1.16 Ebstein Anomaly

Cardiovascular review for the USMLE Step 1 exam.

1.14 Transposition of the Great Vessels

Cardiovascular system review for the USMLE Step 1 exam.

1.13 Ventricular Septal Defects

Cardiovascular system review for the USMLE Step 1 Exam.

1.12 Tetralogy of Fallot

Cardiovascular system review for the USMLE Step 1 exam.

1.11 Patent Ductus Arteriosus (PDA)

Cardiovascular system review for the USMLE Step 1 exam.

• Patent ductus arteriosus (PDA) is a congenital heart defect where the ductus arteriosus, a connection between the pulmonary artery and aorta, fails to close after birth.
• PDA results in oxygenated blood being shunted into pulmonary circulation, leading to volume overload in the pulmonary circulation and eventually the left side of the heart.
• Symptoms include tachycardia, tachypnea, machine-like constant murmur, bounding pulses, respiratory distress, and pneumonia.
• Treatment options include fluid restriction, supportive care, and pharmacological interventions such as indomethacin, acetaminophen, or ibuprofen to reduce prostaglandin production and close the PDA.
• If these interventions don't work, surgical ligation may be performed to close the PDA.
• PDA is so painful to watch, you have to take NSAIDs afterwards.

1.10 Localization of MI on ECG

Cardiovascular system review for the USMLE Step 1 exam T

• Myocardial infarction (MI) can be localized by identifying changes in various ECG leads
• Anterior STEMI: ST elevation in precordial leads V3, V4, indicating occlusion of the distal left anterior descending artery (LAD)
• Lateral MI: ST elevation in leads I, aVL, aVR, and precordial leads V5, V6, caused by an occlusion of the LAD
• Septal MI: ST elevation in leads V1, V2, V3, caused by an occlusion to the LAD
• Inferior MI: ST elevation in leads II, III, aVF, caused by an occlusion of the right coronary artery (RCA)
• Posterior MI: ST elevation in V7, V8, V9, caused by an occlusion of the posterior descending artery (PDA)

1.09 Heart Sound Locations

Cardiovascular system review for the USMLE Step 1 exam.

• Heart sound locations include the aortic, pulmonic, tricuspid, and mitral positions
• Mnemonic to remember the positions: "all physicians take money" (aortic, pulmonic, tricuspid, mitral)
• Aortic position: 2nd intercostal space on the right side of the chest
• Pulmonic position: 2nd intercostal space on the left side of the chest
• Tricuspid position: 5th intercostal space on the left side of the chest
• Mitral position: 6th intercostal space on the left side of the chest at the midclavicular line
• All positions are near the midline except the mitral position

1.08 S2 Splitting

Cardiovascular system review for the USMLE Step 1 exam

• S2 splitting is a phenomenon where the closure of the aortic and pulmonic valves occur at different times, resulting in two heart sounds heard at what is normally S2.
• Four types of splitting: physiologic or normal splitting, wide splitting, fixed splitting, and paradoxical splitting.
• Physiologic splitting is normal and occurs when a person takes a deep breath and the difference between the closure of the aortic and pulmonic valves can be heard.
• Wide splitting is a symptom that is not normal and is associated with diseases that delay right ventricle emptying, such as right bundle branch block and pulmonary stenosis. It gets worse with inhalation.
  • Wide split, worsened by inhalation
• Fixed splitting is similar to wide splitting, but it is not made worse when the patient inhales. It is seen in patients with an atrial septal defect.
  • Fixed split, fixed in place
• Paradoxical splitting is a wide split that is fixed by inspiration and is caused by diseases that delay aortic valve closure, such as aortic stenosis and left bundle branch block.
  • Paradoxially fixded by inspiration

1.05a S3 vs S4 Sounds Only

Compare the S3 and S4 heart sounds directly. This podcast does not explain the physiologic difference between the sounds or the associated diseases. See the individual podasts for that information.

1.07 Diastolic Heart Murmurs

Cardiovacular system reveiw for the USMLE Step 1 exam.

• Diastolic heart murmurs occur when blood flow is turbulent during the diastolic phase of the heart
• Two diastolic murmurs discussed: aortic regurgitation and mitral stenosis
• Aortic regurgitation is caused by blood leaking backwards from the aorta into the left ventricle, resulting in a high pitched decrescendo murmur heard during diastole
• Aortic regurgitation is associated with conditions such as aortic root dilation, bacterial endocarditis, rheumatic fever, and bicuspid valve
  • "A vacuum adds suction. Aortic regurgitation diastolic decrescendo"
• Mitral stenosis involves narrowing of the mitral valve, causing an opening snap followed by a rumbling sound during diastole
• The main cause of mitral stenosis is rheumatic fever
  • "Ms snapped because her husband got strep throat from his lover. MS (mitral stenosis), snap’d (snap diastolic), strep throat (rheumatic fever)"