Monitoring for CardioToxicity Using WeArable deVices While Undergoing cancEr Treatments (MCT-WAVE)

This pilot study will evaluate the validity and feasibility of ambulatory cardiac monitoring to identify markers of cardiotoxicity in adults undergoing cancer treatment. Participants with breast cancer, hematologic malignancy, or multiple myeloma will receive usual care plus two wearable patch monitors: mobile cardiac telemetry using the BodyGuardian Mini Plus ambulatory ECG monitor and an investigational wearable cardiac monitor that records heart sounds. The study will assess arrhythmias detected by mobile cardiac telemetry and explore whether heart sounds are associated with echocardiographic findings and cardiac biomarkers. Participants will wear the devices during cancer treatment, with monitoring periods at baseline and possible repeat monitoring at 6-month and 12-month study visits.