Electrocardiography

Electrocardiography (ECG)

Normal changes in ECG readings that occur during pregnancy include sinus tachycardia, QRS axis shift to the left or right and premature atrial or ventricular beats. Atrial and ventricular premature beats, sinus arrhythmia, sinus arrest with nodal escape rhythm, wandering atrial pacemaker and paroxysmal supraventricular tachycardia, usually do not occur during the birthing process. ST segment elevation, depression, or a change in amplitude of P wave, QRS, or T should be interpreted with caution. Several authors have reported this is not an issue.

In the absence of symptoms, many non-specific ECG changes do not require further evaluation. ECG is more useful for diagnosing arrhythmias than to describe the structural abnormalities.

Echocardiography

Echocardiography (m-mode, two-dimensional, Doppler) is a non-invasive diagnostic tests are selected in pregnancy and poses no hazard to the fetus. This procedure will provide information on cardiovascular reserve, including a definitive diagnosis of a variety of structural abnormalities. Transesophageal echocardiography is safe and useful for investigating complex congenital heart disease and infective endocarditis, especially in patients with prosthetic valves or patients who have had previous surgery.

Normal echocardiography changes during pregnancy include an increase in heart size and left ventricular mass. A small pericardial effusion can be recorded. Other investigations have shown mild valve regurgitation, which has no clinical significance. However, any abnormalities on an echocardiogram requires clinical evaluation.

Chest radiography

Exposure to X-rays, especially during the first trimester, can be harmful to fetuses, and should be avoided during pregnancy. However, a normal chest radiographs with abdominal shielding give give a dose of about 0.1 rad to the mother and only about 0.008 rad to the fetus. This means that the fetus can be exposed to 625 chest radiographs before exceeding 5 rads for the duration of pregnancy.

Changes seen on chest radiographs in a normal pregnancy can describe the presence of heart disease. This includes a mild increase in heart size, heart of a horizontal shift that increases with gestation, the left heart border and supply pulmonary blood vessels filled with a false magnification (pseudoenlargement) in the left atrium associated with lordosis of the spine.

Magneting resonance imaging

This procedure gives only a small role, although there is increasing interest and research in this regard. MRI is an attractive model for investigation, while not involving irradiation. However, lay the flat is a serious problem in pregnancy with heart disease.

Radioisotope scanning

Radioisotope scans, such as thallium scan or positron emission tomography, exposure to irradiation and thus a potential risk in pregnancy. The same information can be obtained using other modalities such as stress echocardiography, which does not use radiation. Exercise testing can be done safely in pregnancy for suspected ischemic heart disease or functional capacity. Fetal bradycardia has been reported with maximal testing and that patients are not allowed to exceed 75% of maximal heart rate.

Invasive Investigations

Cardiac catheterization produces about 0.005 rads of exposure in the fetus that has been protected cover. If cardiac catheterization is required, the access of the radial artery or brachial artery approach should be used instead of the femoral artery, which means less radiation exposure to the fetus. Access from the radial artery is now more popular than the approach of the brachial artery, with a smaller catheter balloons and stents and form a better, percutaneous transluminal coronary angioplasty (PTCA) can be carried out securely via the radial artery route, if needed.