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Atrial Fibrillation in Transthyretin Cardiac Amyloidosis
Quick Takes
- Atrial fibrillation (AF), the most commonly encountered arrhythmia in transthyretin (ATTR) cardiac amyloidosis, is poorly tolerated by patients due to diastolic dysfunction and increased risk of intracardiac thrombus.
- Rhythm control strategies should be considered at the earliest stages possible to mitigate symptoms and risk of stroke.
Study Questions:
What are the predictors, prevalence, and outcomes of atrial fibrillation (AF) in patients with transthyretin cardiac amyloidosis (ATTR-CA)?
Methods:
This was a retrospective cohort study of 382 patients diagnosed with ATTR-CA between January 2004 and January 2018. Clinical data were obtained from electronic medical records. AF burden was obtained by device interrogation in 35%, a variety of electrocardiogram (ECG) monitors (54%), or serial ECGs (11%). Standard echocardiographic measurements and post-AF ablation rhythm monitoring were utilized.
Results:
A total 265 (69%) patients had AF: 45% had paroxysmal, 27% had persistent, 15% had long-standing persistent, and 13% had permanent AF. At the time of ATTR-CA diagnosis, 33% already had AF, and in the remaining 67%, the time from ATTR-CA diagnosis to development of AF was 15 months. Factors associated with development of AF included older age, advanced ATTR-CA stage, and larger left atrial diameters. AF was more common in ATTRwt (no mutation identified) compared to ATTRmut. Rhythm control strategies were substantially more effective if prescribed at earlier stages of the disease. Antiarrhythmics were used in 35% of patients with AF; cardioversion was performed in 45%, and AF ablation in 9%. The mean CHA2DS2-VASc score was 4. During a mean follow-up of 35 months, death occurred in 60%, but no difference in mortality between patients with and without AF was observed. No difference in mortality was noted based on AF type. Cerebrovascular accidents occurred in 16% and were significantly more common in those with AF. On Cox proportional hazards analyses, maintenance of normal sinus rhythm and use of tafamidis were associated with improved survival; advanced ATTR-CA stage and higher New York Heart Association functional class correlated with increased mortality.
Conclusions:
AF was highly prevalent, occurring in 69% of the cohort. Rhythm control strategies including antiarrhythmics, cardioversion, and AF ablation were substantially more effective when performed at earlier stages.
Perspective:
This was the largest study to date evaluating the course of AF in ATTR-CA. While having the diagnosis did not affect survival in this group, its prevalence was high, and maintenance of sinus rhythm was associated with improved survival. Limitations include the descriptive nature of the study, relatively few patients undergoing AF ablation, inability to assess symptoms over time due to retrospective design, and underestimation of AF burden likely due to the heterogeneous measures of recording used, thereby affecting mortality data. Although prospective studies are needed, this current study suggests that rhythm control strategies along with stroke prevention measures should be employed early in the disease course, especially as improved recognition and treatment of ATTR-CA continue to improve survival.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound
Keywords: Amyloid, Anti-Arrhythmia Agents, Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Catheter Ablation, Echocardiography, Electrocardiography, Electrocardiography, Ambulatory, Electric Countershock, Electronic Health Records, Heart Failure, Prealbumin, Secondary Prevention, Stroke, Thrombosis
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