Symptomatic Severe Bradycardia during Pazopanib Treatment.

Pazopanib, a tyrosine kinase inhibitor that targets growth factor receptors, is associated with various side effects, including bradycardia. We report a severe case of symptomatic bradycardia, with a heart rate dropping to 28 beats per minute, in a patient with cardiac angiosarcoma treated with 800 mg/day of pazopanib. Reducing the dosage to 600 mg/day improved the heart rate to 53 beats per minute. This case highlights the risk of severe bradycardia associated with pazopanib, emphasizing the need for vigilant heart rate monitoring.