Cardioversion in Cardiac Amyloidosis

Study Questions:

What are the outcomes of direct-current cardioversion (DCCV) for atrial arrhythmias in patients with cardiac amyloidosis?


Cases of patients with cardiac amyloidosis scheduled for DCCV over a span of 12 years at Mayo Clinic were matched 2:1 with control patients by age, sex, type of atrial arrhythmia, and date of DCCV.


There were 58 cardiac amyloidosis patients (mean age 69 years, 81% male). Cardiac amyloidosis patients had a higher cardioversion cancellation rate (28% vs. 7%; p < 0.001). Intracardiac thrombus was identified on transesophageal echocardiogram (TEE) (81% vs. 25%); 31% of the cardiac amyloidosis patients with intracardiac thrombus on TEE received adequate anticoagulation ≥3 weeks and another 15% had arrhythmia duration <48 hours. DCCV success rate was not different (90% vs. 94%). Procedural complications were more frequent in cardiac amyloidosis versus control patients (14% vs. 2%); complications in cardiac amyloidosis included ventricular arrhythmias in two and severe bradyarrhythmias requiring pacemaker implantation in two patients.


Patients with amyloidosis undergoing DCCV had a high incidence of intracardiac thrombus even among patients who received adequate anticoagulation. Tachyarrhythmias and bradyarrhythmias complicating DCCV were significantly more frequent in amyloid patients compared with control patients.


Amyloidosis causes restrictive cardiomyopathy and it is often accompanied by atrial fibrillation or atrial flutter, which can be poorly tolerated. Prior studies have shown that intracardiac thrombus may be found in cardiac amyloidosis patients despite the absence of atrial fibrillation or flutter. The extremely high rate of intracardiac thrombus on TEE in the present study suggests that TEE or another imaging method should be considered in all patients with amyloidosis undergoing DCCV even if they have had documented therapeutic anticoagulation or if their atrial arrhythmia lasted <48 hours.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound

Keywords: Amyloidosis, Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Atrial Flutter, Bradycardia, Cardiomyopathy, Restrictive, Echocardiography, Transesophageal, Electric Countershock, Geriatrics, Heart Failure, Pacemaker, Artificial, Tachycardia, Thrombosis

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