Atrial Fibrillation Among Patients With Hematologic Malignancies on Tyrosine Kinase Inhibitor Therapy

This study looks at how often atrial fibrillation (AF), an irregular heart rhythm, occurs in people with certain blood cancers who are starting a type of cancer medicine called a Bruton's tyrosine kinase inhibitor (BTKI). Researchers will follow 400 people starting BTKI therapy and compare them to 100 people with similar blood cancers who are not taking a BTKI. Participants will wear a smartwatch and, later, a heart monitor patch to check for AF and other irregular heart rhythms over 12 months. The study will also look at whether AF affects cancer treatment, such as needing to pause, lower the dose, or stop the BTKI, and whether it leads to other health problems such as bleeding, stroke, or heart-related hospital visits.