Clinical Research Directory

Inclusion Criteria: * Age ≥22 * Initiation of BTK inhibitor (acalabrutinib or zanubrutinib) with or without other concurrent systemic therapy as front line or relapsed/refractory therapy for chronic lymphocytic leukemia, ordered by treating oncologist per standard of care * Normal sinus rhythm at the time of consent * Ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use protected health information (in accordance with national and local patient privacy regulations). Exclusion Criteria: * Current use of a class IC or III antiarrhythmic medication * AF or other arrhythmia at the time of consent * Uncontrolled hypertension (≥140/90mmHg) at the time of consent * Inability to provide informed consent * Inability to wear a watch * Arm circumference too small (\< 9 in) or arm circumference too large (\> 14.5in.) to use the QardioArm cuff * Expected survival less than one year. * Pregnancy at time of consent * Lack of access to a personal Apple iPhone. If the patient does not have an Apple iPhone, but another member of the patient's household has an iPhone, the patient may still be enrolled as long as there is no other Apple Watch paired with the phone.