Q-Bank Breakdown: Systolic vs diastolic heart failure — Why Every Answer Choice Matters

Heart failure questions are “free points” only if you train your brain to stop pattern-matching on buzzwords and start interrogating every answer choice. The USMLE loves to give you a convincing vignette and then test whether you can distinguish systolic (HFrEF) from diastolic (HFpEF)—and whether you know what would push the case into an entirely different diagnosis.

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The Vignette (Q-bank style)

A 72-year-old woman comes to the clinic for progressive shortness of breath over 4 months. She reports dyspnea when walking one block and waking at night gasping for air. She sleeps on 3 pillows. History includes long-standing hypertension and type 2 diabetes. She has never had a myocardial infarction. Medications include hydrochlorothiazide and metformin.

Vitals: BP 168/92 mm Hg, HR 88/min, RR 18/min. Exam shows bibasilar crackles and 1+ pitting edema. S4 is present. No murmurs.
ECG shows left ventricular hypertrophy.
Echocardiogram shows left atrial enlargement, concentric LV hypertrophy, normal ejection fraction (60%), and impaired LV relaxation.

Question: Which of the following is the most likely underlying abnormality?

A. Decreased ventricular compliance due to concentric LV hypertrophy
B. Reduced cardiac output due to decreased contractility
C. Loss of dystrophin leading to dilated cardiomyopathy
D. Autoantibodies against desmosomal proteins causing RV failure
E. Pulmonary venous hypertension due to mitral stenosis

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Step 1: Identify the Syndrome

This patient has classic heart failure symptoms:

• Dyspnea on exertion
• Paroxysmal nocturnal dyspnea (PND)
• Orthopnea
• Pulmonary crackles and peripheral edema

Now decide: systolic or diastolic?

Clues pushing strongly toward diastolic HF (HFpEF):

• Older woman with long-standing HTN
• Concentric LV hypertrophy + LVH on ECG
• S4 (stiff ventricle)
• Normal EF (60%)
• Echo: impaired relaxation + left atrial enlargement (chronic high filling pressures)

So: HFpEF driven by stiff ventricle → impaired filling.

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Correct Answer: A. Decreased ventricular compliance due to concentric LV hypertrophy

Why it’s correct (mechanism)

Chronic hypertension → pressure overload → concentric hypertrophy (sarcomeres added in parallel) → decreased ventricular compliance.

Key physiology:

• EF can be normal because systolic function (fraction ejected) is preserved.
• The primary issue is elevated LV end-diastolic pressure (LVEDP) due to poor relaxation/stiffness.
• Elevated LVEDP backs up into the left atrium → left atrial enlargement and pulmonary congestion symptoms.

High-yield equation tie-in:

• Stroke volume depends on filling and ejection:
  $SV = EDV - ESV$
  In HFpEF, EDV falls (can’t fill well), so SV can drop even with preserved EF: $EF = \frac{SV}{EDV}$
  EF can stay “normal” because both SV and EDV decrease proportionally.

HFpEF buzzwords to memorize

• S4
• Concentric LVH
• Older, female, hypertension, diabetes, obesity, CAD
• Amyloidosis or restrictive cardiomyopathy can mimic (also stiff ventricles)

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Now the Real Learning: Why the Distractors Are Wrong (and what they would mean)

B. Reduced cardiac output due to decreased contractility

This describes systolic heart failure (HFrEF).

What you’d expect instead:

• Reduced EF (often <40%)
• Dilated LV (eccentric remodeling; sarcomeres in series)
• S3 (volume overload)
• Common causes: ischemic cardiomyopathy (MI), dilated cardiomyopathy, myocarditis, toxins (alcohol, doxorubicin)

How the vignette rules it out:

• EF is normal
• LVH is concentric, not dilated
• S4, not S3
• No MI history; strong HTN pressure-overload story

USMLE pearl: HFrEF = pump problem. HFpEF = filling problem.

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C. Loss of dystrophin leading to dilated cardiomyopathy

This points to Duchenne/Becker muscular dystrophy → dilated cardiomyopathy → HFrEF.

What you’d expect:

• Much younger patient (child/adolescent for Duchenne; later for Becker)
• Progressive muscle weakness, Gowers sign, calf pseudohypertrophy
• Dilated cardiomyopathy with reduced EF

Why it’s wrong here:

• 72-year-old woman with HTN and LVH
• No neuromuscular symptoms
• Echo shows concentric hypertrophy, not dilation

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D. Autoantibodies against desmosomal proteins causing RV failure

This is getting at arrhythmogenic right ventricular cardiomyopathy (ARVC)—classically due to mutations in desmosomal proteins (e.g., plakoglobin, desmoplakin), not “autoantibodies.”

What you’d expect:

• Young person, syncope or palpitations
• Ventricular arrhythmias, sudden death (often with exercise)
• ECG: T-wave inversions in V1–V3, epsilon wave
• RV dilation/fibrofatty replacement → RV failure signs later (JVD, hepatomegaly)

Why it’s wrong here:

• Symptoms are classic left-sided HF with pulmonary congestion
• Echo shows LV hypertrophy, not RV pathology
• The stem describes HFpEF physiology, not an arrhythmia syndrome

USMLE pearl: ARVC is a sudden death/arrhythmia question first, heart failure question second.

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E. Pulmonary venous hypertension due to mitral stenosis

Mitral stenosis can cause dyspnea and pulmonary congestion because it raises left atrial pressure, but the rest of the picture doesn’t fit.

What you’d expect:

• Opening snap + diastolic rumble at apex
• Often history of rheumatic fever
• Marked left atrial enlargement (yes), possibly atrial fibrillation
• Echo: thickened mitral valve with restricted opening

Why it’s wrong here:

• No murmur, no opening snap
• The echo focuses on concentric LVH + impaired relaxation and normal EF (primary ventricular filling problem)
• Mitral stenosis is a valvular inflow obstruction problem, not LV compliance from hypertrophy

Quick distinction:

• MS: problem at the valve (LA can’t empty into LV)
• HFpEF: problem in the LV (LV can’t relax/fill)

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High-Yield Comparison Table: HFrEF vs HFpEF

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The “Answer Choice Mindset” for Heart Failure Questions

When you see “HF symptoms,” force a 10-second checklist:

1. EF normal or low? (echo is king)
2. S3 vs S4?
3. Concentric vs eccentric remodeling?
4. Most likely cause given demographics and risk factors?
5. Anything that screams valvular disease, restrictive disease, or primary arrhythmia disorder?

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Takeaway (what you should remember on test day)

• HFpEF = stiff ventricle → impaired filling → S4, concentric LVH, LA enlargement, normal EF.
• Long-standing hypertension is the classic driver via pressure overload → concentric hypertrophy.
• Distractors often name HFrEF etiologies (dystrophin, DCM) or “nearby” causes of dyspnea (mitral stenosis, ARVC). Treat each answer as its own mini-diagnosis.