DIP Episode 167 - USMLE Step 2CK Rapid Review Series 21 (Cardio)

Source / episode info

• Episode: 167
• Title: Divine Intervention Episode 167 – USMLE Step 2 CK Rapid Review Series 21 (Cardio).
• Published: 2019-10-11
• Source: Episode page

One-liner

This episode provides a rapid review of core cardiovascular topics, including differentiating murmurs (AS vs HOCM), managing acute coronary syndromes and arrhythmias (WPW, VTAC), diagnosing endocarditis based on risk factors, evaluating peripheral vascular disease (PAD/AAA), and mastering the workup of aortic dissection.

High-yield summary

• Aortic Stenosis (AS) vs. Hypertrophic Cardiomyopathy (HOCM): AS is typically seen in older patients with calcific valve disease; HOCM is more common in younger individuals. Key physical exam differences include the murmur location and radiation, and specific pulse characteristics (pulsus parvus et tardus for AS; pulsus bicuspidus for HOCM).
• Aortic Dissection: The defining feature is whether the dissection involves the ascending aorta (Stanford Type A -> Surgical emergency); if not, it is Type B and managed medically. Beta-blockers are mandatory regardless of type to reduce shear stress.
• Endocarditis Workup: Diagnosis requires considering the source/risk factor: IV drug use strongly suggests Staphylococcus aureus affecting the tricuspid valve; dental procedures suggest subacute endocarditis (e.g., Streptococcus viridans); SLE suggests Libman-Sacks endocarditis.
• Acute Coronary Syndromes (ACS): STEMI requires immediate reperfusion therapy. Unstable Angina/NSTEMI require urgent coronary angiography, as a negative stress test does not rule out disease.
• AAA Screening: Guidelines mandate screening for men over 65 with a history of smoking, or any man over 50 with a family history of AAA.

Learning objectives

• Differentiate the physical exam findings and pathophysiology between aortic stenosis, hypertrophic cardiomyopathy, mitral regurgitation, and mitral valve prolapse.
• Apply appropriate diagnostic workup for acute coronary syndromes (ACS) based on clinical presentation and ECG/troponin status.
• Determine the correct management pathway for Stanford Type A vs. Type B aortic dissection.
• Identify key risk factors and pathogens associated with endocarditis in specific populations (e.g., IVDU, dental).
• Interpret vascular indices (Ankle-Brachial Index, Toe-Brachial Index) to diagnose peripheral arterial disease (PAD).

Board exam buzzwords

Rapid review table

Board-speak -> diagnosis

Differential diagnosis / distinguishing features

Aortic Dissection Types

Acute Coronary Syndromes (ACS)

Management pearls

• For suspected Aortic Dissection: Always initiate IV beta-blockers first, regardless of whether it is Type A or Type B, to reduce shear stress and heart rate.
• AAA Screening Guidelines: Screen men \ge 65 years old with a history of smoking, OR any man \ge 50 years old with a family history of AAA.
• ACS Workup: If the patient presents with acute chest pain and ECG changes (ST elevation/new LBBB), assume STEMI until proven otherwise; immediate coronary angiography is required.
• DVT Management: Diagnosis via duplex ultrasound; treatment involves prophylactic heparin (or alternative if high bleeding risk); IVC filter placement is reserved for patients who cannot take anticoagulation.

Don't miss

Integration & clinical reasoning

• Vascular/Cardiac Integration: The pathophysiology of PAD and AAA are both rooted in chronic atherosclerosis and hypertension, leading to vessel wall weakening and plaque formation.
• Endocrine/Infectious Integration: Lupus (SLE) can cause Libman-Sacks endocarditis, linking autoimmune disease with valvular pathology.
• Vascular/Nephrology Integration: Severe AAA repair carries a high risk of acute kidney injury (AKI), often due to renal artery clamping or embolization, necessitating careful monitoring and potential use of nephroprotective agents.

OMM / COMLEX integration

• Standard emergency management for acute coronary syndromes, aortic dissection, and AAA rupture takes absolute priority over OMT. Stabilization (ABCDE approach) must be completed first.
• In the context of severe sepsis/septic shock leading to endocarditis, local wound care and infection control are paramount; OMM is adjunctive only after hemodynamic stabilization with vasopressors and antibiotics.

Concept connections / cross-references

• For detailed information on the pathophysiology of atherosclerosis and vascular calcification: [Episode 10]
• For comprehensive review of autoimmune diseases and their cardiac manifestations (e.g., Libman-Sacks): [Episode 45]
• For general principles of cardiovascular physiology, including wall tension and pressure/volume overload: [Episode 37]

High-yield association table

Key terms glossary

Study optimization

Question pattern recognition

• Physical Exam Pattern: A systolic ejection murmur heard best at RUSB that increases with squatting/preload suggests Aortic Stenosis.
• Vascular Pattern: Pain in the calf/foot, worse with walking and relieved by rest, points to Peripheral Arterial Disease (PAD). If pain is bilateral and involves the iliac branches, consider Leriche syndrome.
• Emergency Pattern: Acute chest pain radiating to the back, coupled with differential blood pressures, mandates immediate suspicion and workup for Aortic Dissection.

Test yourself

Common mistakes to avoid

Common traps