Acyanotic Heart Disease PRECIOUS PEDERSEN 1442

INTRODUCTION Left to right shunting lesions, increased pulmonary blood flow The blood is shunted through an abnormal opening from the left side of the heart to the right side of the heart Pulmonary blood flow increases because of the extra volume in the right side. There is a “step-up” 02 saturation in the right side of the heart (abnormal increased) because of the addition of more highly saturated blood. Physiologic effects include increased pulmonary blood flow, increased cardiac workload (including ventricular strain, dilation, and hypertrophy).

Acyanotic Heart Disease Pink Baby (L  R shunt)  L  R shunts cause CHF and pulmonary hypertension.  This leads to RV enlargement, RV failure  These babies present with CHF and respiratory distress.  They are not typically cyanotic, however, if left alone, it can cause extra flow and this is a condition called Eisenmenger syndrome  Examples: Patent Ductus Arteriosus (PDA) Ventricular Septal Defect (VSD) Atrial Septal Defect (ASD) Coarctation of the Aorta

Atrial Septal Defect (ASD)

▪ Defect in the septum that divides right and left atria; most common type is ostium secundum (90% of cases). ▪ Ostium primum type is associated with Down syndrome. Clinical presentation of ASDs: ▪ Widely split and fixed S2 because of increased venous pressure and delayed closure of pulmonic valve. ▪ Paradoxical emboli are an important complication. Passage of a clot (thrombus) from a vein to an artery

Ventricular septal defect (VSD) ▪ Gross morphology: Defect in the interventricular septum. ▪ Most VSDs are in the membranous septum (90%).Many close spontaneously, and particularly those limited to the muscular septum ▪ Incidence: VSD is present in 30–60% of all patients with a congenital heart defect, making it the most common congenital heart defect and the most common cause of a left-to-right shunt.

Complications of VSDs ■ Paradoxical embolus: An embolus passes into the right ventricle and then into the left ventricle through the VSD. From the left ventricle, the embolus travels via the aorta to the systemic arteries. ■ Endocarditis ■ Left-to-right shunt with increased flow of blood to the right ventricle, leading to hypertrophy and dilation and eventually to Eisenmenger syndrome Clinical presentation of VSD: ▪ Wide physiologic splitting of S2 and holosystolic murmur. Spontaneous closure of VSD occurs in up to 50% of patients.

Patent ductus arteriosus (PDA) ▪ Failure of ductus arteriosus to close; associated with congenital rubella ▪ Results in left-to-right shunt between the aorta and the pulmonary artery During development, the ductus arteriosus normally shunts blood from the pulmonary artery to the aorta, bypassing the lungs. ▪ Asymptomatic at birth with holosystolic 'machine-like' murmur; ▪ The classic sign of a persistent PDA is a continuous “machine-like ” murmur. ▪ May lead to Eisenmenger syndrome, resulting in lower extremity cyanosis ▪ In the normal neonate, spontaneous closure of the ductus arteriosus in response to an increase in PaO2 associated with breathing normally occurs within the first 12hours of life.

Clinical presentation of PDA ■ Use of prostaglandin E will keep the shunt open. Use of indomethacin will close a PDA. Treatment ▪ involves indomethacin, which decreases PGE, resulting in PDA closure (PGE maintains patency of the ductus arteriosus)

Coarctation of aorta ▪ Narrowing of the aorta, classically divided into infantile and adult forms ▪ Infantile form is associated with PDA; coarctation lies after (distal to) the aortic arch, but before (proximal to) the PDA. l. Presents as lower extremity cyanosis in infants, often at birth 2. Associated with Turner syndrome

Coarctation of aorta ▪ Adult form is not associated with PDA; coarctation lies after (distal to) the aortic arch. l. Presents as hypertension in the upper extremities and hypotension with weak pulses in the lower extremities; classically discovered in adulthood 2. Collateral circulation develops across the intercostal arteries; engorged arteries cause 'notching' of ribs on x-ray 3. Associated with bicuspid aortic valve

THANK YOU !!!

References ▪ Sattar, Husain A. Fundamentals of Pathology. Chicago: Pathoma LLC, Print. ▪ Hoffmann JI, Kaplan S. The incidence of congenital heart disease. J Am Coll Cardiol 2002;39: ▪ Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics, 18th ed. 2007, Saunders.