Abstract
We report a case of a 70-year-old woman who presented for a cavotricuspid isthmus atrial flutter ablation that was aborted prematurely. On subsequent imaging, she was discovered to have a right atrial diverticulum, which was present on prior imaging but not reported, likely due to unfamiliarity with the entity. (Level of Difficulty: Intermediate.)
Key Words: atrial flutter, echocardiography, imaging, supraventricular arrhythmias, ultrasound
Central Illustration
A 70-year-old woman with hypertension, pectus excavatum, typical atrial flutter, and heart failure presented for cavotricuspid isthmus (CTI) ablation.
Three years prior to the ablation, a transthoracic echocardiogram (TTE) demonstrated a left ventricular ejection fraction (LVEF) of 25% with apical hypokinesis. Two years later, a repeat TTE on guideline-directed medical therapy demonstrated an LVEF of 68%. A cardiac magnetic resonance (CMR) study demonstrated a volumetric LVEF of 61% without significant valvular disease or late gadolinium enhancement.
Nine months prior to the ablation, she was hospitalized for palpitations and lightheadedness and was diagnosed with typical atrial flutter. Anticoagulation was deferred due to recent nonsteroidal anti-inflammatory drug–related gastrointestinal hemorrhage. She spontaneously converted to sinus rhythm.
Following resolution of the gastrointestinal hemorrhage, she was started on anticoagulation with plan for atrial flutter ablation, given her symptoms while in her arrhythmia. She presented for her ablation, which was performed using electroanatomic mapping without fluoroscopy. However, despite extensive ablation, CTI block could not be achieved. Further mapping of the right atrium (RA) revealed a very narrow/compressed RA with an atypical tricuspid annular morphology. An intracardiac echocardiography catheter revealed a large outpouching of the RA at the site of the CTI that extended over the small right ventricle (Figures 1A, Supplemental Figure 1, Videos 1 and 2). Her atrial flutter degenerated into atrial fibrillation. She was cardioverted and initiated on amiodarone. The case was aborted to obtain further imaging.
Figure 1.
Imaging of the Right Atrial Diverticulum
(A) Intracardiac echocardiography (ICE) images of the right atrium (RA), right atrial diverticulum (RAD), tricuspid valve (TV), superior vena cava (SVC), and inferior vena cava (SVC) (Video 1). (B) Transthoracic echocardiogram apical 4 chamber view highlighting the RAD as well as the RA, RV, left atrium (LA), and left ventricle (LV) (Video 3). (C) Transthoracic echocardiogram subcostal view highlighting the RAD (Video 4). (D) Computed tomography and (E) cardiac magnetic resonance views of the RAD as well as prominent pectus excavatum.
A TTE was subsequently obtained which showed a diverticulum in the RA (Figures 1B and 1C, Videos 3 and 4). She underwent a gated cardiac computed tomography scan, which demonstrated a saccular outpouching in the RA measuring 6.9 × 3.8 × 5.8 cm (Figure 1D). Upon review of her prior CMR, the atrial pouch had been previously visualized (Figure 1E). She was seen in follow-up without recurrence of her atrial arrhythmias on amiodarone.
Diverticula of the RA have been previously described to be associated with various supraventricular arrhythmias.1,2 In a 2004 literature review of 23 cases of RA aneurysms/diverticula, 9 presented with atrial fibrillation, Wolff-Parkinson-White syndrome, and other supraventricular tachycardias.2 These arrhythmias are perhaps related to the abnormal tissue, which may act as a substrate for or focus of arrhythmias. The optimal management strategy is not well established and is related to severity of sequelae, with surveillance, anticoagulation, catheter ablation, and surgical excision described.1, 2, 3 In this case, as the safety and efficacy of ablation within the diverticulum itself is unclear and the patient has not had recurrence of arrhythmia, further ablation has not been pursued.
The embryological origin of these diverticula remains unclear, but they may be associated with other congenital cardiac malformations including hypertrophic cardiomyopathy.1 The prevalence is not known, as these rare abnormalities are likely underreported, given that patients may be asymptomatic, but with increasing use of imaging, these may be detected more frequently. Early recognition of RA diverticula on imaging can be informative for risk of arrhythmias as well as for ablation planning.
Funding Support and Author Disclosures
Dr Waks has received grant support from Anumana. Dr Strom has received funding from the National Institutes of Health/National Heart, Lung, and Blood Institute (1K23HL144907); has received grant support from Edwards Lifesciences, Ultromics, HeartSciences, and Anumana; has received consulting fees from Bracco Diagnostics and General Electric Healthcare; and has served on the advisory boards for Edwards Lifesciences, Ultromics, and EchoIQ. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Appendix
For a supplemental figure and videos, please see the online version of this paper.
Appendix
Intracardiac echocardiography of the right atrium and right atrial diverticulum with ablation catheter in place.
Intracardiac echocardiography showing ablation area.
Transthoracic echocardiogram apical 4-chamber view with prominent right atrial diverticulum.
Transthoracic echocardiogram subcostal view with prominent right atrial diverticulum.
References
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Supplementary Materials
Intracardiac echocardiography of the right atrium and right atrial diverticulum with ablation catheter in place.
Intracardiac echocardiography showing ablation area.
Transthoracic echocardiogram apical 4-chamber view with prominent right atrial diverticulum.
Transthoracic echocardiogram subcostal view with prominent right atrial diverticulum.