1A 48-year-old woman comes for a routine visit and feels completely well. She has no significant medical history and takes no medications. Her BP is 176/98 mm Hg; repeat measurement one week later is 178/100 mm Hg. Home BP monitoring shows an average of 174/102 mm Hg. Physical examination, ECG, electrolytes, creatinine, glucose, TSH, and urinalysis are normal.
Lifestyle counseling is initiated.
What is the most appropriate initial pharmacologic approach?
Answer: Start 2 antihypertensive medications
Why:
* Her BP is ≥20/10 mm Hg above the usual treatment target.
* When BP is substantially above goal, monotherapy is unlikely to achieve adequate control.
* Initial therapy can use 2 complementary agents, such as:
* ACE inhibitor/ARB + thiazide
* ACE inhibitor/ARB + dihydropyridine calcium-channel blocker
* Thiazide + dihydropyridine calcium-channel blocker
* Her normal labs and lack of suggestive symptoms/signs make routine extensive evaluation for secondary causes unnecessary initially.
Key Step 2 takeaway:
BP ≥20/10 above target → start 2 drugs rather than waiting for monotherapy to fail.
Other differentials / traps:
* Lifestyle measures alone: appropriate for mild BP elevations, but insufficient for marked persistent elevation.
* 1-drug therapy: generally used when BP is closer to goal.
* Secondary hypertension workup: consider when there are clues such as hypokalemia, abruptefractory hypertension, renal dysfunction, or episodic symptoms suggestive of pheochromocytoma.
* ACE inhibitor/ARB: particularly useful when CKD with albuminuria is present; otherwise, thiazides and dihydropyridine CCBs are also first-line options.
2A 32-year-old man presents with 3 days of fever, cough, and weakness. He has multiple needle-track marks on his arms. Chest imaging shows multiple bilateral peripheral round pulmonary lesions. Cardiac examination reveals a systolic murmur.
Which characteristic of the murmur would most strongly support the underlying cardiac lesion?
Answer: Holosystolic murmur that increases with inspiration
Why:
* IV drug use + multiple peripheral pulmonary nodules → right-sided infective endocarditis with septic pulmonary emboli.
* The tricuspid valve is the most commonly affected valve in IV drug–associated endocarditis.
* Tricuspid regurgitation produces a holosystolic murmur best heard at the lower left sternal border.
* Inspiration increases right-sided venous return, increasing the intensity of tricuspid regurgitation (Carvallo sign).
Key Step 2 takeaway:
Right-sided murmur that gets louder with inspiration → think tricuspid regurgitation.
Other differentials / traps:
* Aortic regurgitation: early diastolic murmur; best heard with the patient sitting forward.
* Hypertrophic cardiomyopathy: systolic murmur that increases with standing/Valsalva due to decreased LV volume.
* Aortic stenosis: systolic ejection murmur; typically decreases with standing.
* Paradoxical S2 splitting: suggests delayed aortic valve closure (eg, LBBB), not tricuspid regurgitation.
3A 63-year-old woman with heart failure with reduced ejection fraction is taking sacubitril/valsartan along with carvedilol and furosemide. Her medications and laboratory values have been stable.
She suddenly develops progressive swelling of the lower face, described as “puffiness,” without rash or itching. The swelling began within hours and is continuing to worsen.
What is the most appropriate immediate management?
Answer: Emergency evaluation for angioedema
Why:
* Sacubitril inhibits neprilysin, which normally breaks down bradykinin.
* Increased bradykinin → vasodilation + increased vascular permeability → angioedema.
* Angioedema can progress rapidly to laryngeal edema and airway obstruction, even if the patient initially has isolated facial swelling.
* The priority is airway assessment and emergency evaluation, not simply stopping the medication and waiting.
Key Step 2 takeaway:
Sacubitril/valsartan + acute facial/tongue swelling → think bradykinin-mediated angioedema → emergency airway evaluation.
Other differentials / traps:
* ACE inhibitors: also cause bradykinin-mediated angioedema; discontinue the ACE inhibitor and provide urgent airway assessment.
* ARB alone: much less strongly associated with angioedema because ARBs do not inhibit bradykinin breakdown.
* Allergic angioedema: often accompanied by urticaria, pruritus, or other allergic features and is histamine-mediated.
* Heart failure edema: typically dependent/peripheral edema, not abrupt isolated facial swelling.
4A 34-year-old man who recently emigrated from Brazil presents with a 5-month history of progressive exertional dyspnea, 1+ pedal edema, mild JVD, an S_3 gallop, and prominent cardiomegaly on chest X-ray. His past medical history is notable for an episode of megacolon treated 2 years ago.
What is the underlying category of infectious etiology responsible for his clinical presentation?
Answer: Protozoal disease (Chagas disease, caused by Trypanosoma cruzi)
Why:
Demographic + GI clues: Immigrants from Latin America presenting with megacolon or megaesophagus (due to neurogenic destruction of myenteric plexus smooth muscle tone) strongly points to T. cruzi.
Cardiac pathology: Chronic T. cruzi infection leads to prolonged myocarditis, resulting in biventricular dilated cardiomyopathy (cardiomegaly, S_3, peripheral edema, JVD, apical aneurysm/thrombus).
Key Step 2 takeaway:
Chagas disease (Trypanosoma cruzi) is endemic to South/Central America and classically presents with the triad of dilated cardiomyopathy, megaesophagus, and megacolon.
Other differentials / traps:
Diphtheric myocarditis trap: Rare due to widespread vaccination; presents acutely alongside upper respiratory pseudomembranes, not chronic GI motility disorders.
Giant cell myocarditis trap: Causes a rapidly progressive, frequently fatal acute myocarditis/arrhythmia in younger patients, without associated megacolon.
Coronary artery disease trap: Unlikely cause of heart failure in a young patient without cardiovascular risk factors or ischemic chest pain.
Rickettsial myocarditis trap: Can cause acute myocarditis, but typically presents with systemic rash and systemic fevers, lacking chronic GI dilatation features.
5A 74-year-old woman with a history of heart failure with reduced ejection fraction and persistent atrial fibrillation presents with a several-day history of nausea, decreased appetite, lethargy, increasing fatigue, and palpitations. Her home medications include furosemide, sacubitril-valsartan, metoprolol, digoxin, and apixaban. Vital signs show HR 55/\text{min} with an irregularly irregular rhythm. ECG demonstrates atrial fibrillation with non-specific T-wave changes.
What diagnostic test is most appropriate to confirm the underlying etiology of her symptoms?
Answer: Serum blood medication level (Digoxin level)
Why:
Narrow Therapeutic Index: Digoxin has a very narrow therapeutic window and is cleared renally. Loop diuretic (furosemide) use can lead to dehydration or hypokalemia, both of which severely precipitate or exacerbate Digoxin Toxicity.
Clinical Picture: Toxicity presents with non-specific GI upset (anorexia, nausea, vomiting), neurologic/visual disturbances (lethargy, confusion, xanthopsia/yellow-green color vision alterations), and cardiac conduction abnormalities (bradycardia, atrial fibrillation with slow ventricular response, AV block, ventricular arrhythmias).
Key Step 2 takeaway:
Suspect digoxin toxicity in an elderly patient on heart failure/AFib regimens presenting with acute gastrointestinal symptoms, fatigue, and bradyarrhythmias. Diagnose by checking a serum digoxin level.
Other differentials / traps:
Thyroid function studies trap: Hypothyroidism can cause fatigue, lethargy, and anorexia, but it would not explain the rapid onset alongside acute GI distress in a patient on digoxin and diuretics.
Coagulation profile trap: Apixaban is a direct factor Xa inhibitor; routine coagulation studies (PT/PTT) are unhelpful and do not correlate with efficacy or toxicity.
Echocardiography trap: Not indicated as an initial diagnostic step when the patient has no acute volume overload signs (no pulmonary edema, JVD, or peripheral edema) to suggest heart failure decompensation.
ECG Stress Test trap: Indicated for suspected stable CAD/angina; inappropriate during acute drug toxicity and in patients with baseline resting ECG changes or slow ventricular rates.
6A 58-year-old asymptomatic man presents for follow-up of a heart murmur heard during a routine physical exam. He reports no dyspnea, chest pain, syncope, or edema. Cardiac examination reveals a 3/6 holosystolic murmur best heard at the apex. Transthoracic echocardiogram reveals severe primary mitral regurgitation due to mitral valve prolapse (leaflets bulging into the left atrium) with a dilated left ventricle and a left ventricular ejection fraction (LVEF) of 52%.
What is the most appropriate next step in management for this patient?
Answer: Referral for mitral valve repair (surgical valve repair)
Why:
Primary Severe MR Surgical Indications: Surgery is indicated for primary severe MR if the patient is symptomatic OR if asymptomatic with evidence of LV dysfunction (LVEF \le 60\% or severe LV dilation/increased end-systolic diameter).
"Normal" LVEF Fallacy in Severe MR: Because a large portion of the stroke volume regurgitates backward into the low-resistance left atrium during systole, the baseline LVEF in severe MR is over-estimated. An LVEF of 52\% actually reflects significant underlying LV systolic dysfunction.
Key Step 2 takeaway:
For primary chronic severe mitral regurgitation, an LVEF \le 60\% (even if completely asymptomatic) is an immediate indication for surgical mitral valve intervention (preferably valve repair over replacement).
Other differentials / traps:
Medical therapy (ARBs/Beta-blockers) trap: Afterload-reducing agents or beta-blockers have limited benefit in primary structural MR and delay necessary definitive surgical repair (medical management is reserved primarily for secondary/functional MR).
Repeat echocardiogram in 6 months trap: Monitoring is appropriate only for asymptomatic severe primary MR with preserved LV function (\text{LVEF} > 60\%). Once LVEF drops to \le 60\%, surgery should not be delayed.
Exercise program referral trap: Physical rehabilitation does not address the mechanical overload and progressive cardiac remodeling caused by severe valvular dysfunction.
7A 13-year-old girl who recently immigrated from Southeast Asia presents for a routine health examination. Her history includes a febrile illness one year ago followed by transient joint pain and swelling in her knees and wrists treated with NSAIDs. Vital signs are normal. Cardiac exam demonstrates a diminished S_1 and a 2/6 high-pitched holosystolic murmur at the apex radiating to the axilla. Echocardiogram confirms mild mitral regurgitation.
What long-term pharmacologic therapy is indicated to prevent progression of her cardiac condition?
Answer: Antibiotic prophylaxis with Penicillin (intramuscular benzathine penicillin G every 3–4 weeks)
Why:
Pathophysiology: The patient has Rheumatic Heart Disease (RHD) secondary to Acute Rheumatic Fever (ARF) triggered by Group A Streptococcus (GAS) pharyngitis.
Prevention of Recurrence: Patients with prior ARF are at high risk for recurrent GAS pharyngitis, which triggers immune-mediated progression of valvular damage (most commonly mitral regurgitation/stenosis). Continuous penicillin prophylaxis prevents recurrent streptococcal infections.
Duration Rule: Because she has ARF with carditis and persistent valvular disease (mitral regurgitation), prophylaxis is required for 10 years or until age 40 (whichever is longer).
Key Step 2 takeaway:
All patients with a history of acute rheumatic fever require long-term secondary prevention with penicillin to prevent recurrent GAS infections and worsening rheumatic heart disease.
Other differentials / traps:
"No therapy indicated" trap: A common distraction when patients are currently asymptomatic; withholding prophylaxis leaves the patient vulnerable to recurrent GAS infections and severe, irreversible valvular deformity.
Methotrexate trap: Used for autoimmune arthritides (like Rheumatoid Arthritis); it plays no role in eradicating or preventing GAS infections in rheumatic heart disease.
Metoprolol / Warfarin trap: Indicated for rate control and anticoagulation in patients with rheumatic mitral stenosis complicated by atrial fibrillation, which is not present in this mild MR case.
8In a clinical trial of patients with recent myocardial infarction, heart failure, and reduced left ventricular ejection fraction (mean \text{LVEF} = 33\%) receiving baseline therapy with a beta-blocker and an angiotensin system inhibitor, the addition of a study drug significantly improved long-term overall survival (reduced all-cause mortality) compared to placebo.
Which specific class of heart failure medication was added to achieve this mortality benefit?
Answer: Mineralocorticoid receptor antagonist (Eplerenone or Spironolactone)
Why:
Aldosterone Blockade: Mineralocorticoid receptor antagonists (MRAs) block the deleterious cardiac remodeling effects of aldosterone (myocardial fibrosis, ventricular dilatation, and arrhythmia substrate development).
Mortality Reduction in HFrEF: Adding an MRA to baseline guideline-directed medical therapy (ACEi/ARB/ARNI + Beta-blocker) reduces all-cause mortality and hospitalizations in patients with \text{LVEF} \le 35\% and symptomatic HFrEF or post-MI LV dysfunction.
Key Step 2 takeaway:
The core classes of medications that confer long-term mortality benefit in HFrEF are:
1. ARNI / ACE inhibitors / ARBs
2. Beta-blockers (Metoprolol succinate, Carvedilol, Bisoprolol)
3. Mineralocorticoid receptor antagonists (Eplerenone, Spironolactone)
4. SGLT2 inhibitors (Dapagliflozin, Empagliflozin)
Other differentials / traps:
Loop/Thiazide Diuretics (e.g., Hydrochlorothiazide, Furosemide) trap: Provide rapid symptomatic relief from congestion and reduce hospitalizations, but do not improve overall long-term survival.
Digoxin trap: Reduces heart failure hospitalizations and controls symptoms in HFrEF, but has no mortality benefit (and has a narrow therapeutic window).
Calcium Channel Blockers (e.g., Amlodipine, Diltiazem) trap: Non-dihydropyridines (Diltiazem) are contraindicated in HFrEF due to negative inotropic effects; dihydropyridines (Amlodipine) may be used for hypertension but provide no mortality reduction in heart failure.
Ranolazine trap: An antianginal agent that reduces intracellular sodium/calcium overload during ischemia, but plays no role in improving survival in heart failure.
9A 65-year-old woman presents with a 2-month history of progressive exertional dyspnea and bilateral lower extremity edema. Vital signs show BP 145/94 mmHg and BMI 40 kg/m². Physical examination reveals crackles at the lung bases, JVD of 9 cm H₂O, and bilateral pitting pedal edema. Echocardiogram shows mild concentric left ventricular (LV) hypertrophy, left atrial enlargement, and an LV ejection fraction of 65% with no regional wall motion abnormalities.
What is the strongest predisposing risk factor (etiological driver) for this patient's underlying cardiac condition?
Answer: Obesity and sedentary lifestyle (alongside chronic hypertension)
Why:
Pathophysiology of HFpEF: The patient has Heart Failure with Preserved Ejection Fraction (HFpEF, LVEF e 50\%). Obesity and a sedentary lifestyle generate a state of chronic systemic inflammation (via adipocyte cytokine release). This drives systemic microvascular endothelial inflammation, myocardial interstitial fibrosis, and concentric sarcomere hypertrophy, resulting in a stiff, non-compliant LV that cannot relax during diastole.
Role of Hypertension: Chronic hypertension increases LV afterload, further promoting concentric LV hypertrophy and compounding diastolic dysfunction.
Key Step 2 takeaway:
HFpEF is caused by LV diastolic dysfunction (impaired relaxation and compliance) secondary to chronic systemic inflammation and pressure overload; its primary risk factors are obesity, sedentary lifestyle, and chronic hypertension.
Other differentials / traps:
Valvular heart disease trap: Severe regurgitant lesions typically cause volume overload and progressive dilated cardiomyopathy (HFrEF); this patient only has mild, non-hemodynamically significant mitral regurgitation.
Hereditary sarcomere gene mutation trap: Causes Hypertrophic Cardiomyopathy (HCM), which typically displays asymmetrical septal hypertrophy rather than symmetrical/concentric hypertrophy in an elderly hypertensive, obese patient.
Alcohol use / Viral infection traps: Heavy alcohol intake and viral myocarditis (e.g., Coxsackievirus B) lead to cardiomyocyte destruction and dilation, presenting as HFrEF (systolic failure), not HFpEF.
10A 68-year-old man with reduced cardiac pumping function has worsening fatigue and exertional dyspnea despite guideline-directed therapy. Exam shows mild peripheral edema. Labs: Na⁺ 128 mEq/L, K⁺ 3.2 mEq/L, Cr 1.5 mg/dL, mild AST/ALT elevation. Echo shows LVEF 20%.
Which laboratory abnormality is most strongly associated with poor long-term prognosis?
Answer: Hyponatremia
Why:
* Chronic HF → ↓ cardiac output → ↓ renal perfusion.
* ↑ ADH causes disproportionate free-water retention, producing dilutional hyponatremia.
* Na⁺ <130 mEq/L is a marker of advanced/severe HF and independently predicts mortality.
* Mild transaminitis usually reflects hepatic congestion; hypokalemia/metabolic abnormalities from diuretics are correctable.
Key Step 2 takeaway:
Heart failure + Na⁺ <130 = severe disease + poor prognosis.
Other differentials / traps:
* ↑ AST/ALT → often hepatic congestion; not the strongest prognostic marker.
* Hypokalemia → ↑ arrhythmia risk but usually correctable.
* Hyperphosphatemia → may reflect CKD but isn’t a classic HF mortality marker.
* Metabolic alkalosis → commonly due to loop diuretics.
11A 52-year-old woman has several years of progressive exertional dyspnea and now becomes short of breath at rest. She has occasional hemoptysis and bilateral ankle edema. On exam, an early diastolic sound is followed by a low-pitched diastolic rumble.
What hemodynamic changes would you expect across the pulmonary circulation and left ventricle?
Answer: ↑ Pulmonary artery systolic pressure, ↑ pulmonary artery diastolic pressure, normal LV diastolic pressure
Why:
* The opening snap + diastolic rumble indicates mitral stenosis.
* Narrowed mitral valve → impaired LA → LV filling → ↑ LA pressure.
* ↑ LA pressure is transmitted backward → ↑ pulmonary venous and pulmonary artery pressures.
* The LV is downstream of the obstruction, so LV diastolic pressure remains normal.
Key Step 2 takeaway:
Mitral stenosis → ↑ LA pressure → ↑ pulmonary pressures → normal LV pressure.
Other differentials / traps:
* LV failure: ↑ LV diastolic pressure → secondary pulmonary HTN.
* Mitral regurgitation: ↑ LA pressure + volume overload.
* Aortic stenosis: ↑ LV systolic pressure, not the classic MS pattern.
* Severe chronic MS can eventually cause reactive pulmonary vasoconstrictionemodeling and right-sided failure.
12A 62-year-old man has 2 weeks of progressive exertional dyspnea and a dry nighttime cough. He has no edema, JVD, crackles, or S3. Which laboratory finding would be most useful for ruling out a cardiac cause of his symptoms?
Answer: Low serum BNP (<100 pg/mL)
Why:
* BNP is released by ventricular myocytes in response to wall stretch/volume overload.
* BNP >100 pg/mL is highly sensitive for heart failure.
* Therefore, a low BNP has strong rule-out value in a patient with dyspnea.
* BNP can be falsely low in obesity due to increased clearance; this patient is not obese.
Key Step 2 takeaway:
High sensitivity → negative test rules OUT.
For unexplained dyspnea: low BNP → HF unlikely.
Other differentials / traps:
* S3: highly specific but poorly sensitive → absence does NOT rule out HF.
* JVD/crackles: moderate sensitivity → absence doesn’t reliably exclude HF.
* Cardiothoracic ratio >0.5: only moderately sensitive; HF can occur without cardiomegaly.
13A 67-year-old woman with asymptomatic moderate mitral regurgitation is scheduled for laparoscopic cholecystectomy. Echocardiography shows EF 65%, no pulmonary hypertension, and no heart failure symptoms. What is the appropriate preoperative management of her valve disease?
Answer: No further cardiac intervention or testing
Why:
* She has moderate MR but is asymptomatic with preserved LV function.
* No significant cardiopulmonary effects: normal EF + no pulmonary hypertension.
* Laparoscopic cholecystectomy is an intermediate-risk noncardiac surgery.
* Asymptomatic moderate/severe VHD can proceed without intervention when there are no significant cardiopulmonary effects.
Key Step 2 takeaway:
Asymptomatic VHD + preserved LV function + no cardiopulmonary effects → proceed with surgery.
Other differentials / traps:
* TEE/cardiac cath: not routinely needed when TTE provides adequate information.
* Pharmacologic stress testing: only if indicated by overall cardiac risk/functional capacity—not simply because VHD exists.
* Valve intervention: reserved for patients who meet usual indications for valve repaireplacement.
14A 38-year-old woman presents with an episode of syncope after 2 weeks of weakness, poor appetite, and low-grade fever. She has poor dentition and an early diastolic murmur along the left sternal border. ECG shows sinus rhythm with a 2:1 second-degree AV block. Labs show leukocytosis and mild anemia.
What complication best explains the cardiac conduction abnormality?
Answer: Perivalvular abscess due to aortic valve infective endocarditis
Why:
* Fever + poor dentition + early diastolic murmur → aortic valve infective endocarditis (often due to viridans streptococci).
* New AV conduction abnormality/heart block in infective endocarditis = think perivalvular abscess.
* The aortic valve annulus lies adjacent to the interventricular septum, where the cardiac conduction system runs → an abscess can extend into this region and cause AV block.
* TEE is more sensitive than TTE for detecting a perivalvular abscess.
Key Step 2 takeaway:
IE + new AV block = perivalvular abscess until proven otherwise.
Especially with aortic valve IE.
Other differentials / traps:
* Lyme disease: can cause AV block, but does not typically cause valvular destructionegurgitation.
* Tricuspid IE: holosystolic TR murmur that increases with inspiration, not an early diastolic AR murmur.
* Mitral valve perforation: causes acute mitral regurgitation → holosystolic murmur + heart failure.
* Acute pericarditis: pleuritic chest pain, friction rub, diffuse ST elevations—not isolated AV block with an AR murmur.
15A 61-year-old woman has persistent hypertension despite home BP monitoring confirming an average of 148/88 mm Hg. She has no other major medical conditions except osteoporosis, for which she takes calcium, vitamin D, and alendronate. Renal function, electrolytes, TSH, urinalysis, and ECG are normal.
Which antihypertensive medication would be the best initial choice for this patient?
Answer: Chlorthalidone (thiazide diuretic)
Why:
* She has confirmed hypertension requiring pharmacologic treatment.
* Thiazides are first-line antihypertensives.
* Thiazides increase calcium reabsorption in the distal convoluted tubule, decreasing urinary calcium loss.
* This can reduce bone mineral loss, making thiazides particularly useful in patients with osteoporosis.
Key Step 2 takeaway:
Hypertension + osteoporosis → think thiazide.
Thiazides lower BP and decrease urinary calcium wasting.
Other differentials / traps:
* β-blockers: not preferred as routine first-line therapy in uncomplicated hypertension, especially in older adults.
* ACE inhibitor/ARB: appropriate first-line options but no specific advantage for this patient’s osteoporosis.
* CCB: also first-line but does not provide the bone-protective calcium-retaining effect.
* Stopping calcium supplements: unnecessary; thiazide-associated hypercalcemia is usually mild, but electrolytes should be monitored.
16A 50-year-old man presents for cardiovascular disease prevention. He has a 10-pack-year smoking history, a sedentary lifestyle, a BMI of 29.8 kg/m², and a father who had a myocardial infarction at age 62. His blood pressure is 138/86 mm Hg. Laboratory studies show total cholesterol of 225 mg/dL, LDL of 139 mg/dL, HDL of 48 mg/dL, and triglycerides of 190 mg/dL. He has no history of cardiovascular disease or diabetes.
What is the most important next step in determining whether he should begin statin therapy?
Answer: Calculate his 10-year ASCVD risk using the Pooled Cohort Equations.
Why:
In primary prevention, patients without established ASCVD, LDL ≥190 mg/dL, or diabetes (age 40–75) generally require an individualized cardiovascular risk assessment.
The Pooled Cohort Equations incorporate age, sex, race, total cholesterol, HDL, systolic blood pressure, antihypertensive treatment, diabetes, and smoking status.
Statin therapy is generally recommended when 10-year ASCVD risk is ≥7.5%, with the strength of recommendation depending on the risk level and clinical context.
Lifestyle modification is recommended for everyone, regardless of whether a statin is started.
Key Step 2 takeaway:
Primary prevention + no automatic statin indication → calculate 10-year ASCVD risk before deciding on statin therapy.
Other differentials / traps:
Family history: A father with MI at age 62 does not meet the usual definition of premature ASCVD in a male first-degree relative (before age 55).
High-sensitivity CRP: May help refine risk in selected borderline or intermediate-risk patients, but is not the initial step.
Exercise stress testing: Not indicated routinely in asymptomatic patients to screen for coronary artery disease.
Repeat LDL after lifestyle changes: LDL 139 mg/dL alone does not determine the need for a statin; LDL ≥190 mg/dL is a separate indication for treatment.
17A 65-year-old man with hypertension and coronary artery disease presents with progressive leg swelling, a 9-kg weight gain, and orthopnea. Examination reveals jugular venous distension, bibasilar decreased breath sounds, a laterally displaced point of maximal impulse, and bilateral pitting edema. Chest x-ray shows cardiomegaly and pulmonary vascular congestion. Laboratory studies reveal BUN of 50 mg/dL and creatinine of 2.0 mg/dL, with a bland urinalysis. After 4 days of intravenous furosemide, his edema resolves and creatinine decreases to 1.1 mg/dL.
What mechanism best explains the improvement in renal function following diuretic therapy?
Answer: Reduction in renal venous pressure.
Why:
Acute decompensated heart failure can cause cardiorenal syndrome through both reduced forward blood flow and elevated renal venous pressure.
Renal venous congestion increases pressure downstream of the glomerulus, reducing the net glomerular filtration pressure and GFR.
IV furosemide removes excess fluid, decreasing central and renal venous pressures and helping restore GFR.
The elevated BUN/creatinine ratio (25:1) and bland urinalysis support prerenal AKI rather than intrinsic renal injury.
Key Step 2 takeaway:
Heart failure + AKI + venous congestion → renal venous hypertension. Diuresis can improve creatinine by relieving congestion, even though it reduces total body fluid.
Other differentials / traps:
Efferent arteriolar vasodilation: ACE inhibitors/ARBs can cause this, potentially decreasing intraglomerular pressure and GFR.
Increased afferent arteriolar resistance: Decreases renal blood flow and GFR; successful decongestion generally reduces maladaptive vasoconstriction.
Acute tubular necrosis: Usually has evidence of tubular injury, such as muddy brown casts, and does not typically resolve simply with diuresis.
Decreased filtration fraction: The filtration fraction generally increases as the glomerular filtration pressure is restored.
18A 53-year-old man presents with sudden-onset squeezing chest pain and severe dyspnea that worsens when lying down. His blood pressure is 112/80 mm Hg, and his pulse is 110/min. Examination reveals bibasilar crackles and a grade III/VI early systolic murmur at the cardiac apex. ECG shows ST-segment elevations in leads II, III, and aVF.
Which hemodynamic parameter is most likely to be significantly increased in this patient?
Answer: Left ventricular end-diastolic pressure (LVEDP).
Why:
Inferior STEMI can cause acute mitral regurgitation (MR) due to dysfunction or rupture of the posteromedial papillary muscle, which is commonly supplied by the right coronary artery alone.
In acute MR, blood regurgitates from the LV into the left atrium during systole. The noncompliant left atrium cannot accommodate the sudden increase in volume, causing a sharp rise in left atrial pressure.
During diastole, this elevated left atrial pressure is transmitted to the LV, increasing LV filling pressure and LVEDP.
Increased left atrial pressure is transmitted backward into the pulmonary veins, causing acute pulmonary edema and severe dyspnea.
Key Step 2 takeaway:
Acute MI + new apical systolic murmur + sudden pulmonary edema → acute MR from papillary muscle dysfunctionupture. Acute MR markedly increases left atrial pressure and LVEDP without immediate enlargement of the left atrium.
Other differentials / traps:
Increased left atrial size/compliance: Seen with chronic MR, as the atrium has time to remodel and accommodate regurgitant volume.
Increased LV compliance: Develops with chronic volume overload, not abruptly during acute MR; acute ischemia may instead decrease LV compliance.
Increased systolic aortic flow: Incorrect; some of the LV stroke volume is ejected backward into the left atrium, reducing effective forward output.
Aortic stenosis: Typically produces a systolic ejection murmur at the right upper sternal border radiating to the carotids, not a new apical murmur with acute pulmonary edema after MI.
19A 42-year-old woman presents with depression, poor sleep, mild headaches, and muscle weakness. Her medical history includes recurrent kidney stones and episodes of anxiety. Blood pressure is 160/105 mm Hg. Laboratory studies reveal a serum calcium level of 11.7 mg/dL, with normal renal function, potassium, and bicarbonate.
What is the most likely underlying cause of her hypertension?
Answer: Primary hyperparathyroidism.
Why:
Hypercalcemia + recurrent nephrolithiasis + neuropsychiatric symptoms + muscle weakness strongly suggests primary hyperparathyroidism.
Excess PTH increases bone resorption, renal calcium reabsorption, and indirectly intestinal calcium absorption, causing hypercalcemia.
Hyperparathyroidism is associated with hypertension, potentially through increased sympathetic activity, renin secretion, and peripheral vasoconstriction.
The most common cause of primary hyperparathyroidism is a parathyroid adenoma.
Key Step 2 takeaway:
Hypertension + hypercalcemia + kidney stones → suspect primary hyperparathyroidism.
Other differentials / traps:
Primary hyperaldosteronism: Hypertension with hypokalemia and metabolic alkalosis; does not explain hypercalcemia and kidney stones.
Cushing syndrome: Look for central obesity, abdominal striae, thin skin, and hyperglycemia.
Renal artery stenosis: Consider an abdominal bruit, resistant hypertension, recurrent flash pulmonary edema, or a marked creatinine rise after ACE inhibitor/ARB initiation.
Renal parenchymal disease: Usually associated with abnormal urinalysis or impaired renal function rather than isolated hypercalcemia.
20A 1-day-old term newborn develops central cyanosis shortly after birth. Examination reveals a grade II/VI holosystolic murmur at the left lower sternal border. The lungs are clear. Chest radiograph shows decreased pulmonary vascular markings without cardiomegaly. ECG demonstrates left axis deviation and tall, peaked P waves.
What is the most likely congenital cardiac diagnosis?
Answer: Tricuspid valve atresia.
Why:
Absent tricuspid valve prevents blood from flowing directly from the right atrium (RA) into the right ventricle (RV), resulting in a hypoplastic RV.
An atrial septal defect (ASD) or patent foramen ovale (PFO) is necessary for blood to pass from the RA to the left atrium; otherwise, survival is not possible.
Tall, peaked P waves indicate right atrial enlargement, while left axis deviation reflects left-sided volume overload.
Pulmonary blood flow is reduced due to RV/outflow tract hypoplasia, often with pulmonary stenosis. A coexisting VSD may permit blood to reach the pulmonary circulation and produce a holosystolic murmur.
Key Step 2 takeaway:
Cyanotic newborn + left axis deviation + tall P waves + decreased pulmonary vascular markings → tricuspid atresia.
Other differentials / traps:
Complete AV canal defect: Usually causes a left-to-right shunt, increased pulmonary vascular markings, and cardiomegaly; associated with Down syndrome.
Isolated VSD: Typically acyanotic initially, with a holosystolic murmur and potentially increased pulmonary vascular markings.
Total anomalous pulmonary venous return (TAPVR): Cyanosis with right-sided enlargement and usually increased pulmonary vascular markings; obstructed TAPVR can produce pulmonary edema.
Truncus arteriosus: Cyanosis with a single arterial trunk, usually increased pulmonary blood flow and cardiomegaly.
21A 75-year-old man is evaluated for a heart murmur discovered during a routine examination. He denies exertional chest pain, dyspnea, fatigue, dizziness, or syncope. His medical history includes hypertension treated with chlorthalidone and amlodipine.
Physical examination reveals a sustained apical impulse, a single soft S2, an S4, and a grade 3/6 late-peaking systolic murmur at the right upper sternal border that radiates to the carotid arteries. His carotid pulses are weak and delayed. Echocardiography shows a heavily calcified trileaflet aortic valve with a valve area of 0.9 cm², concentric left ventricular hypertrophy, and an ejection fraction of 45%, without regional wall motion abnormalities.
What is the most appropriate next step in management, and why is intervention indicated despite the absence of symptoms?
Answer: Aortic valve replacement (SAVR or TAVR, depending on the patient's clinical and procedural assessment).
Why:
Severe aortic stenosis (AS): A valve area ≤1.0 cm² supports severe AS. Other criteria include peak aortic jet velocity ≥4 m/s or mean transvalvular gradient ≥40 mm Hg.
Classic examination findings: Late-peaking systolic murmur radiating to the carotids, delayed and diminished carotid upstroke (pulsus parvus et tardus), and a soft or absent A2 component of S2.
Left ventricular pressure overload: Chronic obstruction causes concentric LV hypertrophy, a sustained apical impulse, and an S4.
LVEF of 45%: Severe AS with an LVEF below 50% is an indication for valve replacement even when the patient reports no symptoms. Relieving the obstruction may improve LV function.
22A 50-year-old man with a mechanical aortic valve replacement takes warfarin and presents for a routine screening colonoscopy. He has no abdominal pain, fever, or evidence of gastrointestinal infection. Vital signs are normal.
What is the most appropriate strategy to prevent infective endocarditis before this procedure?
Answer: No antibiotic prophylaxis needed.
Why:
A prosthetic heart valve places the patient at high risk for infective endocarditis (IE).
However, prophylaxis depends on both the patient's cardiac risk and the type of procedure.
Routine GI procedures, including screening colonoscopy, do not require IE prophylaxis in the absence of active infection.
Prophylaxis is generally given 30–60 minutes before qualifying procedures when indicated.
Key Step 2 takeaway:
High-risk heart condition ≠ antibiotics before every procedure. Prosthetic valves require prophylaxis for dental procedures involving gingival manipulation, certain respiratory procedures involving mucosal incision, and procedures involving infected skin/soft tissue or infected GI/GU tissue—not routine colonoscopy without infection.
Other differentials / traps:
Dental cleaning or extraction involving gingival manipulation: Amoxicillin is the usual first-line prophylaxis.
Bronchoscopy with biopsy or tonsillectomy: Prophylaxis may be indicated because respiratory mucosa is penetrated.
Colonoscopy with active GI infection: Consider antibiotics appropriate to the infection; this is distinct from routine IE prophylaxis.
Mechanical valve + warfarin: Warfarin is for prevention of valve thrombosis; it does not change the indication for IE prophylaxis.
23A 25-year-old woman presents with transient, painless vision loss in her right eye. She was diagnosed with hypertension 6 months ago and now has a blood pressure of 164/103 mm Hg despite no antihypertensive treatment. Her BMI is 26 kg/m², and her grandmother had a stroke at age 50.
Laboratory studies show normal renal function, potassium of 3.5 mEq/L, elevated plasma renin activity, and a plasma aldosterone-to-renin ratio of 10. Physical examination reveals a systolic-diastolic bruit in the epigastrium.
What is the most appropriate next step in management?
Answer: CT angiography of the abdomen to evaluate for fibromuscular dysplasia (FMD).
Why:
Young woman with early-onset hypertension suggests a secondary cause of hypertension.
Elevated renin suggests activation of the renin–angiotensin–aldosterone system, as occurs with renal artery stenosis.
Abdominal systolic-diastolic bruit supports renovascular disease.
Transient monocular vision loss (amaurosis fugax) suggests retinal ischemia and raises concern for cervicocephalic arterial involvement.
FMD is a noninflammatory, nonatherosclerotic disease of medium-sized arteries, classically affecting the renal and internal carotid arteries.
Key Step 2 takeaway:
Young woman with hypertension before age 35, elevated renin, an abdominal bruit, or unexplained neurologic/visual symptoms → suspect fibromuscular dysplasia. Confirm with vascular imaging, commonly CT angiography.
Other differentials / traps:
Primary hyperaldosteronism: Elevated aldosterone with suppressed renin; aldosterone-to-renin ratio is typically elevated. Confirm with appropriate testing before adrenal localization.
Pheochromocytoma: Episodic headache, sweating, palpitations, and hypertension; evaluate with plasma free or urinary fractionated metanephrines.
Cushing syndrome: Features such as proximal muscle weakness, purple striae, central adiposity, and glucose intolerance; screen with a cortisol-based test.
Atherosclerotic renal artery stenosis: More likely in older patients with atherosclerotic risk factors; FMD is more characteristic in younger women.
Imaging trap: Duplex ultrasonography can be used as an initial noninvasive test, but CT angiography is an appropriate next step in a patient with strong suspicion for FMD. Catheter angiography is generally reserved for inconclusive testing or when intervention is planned.