It's All About That Flow
Which two physiologic changes contribute to the functional closure of the foramen ovale?
A neonate experiences a rapid decrease in pulmonary vascular resistance after birth increases blood return to the LA increasing LA pressure over RA pressure
An asymptomatic 4-year-old has a fixed, widely split S2 and a systolic murmur at the left upper sternal border. Which congenital heart lesion is most likely?
A fixed split S2 is a classic finding associated with an ASD.
A cyanotic neonate has an echocardiogram demonstrating the aorta arising from the right ventricle and the pulmonary artery arising from the left ventricle. Which congenital lesion is present?
Dextro-transposition of the great arteries (d-TGA).
An infant with heart failure has pulmonary crackles, tachypnea, and cardiomegaly. Are these findings most consistent with left-sided or right-sided heart failure?
Left-sided failure causes pulmonary venous congestion, whereas right-sided failure primarily causes systemic venous congestion.
A school-aged child presents with sharp chest pain that improves when leaning forward. ECG shows diffuse ST-segment elevation. Which cardiac condition is most likely?
Acute pericarditis.
Positional chest pain and diffuse ST elevation are characteristic findings of pericardial inflammation.
A child with a large VSD has a Qp:Qs ratio of 2.5:1. What does this ratio indicate about pulmonary versus systemic blood flow?
Pulmonary blood flow is 2.5 times systemic blood flow, indicating significant left-to-right shunting.
A 6-week-old infant with a large VSD develops diaphoresis during feeds, tachypnea, and poor weight gain. What is the primary mechanism responsible for these symptoms?
Pulmonary overcirculation due to left-to-right shunting as PVR decreases.
A newborn with pulmonary atresia has progressively worsening cyanosis as the ductus arteriosus closes. Which medication should be initiated, and what is its purpose?
PGE to maintain pulmonary blood flow
A child with dilated cardiomyopathy has reduced ejection fraction and significant ventricular dilation. Is the primary abnormality systolic or diastolic dysfunction?
Dilated cardiomyopathy is characterized by impaired contractility and ventricular dilation.
A child presents with fever, a new heart murmur, and positive blood cultures. Echocardiography demonstrates a vegetation on the mitral valve. What major systemic complication is associated with this finding?
Systemic septic embolization, including embolic stroke.
Left-sided endocarditis can embolize to the brain, kidneys, spleen, and other systemic organs.
A child has a normal oxygen saturation but low cardiac output and elevated lactate. Explain why normal SpO₂ does not guarantee adequate tissue oxygen delivery.
Oxygen delivery depends on cardiac output and arterial oxygen content, not saturation alone.
DO₂ = cardiac output × CaO₂. A reduction in
A newborn has weak femoral pulses, cool lower extremities, and a significant upper-to-lower extremity blood pressure gradient. Which lesion should be suspected, and which medication is required if you are concerned about systemic perfusion?
Critical coarctation of the aorta; prostaglandin E1 (PGE1)
An infant with unrepaired Tetralogy of Fallot suddenly becomes severely cyanotic while crying. Why does the knee-to-chest position improve oxygenation?
It increases SVR, decreasing right-to-left shunting across the VSD and promoting pulmonary blood flow.
A patient with systolic heart failure is started on enalapril. What is the primary hemodynamic benefit of this medication?
CE inhibition decreases angiotensin II-mediated vasoconstriction and aldosterone-mediated fluid retention. This will reduce systemic vascular resistance and ventricular afterload.
A child presents with fever for six days, bilateral nonpurulent conjunctivitis, strawberry tongue, and swollen hands. Which acquired cardiac disease is suspected, and what is its most concerning cardiovascular complication?
Kawasaki disease; coronary artery aneurysm.
Kawasaki disease causes systemic vasculitis, and untreated coronary involvement can lead to aneurysms and thrombosis.
A neonate with a large left-to-right shunt develops tachypnea, hepatomegaly, and poor feeding several weeks after birth. What physiologic change explains the delayed onset of heart failure?
The normal postnatal decline in PVR increases pulmonary blood flow and volume overload.
he fall in PVR increases left-to-right shunting, leading to pulmonary overcirculation and congestive symptoms.
A child with a complete atrioventricular canal defect undergoes surgical repair. Which two major cardiac complications should be closely monitored in the immediate postoperative period?
Junctional ectopic tachycardia or complete heart block, and pulmonary hypertensive crisis.
The repair involves tissue near the conduction system, and these patients can have significant pulmonary vascular disease.
A neonate presents with profound hypoxemia, pulmonary edema, severe respiratory distress, and metabolic acidosis. Echocardiography identifies infracardiac TAPVR with pulmonary venous obstruction. What is the definitive treatment?
Emergency surgical relief of the pulmonary venous obstruction and repair of TAPVR.
A child with hypertrophic cardiomyopathy and dynamic LVOT obstruction becomes hypotensive after receiving a vasodilator. Why can reducing afterload worsen cardiac output in this patient?
Reduced afterload can increase dynamic LVOT obstruction, impairing forward flow.
A previously healthy 12-year-old develops tachycardia, hypotension, elevated troponin, and severely decreased ventricular function following a viral illness. What diagnosis is most likely, and which advanced support may be necessary if shock is refractory?
Fulminant myocarditis; VA-ECMO may be necessary.
An infant with parallel systemic and pulmonary circulations has profound hypoxemia despite adequate ventricular function. Which physiologic requirement must be present to sustain life, and what catheter-based intervention can improve it?
In transposition of the great arteries, parallel circulations require intercirculatory mixing to deliver oxygenated blood systemically.
An infant with a large VSD has progressively increasing pulmonary vascular resistance and develops bidirectional shunting. What long-term complication is developing, and why may closing the VSD eventually become contraindicated?
Eisenmenger physiology from irreversible pulmonary vascular disease.
When PVR becomes severely elevated and irreversible, defect closure may worsen RV failure because the shunt acts as a pressure-relief pathway.
A child following Fontan palliation develops elevated central venous pressure, pleural effusions, and reduced cardiac output. Ventricular systolic function is preserved. Which two physiologic factors should be prioritized when evaluating impaired pulmonary blood flow?
Elevated PVR and inadequate transpulmonary pressure gradient, including possible Fontan pathway obstruction.
A child with restrictive cardiomyopathy develops pulmonary congestion despite preserved ventricular ejection fraction. Explain the underlying mechanism and why aggressive diuresis may compromise cardiac output
Impaired ventricular compliance causes elevated filling pressures despite preserved systolic function; excessive diuresis reduces preload and ventricular filling.
A postoperative cardiac patient suddenly develops hypotension, tachycardia, rising CVP, narrowing pulse pressure, and muffled heart sounds. What life-threatening complication should be suspected, and what is the definitive immediate intervention?
Cardiac tamponade; urgent drainage of the pericardial collection, potentially requiring surgical re-exploration or aggressive chest-tube striping if indicated