A reaction in patients with (initially) noncyanotic heart defects that leads to the reversal of the left-to-right shunt and the development of a cyanotic heart defect.Right-to- L eft shunts = ea RLy cyanosis. Left-to- R ight shunts = Late R cyanosis. Right-to-left shunt: blood flows from the right to the left heart via a shunt → deoxygenated blood entering the systemic circulation → cyanosis.Right ventricular pressure overload → right-sided heart hypertroph y ( cardiomegaly on x-ray) and heart failure but no cyanosis.Oxygenated blood from the lungs is shunted back into the pulmonary circulation via an atrial septal defect ( ASD), ventricular septal defect ( VSD), or patent ductus arteriosus ( PDA) → pulmonary hypertension.The shunts are classified according to the direction of the blood flow as either left-to-right or right-to-left.CHDs may lead to the formation of pathological connections ( shunts) between the right and left heart chambers, allowing blood to flow along the pressure gradient from high pressure to low pressure.Congenital heart defects (CHDs) are caused by the disruption of the normal sequence of cardiac morphogenesis.The “ 3 Ds” of acyanotic CHDs (in order of frequency): VS D, A S D, P DA Pathogenesis Principles Common complications include arrhythmias, embolisms, and infective endocarditis, especially if treatment is delayed. Supportive medical therapy is required in cases of heart failure (e.g., diuretics, inotropic agents) or if surgery cannot be performed (e.g., prostaglandin). Acyanotic heart defects requiring treatment are repaired via catheter procedures or surgery. Chest x-ray, MRI, or cardiac catheterization may also be required to determine indications for surgery and plan the procedure. Characteristic heart murmurs are important clues for establishing the diagnosis, which is typically confirmed by visualizing the defect on echocardiography. Infants may be asymptomatic or present with exercise intolerance, failure to thrive, and symptoms of heart failure. The symptoms depend on the extent of the malformation and the resulting impairment of cardiac function. Acyanotic heart defects are pathophysiologically characterized by a left-to-right shunt, which causes pulmonary hypertension and right heart hypertrophy. Common causes include genetic defects (e.g., trisomies), maternal infections (e.g., rubella), or maternal use of drugs or alcohol during pregnancy. Acyanotic heart defects are congenital cardiac malformations that affect the atrial or ventricular walls, heart valves, or large blood vessels.
0 kommentar(er)
