[Risks of pharmacotherapy in heart diseases in pregnancy]

Normal physiological changes in the cardiovascular system in pregnancy such as increase in cardiac output, vasodilatation and hypervolemia are of clinical relevance as they are able to aggravate, mask or even imitate cardiovascular diseases. There is an increase of cardiac size and volume during pregnancy; furthermore hormonal changes lead to diaphragmatic elevation and barrel-shaped thorax followed by a rotation of the cardiac axis to the left (15 degrees-30 degrees). Cardiac topography and size, changes in cardiac functioning and physiology as well as hemodynamic changes lead to auscultatory and ECG changes (i.e. S1-Q3-type, ST-depression, T wave flattening). In addition there is a high incidence of functional systolic and diastolic sounds during pregnancy, which are also able to imitate cardiovascular diseases. The physiological changes in pregnancy are similar to those under heavy exercise. This results in continuous cardiac stress during the whole pregnancy. This stress is specifically high from the 28th to the 34th week of pregnancy and in the post-partum period; the maximum of cardiac stress is reached during labor. Important for the specific cardiac risk during pregnancy is not the type of heart disease but cardiac functioning and the severity of complaints before pregnancy. Principally it has to be expected that preexisting heart diseases will experience an aggravation of one grade according to NYHA during pregnancy. In cases of heart diseases with shunt defects, with shunt defect and injured myocardium, with continuous arrhythmia or atrial fibrillation, patients are at extremely high risk of cardiac death. A termination of pregnancy should be considered in all patients with heart diseases grade III or IV according to NYHA, severe pulmonary hypertension, Eisenmenger's syndrome, severe aortic or pulmonary stenosis, Marfan's syndrome, and severe continuous cardiac insufficiency. The drug therapy of cardiac diseases during pregnancy depends on the specific type of heart disease. Prescription of most drugs is principally possible during pregnancy and breast feeding. However, for most drugs there is only very limited therapeutic experience during this period. Definitively contraindicated during pregnancy and breast feeding are ACE inhibitors, angiotensin I and II blocking agents, vasopeptidase inhibitors and molsidomin, a NO-prodrug. In life-threatening conditions, however, sometimes it will be necessary to administer drugs with only poor experiences in pregnancy.