Intramural Atrial Hematoma After Catheter Ablation for Atrial Tachyarrhythmias
A 50-year-old woman with a 10-year history of recurrent atrial tachyarrhythmias consisting of atrial fibrillation and typical/atypical atrial flutter underwent radiofrequency ablation. She underwent electrical isolation of all 4 pulmonary veins for treatment of the atrial fibrillation, and then cavotricuspid ablation for typical right-sided atrial flutter.
We noted that one of the atrial flutters had originated from the coronary sinus; thus, ablation was attempted within the coronary sinus to electrically isolate it. After the procedure, the patient was noted to be hypotensive. Transthoracic echocardiography revealed a large pericardial effusion with obliteration of the right ventricle and tamponade physiology (Figure 1A and Movie I). She underwent successful pericardiocentesis, and an indwelling pericardial drain was placed with complete resolution of hypotension. Follow-up surveillance transthoracic echocardiography revealed the evolution of a new left atrial mass consistent with either an intramural hematoma or dissection and thrombosis of the coronary sinus (Figure 1B and 1C; Movies II and III). Cardiac magnetic resonance (CMR) imaging was subsequently performed for superior tissue characterization and image resolution, to discriminate between these 2 possible diagnoses. Postcontrast-enhanced imaging demonstrated a well-demarcated 2.7×3.0 cm homogeneous mass arising from within the lateral left atrial wall (Figure 2, black arrow; Movie IV). Furthermore, finger-like extensions of the mass within the thickness of the atrial wall, as visualized by CMR, strongly supported the diagnosis of intramural atrial hematoma (Figure 2, white arrows) over coronary sinus thrombosis. The patient was followed in-house, with serial transthoracic echocardiography demonstrating a stable-to-improving left atrial hematoma, and the patient was discharged home, in sinus rhythm, about 10 days after ablation. Subsequent follow-up transthoracic echocardiography as an outpatient 1 month after discharge revealed complete resolution of the hematoma.
Intramural atrial hematomas are rare, but they have been described as occurring both spontaneously1–3 and iatrogenically.4 Lombardo et al1 ultimately made the diagnosis of spontaneous atrial hematoma by surgical exploration after the presumptive diagnosis of left atrial tumor was made on the basis of the results of 3 imaging modalities including transthoracic echocardiography, cardiac computed tomography, and CMR imaging. In our case, the clinical context favored a traumatic process resulting in an intramural atrial hematoma or coronary sinus thrombosis. The CMR images, showing tracking of a nonenhancing density within the wall of the atrium, strongly suggested intramural hematoma. Consequently, the patient was carefully observed, and no surgical intervention was undertaken. This case highlights the usefulness of cardiac imaging, specifically CMR, in the noninvasive evaluation of an unidentified cardiac mass. It also demonstrates a potential complication of catheter ablation procedures that is essentially asymptomatic and that has been described only recently in the literature.4
The online-only Data Supplement, consisting of Movies I through IV, is available with this article at http://circ.ahajournals.org/cgi/content/ full/115/18/e446/DC1.