Why does pda cause bounding pulse

In the fetal life, the ductus arteriosus is a conduit for oxygenated blood between the pulmonary artery and the descending aorta.

Oxygen rich blood from the maternal circulation is present in the fetal right heart which is oxygen poor in the adult and travels through the pulmonary artery through the ductus arteriosus to the aorta to supply oxygen rich blood to the fetal systemic circulation. This conduit allows for oxygen rich blood to bypass the non-functional, high-pressured fetal lungs and supply the fetal circulation with oxygen more efficiently.

As pulmonary pressures decrease dramatically at birth, this conduit for blood between the pulmonary artery and aorta normally should close. As the name PDA implies, this conduit remains open. Consequently, in the adult circulation the pressures in the aorta are higher in the pulmonary artery and blood follows the pass of least resistance from the aorta through the PDA to the pulmonary artery during both systole and diastole.

This scenario sets up a circuit for pulmonary overcirculation with blood that should be expelled from the aorta during systole rushing into the pulmonary artery and blood running off during diastole into the pulmonary artery, the pulmonary vasculature and once again into the left side of the heart. The end result is increased blood volume within the left side of the heart and eccentric hypertrophy of the left ventricle ensues.

This volume overload of the left heart results ultimately in left-sided heart failure characterized classically with pulmonary edema secondary to left atrial enlargement and pulmonary venous congestion. A classic continuous holosystolic basilar heart murmur often described as machinery is heard in puppies and sometimes kittens.

Femoral pulses are bounding due to the diastolic runoff of blood that occurs making a larger difference between systolic and diastolic pressures pulse pressures. A small ductus rarely causes symptoms. Over time, a large shunt results in left heart enlargement, pulmonary artery hypertension, and elevated pulmonary vascular resistance, ultimately leading to Eisenmenger syndrome Eisenmenger Syndrome Eisenmenger syndrome is a complication of uncorrected large intracardiac or aortic to pulmonary artery left-to-right shunts.

Increased pulmonary resistance may develop over time, eventually Clinical presentation depends on patent ductus arteriosus size and gestational age at delivery. Premature infants may present with respiratory distress, apnea, worsening mechanical ventilation requirements, or other serious complications eg, necrotizing enterocolitis Necrotizing Enterocolitis Necrotizing enterocolitis is an acquired disease, primarily of preterm or sick neonates, characterized by mucosal or even deeper intestinal necrosis.

Signs of heart failure occur earlier in premature infants than in full-term infants and may be more severe. A large ductal shunt in a premature infant often is a major contributor to the severity of the lung disease of prematurity. Most children with a small PDA have normal 1st and 2nd heart sounds and peripheral pulses.

Hearing-impaired health care practitioners can use amplified stethoscopes The murmur extends from systole to beyond the 2nd heart sound S2 into diastole and typically has a different pitch in systole and diastole. Full-term infants with a significant PDA shunt have full or bounding peripheral pulses with a wide pulse pressure.

An apical diastolic rumble due to high flow across the mitral valve or gallop rhythm may be audible if there is a large left-to-right shunt or heart failure develops. Premature infants with a significant shunt have bounding pulses and a hyperdynamic precordium.

A heart murmur occurs in the pulmonary area; the murmur may be continuous, systolic with a short diastolic component, or only systolic, depending on the pulmonary artery pressure. Some infants have no audible heart murmur. Diagnosis is suggested by clinical examination, supported by chest x-ray and ECG, and established by 2-dimensional echocardiography with color flow and Doppler studies.

Chest x-ray and ECG are typically normal if the patent ductus arteriosus is small. If the shunt is significant, chest x-ray shows prominence of the left atrium, left ventricle, and ascending aorta and increased pulmonary vascular markings; ECG may show left ventricular hypertrophy.

Echocardiography provides important information about the hemodynamic significance of a PDA by assessing a number of parameters, including the. In symptomatic premature infants, cyclo-oxygenase COX inhibitor therapy eg, indomethacin , ibuprofen lysine.

In premature infants without respiratory or other compromise, a patent ductus arteriosus is typically not treated. COX inhibitors work by blocking the production of prostaglandins. Over the past decade, it has been recognized that this nonselective approach to PDA therapy has not resulted in better long-term outcomes. More recent efforts have focused on better defining the subgroup of patients with a hemodynamically significant PDA in whom surgery is more likely to be beneficial.

Echocardiography plays an important role in this determination of hemodynamic significance. A variety of catheter-delivered occlusion devices are available eg, coils, septal duct occluder. In infants 1 year who have ductal anatomy unfavorable for transcatheter closure, surgical division and ligation may be preferred over the transcatheter approach. For a patent ductus arteriosus with a shunt large enough to cause symptoms of heart failure or pulmonary hypertension, closure should be done after medical stabilization.

For a persistent PDA without heart failure or pulmonary hypertension, closure can be done electively any time after 1 year. A doctor will close a PDA if the size of the opening is big enough that the lungs could become overloaded with blood, a condition that can lead to an enlarged heart. A doctor also might close a PDA to reduce the risk of developing a heart infection known as endocarditis , which affects the tissue lining the heart and blood vessels.

Endocarditis is serious and requires treatment with intravenous IV antibiotics. Reviewed by: Gina Baffa, MD. Larger text size Large text size Regular text size. What Is Patent Ductus Arteriosus? What Happens in Patent Ductus Arteriosus? What Causes Patent Ductus Arteriosus? Babies with a large PDA might have symptoms such as: a bounding strong and forceful pulse fast breathing not feeding well shortness of breath sweating while feeding tiring very easily poor growth How Is Patent Ductus Arteriosus Diagnosed?

Follow-up tests might include: a chest X-ray an EKG , a test that measures the heart's electrical activity and can show if the heart is enlarged an echocardiogram, a test that uses sound waves to diagnose heart problems. These waves bounce off parts of the heart, creating a picture of the heart.