Heart failure, cardiomyopathies and myocardial disease
The exam tests classification, four-pillar therapy, device selection and recognition of specific cardiomyopathy phenotypes that change management.
Classification and diagnosis
- HFrEF: ejection fraction 40% or less; HFmrEF: 41-49%; HFpEF: 50% or more with structural or diastolic evidence.
- Natriuretic peptides help rule out: NT-proBNP below 125 pg/mL in the non-acute setting makes heart failure unlikely.
Core therapy in HFrEF
- Four pillars: ARNI or ACE inhibitor, beta-blocker (bisoprolol, carvedilol, metoprolol succinate, nebivolol), MRA, SGLT2 inhibitor. Add diuretics for congestion, then titrate.
- Never combine an ARNI with an ACE inhibitor; allow 36 hours washout.
- Additional options: ivabradine when sinus rhythm is 70 bpm or more, hydralazine plus nitrate in self-identified Black patients, vericiguat after worsening events, digoxin for symptom control.
- Devices: ICD for ejection fraction 35% or less after three months of optimal therapy in NYHA II-III; CRT for LBBB with QRS 150 ms or more, or 130-149 ms with additional criteria.
Cardiomyopathy phenotypes
- HCM: avoid preload-reducing drugs; beta-blocker first; septal myectomy or alcohol ablation for obstruction; family screening and sudden-death risk scoring for ICD.
- ARVC: epsilon waves, T-wave inversion V1-V3, desmosomal genes, exercise restriction.
- Cardiac amyloidosis: low voltage despite thick walls, apical-sparing strain pattern, bone scintigraphy, tafamidis.
- Others: peripartum, takotsubo, myocarditis, iron overload.
Worked example
A 72-year-old with NYHA III symptoms, ejection fraction 28% and LBBB with QRS 160 ms after three months of optimal therapy should receive a CRT-D device.
Traps
- Starting or up-titrating beta-blockers during acute decompensation.
- Diagnosing HFpEF without structural or diastolic evidence.
- Missing amyloidosis in a patient with thick walls and low ECG voltage.