Symptomatic Severe Bradycardia during Pazopanib Treatment

Area of Science:

• Oncology
• Pharmacology
• Cardiology

Background:

• Pazopanib is a tyrosine kinase inhibitor targeting growth factor receptors.
• It is used in cancer treatment but associated with cardiovascular side effects.
• Bradycardia is a known potential adverse effect.

Observation:

• A patient with cardiac angiosarcoma developed severe symptomatic bradycardia.
• Heart rate decreased to 28 beats per minute while on 800 mg/day pazopanib.
• The patient had no other apparent cause for the bradycardia.

Findings:

• Reducing pazopanib dosage to 600 mg/day resulted in heart rate normalization to 53 beats per minute.
• This demonstrates a direct correlation between pazopanib dosage and bradycardia severity.
• The patient tolerated the reduced dose without recurrence of severe bradycardia.

Implications:

• Pazopanib treatment requires careful cardiac monitoring, especially heart rate.
• Clinicians should consider dose adjustment for pazopanib-induced bradycardia.
• This case underscores the importance of recognizing and managing cardiovascular toxicities of targeted therapies.