranked as major risk factors for CVD. []
Many of the normal symptoms of pregnancy, such as dyspnea on exertion, orthopnea, ankle edema, and palpitations, are also symptoms of cardiac decompensation. However, angina, resting dyspnea, paroxysmal nocturnal dyspnea, or a sustained arrhythmia are not expected with pregnancy and warrant a further diagnostic workup.
] Almost all pregnant women develop physiologic murmurs, which are usually soft, midsystolic murmurs heard along the left sternal border usually caused by functional pulmonary stenosis due to increased transvalvular flow.

Physical signs
; commonly seen with pregnancy are jugular venous distension, an apical S3, basal crackles, prominent left and right ventricular apical impulses, exaggerated heart sounds, and peripheral edema. Diastolic murmurs are rare with pregnancy despite the increased blood flow through the atrioventricular valves; []their presence should prompt further diagnostic evaluation. [] Systolic murmurs more than 2/6 in intensity, continuous murmurs, and murmurs that are associated with symptoms or electrocardiographic changes should also prompt further investigation such as echocardiography. [
Electrocardiography offers low-cost screening that may identify the need for further study if findings otherwise appear benign. In pregnancy, the axis can shift right or left but usually stays in the normal range
. [] During normal pregnancy, multiple changes can be seen such as
- increased R wave amplitude in leads V1 and V2,
-T wave inversion in lead V2
- a small Q wave
-inverted P wave in lead III.
[]Pregnancy is associated with a higher rate of maternal arrhythmias, [] ranging from 73-93% in some studies. [
If impaired functional status is a concern or the patient s history is unreliable, baseline oxygen saturation and low-level exercise testing (targeted to 70% of age-predicted maximum heart rate; 70% of 220 – age) with oxygen monitoring and oxygen consumption may be helpful. Cardiac catheterization should be avoided in pregnancy and should be reserved only for situations in which therapeutic intervention is being considered. [] Findings such as ventricular hypertrophy, evidence of a prior myocardial infarction or ischemia, atrial enlargements, conduction abnormalities, or arrhythmias should prompt a more extensive workup.[