Management of HFmrEF in Black Patients with Recent‑Onset Cardiomyopathy

Guideline‑Directed Medical Therapy (GDMT) Initiation

Initiate the four foundational GDMT agents—SGLT2 inhibitor, beta‑blocker, ARNI (or ACE‑I), and mineralocorticoid receptor antagonist—immediately in patients with heart failure with mildly reduced ejection fraction (LVEF 41‑49 %) who have experienced a rapid decline, because this strategy improves mortality and hospitalization outcomes across the spectrum of reduced EF. 1
SGLT2 inhibitors (dapagliflozin 10 mg daily or empagliflozin 10 mg daily) lower cardiovascular mortality and HF hospitalizations independent of diabetes status and have minimal impact on blood pressure. 1
Beta‑blockers (carvedilol, metoprolol succinate, or bisoprolol) confer a mortality benefit in all patients with LVEF < 50 % regardless of symptom burden. 1
ARNI (sacubitril/valsartan) provides superior reduction in HF hospitalization and mortality compared with ACE‑I even in the mildly reduced EF range; it should be the preferred first‑line renin‑angiotensin‑neprilysin blockade. 1
Mineralocorticoid receptor antagonists (spironolactone or eplerenone) reduce mortality and sudden cardiac death when LVEF ≤ 35 % on repeat imaging or when patients are symptomatic (NYHA II‑IV). 1

Black race is independently associated with lower follow‑up LVEF in recent‑onset cardiomyopathy (IMAC‑2 cohort, p = 0.02). 3
Higher NYHA functional class and Black race both predict poorer EF recovery in non‑ischemic cardiomyopathy, underscoring the need for aggressive early GDMT. 4
In self‑identified African‑American patients who develop NYHA class III‑IV symptoms, adding hydralazine 37.5 mg TID and isosorbide dinitrate 20 mg TID (titrated to hydralazine 75 mg TID and isosorbide dinitrate 40 mg TID) provides additional mortality benefit. 5

Increase one medication class every 1‑2 weeks, selecting the agent most likely to be tolerated based on heart rate and blood pressure. 2
Target doses:
Before each dose increase, re‑measure blood pressure and heart rate; after any MRA or ARNI/ACE‑I uptitration, re‑check serum potassium and creatinine 1‑2 weeks later. 2
Laboratory monitoring: check potassium and creatinine 1‑2 weeks after initiating or uptitrating an MRA or ARNI, then monthly for the first 3 months, and every 3 months thereafter. 2
Measure natriuretic peptides (BNP or NT‑proBNP) at baseline for prognostication and repeat when clinical status changes. 1
Blood pressure and heart rate should be recorded at every visit; an asymptomatic systolic BP of 90‑100 mmHg does not mandate dose reduction. 6
Schedule clinical follow‑up every 3‑6 months initially to assess symptoms, medication tolerance, vital signs, renal function, and electrolytes. 1

RVOT scar on cardiac MRI reflects myocardial fibrosis and is linked to higher mortality (HR ≈ 3.0) and sudden death (HR ≈ 4.6) in non‑ischemic cardiomyopathy, independent of LVEF. 4
Patients with myocarditis were excluded from early ICD trials; therefore a 3‑6‑month observation on optimal GDMT is essential before device implantation. 4
Primary‑prevention ICD implantation is not indicated at LVEF 41 % because guideline trials enrolled patients with LVEF ≤ 35 % after ≥ 3 months of optimal therapy. 4
If after 3 months of maximally tolerated GDMT the LVEF remains ≤ 35 %, discuss ICD implantation for primary prevention, covering risks, benefits, and survival expectations. 5
If LVEF improves to > 40 % after GDMT, continue all four medication classes indefinitely; abrupt discontinuation is associated with relapse of LV dysfunction (e.g., 5.7 % of patients in the DEFINITE trial experienced ventricular tachyarrhythmias despite EF > 35 %). 4
If LVEF declines again to ≤ 35 % after the 3‑month period, proceed with ICD implantation provided expected survival > 1 year and no prohibitive comorbidities. 5

HFmrEF follows a dynamic course: ~27 % of patients decline to LVEF ≤ 40 % while ~45 % improve to LVEF ≥ 50 % over follow‑up, highlighting the need for serial imaging and continued GDMT even after EF improvement. 1
Repeat transthoracic echocardiography at 3 months to assess LVEF trajectory and determine ICD eligibility, then every 6‑12 months to monitor ventricular remodeling. 1

Do not delay GDMT awaiting symptom development or further LVEF decline; early treatment in asymptomatic or mildly symptomatic LV dysfunction reduces mortality and prevents progression. 1
Do not discontinue GDMT when EF improves above 40 % (HFimpEF); abrupt withdrawal is linked to relapse of LV dysfunction and clinical heart failure. 1
Do not implant an ICD before completing ≥ 3 months of optimal medical therapy in myocarditis‑related cardiomyopathy; early ICD placement has not shown survival benefit. 4
Do not rely on a single LVEF measurement for definitive therapeutic decisions; obtain two consecutive measurements to mitigate variability. 1