This single arm, prospective non-blinded study will enroll 50 patients initiating treatment with BTK inhibitors (ibrutinib, acalabrutinib, zanubrutinib or pirtobrutinib) without documented arrhythmia prior to starting BTK inhibitor therapy, without contraindications to an implanted loop recorder (ILR). They will be offered the option of monitoring arrhythmias using the Medtronic LINQ-2 insertable cardiac monitor (ILR). Monitoring data will be collected prospectively until the patient withdraws consent, the device is removed, or up to 60 months. Investigators hope to obtain information on arrhythmia incidence including AF, ventricular arrhythmia (VA), and actions taken in response to awareness of such episodes.
