Can prednisone or chemotherapy cause tachycardia?

Can Prednisone or Chemotherapy Cause Tachycardia?

Yes, chemotherapy can definitively cause tachycardia through multiple mechanisms, while prednisone is paradoxically more commonly associated with bradycardia rather than tachycardia.

Chemotherapy-Induced Tachycardia

Sinus Tachycardia

Anthracyclines (doxorubicin, daunorubicin, epirubicin) and carmustine are specifically documented to cause sinus tachycardia 1. This represents a direct toxic effect of these chemotherapeutic agents on cardiac rhythm.

Supraventricular Tachycardias

Multiple chemotherapy agents cause supraventricular tachycardias, including 1:

• Alkylating agents: cisplatin, cyclophosphamide, ifosfamide, melphalan
• Anthracyclines: doxorubicin and related agents
• Antimetabolites: capecitabine, 5-fluorouracil, methotrexate
• Taxanes: paclitaxel
• Targeted agents: bortezomib, ponatinib, romidepsin
• Immunotherapy: IL-2, interferons

Atrial Fibrillation (Most Common Tachyarrhythmia)

Atrial fibrillation is the most common chemotherapy-related tachyarrhythmia 1. The following agents are particularly implicated:

• Alkylating agents (cisplatin, cyclophosphamide, ifosfamide, melphalan)
• Anthracyclines
• Antimetabolites (capecitabine, 5-FU, gemcitabine)
• Tyrosine kinase inhibitors (ibrutinib, ponatinib, sorafenib, sunitinib)
• Topoisomerase II inhibitors (amsacrine, etoposide)
• Taxanes and vinca alkaloids 1

Ibrutinib specifically carries a 3% incidence of atrial fibrillation in clinical trials 2.

Ventricular Tachycardia

Life-threatening ventricular tachycardia can occur with 1:

• Alkylating agents (cisplatin, cyclophosphamide, ifosfamide)
• Anthracyclines (doxorubicin)
• Antimetabolites (capecitabine, 5-FU, gemcitabine)
• Arsenic trioxide
• Proteasome inhibitors (bortezomib, carfilzomib)
• Taxanes (paclitaxel)

Clinical Significance

Arrhythmias are present at baseline in 16-36% of treated cancer patients 1. Patients with cancer who develop atrial fibrillation have significantly increased mortality (OR 1.90; 95% CI 1.65-2.19; P < 0.0001) 2.

Prednisone and Cardiac Rhythm

Bradycardia, Not Tachycardia

Contrary to common assumptions, corticosteroids including prednisone are documented to cause bradycardia rather than tachycardia 3, 4. This is a dose-dependent effect that occurs with both intravenous pulse-dose and oral corticosteroids 3, 4.

• Sinus bradycardia has been reported with oral prednisone 40 mg, with heart rates dropping to 30-40 beats/minute 3
• The bradycardia is reversible upon discontinuation and recurs with re-administration 4
• This effect is dose-dependent and can occur with oral methylprednisolone as low as 52 mg 4

Mechanism and Clinical Context

The bradycardic effect of steroids is not well-recognized but should be considered when evaluating rhythm disturbances in patients on corticosteroid therapy 3, 4. The bradycardia typically resolves within 24 hours of discontinuation 3.

Contributing Factors Beyond Direct Drug Effects

Metabolic and Physiological Causes

Tachycardia in cancer patients receiving chemotherapy may also result from 2, 5:

• Electrolyte abnormalities from chemotherapy-induced nausea, vomiting, and diarrhea
• Hypoxia secondary to pulmonary involvement
• Pain and emotional stress increasing sympathetic tone
• Systemic inflammation as a common pathway to arrhythmias

Tumor-Related Factors

The cancer itself increases arrhythmia risk independent of treatment 2:

• Baseline atrial fibrillation prevalence of 2.4% with additional 1.8% incidence post-diagnosis
• Hematologic malignancies and intrathoracic tumors carry >2-fold increased risk
• Direct myocardial infiltration can cause both supraventricular and ventricular arrhythmias

Clinical Pitfalls and Recommendations

Key Considerations

• Do not assume steroids cause tachycardia—they more commonly cause bradycardia 3, 4
• Evaluate for multiple concurrent causes including electrolyte disturbances, hypoxia, and pain rather than attributing tachycardia solely to one agent 2, 5
• Monitor for QT prolongation with many chemotherapy agents, as this predisposes to ventricular tachyarrhythmias 1
• Recognize that arrhythmias may occur during treatment, shortly after, or even years later 1

Management Approach

Identify and correct underlying causes first: hypoxia, pain, electrolyte abnormalities, and volume status 5. For symptomatic tachycardia in hemodynamically stable patients, consider beta-blockers with lower drug interaction potential 5. Avoid medications that worsen tachyarrhythmias, such as theophylline 5.