Loop Recorders Reveal Arrhythmias in Cardiac Amyloidosis

TOPLINE:

In patients newly diagnosed with cardiac amyloidosis (CA), continuous rhythm monitoring using implantable loop recorders found that clinically significant yet asymptomatic arrhythmias were common, varied by amyloid subtype, and were closely linked to the degree of myocardial infiltration and baseline conduction abnormalities.

METHODOLOGY:

• Researchers conducted a prospective observational study (EXCALIBUR) to characterize arrhythmia burden using implantable loop recorders in patients newly diagnosed with CA.
• They included 110 treatment-naive patients (mean age, 70.4 years; 80% men) between May 2021 and June 2022 at a UK specialist center. Of them, 63 had transthyretin amyloid cardiomyopathy (ATTR-CM) and 47 had light‑chain CA (AL-CA).
• All patients underwent comprehensive phenotyping, including cardiac MRI with mapping of the myocardial extracellular volume, and received subcutaneous implantable loop recorders (Reveal LINQ, Medtronic) for continuous rhythm monitoring.
• Loop recorders were set to detect bradycardia (< 50 beats/min), pauses (> 3 seconds), and tachycardia (> 110 beats/min), with daily data downloads reviewed by experts. The team documented Class I pacemaker-indicated clinically significant bradyarrhythmias, new atrial fibrillation (AF), ventricular arrhythmias, and terminal rhythms in fatal cases.
• Patients were followed up for a median duration of 36 months, with a minimum planned follow‑up period of 18 months.