Author + information
- Edward A. El-Am, MD,
- Angela Dispenzieri, MD,
- Martha Grogan, MD and
- Vuyisile T. Nkomo, MD, MPH∗ ()
- ↵∗Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905
We appreciate the interest generated by our paper (1) on direct-current cardioversion (DCCV) in patients with cardiac amyloidosis (CA). In response to comments by Dr. Russo and colleagues, we agree that more studies are needed to assess the risk of ischemic stroke in CA patients beyond the CHA2DS2VASc score; and in response to the comments of Dr. Csecs and colleagues, we also agree that there is a potential role for additional imaging to uncover left atrial appendage thrombus. Ischemic stroke is not an uncommon complication in CA patients, affecting even those on anticoagulation agents or without history of atrial arrhythmia (2,3). The data would suggest that recognition of thrombus and appropriate anticoagulation may not be sufficient in these complex patients.
Whether more widespread use of transesophageal echocardiography (TEE) to look for high-risk features for thrombus such as decreased left atrial appendage emptying velocities or spontaneous echo contrast in all CA patients regardless of rhythm would be beneficial requires further study. Echocardiography or computed tomography or magnetic resonance imaging for examination of left atrial function with left atrial strain is another potential tool that may help identify CA patients at risk of thrombus and thromboembolism. We agree with the clinical utility of intravenous contrast when evaluating the left atrial appendage and have adopted its use in cases where it is difficult to differentiate spontaneous echo contrast from thrombus. The time frame of our study (1) was before clinical adoption and wide use of contrast for left atrial appendage examination (4). Consequently, only 1 patient in the study received intravenous contrast, which confirmed thrombus. Our review of the stored TEE images (digital and tape) in preparation for this response led us to conclude that of the 12 CA cases where DCCV was canceled because of thrombus, contrast would have been helpful in 2 of the cases where the TEE findings were not definitive (i.e., early thrombus vs. dense spontaneous echo contrast).
Spontaneous echo contrast was present in 13 of 15 (87%) of the CA patients without intracardiac thrombus at the time of DCCV. As we reported, the patient with the complication of stroke on the same day following DCCV had spontaneous echo contrast pre-DCCV. However, it was not clear whether the stroke was related to an embolic complication, and whether intravenous contrast would have detected thrombus in this patient is unknown. Late stroke (2 to 7 years post-DCCV) occurred in 4 CA cases, and only 2 of these had TEE-guided DCCV of which 1 case had spontaneous echo contrast. Computed tomography or magnetic resonance imaging data were available in only 3 patients with left atrial appendage thrombus at time of DCCV, and left atrial anatomy was not noted by radiology to be unusual or abnormal.
In response to Dr. Csecs and colleagues’ question of antiarrhythmic drug use at the time of DCCV, 19 of 58 CA patients (33%) were receiving antiarrhythmic drugs (17 amiodarone, 1 sotalol, 1 flecainide).
Among the patients receiving amiodarone, 1 converted to sinus rhythm before DCCV, 1 failed cardioversion, and amiodarone was stopped in 6 because of intracardiac thrombus. Of the 9 of 17 patients on amiodarone successfully cardioverted by DCCV, atrial arrhythmias recurred in 4, and 1 had post-DCCV complete heart block requiring pacemaker implantation.
The patient on sotalol underwent successful DCCV, but had a recurrence of atrial arrhythmia 1 week later and was switched to amiodarone and underwent repeat successful DCCV. Atrial arrhythmia recurred 3 years later, and the patient underwent pulmonary vein isolation ablation. The patient on flecainide had ventricular tachycardia complicating DCCV and was successfully treated with overdrive pacing. Flecainide was subsequently stopped.
Among the 25 patients with atrial arrhythmia recurrence, 18 of 25 were subsequently treated with a strategy of rate control and anticoagulation, 4 of 25 were treated with amiodarone (3 subsequently underwent repeat DCCV), and the remaining 3 underwent atrioventricular node ablation and pacemaker implantation (Figure 1).
As our primary paper and the comments of Dr. Russo and colleagues and Dr. Csecs and colleagues demonstrate, there is much to learn about the recognition and management of thrombus and atrial arrhythmias in patients with CA.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2019 American College of Cardiology Foundation
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