Diltiazem Should NOT Be Given to Patients with Ejection Fraction 25-30%
Diltiazem is explicitly contraindicated in patients with heart failure with reduced ejection fraction (HFrEF), as major guidelines clearly state it increases the risk of heart failure worsening and hospitalization. 1
Guideline-Based Contraindication
The 2016 European Society of Cardiology (ESC) Guidelines for Heart Failure provide a Class III recommendation (meaning "not recommended") stating that diltiazem or verapamil should not be used in patients with HFrEF because they increase the risk of heart failure worsening and heart failure hospitalization. 1 This is the highest level of "do not use" recommendation in guideline terminology.
The FDA drug label for diltiazem specifically warns about congestive heart failure, noting that while diltiazem has negative inotropic effects in isolated tissue preparations, caution should be exercised when using the drug in patients with impaired ventricular function, and experience in such patients is "very limited." 2
Why This Matters for Your Patient
With an ejection fraction of 25-30%, your patient has severe left ventricular systolic dysfunction. The concern is multifaceted:
- Negative inotropic effects: Diltiazem reduces myocardial contractility, which can further compromise an already failing heart 2
- Risk of hemodynamic decompensation: The drug can precipitate acute worsening of heart failure 2
- Conduction abnormalities: Diltiazem prolongs AV node conduction and can cause bradycardia or heart block, particularly problematic in patients with underlying cardiac dysfunction 2
What Should Be Used Instead
For rate control in atrial fibrillation (the most common reason diltiazem is considered):
Beta-blockers are the first-line agents for rate control in patients with reduced ejection fraction (LVEF <40%). 3 They not only control heart rate but also reduce mortality in HFrEF patients. 1
The American Heart Association explicitly recommends avoiding non-dihydropyridine calcium channel blockers (diltiazem, verapamil) in patients with reduced left ventricular function (LVEF ≤40%) due to their negative inotropic effects. 3
Evidence Nuances and Common Pitfalls
Pitfall #1: "But I've seen it used in the ED for acute rate control"
While some recent observational studies suggest short-term IV diltiazem may be used cautiously in selected HFrEF patients for acute atrial fibrillation, these studies show concerning signals:
- A 2024 study found worsening heart failure occurred in 17% of patients with reduced EF versus 4.8% with preserved EF (p=0.005) 4
- A 2018 study showed significantly higher acute kidney injury rates in low EF patients (10% vs 3.6%, p=0.002) 5
- These studies involved highly selected patients in monitored settings, not general use 4, 5, 6
Pitfall #2: "What if beta-blockers don't work?"
If beta-blockers fail to achieve adequate rate control in atrial fibrillation with HFrEF:
- Consider AV nodal ablation if the patient otherwise meets criteria for cardiac resynchronization therapy (CRT), as this ensures near 100% ventricular pacing 3
- Digoxin can be added for additional rate control without negative inotropic effects
- Amiodarone may be considered for rhythm control in selected cases
Pitfall #3: "The patient is hemodynamically stable"
Current hemodynamic stability does not negate the guideline contraindication. The concern is precipitating decompensation in a patient with minimal cardiac reserve. 1
The Bottom Line Algorithm
For a patient with EF 25-30%:
- Do NOT use diltiazem - Class III contraindication 1
- Use beta-blockers as first-line for rate control (if indicated) 3
- Ensure guideline-directed medical therapy including ACE inhibitors/ARBs, beta-blockers, and mineralocorticoid receptor antagonists 1
- Consider device therapy (ICD, potentially CRT) if the patient meets criteria with LVEF ≤35% 1
The only potential exception would be an acute, life-threatening situation in a monitored ICU setting where no other options exist, but even then, the risk-benefit strongly favors alternative agents. 4, 5