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Left Ventricular Outflow Tract to Right Atrial Fistula After Aortic Valve Replacement
Left Ventricular Outflow Tract to Right Atrial Fistula After Aortic Valve Replacement Kathirvel Subramaniam, MD,* and Lawrence Wei, MD†
A
ORTIC VALVE REPLACEMENT and surgical procedures on the aorta can be complicated with fistula formation between the left side of the heart (the aorta and the left ventricle) and the right atrium.1,2 Patients with such fistulous communication may be asymptomatic or present with nonspecific symptoms. Diagnosis may be missed or delayed unless there is a high index of suspicion for this complication. Echocardiography provides definitive diagnosis in most of these patients.3 Anesthesiologists practicing intraoperative transesophageal echocardiography (TEE) should be aware of the diagnostic features and differential diagnosis of this complication. The fistula can be misinterpreted as tricuspid or aortic regurgitation by echocardiography. Early surgical treatment is recommended to prevent the development of right-sided congestive heart failure. The diagnosis and management of a patient who developed a left ventricular outflow tract (LVOT) to right atrial (RA) fistula after mechanical aortic valve replacement are described. CASE REPORT A 60-year-old man with a past medical history of hypertension, hyperlipidemia, and aortic stenosis underwent #22 St Jude mechanical aortic valve replacement (St Jude Medical Inc, St Paul, MN) 5 years earlier. He had no coronary artery disease, and his right-sided heart pressures were normal by cardiac catheterization preoperatively. He developed fever, chills, and night sweats 2.5 years later, and a blood culture grew group D streptococcus at that time. Transthoracic echocardiography (TTE) showed trace aortic insufficiency (AI), severe tricuspid regurgitation (TR) with an estimated right ventricular systolic pressure (RVSP) of 86 mmHg, and dilated hypokinetic right ventricle. TEE performed after 6 weeks of antibiotic therapy showed trace TR and mild AI. The right atrium was mildly dilated, and estimated RVSP was 33 mmHg. He never had any cardiovascular complaints and was followed up with yearly TTE. TTE performed 2 years earlier showed moderate AI and moderate TR (RVSP ⫽ 40 mmHg). A more recent TEE examination performed 2 months before surgery showed a defect in the aortic root and a high-velocity jet originating from the aortic root to the right atrium during both systole and diastole. The aortic valve prosthesis was well seated with trace AI, and there was biatrial and right ventricular enlargement. Computed tomography angiography (CTA) identified the exact location of a fistulous communication between the LVOT and the RA (Figs 1 and 2). The patient was referred to a cardiac surgeon who believed that the fistula should be surgically closed to prevent the development of right-heart failure from the left-to-right shunt. Coro-
From the Departments of *Cardiac Anesthesiology and †Surgery, University of Pittsburgh–Presbyterian University Hospital, Pittsburgh, PA. Address reprint requests to Kathirvel Subramaniam, MD, Department of Anesthesiology, C-Wing, Presbyterian University Hospital, 200 Lothrop Street, Pittsburgh, PA 15213. E-mail: subramaniamk@ upmc.edu © 2009 Elsevier Inc. All rights reserved. 1053-0770/09/2303-0015$36.00/0 doi:10.1053/j.jvca.2008.11.017 Key words: fistula, right atrium, left ventricular outflow 360
Fig 1. A CTA image of the heart showing left ventricular outflowright atrial fistula. RV, right ventricle; LV, left ventricle; AV prosthesis, aortic valve prosthesis.
nary angiography showed no evidence of significant CAD. He was listed for redo sternotomy and closure of the fistula. After induction of general anesthesia, a TEE examination was performed. Two-dimensional echocardiography showed biatrial and right ventricular enlargement with good biventricular function. Color Doppler imaging showed a color-flow jet above the septal leaflet of the tricuspid valve by a midesophageal 4-chamber view (Fig 3 and Video 1 [supplementary videos accompanying this article are available online]) and confirmed the fistula between the LVOT close to the aortic annulus and the right atrium (deep transgastric long-axis view, Fig 4 and Video 2). The aortic valve prosthesis was well seated with no vegetations or paravalvular leak. The tricuspid annulus was enlarged (49 mm, measured with a midesophageal 4-chamber view) with no significant TR. Transatrial primary surgical closure of the fistula was performed under cardiopulmonary bypass (CPB). Ascending aortic and bicaval venous cannulations were performed to initiate CPB. Antegrade cardioplegia was used. The right atrium was opened, and communication with the LVOT was identified. There was no evidence of current or previous endocarditis. The aortic valve sutures had traversed the tricuspid annulus. The septal and anterior leaflets were freed from these sutures. The defect was closed with pledgeted sutures, and the leaflets were reattached to the annulus. Tricuspid annuloplasty was then performed. Postbypass TEE and postoperative TTE (performed on the third postoperative day) showed no evidence of a residual LVOT-to-RA fistula by color Doppler imaging. Immediately postbypass, he was in complete heart block with junctional escape rhythm (40 beats/min). He was ventricularly paced with epicardial wires for 2 days to observe whether his rhythm came back. Because he did not return back to sinus rhythm, a cardiology consult was requested. A dual-chamber perma-
Journal of Cardiothoracic and Vascular Anesthesia, Vol 23, No 3 (June), 2009: pp 360-363
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Fig 2. A CTA image of the heart showing LVOT-RA fistula. RA, right atrium; RV, right ventricle; LV, left ventricle; LA, left atrium; IVS, interventricular septum; MV, mitral valve.
nent pacemaker was inserted, and he was discharged home on the seventh postoperative day. He had a follow-up visit a month later and is progressing well. DISCUSSION
Fistulae from the aorta and LV to the RA can be congenital (known as Gerbode-type defect) or acquired.4 The acquired
fistula can result from trauma; myocardial infarction; infective endocarditis; aortic dissections; and surgical procedures involving the mitral valve, ventricular septum, aortic valve, and aortic root.3,5-9 The acquired defect occurs between the LV and the RA through the superior aspect of the membranous (atrioventricular) septum above the insertion of the tricuspid valve (TV) in the membranous septum. The more common congenital type is a communication between the LV and the RA through a defect in the interventricular septum and the septal leaflet of the TV. Therefore, unlike the acquired defect, this is an indirect LV-to-RA shunt because the blood first travels between the left and right ventricles below the tricuspid valve and then is quickly shunted through a defect (ie, cleft) in the TV to the RA (Fig 5).10 The timing of presentation of the postoperative fistula varies from the immediate postoperative period to months or years after the initial surgical procedure.1,2,11 Patients may be completely asymptomatic, and the mode of presentation varies from slow gradual onset of right-sided congestive heart failure to sudden hemodynamic compromise based on the size of the shunt.11,12 The etiology of the fistula in this patient was unclear. The patient had a history of probable endocarditis, although no evidence of endocarditis (aortic root abscess, paravalvular leak, or vegetations) was detected by echocardiography at any point of his illness. It is possible that the defect was present even from the time of aortic valve replacement as indicated by intraoperative surgical findings. Direct injury to the membranous septum or extensive debridement of calci-
Fig 3. A transesophageal echocardiographic image: a midesophageal 4-chamber view showing the color Doppler flow of the LVOT-to-RA fistula above the tricuspid valve.
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Fig 4. A transesophageal echocardiographic image: a deep transgastric long-axis view showing the color Doppler flow from the LVOT to the right atrium above the aortic annulus.
fied aortic valve could have resulted in the fistula between the LVOT and the RA.12,13 A color-flow fistula jet can be misdiagnosed as TR or AI by echocardiographers. The initial TTE reported severe TR, and it is more likely that the echocardiographers had mistaken the fistula jet as TR because both occur during systole. The jet from the fistula can be mistaken for TR in the midesophageal 4-chamber view but usually can be differentiated by using the deep transgastric long-axis view. Measurement of fistula jet velocity using continuous-wave Doppler (CWD) will help in differentiating the high-velocity LVOT-RA jet from the lowvelocity TR jet (unless it is associated with severe pulmonary hypertension). Aligning the CWD to the jet can be challenging as in the present patient, and improper alignment will underestimate the velocity. The color-flow jet of the fistula also can be confused with AI. The AI jet is timed with diastole, whereas the fistula jet appears both in systole and diastole. The LVOTto-RA jet appears predominantly in early systole as in this patient, but the aorta-to-RA jet can be seen during both systole and diastole because of the pressure gradient between the chambers during both phases of the cardiac cycle.1 Color Doppler echocardiographic imaging has replaced angiography as the diagnostic test in these patients. TEE has better sensitivity and specificity in the diagnosis of fistulae associated with prosthetic valves and infective endocarditis compared with TTE.14,15 TEE provided the diagnosis in most of the cases reported in the literature. In this patient, TEE provided clues to the fistula, which was later confirmed by CTA. Multidetector row CTA of the aorta is a noninvasive diagnostic
method that provides accurate preoperative diagnosis in the most complicated aortic pathology. The advantages include shorter imaging time, greater axial coverage, motion artifact suppression, improved resolution, decreased contrast dose (one
Fig 5. A schematic representation of 2 types of Gerbode defects. (A), acquired type; (B), congenital type; RA, right atrium; RV, right ventricle; LV, left ventricle; LA, left atrium; IVS, interventricular septum; MV, mitral valve; TV, tricuspid valve. (Reprinted with permission from CTSNet, Inc.10)
LVOT TO RA FISTULA
363
half to one third the dose required for angiography) and realtime interactive 3-dimensional display facilities on work stations.16 The disadvantage of CTA is the lack of dynamic information such as aortic valve function in which TEE plays an important role. LVOT-RA fistulae can be treated by primary surgical closure with pledgetted sutures, Gore-Tex patch (Gore Medical Products, Newark, DE), pericardial patch, or Teflon patch (DuPont, Wilmington, DE). Fistulae associated with infective endocarditis were closed by a pericardial patch or Gore-Tex patch.2,17 Noninfective fistulae were closed with a
Teflon patch.9,12 There is one report in the literature in which the patient was managed with observation and followed up with serial echocardiograms without surgical treatment.1 Postbypass TEE examination helps to rule out any residual shunts or valvular regurgitations and evaluate the ventricular function. The present patient had mild TR, but the tricuspid annulus was dilated (49 mm). Tricuspid valve repair was performed because intraoperative TEE may underestimate the severity of TR. Varying degrees of heart block are common after this surgery because of the closeness of the conduction system to the site of surgery.
REFERENCES 1. Ramasubbu K, Coselli J, Zoghbi WA: Unusual complication of aortic root reconstruction with sparing of the aortic valve: Left ventricular outflow tract to right atrial fistula. J Am Soc Echocardiogr 19:469.e5-469.e9, 2006 2. Hilberath JN, Shook D, Shernan SK, et al: Left ventricular outflow tract to right atrial fistula diagnosed by intraoperative transesophageal echocardiography. Anesth Analg 104:261-262, 2007 3. Dzwonczyk T, Davidson WR Jr: The spectrum of left ventricularright atrial communications in the adult: Essentials of echocardiographic assessment. J Am Soc Echocardiogr 8:263-269, 1995 4. Eroglu S, Sade E, Bozbas H, et al: Echocardiographic diagnosis of left ventricular-right atrial communication (Gerbode-type defect) in an adult with chronic renal failure: A case report. Eur J Echocardiogr 9:314-315, 2008 5. McNalley MC, Sugg WL: Traumatic communication between the aorta, right atrium, and left atrium. A case report. J Thorac Cardiovasc Surg 54:150-152, 1967 6. Moaref AR, Aslani A, Zamirian M, et al: Left ventricular to right atrial communication (Gerbode-type defect) after mitral valve replacement. J Am Soc Echocardiogr 21:408.e1-408.e2, 2008 7. Ozay B, Okmen AS, Idiz M, et al: Aorta-right atrial fistula after VSD operation. Thorac Cardiovasc Surg 55:122-123, 2007 8. Alphonso N, Dhital K, Chambers J, et al: Gerbode’s defect resulting from infective endocarditis. Eur J Cardiothorac Surg 23:844846, 2003 9. Frank MW, Stout MJ: Acute aortic dissection with an aorta-right atrium fistula. Tex Heart Inst J 30:335-336, 2003
10. Tatewaki H, Alesnik JP, Morales DLS: Acquired left ventricle to right atrial shunt (Gerbode defect) and massive pulmonary embolus. Available at: www.ctsnet.org/sections/clinicalresources/clinicalcases/ article-14.html. Accessed October 5, 2008 11. Ozer N, Deniz A, Atalar E, et al: Aorta-right atrial fistula: A rare complication of prosthetic aortic valvular endocarditis. J Am Soc Echocardiogr 20:538.e5-538.e6, 2007 12. Frigg C, Cassina T, Siclari F, et al: Unusual complication after aortic valve replacement. Interact Cardiovasc Thorac Surg 7:149-150, 2008 13. Silverman NA, Sethi GK, Scott SM: Acquired left ventricularright atrial fistula following aortic valve replacement. Ann Thorac Surg 30:482-486, 1980 14. Elian D, Di Segni E, Kaplinsky E, et al: Acquired left ventricular-right atrial communication caused by infective endocarditis detected by transesophageal echocardiography: Case report and review of the literature. J Am Soc Echocardiogr 8:108-110, 1995 15. Karalis DG, Bansal RC, Hauck AJ, et al: Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications. Circulation 86: 353-362, 1992 16. Yu T, Zhu X, Tang L, et al: Review of CT angiography of aorta. Radiol Clin North Am 45:461-483, 2007 17. Joyce FS, McCarthy PM, Stewart WJ, et al: Left ventricular to right atrial fistula after aortic homograft replacement for endocarditis. Eur J Cardiothorac Surg 8:100-102, 1994
A
ORTIC VALVE REPLACEMENT and surgical procedures on the aorta can be complicated with fistula formation between the left side of the heart (the aorta and the left ventricle) and the right atrium.1,2 Patients with such fistulous communication may be asymptomatic or present with nonspecific symptoms. Diagnosis may be missed or delayed unless there is a high index of suspicion for this complication. Echocardiography provides definitive diagnosis in most of these patients.3 Anesthesiologists practicing intraoperative transesophageal echocardiography (TEE) should be aware of the diagnostic features and differential diagnosis of this complication. The fistula can be misinterpreted as tricuspid or aortic regurgitation by echocardiography. Early surgical treatment is recommended to prevent the development of right-sided congestive heart failure. The diagnosis and management of a patient who developed a left ventricular outflow tract (LVOT) to right atrial (RA) fistula after mechanical aortic valve replacement are described. CASE REPORT A 60-year-old man with a past medical history of hypertension, hyperlipidemia, and aortic stenosis underwent #22 St Jude mechanical aortic valve replacement (St Jude Medical Inc, St Paul, MN) 5 years earlier. He had no coronary artery disease, and his right-sided heart pressures were normal by cardiac catheterization preoperatively. He developed fever, chills, and night sweats 2.5 years later, and a blood culture grew group D streptococcus at that time. Transthoracic echocardiography (TTE) showed trace aortic insufficiency (AI), severe tricuspid regurgitation (TR) with an estimated right ventricular systolic pressure (RVSP) of 86 mmHg, and dilated hypokinetic right ventricle. TEE performed after 6 weeks of antibiotic therapy showed trace TR and mild AI. The right atrium was mildly dilated, and estimated RVSP was 33 mmHg. He never had any cardiovascular complaints and was followed up with yearly TTE. TTE performed 2 years earlier showed moderate AI and moderate TR (RVSP ⫽ 40 mmHg). A more recent TEE examination performed 2 months before surgery showed a defect in the aortic root and a high-velocity jet originating from the aortic root to the right atrium during both systole and diastole. The aortic valve prosthesis was well seated with trace AI, and there was biatrial and right ventricular enlargement. Computed tomography angiography (CTA) identified the exact location of a fistulous communication between the LVOT and the RA (Figs 1 and 2). The patient was referred to a cardiac surgeon who believed that the fistula should be surgically closed to prevent the development of right-heart failure from the left-to-right shunt. Coro-
From the Departments of *Cardiac Anesthesiology and †Surgery, University of Pittsburgh–Presbyterian University Hospital, Pittsburgh, PA. Address reprint requests to Kathirvel Subramaniam, MD, Department of Anesthesiology, C-Wing, Presbyterian University Hospital, 200 Lothrop Street, Pittsburgh, PA 15213. E-mail: subramaniamk@ upmc.edu © 2009 Elsevier Inc. All rights reserved. 1053-0770/09/2303-0015$36.00/0 doi:10.1053/j.jvca.2008.11.017 Key words: fistula, right atrium, left ventricular outflow 360
Fig 1. A CTA image of the heart showing left ventricular outflowright atrial fistula. RV, right ventricle; LV, left ventricle; AV prosthesis, aortic valve prosthesis.
nary angiography showed no evidence of significant CAD. He was listed for redo sternotomy and closure of the fistula. After induction of general anesthesia, a TEE examination was performed. Two-dimensional echocardiography showed biatrial and right ventricular enlargement with good biventricular function. Color Doppler imaging showed a color-flow jet above the septal leaflet of the tricuspid valve by a midesophageal 4-chamber view (Fig 3 and Video 1 [supplementary videos accompanying this article are available online]) and confirmed the fistula between the LVOT close to the aortic annulus and the right atrium (deep transgastric long-axis view, Fig 4 and Video 2). The aortic valve prosthesis was well seated with no vegetations or paravalvular leak. The tricuspid annulus was enlarged (49 mm, measured with a midesophageal 4-chamber view) with no significant TR. Transatrial primary surgical closure of the fistula was performed under cardiopulmonary bypass (CPB). Ascending aortic and bicaval venous cannulations were performed to initiate CPB. Antegrade cardioplegia was used. The right atrium was opened, and communication with the LVOT was identified. There was no evidence of current or previous endocarditis. The aortic valve sutures had traversed the tricuspid annulus. The septal and anterior leaflets were freed from these sutures. The defect was closed with pledgeted sutures, and the leaflets were reattached to the annulus. Tricuspid annuloplasty was then performed. Postbypass TEE and postoperative TTE (performed on the third postoperative day) showed no evidence of a residual LVOT-to-RA fistula by color Doppler imaging. Immediately postbypass, he was in complete heart block with junctional escape rhythm (40 beats/min). He was ventricularly paced with epicardial wires for 2 days to observe whether his rhythm came back. Because he did not return back to sinus rhythm, a cardiology consult was requested. A dual-chamber perma-
Journal of Cardiothoracic and Vascular Anesthesia, Vol 23, No 3 (June), 2009: pp 360-363
LVOT TO RA FISTULA
361
Fig 2. A CTA image of the heart showing LVOT-RA fistula. RA, right atrium; RV, right ventricle; LV, left ventricle; LA, left atrium; IVS, interventricular septum; MV, mitral valve.
nent pacemaker was inserted, and he was discharged home on the seventh postoperative day. He had a follow-up visit a month later and is progressing well. DISCUSSION
Fistulae from the aorta and LV to the RA can be congenital (known as Gerbode-type defect) or acquired.4 The acquired
fistula can result from trauma; myocardial infarction; infective endocarditis; aortic dissections; and surgical procedures involving the mitral valve, ventricular septum, aortic valve, and aortic root.3,5-9 The acquired defect occurs between the LV and the RA through the superior aspect of the membranous (atrioventricular) septum above the insertion of the tricuspid valve (TV) in the membranous septum. The more common congenital type is a communication between the LV and the RA through a defect in the interventricular septum and the septal leaflet of the TV. Therefore, unlike the acquired defect, this is an indirect LV-to-RA shunt because the blood first travels between the left and right ventricles below the tricuspid valve and then is quickly shunted through a defect (ie, cleft) in the TV to the RA (Fig 5).10 The timing of presentation of the postoperative fistula varies from the immediate postoperative period to months or years after the initial surgical procedure.1,2,11 Patients may be completely asymptomatic, and the mode of presentation varies from slow gradual onset of right-sided congestive heart failure to sudden hemodynamic compromise based on the size of the shunt.11,12 The etiology of the fistula in this patient was unclear. The patient had a history of probable endocarditis, although no evidence of endocarditis (aortic root abscess, paravalvular leak, or vegetations) was detected by echocardiography at any point of his illness. It is possible that the defect was present even from the time of aortic valve replacement as indicated by intraoperative surgical findings. Direct injury to the membranous septum or extensive debridement of calci-
Fig 3. A transesophageal echocardiographic image: a midesophageal 4-chamber view showing the color Doppler flow of the LVOT-to-RA fistula above the tricuspid valve.
362
SUBRAMANIAM AND WEI
Fig 4. A transesophageal echocardiographic image: a deep transgastric long-axis view showing the color Doppler flow from the LVOT to the right atrium above the aortic annulus.
fied aortic valve could have resulted in the fistula between the LVOT and the RA.12,13 A color-flow fistula jet can be misdiagnosed as TR or AI by echocardiographers. The initial TTE reported severe TR, and it is more likely that the echocardiographers had mistaken the fistula jet as TR because both occur during systole. The jet from the fistula can be mistaken for TR in the midesophageal 4-chamber view but usually can be differentiated by using the deep transgastric long-axis view. Measurement of fistula jet velocity using continuous-wave Doppler (CWD) will help in differentiating the high-velocity LVOT-RA jet from the lowvelocity TR jet (unless it is associated with severe pulmonary hypertension). Aligning the CWD to the jet can be challenging as in the present patient, and improper alignment will underestimate the velocity. The color-flow jet of the fistula also can be confused with AI. The AI jet is timed with diastole, whereas the fistula jet appears both in systole and diastole. The LVOTto-RA jet appears predominantly in early systole as in this patient, but the aorta-to-RA jet can be seen during both systole and diastole because of the pressure gradient between the chambers during both phases of the cardiac cycle.1 Color Doppler echocardiographic imaging has replaced angiography as the diagnostic test in these patients. TEE has better sensitivity and specificity in the diagnosis of fistulae associated with prosthetic valves and infective endocarditis compared with TTE.14,15 TEE provided the diagnosis in most of the cases reported in the literature. In this patient, TEE provided clues to the fistula, which was later confirmed by CTA. Multidetector row CTA of the aorta is a noninvasive diagnostic
method that provides accurate preoperative diagnosis in the most complicated aortic pathology. The advantages include shorter imaging time, greater axial coverage, motion artifact suppression, improved resolution, decreased contrast dose (one
Fig 5. A schematic representation of 2 types of Gerbode defects. (A), acquired type; (B), congenital type; RA, right atrium; RV, right ventricle; LV, left ventricle; LA, left atrium; IVS, interventricular septum; MV, mitral valve; TV, tricuspid valve. (Reprinted with permission from CTSNet, Inc.10)
LVOT TO RA FISTULA
363
half to one third the dose required for angiography) and realtime interactive 3-dimensional display facilities on work stations.16 The disadvantage of CTA is the lack of dynamic information such as aortic valve function in which TEE plays an important role. LVOT-RA fistulae can be treated by primary surgical closure with pledgetted sutures, Gore-Tex patch (Gore Medical Products, Newark, DE), pericardial patch, or Teflon patch (DuPont, Wilmington, DE). Fistulae associated with infective endocarditis were closed by a pericardial patch or Gore-Tex patch.2,17 Noninfective fistulae were closed with a
Teflon patch.9,12 There is one report in the literature in which the patient was managed with observation and followed up with serial echocardiograms without surgical treatment.1 Postbypass TEE examination helps to rule out any residual shunts or valvular regurgitations and evaluate the ventricular function. The present patient had mild TR, but the tricuspid annulus was dilated (49 mm). Tricuspid valve repair was performed because intraoperative TEE may underestimate the severity of TR. Varying degrees of heart block are common after this surgery because of the closeness of the conduction system to the site of surgery.
REFERENCES 1. Ramasubbu K, Coselli J, Zoghbi WA: Unusual complication of aortic root reconstruction with sparing of the aortic valve: Left ventricular outflow tract to right atrial fistula. J Am Soc Echocardiogr 19:469.e5-469.e9, 2006 2. Hilberath JN, Shook D, Shernan SK, et al: Left ventricular outflow tract to right atrial fistula diagnosed by intraoperative transesophageal echocardiography. Anesth Analg 104:261-262, 2007 3. Dzwonczyk T, Davidson WR Jr: The spectrum of left ventricularright atrial communications in the adult: Essentials of echocardiographic assessment. J Am Soc Echocardiogr 8:263-269, 1995 4. Eroglu S, Sade E, Bozbas H, et al: Echocardiographic diagnosis of left ventricular-right atrial communication (Gerbode-type defect) in an adult with chronic renal failure: A case report. Eur J Echocardiogr 9:314-315, 2008 5. McNalley MC, Sugg WL: Traumatic communication between the aorta, right atrium, and left atrium. A case report. J Thorac Cardiovasc Surg 54:150-152, 1967 6. Moaref AR, Aslani A, Zamirian M, et al: Left ventricular to right atrial communication (Gerbode-type defect) after mitral valve replacement. J Am Soc Echocardiogr 21:408.e1-408.e2, 2008 7. Ozay B, Okmen AS, Idiz M, et al: Aorta-right atrial fistula after VSD operation. Thorac Cardiovasc Surg 55:122-123, 2007 8. Alphonso N, Dhital K, Chambers J, et al: Gerbode’s defect resulting from infective endocarditis. Eur J Cardiothorac Surg 23:844846, 2003 9. Frank MW, Stout MJ: Acute aortic dissection with an aorta-right atrium fistula. Tex Heart Inst J 30:335-336, 2003
10. Tatewaki H, Alesnik JP, Morales DLS: Acquired left ventricle to right atrial shunt (Gerbode defect) and massive pulmonary embolus. Available at: www.ctsnet.org/sections/clinicalresources/clinicalcases/ article-14.html. Accessed October 5, 2008 11. Ozer N, Deniz A, Atalar E, et al: Aorta-right atrial fistula: A rare complication of prosthetic aortic valvular endocarditis. J Am Soc Echocardiogr 20:538.e5-538.e6, 2007 12. Frigg C, Cassina T, Siclari F, et al: Unusual complication after aortic valve replacement. Interact Cardiovasc Thorac Surg 7:149-150, 2008 13. Silverman NA, Sethi GK, Scott SM: Acquired left ventricularright atrial fistula following aortic valve replacement. Ann Thorac Surg 30:482-486, 1980 14. Elian D, Di Segni E, Kaplinsky E, et al: Acquired left ventricular-right atrial communication caused by infective endocarditis detected by transesophageal echocardiography: Case report and review of the literature. J Am Soc Echocardiogr 8:108-110, 1995 15. Karalis DG, Bansal RC, Hauck AJ, et al: Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications. Circulation 86: 353-362, 1992 16. Yu T, Zhu X, Tang L, et al: Review of CT angiography of aorta. Radiol Clin North Am 45:461-483, 2007 17. Joyce FS, McCarthy PM, Stewart WJ, et al: Left ventricular to right atrial fistula after aortic homograft replacement for endocarditis. Eur J Cardiothorac Surg 8:100-102, 1994