Can COVID-19 (Coronavirus Disease 2019) cause bradycardia (abnormally slow heart rate)?

COVID-19 Can Cause Bradycardia

Yes, COVID-19 can cause bradycardia as both an acute cardiovascular complication during infection and potentially as a long-term sequela. 1

Mechanisms of COVID-19-Associated Bradycardia

COVID-19 can affect the cardiovascular system through several mechanisms:

1. Direct viral injury to myocytes or vascular endothelium 1
2. Inflammatory damage to cardiac pacemaker cells 2
3. Cytokine effects on the sinoatrial node - high levels of pro-inflammatory cytokines may act directly on the SA node 2
4. Hypoxia from respiratory involvement 2
5. Exaggerated response to medications used in COVID-19 treatment 2

Clinical Presentation and Characteristics

• Bradycardia typically develops during the course of COVID-19 infection, often appearing between days 5-15 of illness 2, 3
• Heart rates during COVID-19-associated bradycardia typically range from 42-49 beats per minute 2
• Episodes can last from 1-14 days 2
• Most cases are self-limiting and resolve without permanent intervention 3
• Bradycardia can occur in patients with or without pre-existing cardiovascular disease 2

Incidence and Risk Factors

Bradycardia appears to be relatively common in COVID-19 patients:

• In some studies, more than 1 in 3 patients (37%) receiving remdesivir for COVID-19 developed bradycardia 4
• Risk factors for developing bradycardia include:
  • Age ≥65 years (OR 1.76) 4
  • Hypertension (OR 1.37) 4
  • Obesity (OR 1.32) 4

Severity and Clinical Significance

Bradycardia in COVID-19 patients can range from mild to severe:

• Mild bradycardia (51-59 bpm): Most common, occurring in 26.7% of patients in one study 4
• Moderate bradycardia (41-50 bpm): Occurs in approximately 9.7% of patients 4
• Severe bradycardia (≤40 bpm): Relatively rare, affecting only about 0.7% of patients 4

Importantly, bradycardia in COVID-19 patients has been associated with:

• Increased mortality 5
• Longer hospital stays 5
• May be a warning sign of an impending cytokine storm 2

Types of Bradyarrhythmias in COVID-19

COVID-19 can cause various forms of bradyarrhythmias:

• Sinus bradycardia: Most common form 3
• Complete heart block: Can occur even in patients with preserved left ventricular ejection fraction 6
• In severe cases, pacemaker insertion may be required (76.3% of severe cases in one review) 6

Management Considerations

For patients with COVID-19 who develop bradycardia:

• Monitor cardiac function closely, especially in high-risk patients (elderly, those with hypertension or obesity)
• Most cases are self-limiting and resolve without intervention 3
• For symptomatic cases, medications like atropine may be used for acute management 3
• Consider the contribution of medications (though studies show mixed results regarding remdesivir's role in bradycardia) 5, 4
• Permanent pacemakers may be needed in cases of persistent high-grade AV block 6

Important Clinical Pitfalls

1. Don't confuse with medication effects - While medications like remdesivir have been implicated, the relationship isn't consistently proven 5
2. Monitor beyond acute phase - Bradycardia can develop several days into the illness 2
3. Don't overlook in mild cases - Bradycardia can occur even in patients who don't require ICU care 3
4. Consider as warning sign - Bradycardia may signal the onset of a serious inflammatory response 2
5. Follow-up is essential - While most cases resolve, some patients may develop long-term cardiac sequelae 1

COVID-19-associated bradycardia represents one of many potential cardiovascular manifestations of this multisystem disease and warrants careful clinical attention and monitoring.