Heart failure questions love to disguise themselves as “shortness of breath + edema,” then punish you for not reading the fine print: EF, wall thickness, blood pressure history, murmurs, and even the patient’s age/sex. The fastest way to climb in Q-banks is to stop thinking “heart failure = one disease” and start treating every answer choice like a mini-diagnosis that must match the vignette.
Tag: Cardiovascular > Heart Failure & Cardiomyopathies
The Clinical Vignette (USMLE-style)
A 72-year-old woman comes to the clinic for progressive exertional dyspnea and fatigue for 6 months. She has long-standing hypertension and type 2 diabetes. She sleeps on two pillows and occasionally wakes up short of breath at night. Exam shows BP 168/86 mm Hg, bibasilar crackles, an S4, and mild bilateral ankle edema. BNP is elevated. Transthoracic echocardiogram shows:
- LVEF: 60%
- Concentric left ventricular hypertrophy
- Left atrial enlargement
- No significant valvular disease
Which of the following is the most likely underlying abnormality?
A. Reduced myocardial contractility due to dilated left ventricle
B. Impaired LV relaxation due to concentric hypertrophy
C. Chordae tendineae rupture causing acute severe mitral regurgitation
D. Ventricular septal rupture after myocardial infarction
E. Amyloid deposition causing restrictive cardiomyopathy
Step 1/2 Approach: Identify the Heart Failure Phenotype First
Key clues in the stem
- Older woman + long-standing HTN
- S4 (stiff ventricle)
- Concentric LVH + LA enlargement
- Preserved EF (60%)
- Congestion symptoms (orthopnea/PND) can occur in both HFrEF and HFpEF
Diagnosis: HFpEF (diastolic heart failure)
HFpEF = impaired filling (diastolic dysfunction) with preserved systolic function. The ventricle is stiff, pressures back up into the LA and lungs → dyspnea, crackles, elevated BNP.
Correct Answer: B. Impaired LV relaxation due to concentric hypertrophy
What’s happening physiologically?
Chronic hypertension causes pressure overload → concentric hypertrophy (sarcomeres added in parallel) → decreased LV compliance and impaired relaxation.
- In diastolic dysfunction, the LV end-diastolic pressure rises even when volume is not huge.
- That increased pressure transmits backward → LA enlargement and pulmonary congestion.
- S4 fits because atrial contraction is pushing against a stiff ventricle.
High-yield hemodynamics
HFpEF typically shows:
- Normal EF
- Normal or low end-diastolic volume
- Increased LV end-diastolic pressure
- Increased pulmonary capillary wedge pressure (when decompensated)
Why Each Distractor Is Wrong (and What It Would Look Like)
A. Reduced myocardial contractility due to dilated left ventricle (HFrEF)
This is systolic failure: the LV can’t pump effectively.
What you’d expect instead:
- Reduced EF (often < 40%)
- Dilated LV (eccentric remodeling)
- S3 more common than S4
- Etiologies: ischemic cardiomyopathy (most common), dilated cardiomyopathy (alcohol, doxorubicin, viral myocarditis), chronic volume overload
Q-bank tip: If echo says dilated ventricle + low EF, your brain should immediately go to HFrEF and its causes/therapies.
C. Chordae tendineae rupture causing acute severe mitral regurgitation
This is an acute mechanical complication (often after MI or endocarditis) and causes sudden pulmonary edema.
What you’d expect instead:
- Acute onset severe dyspnea, frothy sputum
- New loud holosystolic murmur at apex radiating to axilla (may be soft if pressures equalize rapidly)
- Echo: flail leaflet, severe MR
- Often a history of recent MI (papillary muscle dysfunction/rupture) or infection
Why wrong here: chronic symptoms + concentric LVH + preserved EF with no valvular disease.
D. Ventricular septal rupture after myocardial infarction
Another acute post-MI mechanical complication.
What you’d expect instead:
- Occurs typically 3–5 days post-MI (macrophage-mediated weakening)
- Harsh holosystolic murmur at left sternal border + thrill
- Rapid hemodynamic collapse, biventricular failure, pulmonary edema
Why wrong here: no recent MI story, no characteristic murmur, and echo didn’t show a VSD.
E. Amyloid deposition causing restrictive cardiomyopathy
Restrictive CM can mimic HFpEF because it also causes diastolic dysfunction, but the vignette points elsewhere.
Amyloidosis clues:
- Thickened ventricular walls on echo that are not explained by HTN
- Low voltage on ECG despite “LVH” appearance on echo (discordance = classic)
- Systemic signs: nephrotic syndrome, macroglossia, carpal tunnel, autonomic dysfunction
- Often more dramatic right-sided failure, hepatomegaly, ascites
Why wrong here: classic hypertensive HFpEF picture (concentric LVH from pressure overload), no systemic amyloid clues.
HFrEF vs HFpEF: The Table You Should Memorize
| Feature | HFrEF (Systolic) | HFpEF (Diastolic) |
|---|---|---|
| EF | Low (<40%) | Normal/preserved (≥50%) |
| Primary problem | ↓ Contractility | ↓ Relaxation/compliance |
| LV size | Dilated | Normal size or small |
| Remodeling | Eccentric hypertrophy (volume overload) | Concentric hypertrophy (pressure overload) |
| Heart sound | S3 common | S4 common |
| Typical patient | Post-MI, cardiomyopathy | Older, female, HTN, obesity, DM |
| BNP | Often elevated | Often elevated |
| Stroke volume | ↓ | Often near normal at rest, ↓ with exertion due to filling limits |
High-Yield Therapy Pearls (Step 2 favorite)
HFrEF: therapies that improve mortality
Think: block maladaptive neurohormonal pathways.
- ARNI (sacubitril/valsartan) or ACEi/ARB
- Evidence-based beta-blockers: metoprolol succinate, carvedilol, bisoprolol
- Mineralocorticoid receptor antagonists: spironolactone/eplerenone
- SGLT2 inhibitors: empagliflozin/dapagliflozin
- Add-ons for selected patients: hydralazine + nitrates (esp. Black patients or ACEi intolerance), ivabradine (high HR), ICD/CRT when indicated
HFpEF: symptom control + comorbidity domination
HFpEF is more about managing filling pressures and the diseases driving stiffness.
- Control blood pressure (huge)
- Diuretics for congestion (watch preload dependence)
- SGLT2 inhibitors have outcome benefit in HFpEF as well
- Manage AFib (rate/rhythm) to preserve diastolic filling time
- Address ischemia, obesity, sleep apnea, diabetes
Trap: Drugs that clearly reduce mortality in HFrEF do not translate as cleanly to HFpEF. On exams, HFpEF management leans on BP control and diuresis.
Micro–Rapid Fire: Common USMLE Heart Failure Associations
- S3 = volume overload, dilated ventricle → think HFrEF
- S4 = stiff ventricle (LVH, ischemia) → think HFpEF
- Concentric hypertrophy = pressure overload (HTN, aortic stenosis)
- Eccentric hypertrophy = volume overload (regurg lesions, shunts)
- BNP rises with ventricular stretch (both types, not just HFrEF)
The Takeaway: “Every Answer Choice Is a Mini-Vignette”
In this question, the test-writer handed you HFpEF on a platter: older hypertensive patient + concentric LVH + preserved EF + S4. The distractors were all plausible causes of dyspnea/edema—but each had a signature timing (acute vs chronic), murmur pattern, echo finding, or systemic clue that didn’t match.
When you review, don’t just mark B correct—teach yourself why A, C, D, and E each represent a different heart failure pathway.