A Five-Chambered Heart: Rare Coronary Artery Anomaly with Fistula Draining into a Separate Interventricular Cavity Samir M. Ali, MD, Henrik Egeblad, MD, Fritz Efsen, MD, and Jens M0gelvang, MD, Copenhagen, Denmark
The combination of color flow Doppler imaging, contrast echocardiography, magnetic resonance imaging, and coronary arteriography documented the presence of a right coronary artery fistula that opened into a separate cavity in the anterior part of the interventricular septum in a 32-year-old man. Although a traumatic origin could not be excluded, the abnormality was most likely a congenital anomaly. Because there were no significant symptoms and no signs of hemodynamic burden on the heart, a conservative management was decided and no complications occurred during 3 years of follow-up. So far the literature includes only one similar case described by autopsy findings. (JAM Soc EcHOCARDIOGR 1992;5:451-5.)
Coronary artery fistulas are rare abnormalities. An incidence of0.12% was found in a study of 126,595 consecutive patients who underwent coronary arteriography.1 In 95% of the cases coronary artery fistulas are congenital, whereas a traumatic origin is likely in 5%. Occasionally coronary artery fistulas are found in combination with ventricular or coronary artery aneurysms. 2 We report the findings in a patient with a dilated .and tortuous right coronary artery that opened into a large independent cavity in the interventricular septum. So far this abnormality has only been described in a necropsy study. 3
CASE REPORT
The patient was a 32-year-old man who had palpitations during emotional stress but otherwise showed no symptoms. Ten years earlier he had been involved in a traffic accident but did not recall any chest injury. No earlier medical record was available. When he was seen in our department, physical examination was normal apart from a grade 4/6 machinery murmur with maximum intensity at the lower left sternal From Medical Department B and Department of Radiology X, Cardiovascular Section, Rigshospitalet and MR Imaging Department, Hvidovre Hospital, University Hospitals of Copenhagen. Reprint requests: Samir Ali, MD, Medical Department B, Rigshospitalet, DK-2100 Copenhagen 0, Denmark. 27/l/37990
border. Blood pressure was 100/60 mm Hg. Electrocardiogram (ECG) showed sinus rhythm with normal QRS complexes but 7 mV deeply negative T waves in VI to v4. Chest X-ray examination was normal. No explanation of the murmur was found by conventional two-dimensional echocardiography, which was interpreted as showing an unusually prominent septomarginal trabecula or possibly a tumor crossing through the anterior part of the right ventricle (Figure 1). A Doppler study was not performed at this time. Catheterization of the right side of the heart showed normal pressures and no sign of left-to-right shunt. Palpation with the catheter and ventriculography indicated obliteration of the anterior part of the right ventricle. Endomyocardial biopsy from the suspected tumor was performed by guidance of two-dimensional echocardiography, but histologic examination showed normal myocardium. Left heart pressures and left ventricular ventriculography were normal. Coronary arteriography showed a normal left coronary artery. The right coronary artery was severely dilated and tortuous with unexpectedly slow flow in the light of the dilation. Contrast medium appeared with low intensity in a poorly delineated anteroapical cavity (Figure 2). These findings prompted another echocardiographic study combined with color flow Doppler imaging. A careful examination from many views revealed that the anterior part of the interventricular septum contained an independent cavity with a diameter of 4 em and with continuous counter451
452
Ali et al.
Journal of the American Society of Echocardiography
Figure 1 Two-dimensional echocardiogram in the standard apical four-chamber view showing an abnormal cavity (C) embedded in the peripheral part of the interventricular septum. The drainage channel is seen in cross section behind the cavity (arrow). The irregular part of the interventricular septum posteriorly to the abnormal cavity was initially suspected to be a prominent septomarginal trabecula or a myocardial tumor. R V, Right ventricle; LV, left ventricle; RA, right atrium; LA, left atrium.
clockwise flow in the apical four-chamber view. No communication with the heart cavities, aorta, or pulmonary artery could be demonstrated. However, a large fistula opened from the inferoapical wall into the abnormal cavity (Figure 3). Continuous wave Doppler recording in alignment with the fistula showed a gradient of 60 rnrn Hg from the fistula to the cavity in diastole and reverse flow in systole, also with a gradient of approximately 60 rnrn Hg (Figure 3). A tubular structure with a diameter of 3 to 4 rnrn was located behind and below the sac in the septum and appeared to serve as drainage (Figure 1). Here, a low-frequency rumbling sound and biphasic flow in posterior direction could be recorded by means of pulsed Doppler examination. Coronary arteriography was repeated with saline solution contrast echocardiography. Injection in the left coronary artery lead to the appearance of few bubbles in the left ventricle, probably through Thebesian veins. Right coronary artery injection confirmed dilation of the artery with a diameter of 0.8 em. Through the fistula, bubbles slowly filled the
abnormal cavity in the interventricular septum. The bubbles exhibited slow counter-clockwise flow in the sac in the four-chamber view and drained through the tubular structure below the cavity. Some bubbles remained circulating in the cavity for up to 5 minutes. No bubbles appeared in the atria, ventricles, or aorta. Magnetic resonance imaging confirmed the presence of an enlarged and tortuous right coronary artery and an abnormal cavity with a diameter of 4 1/z em embedded in the septum. Exercise ECG showed a normal functional capacity and no ECG changes. Myocardial stress scintigraphy did not reveal ischemia either reversible or irreversible. No arrhythmias were observed during 4 days of continuous monitoring. All peripheral pulses were normal and computed tomography of the brain with intravenous injection of contrast medium did not reveal any cerebrovascular malformation. At follow-up 3 years after the diagnosis of the murmur, the clinical and echocardiographic presentation was unchanged although the patient's palpitations had disappeared.
Volume 5 Number 4 July-August 1992
Rare coronary artery anomaly 453
Figure 2 Right coronary arteriogram (90-degree right lateral projection) showing dilated and tortuous artery ending in a vaguely defined cavity.
DISCUSSION
Coronary artery fistulas are commonly revealed in childhood but some cases remain undiscovered for many years. The awareness of a possible coronary artery fistula should therefore also be high in adult cardiology when a patient has a continuous murmur and an abnormal ECG. Angina pectoris or signs of left-to-right shunt may be diagnostic clues in the presence of a large fistula. Th\ recent echocardiographic literature has documented the usefulness of Doppler echocardiography, contrast echocardiography, and particularly color Doppler imaging in pa4 9 tients with coronary artery fistulas. · Large coronary artery fistulas are readily revealed by color Doppler echocardiography, but suspicion of the diagnosis needs careful examination . The location of coronary fistulas are not confined to standard views (Figure 3) . The murmur and the ECG in our patient arouse suspicion of a sinus V alsalva aneurysm or an arteriovenous fistula. However, the primary echocardio-
gram with no Doppler study was misinterpreted, leading to endomyocardial biopsy because of a vague suspicion of a right ventricular tumor. Usually a coronary artery fistula is an isolated malformation with direct communication between a coronary artery branch and a cardiac chamber. Occasionally coronary artery fistulas may be associated 2 with arterial or ventricular aneurysms, but opening of a coronary artery fistula into an independent abnormal cavity is a very unusual finding . A careful review of the literature revealed only one corresponding case; here the autopsy findings in a 55-year-old 3 patient with known hypertension were reported. The patient died suddenly, and autopsy showed a ruptured aneurysm of the basilar artery with massive subarachnoid hemorrhage. Examination of the heart showed a peculiar 4 x 4 X 5 em sac in the apical part of the septum. A dilated, tortuous circumflex coronary artery opened into this cavity. The sac was separated entirely from both ventricles but drained into a channel located behind the sac. Apparently,
journal of the American Society of Echocardiography
454 Ali et al.
Figure 3 Oblique view with the transducer located near the antero-inferior border of the cavity (C) with a scanning plane almost perpendicular to Figure l. The scanning plane intersects the dilated tortuous right coronary artery (RCA) inferiorly to the abnormal cavity (C), the interventricular septum (IVS) and the left ventricle (LV) (cf. Figure 1). In the upper panel the colors reveal antegrade flow in RCA in diastole and retrograde flow in systole. With slight angulation of the transducer (lower panel), the opening of the fistula into the cavity is dem-
onstrated. Continuous wave Doppler recording guided by the color-coded echocardiogram shows antegrade flow from the fistula to the cavity in diastole and retrograde flow in systole in both cases with a gradient of approximately 60 mm Hg.
the patient had been without cardiac symptoms, but a heart murmur had been known since the age of 18 years. The authors considered the sac a dilated part of a coronary artery fistula.
A hydatid cyst might have been suspected from the two-dimensional echocardiographic image of our patient, 10 but blood flow is not seen in hydatid cysts. Although a definite cause of the malformation in our
Volume 5 Number 4 July-August 1992
patient could not be established, it is likely that the sac represented an aneurysm or pseudoaneurysm on the right coronary artery or on a minor arteriovenous fistula. As the cavity drained into a large channel directed towards the coronary sinus, it is also possible to consider the cavity as a diverticulum on the coronary sinus. u The severely enlarged and tortuous right coronary artery contrasted with the absence of left-to-right shunt and with the slow flow in the artery. However, near closure of a large coronary arteriovenous fistula has previously been reported. 12 A traumatic origin of the cardiac abnormality was considered. However, there was no definite earlier chest trauma in our patient, and the report of a corresponding anatomic finding in another patient made a congenital origin more likely. 3 In the previously reported patient, the murmur had been recognized early in life and the patient had no cardiac symptoms until he died 37 years later from a ruptured cerebral aneurysm. In our patient diastolic flow from the artery into the sac and reverse flow in systole was the apparent explanation of the continuous murmur. This flow pattern can be explained by the alternating relaxation and contraction of the myocardium surrounding the sac. The patient had no significant symptoms, and in spite of the electrocardiographic findings the abnormality did not produce any detectable ischemia or hemodynamic burden on the heart. No sign of other vascular malformations were demonstrated. A conservative management was therefore decided and the 3-year follow-up confirmed an eventless course. Our report illustrates the importance of color Doppler echocardiography in patients with unclarified murmurs. The technique proved very useful for characterization of the bizarre cardiovascular pathoanatomy and pathophysiology of the patient. Despite uncertain cause of the anomaly and the severely abnormal auscultation and ECG, the results of the combined examinations and the history of the previously reported patient suggested a congenital malformation with a good prognosis. Continuous follow-up with color Doppler echocardiography will be
Rare coronary artery anomaly
455
carried out. Repeated invasive examination and open-heart operation are to be considered if symptoms or signs of ischemia or significant left-to-right shunt should occur.
REFERENCES l. Yamanaka 0, Hobbs R. Coronary artery anomalies in
2.
3. 4. 5.
6.
7. 8.
9. 10.
11.
12.
126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21:28-40. Ludomirsky A, O'Laughlin MP, Reul GJ, Mullins CE. Congenital aneurysm of the right coronary artery with fistula connection to the right atrium. Am Heart J 1990;119: 672-5. Knoblich R, Rawson AJ. Arteriovenous fistula of the heart. Am Heart J 1956;52:474-81. Nishihimi T, Oku H, Hirota K, et al. Right and left coronary artery to left ventricle fistula detected by color Doppler flow mapping. Am Heart J 1987;114:890-4. Kimball T, Daniels S, Meyer R, Knilans T, Plowden J, Schwartz D. Color flow mapping in the diagnosis of coronary artery fistula in the neonate: benefits and limitations. Am Heart J 1989;117:968-71. Velvis H, Schmidt KG, Silverman NH, Turley K. Diagnosis of coronary artery fistula by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging. JAm Coli Cardiol 1989;14:968-76. Shakudo M, Yoshikawa], Yoshida K, Yamaura Y. Non-invasive diagnosis of coronary artery fistula by color Doppler flow mapping. JAm Coli Cardiol1989;13:1572-7. Miyatake K, Okamoto M, Kinoshita N, Fusejima K, Sakakibara H, Nimura Y. Doppler echocardiographic features of coronary arteriovenous fistula. Complementary roles of cross sectional echocardiography and the Doppler technique. Br Heart J 1984;51:508-18. Cooper M, Bernstein D, Silverman N. Recognition of left coronary artery fistula to the left and right ventricles by contrast echocardiography. JAm Coli Cardiol 1985;6:923-6. Oliver JM, Sotillo JF, Dominguez FJ, et al. Two-dimensional echocardiographic features of echinococcosis of the heart and great vessels. Clinical and surgical implications. Circulation 1988;78:327-37. Guiraudon GM, Guiraudon CM, Klein GJ, Sharma AD, Yee R. The coronary sinus diverticulum: a pathologic entity associated with the Wolf-Parkinson-White syndrome. Am J Cardiol 1988;62:733-5. Shubrooks SJ, Naggar CZ. Spontaneous near closure of coronary artery fistula. Circulation 1978;57: 197-9.
The combination of color flow Doppler imaging, contrast echocardiography, magnetic resonance imaging, and coronary arteriography documented the presence of a right coronary artery fistula that opened into a separate cavity in the anterior part of the interventricular septum in a 32-year-old man. Although a traumatic origin could not be excluded, the abnormality was most likely a congenital anomaly. Because there were no significant symptoms and no signs of hemodynamic burden on the heart, a conservative management was decided and no complications occurred during 3 years of follow-up. So far the literature includes only one similar case described by autopsy findings. (JAM Soc EcHOCARDIOGR 1992;5:451-5.)
Coronary artery fistulas are rare abnormalities. An incidence of0.12% was found in a study of 126,595 consecutive patients who underwent coronary arteriography.1 In 95% of the cases coronary artery fistulas are congenital, whereas a traumatic origin is likely in 5%. Occasionally coronary artery fistulas are found in combination with ventricular or coronary artery aneurysms. 2 We report the findings in a patient with a dilated .and tortuous right coronary artery that opened into a large independent cavity in the interventricular septum. So far this abnormality has only been described in a necropsy study. 3
CASE REPORT
The patient was a 32-year-old man who had palpitations during emotional stress but otherwise showed no symptoms. Ten years earlier he had been involved in a traffic accident but did not recall any chest injury. No earlier medical record was available. When he was seen in our department, physical examination was normal apart from a grade 4/6 machinery murmur with maximum intensity at the lower left sternal From Medical Department B and Department of Radiology X, Cardiovascular Section, Rigshospitalet and MR Imaging Department, Hvidovre Hospital, University Hospitals of Copenhagen. Reprint requests: Samir Ali, MD, Medical Department B, Rigshospitalet, DK-2100 Copenhagen 0, Denmark. 27/l/37990
border. Blood pressure was 100/60 mm Hg. Electrocardiogram (ECG) showed sinus rhythm with normal QRS complexes but 7 mV deeply negative T waves in VI to v4. Chest X-ray examination was normal. No explanation of the murmur was found by conventional two-dimensional echocardiography, which was interpreted as showing an unusually prominent septomarginal trabecula or possibly a tumor crossing through the anterior part of the right ventricle (Figure 1). A Doppler study was not performed at this time. Catheterization of the right side of the heart showed normal pressures and no sign of left-to-right shunt. Palpation with the catheter and ventriculography indicated obliteration of the anterior part of the right ventricle. Endomyocardial biopsy from the suspected tumor was performed by guidance of two-dimensional echocardiography, but histologic examination showed normal myocardium. Left heart pressures and left ventricular ventriculography were normal. Coronary arteriography showed a normal left coronary artery. The right coronary artery was severely dilated and tortuous with unexpectedly slow flow in the light of the dilation. Contrast medium appeared with low intensity in a poorly delineated anteroapical cavity (Figure 2). These findings prompted another echocardiographic study combined with color flow Doppler imaging. A careful examination from many views revealed that the anterior part of the interventricular septum contained an independent cavity with a diameter of 4 em and with continuous counter451
452
Ali et al.
Journal of the American Society of Echocardiography
Figure 1 Two-dimensional echocardiogram in the standard apical four-chamber view showing an abnormal cavity (C) embedded in the peripheral part of the interventricular septum. The drainage channel is seen in cross section behind the cavity (arrow). The irregular part of the interventricular septum posteriorly to the abnormal cavity was initially suspected to be a prominent septomarginal trabecula or a myocardial tumor. R V, Right ventricle; LV, left ventricle; RA, right atrium; LA, left atrium.
clockwise flow in the apical four-chamber view. No communication with the heart cavities, aorta, or pulmonary artery could be demonstrated. However, a large fistula opened from the inferoapical wall into the abnormal cavity (Figure 3). Continuous wave Doppler recording in alignment with the fistula showed a gradient of 60 rnrn Hg from the fistula to the cavity in diastole and reverse flow in systole, also with a gradient of approximately 60 rnrn Hg (Figure 3). A tubular structure with a diameter of 3 to 4 rnrn was located behind and below the sac in the septum and appeared to serve as drainage (Figure 1). Here, a low-frequency rumbling sound and biphasic flow in posterior direction could be recorded by means of pulsed Doppler examination. Coronary arteriography was repeated with saline solution contrast echocardiography. Injection in the left coronary artery lead to the appearance of few bubbles in the left ventricle, probably through Thebesian veins. Right coronary artery injection confirmed dilation of the artery with a diameter of 0.8 em. Through the fistula, bubbles slowly filled the
abnormal cavity in the interventricular septum. The bubbles exhibited slow counter-clockwise flow in the sac in the four-chamber view and drained through the tubular structure below the cavity. Some bubbles remained circulating in the cavity for up to 5 minutes. No bubbles appeared in the atria, ventricles, or aorta. Magnetic resonance imaging confirmed the presence of an enlarged and tortuous right coronary artery and an abnormal cavity with a diameter of 4 1/z em embedded in the septum. Exercise ECG showed a normal functional capacity and no ECG changes. Myocardial stress scintigraphy did not reveal ischemia either reversible or irreversible. No arrhythmias were observed during 4 days of continuous monitoring. All peripheral pulses were normal and computed tomography of the brain with intravenous injection of contrast medium did not reveal any cerebrovascular malformation. At follow-up 3 years after the diagnosis of the murmur, the clinical and echocardiographic presentation was unchanged although the patient's palpitations had disappeared.
Volume 5 Number 4 July-August 1992
Rare coronary artery anomaly 453
Figure 2 Right coronary arteriogram (90-degree right lateral projection) showing dilated and tortuous artery ending in a vaguely defined cavity.
DISCUSSION
Coronary artery fistulas are commonly revealed in childhood but some cases remain undiscovered for many years. The awareness of a possible coronary artery fistula should therefore also be high in adult cardiology when a patient has a continuous murmur and an abnormal ECG. Angina pectoris or signs of left-to-right shunt may be diagnostic clues in the presence of a large fistula. Th\ recent echocardiographic literature has documented the usefulness of Doppler echocardiography, contrast echocardiography, and particularly color Doppler imaging in pa4 9 tients with coronary artery fistulas. · Large coronary artery fistulas are readily revealed by color Doppler echocardiography, but suspicion of the diagnosis needs careful examination . The location of coronary fistulas are not confined to standard views (Figure 3) . The murmur and the ECG in our patient arouse suspicion of a sinus V alsalva aneurysm or an arteriovenous fistula. However, the primary echocardio-
gram with no Doppler study was misinterpreted, leading to endomyocardial biopsy because of a vague suspicion of a right ventricular tumor. Usually a coronary artery fistula is an isolated malformation with direct communication between a coronary artery branch and a cardiac chamber. Occasionally coronary artery fistulas may be associated 2 with arterial or ventricular aneurysms, but opening of a coronary artery fistula into an independent abnormal cavity is a very unusual finding . A careful review of the literature revealed only one corresponding case; here the autopsy findings in a 55-year-old 3 patient with known hypertension were reported. The patient died suddenly, and autopsy showed a ruptured aneurysm of the basilar artery with massive subarachnoid hemorrhage. Examination of the heart showed a peculiar 4 x 4 X 5 em sac in the apical part of the septum. A dilated, tortuous circumflex coronary artery opened into this cavity. The sac was separated entirely from both ventricles but drained into a channel located behind the sac. Apparently,
journal of the American Society of Echocardiography
454 Ali et al.
Figure 3 Oblique view with the transducer located near the antero-inferior border of the cavity (C) with a scanning plane almost perpendicular to Figure l. The scanning plane intersects the dilated tortuous right coronary artery (RCA) inferiorly to the abnormal cavity (C), the interventricular septum (IVS) and the left ventricle (LV) (cf. Figure 1). In the upper panel the colors reveal antegrade flow in RCA in diastole and retrograde flow in systole. With slight angulation of the transducer (lower panel), the opening of the fistula into the cavity is dem-
onstrated. Continuous wave Doppler recording guided by the color-coded echocardiogram shows antegrade flow from the fistula to the cavity in diastole and retrograde flow in systole in both cases with a gradient of approximately 60 mm Hg.
the patient had been without cardiac symptoms, but a heart murmur had been known since the age of 18 years. The authors considered the sac a dilated part of a coronary artery fistula.
A hydatid cyst might have been suspected from the two-dimensional echocardiographic image of our patient, 10 but blood flow is not seen in hydatid cysts. Although a definite cause of the malformation in our
Volume 5 Number 4 July-August 1992
patient could not be established, it is likely that the sac represented an aneurysm or pseudoaneurysm on the right coronary artery or on a minor arteriovenous fistula. As the cavity drained into a large channel directed towards the coronary sinus, it is also possible to consider the cavity as a diverticulum on the coronary sinus. u The severely enlarged and tortuous right coronary artery contrasted with the absence of left-to-right shunt and with the slow flow in the artery. However, near closure of a large coronary arteriovenous fistula has previously been reported. 12 A traumatic origin of the cardiac abnormality was considered. However, there was no definite earlier chest trauma in our patient, and the report of a corresponding anatomic finding in another patient made a congenital origin more likely. 3 In the previously reported patient, the murmur had been recognized early in life and the patient had no cardiac symptoms until he died 37 years later from a ruptured cerebral aneurysm. In our patient diastolic flow from the artery into the sac and reverse flow in systole was the apparent explanation of the continuous murmur. This flow pattern can be explained by the alternating relaxation and contraction of the myocardium surrounding the sac. The patient had no significant symptoms, and in spite of the electrocardiographic findings the abnormality did not produce any detectable ischemia or hemodynamic burden on the heart. No sign of other vascular malformations were demonstrated. A conservative management was therefore decided and the 3-year follow-up confirmed an eventless course. Our report illustrates the importance of color Doppler echocardiography in patients with unclarified murmurs. The technique proved very useful for characterization of the bizarre cardiovascular pathoanatomy and pathophysiology of the patient. Despite uncertain cause of the anomaly and the severely abnormal auscultation and ECG, the results of the combined examinations and the history of the previously reported patient suggested a congenital malformation with a good prognosis. Continuous follow-up with color Doppler echocardiography will be
Rare coronary artery anomaly
455
carried out. Repeated invasive examination and open-heart operation are to be considered if symptoms or signs of ischemia or significant left-to-right shunt should occur.
REFERENCES l. Yamanaka 0, Hobbs R. Coronary artery anomalies in
2.
3. 4. 5.
6.
7. 8.
9. 10.
11.
12.
126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21:28-40. Ludomirsky A, O'Laughlin MP, Reul GJ, Mullins CE. Congenital aneurysm of the right coronary artery with fistula connection to the right atrium. Am Heart J 1990;119: 672-5. Knoblich R, Rawson AJ. Arteriovenous fistula of the heart. Am Heart J 1956;52:474-81. Nishihimi T, Oku H, Hirota K, et al. Right and left coronary artery to left ventricle fistula detected by color Doppler flow mapping. Am Heart J 1987;114:890-4. Kimball T, Daniels S, Meyer R, Knilans T, Plowden J, Schwartz D. Color flow mapping in the diagnosis of coronary artery fistula in the neonate: benefits and limitations. Am Heart J 1989;117:968-71. Velvis H, Schmidt KG, Silverman NH, Turley K. Diagnosis of coronary artery fistula by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging. JAm Coli Cardiol 1989;14:968-76. Shakudo M, Yoshikawa], Yoshida K, Yamaura Y. Non-invasive diagnosis of coronary artery fistula by color Doppler flow mapping. JAm Coli Cardiol1989;13:1572-7. Miyatake K, Okamoto M, Kinoshita N, Fusejima K, Sakakibara H, Nimura Y. Doppler echocardiographic features of coronary arteriovenous fistula. Complementary roles of cross sectional echocardiography and the Doppler technique. Br Heart J 1984;51:508-18. Cooper M, Bernstein D, Silverman N. Recognition of left coronary artery fistula to the left and right ventricles by contrast echocardiography. JAm Coli Cardiol 1985;6:923-6. Oliver JM, Sotillo JF, Dominguez FJ, et al. Two-dimensional echocardiographic features of echinococcosis of the heart and great vessels. Clinical and surgical implications. Circulation 1988;78:327-37. Guiraudon GM, Guiraudon CM, Klein GJ, Sharma AD, Yee R. The coronary sinus diverticulum: a pathologic entity associated with the Wolf-Parkinson-White syndrome. Am J Cardiol 1988;62:733-5. Shubrooks SJ, Naggar CZ. Spontaneous near closure of coronary artery fistula. Circulation 1978;57: 197-9.
