left atrial intramural hematoma ( laih ) is an exceedingly rare occurrence.1 ) it is defined as a false , blood - filled cavity or lumen in the left atrial ( la ) walls or interatrial septum , creating a new chamber which may or may not be connected with the true la chamber.2 ) the few reports available in the existing literature relate laih primarily to cardiac procedures such as transcatheter arrhythmia ablation and cardiac surgeries . it is also known to occur spontaneously or in association with amyloidosis , mitral calcification , myocardial infarction , and chest trauma.1)3 ) the true incidence , etiology , pathophysiology , clinical course , and management of laih have yet to be fully elucidated . the purpose of our review is to better define the etiology , clinical course , and management of laih in the hope of improving the recognition and outcome of this rare entity . a 51-year - old woman had recurrent attacks of atrial tachycardia and atrial fibrillation that did not resolve upon treatment with multiple anti - arrhythmic drugs . a single trans - septal puncture was performed under fluoroscopic guidance without any difficulties , and an sl1 sheath ( st . jude medical inc . , saint paul , mn , usa ) was introduced into the la , through which a lasso catheter was snaked . a7french sheath , 4-pole , 3.5 mm irrigation tip ablation catheter ( biosense webster inc . , los angeles , ca , usa ) was also introduced through the same trans - septal puncture and along the lasso catheter into the la . a navx ( navigation & visualization technology ) system was used for electroanatomic three - dimensional mapping . ablation was carried out with a stockert radiofrequency rf generator with temperature limited to 40 and power limited to 35 w in the anterior and 20 w in the posterior la regions . incessant atrial tachycardia at a cycle length of 290 ms was present at the outset . large areas of scar tissue were present in most parts of the la , especially the anterior and roof areas , but normal signals were recorded in the right atrium , suggesting a diagnosis of isolated la cardiomyopathy . tiny pulmonary vein ( pv ) potentials were evident inside the left superior and inferior pvs . multiple changing circuits of reentrant atrial tachycardia were identified by entrainment mapping and were ablated in the anterior la and roof . a stable sinus rhythm was restored , and no tachycardia was inducible despite atrial bursts down to 200 ms . regarding the anticoagulation regimen , the patient stopped taking dabigatran 36 hours before the procedure . a bolus of 8000 iu ( 100 mg / kg ) heparin was given just after the trans - septal puncture , and activated clotting time was maintained at 350 - 400 seconds throughout the procedure . enoxaparin ( 60 mg ) was administered 6 hours after the removal of the sheaths . the morning after the procedure , the patient was in sinus rhythm and was feeling well . a routine transthoracic echocardiogram ( tte ) revealed a large mass ( 67 cm ) occupying most of the la cavity . additionally , tte showed a mitral mean gradient of 6 mmhg , mild tricuspid regurgitation with a mild increase in pulmonary pressure , normal left ventricular dimensions and ejection fraction , and no pericardial effusion . as no further morphological definition of the mass was possible at this stage , transesophageal echocardiography was performed , which revealed a large multi - loculated mass occupying most of the la space and partially obstructing the left ventricular inflow ( fig . the mass originated from the roof of the la cavity and extended to the atrioventricular groove . the interatrial septum was intact , delimited by a smooth well - defined wall , and contained some echo - free areas with thrombus - like organization . also , there was no signal over the interatrial septum in a color - doppler study . for further understanding of the origin of the mass ( intra- vs. extra - cardiac ) , cardiac computed tomographic angiography ( ct - a ) imaging was performed , which showed a homogeneous non - enhancing intramural mass consistent with a hematoma located in the posterosuperior la wall . after considering the risk of expansion of the hematoma versus the risk of thromboemboli after an extensive la ablation , we decided to pursue a watchful follow - up while continuing anticoagulation with intravenous unfractionated heparin . she was discharged on postoperative day 3 in sinus rhythm on dabigatran ( 110 mg twice daily ) . the size of the hematoma decreased significantly during the following 8 days . a subsequent follow - up tte in an outpatient clinic 50 days after discharge revealed significant resolution of the hematoma ( fig . intramural hematoma is a very uncommon cause of la masses.4 ) complex radiofrequency ablation procedures for the treatment of la arrhythmias , including atrial fibrillation , have a 6% rate of major complications such as pericardial effusion , embolic events , pulmonary vein dissection , and bleeding secondary to anticoagulation . intramural atrial hematomas are extremely rare.5)6 ) varying presentation and clinical course are unique characteristics of laih . in fact , prompt diagnosis of laih tends to be difficult , given its often confusing clinical presentation with hemodynamic instability.2 ) although symptoms usually occur during the 24 hours after a procedure,1 ) relatively gradual development of the hematoma has also been reported.5 ) a presumptive diagnosis of la masses is most often made on the basis of the results of three imaging modalities , i.e. echocardiography , computed tomography , and cardiac magnetic resonance imaging.7 ) in our patient , although echocardiography was useful for the initial documentation of the hematoma , ct - a was necessary to show not only the size but also the extent of the mass . knowledge of these features was critical in this case to ensure that the pvs were not compromised . consequently , the patient was carefully observed , and no surgical intervention was undertaken . because the clinical course and outcome of laih are poorly understood , however , operative intervention is of course indicated if hemodynamic collapse exists.2 ) although in previous reports , prompt surgical repair was undertaken in some patients , it may not be necessary in cases of laih with stable hemodynamic status , as was seen in our patient . therefore , hemodynamic instability , which is indicative of a rapid expansion of the hematoma with the occlusion of the la cavity and pv or mitral inflow obstruction , may be the critical determinant of the necessity for surgical repair . nonetheless , as was observed in our patient , laih most frequently occurs along the posterior wall of the la and the atrioventricular groove , both of which provide naturally weakened areas vulnerable to overdistension and forceful manipulation.2 ) consequently , we speculate that the hematoma could have been a result of traumatic catheter manipulations in the weakened areas . specifically , the underlying scarred substrate of the la may have contributed to the intimal tear in our patient . thermal injury has been hypothesized as well . in our patient , however , a very limited amount of burns at a low power were applied in the posterior la . another interesting observation is that the resolution of the hematoma was not prevented by continuation of anticoagulation therapy in our patient . in conclusion this case also highlights the usefulness of cardiac imaging modalities , specifically ct - a , in the noninvasive evaluation of la masses and the final diagnosis of intramural hematomas . we also demonstrated that conservative management and regular echocardiographic observation should be considered in hemodynamically stable cases , and anticoagulation therapy can be continued .
left atrial intramural hematoma is a very rare complication of radiofrequency ablation procedures . a patient with tachyarrhythmia underwent radiofrequency catheter ablation . 
 echocardiography performed the following morning showed a large mass in the left atrium , suggestive of intramural hematoma formation . 
 the patient was in a stable condition ; therefore , it was decided that follow - up should be conservative and her anticoagulation therapy was continued . 
 the size of the hematoma decreased significantly over the following 50 days . 
 this case highlights a rare complication of a complex catheter ablation procedure in the left atrium that was managed via a noninvasive approach , with which all interventionists should be familiar .