Is diltiazem effective in Congestive Heart Failure (CHF)?

From the Guidelines

Diltiazem is not typically recommended as a first-line treatment for congestive heart failure (CHF) due to its potential to worsen heart failure symptoms in certain patients, particularly those with reduced ejection fraction, as it may increase the risk of HF worsening and hospitalization 1, 2. However, in specific cases where CHF patients also have atrial fibrillation or hypertension, diltiazem may be considered under close monitoring, usually at a dose of 30-90 mg every 6-8 hours, with careful adjustment to avoid exacerbating heart failure.

• Its use should be approached with caution, particularly in patients with reduced ejection fraction, and alternative treatments such as beta-blockers, ACE inhibitors, or ARBs are generally preferred for managing CHF 1, 3, 2.
• The European Society of Cardiology (ESC) guidelines recommend avoiding the use of diltiazem and verapamil in patients with heart failure with reduced ejection fraction (HFrEF) due to their negative inotropic effect and risk of worsening HF 1, 4.
• In patients with atrial fibrillation and CHF, rate control therapy is recommended, and diltiazem may be considered as a first-choice drug to control heart rate and reduce symptoms, but with caution and close monitoring 5, 6.
• Overall, the use of diltiazem in CHF should be individualized and carefully considered, taking into account the patient's specific clinical context and potential risks and benefits 1, 2, 7.

From the FDA Drug Label

Although diltiazem has a negative inotropic effect in isolated animal tissue preparations, hemodynamic studies in humans with normal ventricular function have not shown a reduction in cardiac index nor consistent negative effects on contractility (dP/dt) Experience with the use of diltiazem hydrochloride alone or in combination with beta-blockers in patients with impaired ventricular function is very limited. Caution should be exercised when using the drug in such patients.

The effectiveness of diltiazem in Congestive Heart Failure (CHF) is unclear due to very limited experience with its use in patients with impaired ventricular function.

• Key points: + Diltiazem has a negative inotropic effect in isolated animal tissue preparations. + Hemodynamic studies in humans with normal ventricular function have not shown consistent negative effects. + Experience in patients with impaired ventricular function is very limited. Given the limited information and potential negative inotropic effects, caution should be exercised when considering the use of diltiazem in patients with CHF 8.

From the Research

Effectiveness of Diltiazem in Congestive Heart Failure (CHF)

• The study published in Circulation in 1991 9 found that diltiazem increased the frequency of late-onset congestive heart failure in postinfarction patients with early reduction in ejection fraction.
• In contrast, a study published in the Journal of the American College of Cardiology in 1984 10 reported that intravenous and oral diltiazem improved left ventricular performance and reduced myocardial oxygen demand in patients with severe congestive heart failure.
• A study published in the British heart journal in 1987 11 found that long-term administration of oral diltiazem was not regularly associated with a deterioration in clinical, radiographic, or radionuclide ventriculographic estimates of left ventricular function, even in patients with poor baseline left ventricular systolic performance.
• A more recent study published in The American journal of emergency medicine in 2022 12 compared the effectiveness of intravenous metoprolol and diltiazem in patients with atrial fibrillation and concomitant heart failure, and found that diltiazem reduced heart rate more quickly and reduced heart rate by 20% or greater more frequently than metoprolol, with no differences in safety outcomes.

Safety Considerations

• The study published in Circulation in 1991 9 noted that diltiazem increased the frequency of late-onset congestive heart failure in patients with left ventricular dysfunction.
• The study published in the British heart journal in 1987 11 reported that diltiazem was discontinued in one patient due to symptoms indicative of worsening congestive heart failure.
• The study published in The American journal of emergency medicine in 2022 12 found no differences in safety outcomes between diltiazem and metoprolol in patients with atrial fibrillation and concomitant heart failure.

Overall Assessment

• The evidence suggests that diltiazem may have both positive and negative effects on congestive heart failure, depending on the patient population and the specific context in which it is used 9, 11, 10, 12.
• Further studies are needed to fully understand the effects of diltiazem on congestive heart failure and to determine its safety and efficacy in this patient population 12.