Continuous Versus Intermittent cARdiac Electrical moNitorinG

Inclusion Criteria: * Diagnosis of acute promyelocytic leukemia (APL) and being initiated on standard of care arsenic trioxide OR Diagnosis of solid tumor and being initiated on standard of care capecitabine (alone or as part of combination treatment) OR Diagnosis of solid tumor and being initiated on standard of care ribociclib (alone or as part of combination treatment) * At least 18 years of age. * No allergy to adhesive patches. * Able to understand and willing to sign an IRB-approved written informed consent document. Exclusion Criteria: * Younger than 18 years of age * Allergy to adhesive patches