On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Q1: Define restrictive cardiomyopathy and contrast it with the other two WHO cardiomyopathies (2 min)
Restrictive cardiomyopathy (RCM) is a myocardial disorder defined by non-compliant, stiff ventricles that resist filling in diastole, with reduced ventricular diastolic volume and normal or near-normal systolic function, producing biventricular diastolic heart failure with bi-atrial enlargement. It is the rarest of the three cardiomyopathies. By contrast: dilated cardiomyopathy has a dilated LV with reduced EF (systolic failure); hypertrophic cardiomyopathy has asymmetric septal hypertrophy, dynamic LVOT obstruction, hyperdynamic EF and a small cavity. The defining physiology in RCM is a stiff ventricle with preserved pump — the ventricle cannot accept blood, not pump it.
Q2: How do you distinguish restrictive cardiomyopathy from constrictive pericarditis? (3 min)
The bedside signs overlap (raised JVP, Kussmaul, hepatomegaly, ascites) but the management is opposite — pericardiectomy cures constriction but is futile in RCM. The discriminating features:
- BNP/NT-proBNP — markedly raised in RCM, normal or low in constriction. This is the single best discriminator.
- Pericardial calcification on CXR/CT — constriction only (RCM never calcifies the pericardium).
- Septal bounce on echo — constriction; annulus paradoxus (septal e' preserved over 8 cm/s, lateral reduced) — constriction; in RCM both septal and lateral e' are under 5 cm/s.
- Cardiac catheterisation — both show the dip-and-plateau (square-root) sign, but in RCM the LVEDP exceeds RVEDP by over 5 mmHg at end-expiration, whereas in constriction the two diastolic pressures equalise within 5 mmHg. RVSP over 50 mmHg and RVEDP under one-third RVSP favour RCM.
- Pericardial thickness over 3-4 mm on CT/MRI favours constriction.
Q3: Outline the diagnostic work-up for a suspected cardiac amyloidosis (2 min)
- ECG — low voltages (voltage-mass discordance), pseudoinfarct pattern, AF, AV block.
- Echocardiogram — bi-atrial enlargement, granular myocardium, restrictive mitral inflow (E/A over 2, deceleration time under 150 ms), low e' at both annuli, apical sparing on strain.
- Cardiac MRI — diffuse subendocardial LGE with difficulty nulling the myocardium; elevated native T1 and ECV over 40%.
- Serum free light chains, serum and urine immunofixation — diagnose AL; bone marrow biopsy if positive.
- 99mTc-PYP/DPD/HMDP bone scintigraphy — Perugini grade 2-3 uptake diagnoses ATTR non-invasively (after light chains excluded).
- Endomyocardial biopsy with Congo red (apple-green birefringence) and mass spectrometry typing — gold standard if non-invasive work-up inconclusive.
Q4: Discuss the management of ATTR cardiac amyloidosis (3 min)
- Disease-modifying therapy: tafamidis 61 mg orally once daily — a transthyretin tetramer stabiliser. The ATTR-ACT trial (NEJM 2018) showed 30% reduction in all-cause mortality and 32% reduction in CV hospitalisations over 30 months in ATTR-CM (both wild-type and hereditary). Newer agents — patisiran, vutrisiran, acoramidis — are emerging.
- Symptomatic heart-failure therapy — cautious loop diuretic (furosemide 20-40 mg) plus spironolactone 12.5-25 mg; anticoagulate for AF; cautious beta-blocker or amiodarone for rate/rhythm control; pacemaker for high-grade AV block; consider ICD for sustained VT (with caution given competing risks in end-stage disease).
- Avoid — digoxin (binds amyloid fibrils, toxicity) and non-dihydropyridine calcium-channel blockers (negative inotropy, bind amyloid fibrils).
- Advanced therapy — heart transplantation for end-stage disease in selected (combined heart-liver transplant for ATTRv prevents recurrence from the liver-derived mutant TTR); mechanical circulatory support as bridge.
- Multidisciplinary care — amyloidosis centre referral, family screening for hereditary ATTR (genetic testing of first-degree relatives).