Can prednisone exacerbate atrial fibrillation (AFib)?

Prednisone and Atrial Fibrillation Risk

Yes, prednisone can exacerbate atrial fibrillation, particularly at high doses (≥7.5 mg daily), with a 6-fold increased risk of new-onset AF compared to non-users. 1

Mechanism of Prednisone-Induced AF

Prednisone can trigger or worsen atrial fibrillation through several mechanisms:

1. Direct electrophysiological effects:

   • Increases cellular potassium efflux, which shortens atrial action potential duration and effective refractory period 1
   • Creates substrate for re-entry circuits and triggered activity

2. Hemodynamic effects:

   • Mineralocorticoid-like effects causing increased plasma volume
   • Elevation of atrial pressures leading to atrial enlargement 1

3. Long-term cardiovascular effects:

   • Promotes atherosclerosis, diabetes mellitus, hypertension, and heart failure
   • These conditions are established risk factors for AF 1

Risk Factors and Timing

The risk of prednisone-induced AF is:

• Dose-dependent: Significantly higher with doses ≥7.5 mg of prednisone equivalents (OR 6.07; 95% CI 3.90-9.42) 2
• Timing-related: Greatest at the beginning of therapy and with short-term use 1
• Administration-related: More common with oral/systemic use than inhaled corticosteroids 1, 3
• Particularly high in certain populations:
  • Patients with respiratory diseases (asthma/COPD): OR 4.02 (95% CI 2.07-7.81) 2
  • Patients with rheumatic, allergic, or hematologic malignancies: OR 7.90 (95% CI 4.47-13.98) 2

Clinical Implications

• Monitoring: Patients starting high-dose prednisone should be monitored for new-onset AF, especially during the first month of therapy 2
• Risk assessment: Consider baseline cardiovascular risk factors before initiating high-dose prednisone 4
• Dose consideration: Use the lowest effective dose for the shortest duration possible 4
• Special populations: Exercise particular caution in patients with pre-existing cardiac disease or risk factors for AF 1

Paradoxical Effect in Specific Conditions

Interestingly, in certain inflammatory cardiac conditions like cardiac sarcoidosis, prednisone may actually have anti-arrhythmic effects by suppressing inflammation 5. In animal models of atrial tachypacing, prednisone has been shown to suppress AF susceptibility and reduce inflammatory markers 1, 6.

Clinical Pearls

• Even a single pulse of high-dose methylprednisolone can induce AF, as observed in multiple sclerosis patients receiving IV therapy 7
• Smokers and patients with autonomic dysfunction appear to be at higher risk for steroid-induced arrhythmias 7
• Former corticosteroid use is not associated with increased AF risk, suggesting the effect is temporary and related to active use 1
• Low-intermediate doses (<7.5 mg prednisone equivalents) do not significantly increase AF risk (OR 1.42; 95% CI 0.72-2.82) 2

In summary, while prednisone has important therapeutic benefits, clinicians should be aware of its potential to exacerbate or trigger atrial fibrillation, particularly when using high doses. Careful monitoring and risk assessment are essential when initiating corticosteroid therapy.