Cyanotic congenital heart defects: Pathology review


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Cyanotic congenital heart defects: Pathology review


Vascular disorders

Arterial disease

Angina pectoris

Stable angina

Unstable angina

Myocardial infarction

Prinzmetal angina

Coronary steal syndrome

Peripheral artery disease

Subclavian steal syndrome


Aortic dissection


Behcet's disease

Kawasaki disease


Hypertensive emergency

Renal artery stenosis

Coarctation of the aorta

Cushing syndrome

Conn syndrome


Polycystic kidney disease


Orthostatic hypotension


Familial hypercholesterolemia



Chronic venous insufficiency


Deep vein thrombosis




Vascular tumors

Human herpesvirus 8 (Kaposi sarcoma)


Congenital heart defects

Truncus arteriosus

Transposition of the great vessels

Total anomalous pulmonary venous return

Tetralogy of Fallot

Hypoplastic left heart syndrome

Patent ductus arteriosus

Ventricular septal defect

Coarctation of the aorta

Atrial septal defect

Cardiac arrhythmias

Atrial flutter

Atrial fibrillation

Premature atrial contraction

Atrioventricular nodal reentrant tachycardia (AVNRT)

Wolff-Parkinson-White syndrome

Ventricular tachycardia

Brugada syndrome

Premature ventricular contraction

Long QT syndrome and Torsade de pointes

Ventricular fibrillation

Atrioventricular block

Bundle branch block

Pulseless electrical activity

Valvular disorders

Tricuspid valve disease

Pulmonary valve disease

Mitral valve disease

Aortic valve disease


Dilated cardiomyopathy

Restrictive cardiomyopathy

Hypertrophic cardiomyopathy

Heart failure

Heart failure

Cor pulmonale

Cardiac infections



Rheumatic heart disease

Pericardial disorders

Pericarditis and pericardial effusion

Cardiac tamponade

Dressler syndrome

Cardiac tumors

Cardiac tumors

Cardiovascular system pathology review

Acyanotic congenital heart defects: Pathology review

Cyanotic congenital heart defects: Pathology review

Atherosclerosis and arteriosclerosis: Pathology review

Coronary artery disease: Pathology review

Peripheral artery disease: Pathology review

Valvular heart disease: Pathology review

Cardiomyopathies: Pathology review

Heart failure: Pathology review

Supraventricular arrhythmias: Pathology review

Ventricular arrhythmias: Pathology review

Heart blocks: Pathology review

Aortic dissections and aneurysms: Pathology review

Pericardial disease: Pathology review

Endocarditis: Pathology review

Hypertension: Pathology review

Shock: Pathology review

Vasculitis: Pathology review

Cardiac and vascular tumors: Pathology review

Dyslipidemias: Pathology review


Cyanotic congenital heart defects: Pathology review

USMLE® Step 1 questions

0 / 5 complete


USMLE® Step 1 style questions USMLE

of complete

A 1-day-old female newborn is being evaluated in the neonatal intensive care unit for severe respiratory distress and cyanosis. The patient was born at 38 weeks gestation via vaginal delivery to a 30-year-old woman who had minimal prenatal care. Temperature is 36.4°C (97.5°F), pulse is 150/min, blood pressure is 87/55 mm Hg, and respiration rate is 60/min. An electrocardiogram reveals left axis deviation with a superior axis and chest x-ray shows decreased pulmonary markings and a hypoplastic right ventricle. Which of the following is the most likely diagnosis?  


Content Reviewers

Rishi Desai, MD, MPH


Kaia Chessen, MScBMC

Samantha McBundy, MFA, CMI

Yifan Xiao, MD

Marisa Pedron

At the pediatric cardiology clinic, two mothers were chatting about their kids. One mom spoke about a 5 year old boy named Blake, who was a bluish color at birth and had a continuous machine-like heart murmur between the scapulas.

Another mom spoke about her 12 year old son, Paul, who was healthy at birth, but when he was breastfeeding or crying, his skin turned pale, and then blue. As a child, Paul got out of breath easily and needed to squat down to recover. And during his school physical, he was found to have a heart murmur.

Both Blake and Paul have cyanotic congenital heart defects, or CHDs, which usually start causing problems within the first 3-8 weeks of life. They can be broadly grouped into life-threatening cyanotic heart defects, or the less dangerous acyanotic heart defects.

Let’s go over 5 of the life-threatening cyanotic congenital heart defects: persistent truncus arteriosus, transposition of the great vessels, tetralogy of fallot, total anomalous pulmonary venous return, and tricuspid atresia.

Now the first 3 are caused by outflow tract defects that develop during the formation of the aorta and pulmonary artery. In fetal development the heart looks like a long tube; the top part is the truncus arteriosus and the part inferior to that is the bulbus cordis. Neural crest cells migrate into the bulbus cordis and trigger the formation of the aorticopulmonary septum. This structure is formed when two endocardial cushions appear on the right-superior and left-inferior walls. These grow like a spiral - imagine a corkscrew - and they wrap around each other forming a single septum that divides the truncus into the roots of the aorta. One root connects to the primitive left ventricle, and the other connects to the pulmonary artery and primitive right ventricle. That’s how blood gets routed to the right place!


  1. "Pathophysiology of Heart Disease" Wolters Kluwer Health (2015)
  2. "Robbins Basic Pathology" Elsevier (2017)
  3. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  4. "Cyanosis of the newborn infant" The Journal of Pediatrics (1970)
  5. "Diagnosis and management of the newborn with suspected congenital heart disease" Clin Perinatol (2001)

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