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Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References

Background:

Atrial myxomas are the most common primary cardiac neoplasm. The majority (75%–80%) are located in the left atrium at the base of the foramen ovalis. Surgical removal can prevent dangerous obstructive or thromboembolic sequelae.

Hypothesis:

Atypically located tumors may present technical challenges requiring case-specific surgical adaptations when visualization or surrounding cardiac structures are compromised.

Methods:

We describe 3 cases of atypically located atrial myxomas that required preoperative transesophageal echocardiography and computed tomography to afford the optimal surgical approach.

Conclusions:

These cases highlight the potential need for multimodality imaging of atypically located atrial myxomas to determine the optimal technical approach for excision. Clin. Cardiol. 2012 doi: 10.1002/clc.22027

The authors have no funding, financial relationships, or conflicts of interest to disclose.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References

Atrial myxomas are the most common primary cardiac neoplasm, accounting for approximately half of all primary cardiac tumors.1 Although not malignant, myxomas can still have potentially dangerous sequelae due to their propensity to embolize and obstruct atrioventricular valves. In addition to incidentally discovered asymptomatic tumors, patients can present with either cerebral or peripheral emboli and/or congestive heart failure.2,3

Approximately 75% to 80% of these tumors arise from the left atrium and 15% to 20% from the right atrium.4–6 The most common location of left atrial myxomas is the interatrial septum at or near the fossa ovalis.1,6 The remainder of tumors arises from atypical locations such as the mitral or tricuspid valve, posterior or anterior atrial walls, or either ventricle.4 The current method of choice for the diagnosis of cardiac myxomas is transthoracic echocardiography (TTE).7

Surgical removal of atrial myxomas has a low rate of morbidity and mortality and is required to prevent the aforementioned sequelae.8 Standard surgical approach for excision of typically located tumors uses a standard right atriotomy and atrial septotomy, with excision of the tumor and tissue of the foramen ovalis. The tumor's size and specific location dictates the surgical approach. We present 3 cases of atypically located atrial myxomas presenting to our hospital within a 3-month period, and describe each case's use of preoperative imaging to dictate specific anatomy, technical approach, and associated challenges.

Case Report 1

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References

A 49-year-old female with remissive Hodgkin's lymphoma status post-radiation therapy had an acute nonhemorrhagic cerebral vascular accident (CVA) with dense right-sided hemiplegia. She had no prior history of CVAs or cardiac disease. Cardiac catheterization as an outpatient revealed normal coronary arteries, and an electrocardiogram (ECG) was also normal. A transthoracic echochocardiogram (TTE) was suspicious for an atrial mass. A subsequent transesophageal echocardiogram (TEE), displayed in Figure 1, revealed a mobile 1-cm mass arising at a very inferior position on the left interatrial septum. The mitral valve was structurally normal but had mild regurgitation. She received thrombolytics, and within 5 days her hemiplegia resolved, but mild residual intermittent numbness of her right arm and leg persisted. Surgical consultation was obtained and she was scheduled for elective cardiac surgery after she fully recovered from her CVA.

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Figure 1. A transesophageal echocardiogram displaying a 1.0 × 0.5-cm mobile mass in the left atrium arising from a very low position on the left interatrial septum

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She underwent surgical resection of the mass via a left roof atriotomy. Because of the tumor's atypical location seen on TEE, it was anticipated that optimum visualization could not be obtained using the standard atrial septal approach via a right atriotomy or a left atriotomy anterior to the pulmonary veins. A small broad-based jelly-like tumor was visualized attached to the left side of the atrial septum. The tumor was located immediately cephalad and posterior to the right fibrous trigone. Because of the tumors proximity to the conduction system, just posterior to the right fibrous trigone and mitral valve annulus, it was excised at its base, limiting the resection of surrounding left atrium (LA) structures. Pathology confirmed a 1.7 × 1.0-cm-sized papillary atrial myxoma with negative surgical margins. She had an uncomplicated postoperative course. At 6-month follow-up, a TTE revealed normal cardiac function without myxoma recurrence or atrial septal defect (ASD). Her ECG remained normal.

Case Report 2

A 47-year-old female with an unremarkable past medical history underwent a chest computed tomography (CT) for evaluation of an incidentally found pulmonary nodule. She denied any chest discomfort, shortness of breath, lightheadedness, or diaphoresis. She had no personal or family history of cardiac disease. Her CT revealed an undefined 2.5-cm left atrial mass. A TEE confirmed the 2.5 × 2.0-cm sessile mass attached to the superior portion of the fossa ovalis. The tumor extended superiorly onto the dome of the left atrium located between the left and right pulmonary veins. No intracardiac abnormalities were noted, and her ECG was normal.

She was referred for elective surgical excision of the mass. The tumor was approached via a right atriotomy and atrial septotomy at the inferior aspect of the foramen ovalis. A single, large, broad-based, sessile tumor with the consistency of jelly was attached to the superior portion of the fossa ovalis and also involved the intra-atrial septum cephalad to foramen ovalis with extension onto left atrium. An intraoperative decision was made to extend the septotomy to include the superior aspect of the intra-atrial septum and portion of the left atrial dome, and a full-thickness resection of that tissue to incorporate the entire tumor within the resection. The exposed tumor attached to the dome of the left atrium is seen intraoperatively in Figure 2. The atrial dome and septum were reconstructed with a bovine pericardial patch and the right atriotomy was primarily closed. Pathology confirmed a 2.5 × 2.0 × 2.0-cm-sized loculated papillary atrial myxoma with negative margins.

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Figure 2. Four intraoperative images displaying an atrial myxoma attached to the superior portion of the fossa ovalis extending cephalad onto the left atrial dome. Abbreviations: LA, left atrium; RA, right atrium.

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Postresection, she had 2 short asymptomatic bouts of an accelerated junctional rhythm. The cardiac electrophysiology service was consulted, and cardiac studies revealed a new baseline low atrial ectopic bradycardia with intact sinoatrial node function. Her postoperative course was otherwise unremarkable. At 6-month follow-up, a TEE revealed normal cardiac function without myxoma recurrence or ASD. Her asymptomatic low atrial ectopic atrial bradycardia rhythm on ECG persisted.

Case Report 3

A 58-year-old female with a past medical history of hypertension, hyperlipidema, psoriasis, as well as a recent CVA without permanent neurological sequelae, underwent a chest CT for evaluation of pulmonary nodules seen on a chest radiograph. She had no previous history of cardiac abnormalities or symptoms. On CT, a large filling defect noted in the right atrium was interpreted as a thrombus. The patient was referred to cardiology, and a TTE and TEE were performed, revealing a 2.2 × 2.3-cm multilobular pedunculated mass attached to the right side of the fossa ovalis. The tumor was very mobile and partially obstructed the tricuspid valve orifice during diastole. The tricuspid valve was structurally normal and had mild regurgitation without stenosis. The remainder of her TEE was normal, her ECG was normal, and she had no significant coronary artery disease on coronary angiography.

She was referred for surgical excision. The tumor was approached via a right atriotomy with an incision parallel to the atrioventricular groove. The atriotomy revealed a typical myxomatous-appearing tumor with its base on the fossa ovalis. The tumor, demonstrated in Figure 3, was fully excised along with a circumferential rim of normal atrial septum. The intra-atrial septum was closed with a 2-cm-diameter patch of bovine pericardium. Pathology confirmed a 4.7 × 2.6-cm-sized papillary atrial myxoma with negative surgical margins. Her hospital course was uncomplicated. A 6-month follow-up, TTE revealed normal cardiac function, and no recurrence or ASD.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References

Atrial myxomas comprise 50% of all primary cardiac tumors. The majority (75%–80%) are located in the left atrium involving the left side of the intra-atrial septum at the base of the foramen ovalis (FO). Traditionally, tumors at this location are excised using a standard right atriotomy and atrial septotomy with excision of the base of the tumor and tissue of the FO. Septal reconstruction is typically obtained using various patch materials such as bovine pericardium.5,8 Right atrial myxomas may be excised in the same fashion when attached to the FO and are readily approached via a right atriotomy.

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Figure 3. (Top) An intraoperative photo (4.7 cm × 2.6 cm) of a right atrial myxoma. Note attachment to the wall of the right atrium near the base of the tumor. (Bottom) Defect in the atrial septum after removal of myxoma but before closure with a bovine pericardial patch.

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Currently, the method of choice for the diagnosis of cardiac myxomas is TTE.7 Oliveira et al presents a 13-year review describing the ability of transesophageal echocardiogram to better define myxoma location and overall characteristics.7 Diagnosis of atrial myxoma with TTE could lead to a less-defined cardiac anatomy and suboptimal surgical approach.

Excision of atypically located atrial myxomas can be extremely problematic if the standard right atriotomy approach is taken without appropriate imaging. Several possible complications can occur if detailed cardiac anatomy via TEE or cardiac magnetic resonance imaging (MRI) is not obtained. Using a standard surgical approach, it is possibly to dissect directly into the tumor, damage surrounding cardiac and conduction system tissues, or obtain inadequate visualization requiring a modified surgical approach and consequential added atrial/septal reconstruction.

Specific preoperative technical adaptations may be utilized when visualization or surrounding cardiac structures are anticipated to be compromised. As seen in case 1, an atypical approach to the left atrium can be obtained by utilizing a left atriotomy incision anterior to the right pulmonary veins to aid visualization of a myxoma near the cardiac conduction system.8 Case 2 illustrates the occasional need for significant resection of septum and left atrial dome. Nonstandard case-specific techniques may be needed based on imaging, as described in cases 1 and 2.

Adequate imaging can facilitate the surgeons' ability to anticipate possible postoperative complications. Case 1 describes tumors near the conduction system and interatrial septum, including Bachmann's bundle, and case 2 describes tumors requiring significant atrial wall resections. Both cases can result in postoperative bradycardia or heart block, which may require pacemaker insertion.

Right heart myxomas are also atypical and rare.8 Case 3 involves an asymptomatic woman with an incidental large right atrial myxoma obstructing her tricuspid valve as seen in Figure 3. Large right-sided cardiac tumors can require deviation from standard bicaval cannulation due to risk of embolization if manipulated and poor exposure if located too close to the right atrial–inferior vena caval junction. Such tumors may require femoral venous cannulation. Additionally, large mobile tumors that obstruct the atrioventicular valves can lead to sudden death.3 This risk must be appreciated by the operative team prior to surgery to prevent death should sudden significant obstruction occur and rapid cardiac bypass be required.

Conclusion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References

These 3 cases highlight the importance of preoperative TEE imaging. The imaging is crucial for surgical planning, allowing the surgeon to determine the optimal technical approach. Atypical morphology can be anticipated and a surgical plan adapted to accommodate patient specific anatomy. Should a TEE be unable to delineate important anatomical relationships, cardiac MRI may be necessary to definitively define the patient's anatomy. Additionally, the aforementioned technical changes significantly modify preoperative patient counseling, because the possibilities of death, conduction abnormalities, cardiac reconstruction with biologic or other materials, and femoral vessel cannulation must be adequately discussed to provide a truly informed and consented patient.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case Report 1
  5. Discussion
  6. Conclusion
  7. References
  • 1.
    Parissis JT, Zezas S, Sfiras N, et al. An atypical left atrial myxoma causing intracavitary pressure gradient and typical diastolic transmitral flow of severe mitral stenosis. Int J Cardiol. 2005;102: 165167.
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    Sadeghi N, Sadeghi S, Karimi A. Mitral valve recurrence of a left atrial myxoma. Eur J Cardiothorac Surg. 2002;21:568573.
  • 3.
    McCarthy PM, Piehler JM, Schaff HV, et al. The significance of multiple, recurrent, and “complex” cardiac myxomas. J Thorac Cardiovasc Surg 1986;91:389396.
  • 4.
    Erkut B, Kocogullari CU, Arslan S, et al. An atypically localized atrial myxoma: a case report. Heart Surg Forum. 2007;10: E202E204.
  • 5.
    Duran NE, Ozkan M. Left atrial myxoma with atypical localization[in Turkish]. Turk Kardiyol Dern Ars. 2008;36:256258.
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    Charokopos NA, Rouska E, Pliakos C, et al. Atypical atrial myxomas in two asymptomatic patients: a case report. Cardiovasc Ultrasound. 2009;7:45.
  • 7.
    Oliveira R, Branco L, Galrinho A, et al. Cardiac myxoma: a 13-year experience in echocardiographic diagnosis. Rev Port Cardiol. 2010;29:10871100.
  • 8.
    Stevens LM, Lapierre H, Pellerin M, et al. Atrial versus biatrial approaches for cardiac myxomas. Interact Cardiovasc Thorac Surg. 2003;2:521525.