HFrEF Guideline-Directed Medical Therapy
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Direct answer
HFrEF guideline-directed medical therapy means combining four drug classes that each reduce death or heart failure hospitalisation in patients with an ejection fraction of 40 per cent or less. Those classes are an angiotensin receptor-neprilysin inhibitor, an evidence-based beta blocker, a mineralocorticoid receptor antagonist and an SGLT2 inhibitor, started at low doses and titrated upward, with implantable devices added when the ejection fraction stays low.
What you must remember
- ARNI: sacubitril-valsartan replaces an ACE inhibitor or ARB; a 36-hour washout after the ACE inhibitor is mandatory to avoid angioedema.
- Beta blocker: bisoprolol, carvedilol or metoprolol succinate, started low once euvolaemic and titrated slowly; not started during decompensation.
- MRA: spironolactone or eplerenone, started only when potassium is below 5.0 mmol/L and eGFR is above 30; eplerenone avoids gynaecomastia.
- SGLT2 inhibitor: dapagliflozin or empagliflozin reduces cardiovascular death and hospitalisation whether or not the patient has diabetes; sick-day rules and ketoacidosis awareness apply.
- Supporting therapy: intravenous iron for iron deficiency (ferritin below 100, or 100 to 299 with transferrin saturation below 20 per cent); ivabradine when ejection fraction is 35 per cent or less and heart rate stays at 70 or above in sinus rhythm on maximal tolerated beta blocker.
- Hydralazine with isosorbide dinitrate: for patients unable to take ACE inhibitors, ARBs or ARNI, and, in US guidance, added for self-identified Black patients with NYHA class III to IV symptoms on optimal therapy.
- Devices: primary prevention ICD for ejection fraction 35 per cent or less despite three months of therapy with expected survival over a year; cardiac resynchronisation for left bundle branch block with QRS of 150 ms or more.
A medication plan for a patient on the outpatient clinic
A 58-year-old man with ischaemic cardiomyopathy has an ejection fraction of 30 per cent, is NYHA class II and takes ramipril and furosemide.
- Switch the RAAS drug: Stop ramipril and wait 36 hours before starting sacubitril-valsartan at low dose, since the washout prevents angioedema.
- Add a beta blocker: A low-dose beta blocker such as bisoprolol is added once he is euvolaemic, and titrated every two weeks towards the target dose as heart rate and pressure allow.
- Add a mineralocorticoid antagonist: Spironolactone follows if potassium is below 5.0 mmol/L and eGFR is adequate, with potassium and creatinine rechecked within a week of starting.
- Add an SGLT2 inhibitor: Dapagliflozin is then added, which produces a modest diuresis, so the furosemide dose is reviewed.
- Change one thing at a time: Each change is made one at a time where possible, so that a fall in pressure or rise in potassium can be attributed.
- Review at three months: If the ejection fraction remains 35 per cent or less on optimised therapy, an ICD for primary prevention is considered, provided expected survival is over one year.
This sequence reflects the principle that all four pillars are started early and titrated, rather than waiting for one to succeed.
Where the exam tries to catch you
Four traps recur in heart failure questions.
- Trap: switching straight from an ACE inhibitor to sacubitril-valsartan Correct: the 36-hour washout is required, because skipping it risks life-threatening angioedema.
- Trap: assuming an SGLT2 inhibitor is only for diabetes Correct: its heart failure benefit does not depend on diabetes, reflecting the cardiorenal mortality benefit shown in trials.
- Trap: ignoring hyperkalaemia when an MRA is combined with an ARB or ARNI Correct: potassium must be checked, and spironolactone is held when it rises above 5.5 mmol/L.
- Trap: recommending an ICD at first presentation Correct: three months of optimised therapy come first, so the device is not implanted at diagnosis.
In India, the practical barrier is cost, which is why generic beta blockers and spironolactone form the core of many outpatient regimens while newer agents are added as affordable.
Frequently asked questions
Which four drug classes form the foundation of HFrEF therapy?
The four pillars are an angiotensin receptor-neprilysin inhibitor, a beta blocker, a mineralocorticoid receptor antagonist and an SGLT2 inhibitor. Each reduces mortality or heart failure hospitalisation, and all are started together at low doses and titrated.
How long should a patient wait after stopping an ACE inhibitor before starting sacubitril-valsartan?
A washout of 36 hours is required after the last ACE inhibitor dose before sacubitril-valsartan is started. Skipping this interval risks angioedema, which can be life-threatening.
When is an ICD indicated for primary prevention in HFrEF?
An ICD is indicated when the left ventricular ejection fraction remains 35 per cent or less despite at least three months of optimised medical therapy, with NYHA class II or III symptoms and expected survival of more than one year. Device implantation is not performed at first presentation.
What potassium level should be reached before starting spironolactone in HFrEF?
Potassium should be below 5.0 mmol/L, and eGFR above 30, before spironolactone is started. Higher potassium levels during treatment call for dose reduction or withdrawal, with recheck within a short interval.