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Right aortic arch with ruptured aneurysm of anomalous left subclavian artery
CASE REPORTS
Right Aortic Arch with Ruptured Aneurysm of Anomalous Left Subclavian Artery
STEVEN
H. DIKMAN,
MURRAY ALVIN
BARON,
MD
MD,
J. GORDON.
FACC
MD
New York, New York
An aneurysm In the anomalous left subciavian artery developed in an elderly woman with a right aortic arch and an aberrant left subclavian artery (lefl ligamentum arteriosum connected to the left common carotid artery). The aneurysm gradually enlarged, eventually rupturing with exsanguination. A progressive increase in the size of this aneurysm was associated with symptoms and anatomic findings consistent with the subclavian “steal” syndrome.
Aortic arch anomalies associated with an aberrant subclavian artery have been found with various anatomic and embryologic configurations’ and with diverse clinical presentations.2 In this report an unusual variant of this anomaly is described in an elderly woman who had been followed up by one of us for 24 years until her death. An aberrant left subclavian artery was the seat of an aneurysm that gradually enlarged and eventually ruptured with exsanguination. Moreover, a progressive increase in size of this aneurysm was associated with symptoms and anatomic findings consistent with the subclavian “steal” syndrome. Case Report
From the Mount Sinai Hospital and the Mount Sinai School of Medicine of the City University of New York, New York, N. Y. Manuscript accepted September 5, 1973. Address for reprints: Steven H. Dikman, MD. Deoartrnent of Patholoov. Mount Sinai Hospital. 5th’ Ave. and 100th St..-iew York, N. Y. 10629.’
This 77 year old woman was first seen at the age of 53 because of a sensation of heaviness in the substernal region that was fairly constant but seemed to be aggravated at meals. There was no actual pain or dysphagia and no cough or sputum production. Occasional transient hoarseness was noted. Physical examination was normal except for some diffuse enlargement of the thyroid gland. Blood pressure was 140/100 mm Hg and equal in both arms, the heart was not enlarged and there were no murmurs. A chest X-ray film (Fig. 1) revealed a right aortic arch that produced a sharp indentation on the posterior aspect of the esophagus, which indicated the presence of a posterior aortic diverticulum. This diverticulum represented the vestige of a left aortic arch. Over the ensuing years the patient had only minor nonspecific symptoms. At age 73 years an adenocarcinoma of the rectosigmoid was resected. Her chest X-ray film at this time revealed aneurysmal enlargement of the aortic diverticulum (Fig. 2A). During the next year she had symptoms suggestive of angina, and ST-T changes in the precordial leads indicative of myocardial ischemia. She also experienced intermittent hoarseness associated with paralysis of the right vocal cord. The right radial pulse was stronger than the left; the blood pressure in the right arm was 125/90 and in the left arm 110/90 mm Hg. At age 75 years she began to have spells of vertigo, sometimes accompanied by vomiting, that came on suddenly and subsided after 15 to 30 minutes. Neurologic examination was normal except for evidence of an organic mental syndrome. Although the aneurysm of the aorta was progressively enlarging (Fig. 2B), resection was not advised because of her mental status. Her symptoms remained essentially the same over the next 2 years until she died suddenly at home at age 77 years.
AugusllQ74
The Amorkan
Journal of CARDIOLOGY
Volume 34
245
ANEURYSM
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
FIGURE 1. Chest roentgenograms. 1947. A, in the frontal projection, the barium-filled esophagus and the trachea are displaced to the left by a right-sided aortic arch. The prominence in the region usually occupied by a normal aortic knob is caused by a diverticulum of the aortic arch that extends to the left behind the esophagus and protrudes beyond the bounds of the superior mediastinum (arrow). B. in the right anterior oblique view, the anterior displacement and the compression of the esophagus indicate the presence of a retroesophageal mass. This deform&y in conjunctiin with a right aortic arch is characteristic of a posterior aortic diverticulum. Although the diverticulum is large, it is within “normal limits” and does not I,epresent an aneurysm.
FIGURE 2. Chest roentgenograms. A, 1967. Over a 20 year period, the aottic diierticulum has gradually undergone aneurysmal dilatation. The wall of the aneurysm is calcified. The shadow of the descending aorta along the right side of the rnedttstinum (arrow) has not changed slgniflcantty in this time. B, 1969. Two years later, the aneurysm appears considerably larger, thereby indicating an accelerated growth and suggesting impending rupture.
246
August 1974
The Am&can
Jeurnat of CARDIOLOGY
Votume 34
ANEURYSM
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
FIGURE 3. Specimen of heart and major vessels wlth aneurysm of aberrant left subclavian artery (see text for explanation). A, anterior view. B, posterior view. Arrow points to site of rupture. A = aneurysm; AA = ascending aorta; AV = aberrant vessel: H = heart; LCA = left caroffl artery; LSA = left subcfavian artery: RCA = right carotid artery; RDA = right descending aorta; RSA = right subclavian artery; VA = vertebral artery.
Necropsy Findings The left pleural cavity contained 1,000 cc of blood. The heart weighed 290 g, and all chambers were dilated. The valves were normal. The base of the aorta, the ascending aorta and the coronary ostia were in normal position. The aorta arched over the right main bronchus and descended to the right of the midline until just above the diaphragm, where it crossed in front of the vertebral bodies to pass through a normal left-sided hiatus in the diaphragm (Fig. 3A). Four major branches emerged from the aortic arch (Fig.
3, A and B). The left common carotid artery was the most proximal branch and arose from the ascending aorta 6 cm from the root and slightly to the left of the midline. A well defined ligamenturn arteriosum connected this vessel with the left pulmonary artery (not shown in accompanying illustrations). Remnants of a right-sided ductus arteriosus were not found. The right common carotid artery originated 1.5 cm distal to the left carotid artery. The right subclavian artery, the third branch of the aortic arch, arose 1.5 cm distal to the right common carotid artery and coursed over the first rib into the right arm. The right vertebral ar-
FIGURE 4. Narrow opening (arrow) into aneurysm (A) from aberrant vessel.
August 1974
The American Journal of CARDIOLOGY
Volume 34
247
ANEURYSM
OF SUBCLAVIAN
ARTERY-OIKMAN
ET AL.
tery, thyrocervical trunk and internal mammary artery were all in their normal locations. The fourth branch of the aortic arch arose from its left posterior aspect 2 cm distal to the right subclavian artery, and coursed to the left behind the esophagus, displacing it anteriorly (Fig. 3B). The large aberrant artery (4 cm in diameter and 3.5 cm in length) entered a large saccular aneurysm (8 by 6.5 by 5
TRACHEt \ RCC
ESOPHAGUS I. )
cm) through a small (0.8 cm) opening (Fig. 3 and 4). The aneurysm occupied the apex of the left thoracic cavity and was partially covered by the collapsed upper pulmonary lobe. Portions of the wall were severely atherosclerotic and partially calcified. The aneurysm was almost completely occluded by extensive recent and old thrombi. An irregular 2 cm tear was found in an attenuated portion of the poste-
8
LCC
R
DORSAL AORTIC ROOT - SECHENTS 3 to 7
VENTRAL AGRTIC ROOT BETWEEN ARCHES IV L VI
FIGURE 5. Schematic drawings of anatomy. A, ventral view of Edwards’ hypothetic double arch and bilateral ductus arteriosi. The ascending and descending aorta are each depicted in the midline. A diagonal line indicates site of interruption to produce Figure 5C. B, normal conflluration. C, configuration in present case with right aortic arch, aberrant retroesophageal left subclavian artery showing ruptured aneurysm. A ligamentum arteriosum connects the left common carotid artery to the left pulmonary artery. A = aneurysm; LA = liimentum arteriosum: LCC = teft common carotid artery; LPA = left pulmonary artery; LS = Ieft subcfavtan artery; PT = pulmonary trunk; ACC = right common carotid artery; RPA = right pulmonary artery; RS = right subclavlan artery; V = vertebral artery; 8.9 = 8th and 9th dorsal intersegmental arteries. Figure 5A modified from Stewart et al.’ courtesy of authors and Charles C Thomas, Springfield, Ill.
248
Auguef 1974
The Amerken
Journal of CARDIOLOGY
Vdume 34
ANEURYSM
rior wall of the aneurysm (Fig. 3B). Through this opening, the aneurysm communicated with the large left hemothorax. The superior aspect of the aneurysm was fixed to the apex of the parietal pleura by fibrous adhesions. The left subclavian artery arose from the aneurysm near its junction with the aberrant aortic vessel (Fig. 3). As the subclavian artery coursed toward the left arm, it was draped over and partially incorporated into the wall of the aneurysm. The lumen of the subclavian artery was almost totally obliterated by compression from the aneurysm and by thrombi near its orifice. The vertebral artery was patent and appeared to be the major vessel .communicating with the left subclavian artery distal to the obstruction. The remainder of the thoracic and abdominal aorta showed moderate atheromatous change. The major branches of the descending aorta were normally located. The major venous systems within the thorax and abdomen were within normal limits.
Discussion Embryology: In the developing embryo, the fourth aortic arches are paired, one arch going to the left of the trachea and one to the right (Fig. 5A). Normally, the right arch disappears almost entirely, its remnant forming a portion of the right subclavian artery (Fig. 5B). If, instead, the left fourth arch regresses, and the right persists, the result is a right aortic arch. Depending on where the interruption of the left arch occurs, two different configurations can result. In the first, the branching of the great vessels is essentially a mirror image of the normal left arch. This type of right aortic arch is commonly associated with tetralogy of Fallot or a persistent truncus arteriosus.3 In the second type of right aortic arch, a portion of the embryonic left dorsal aorta persists as an aberrant vessel extending toward the left (Fig. 32). In this situation the left subclavian artery usually arises from remnants of the left dorsal aorta and appears as the fourth branch of the adult aortic arch. This type of right aortic arch is not associated with congenital heart disease and is almost always asymptomatic Although the aberrant vessel does indent the posteri-
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
or wall of the esophagus, dysphagia usually does not occur because of the mobility of the esophagus. The ductus arteriosus has been described in various locations when associated with a right aortic arch.’ In our case, the ductus connected the left common carotid artery with the left pulmonary artery. Since both vessels were in front of the trachea, a vascular ring did not result. Aortic aneurysm and subclavian “steal” syndrome: This case documents the .natural history of an aortic aneurysm. A life expectancy of less than 5 years is usually quoted for these aneurysms.4 However, a narrow orifice to a saccular aneurysm is unusual. In this case the narrowing may represent a coarctation that arose during the development of the left dorsal aorta. Degenerative changes in an intact vessel wall or in vestigial remnants of the proximal left aortic arch resulted in an aneurysm at this location. Despite the the relatively slow development of the lesion, the patient’s death was due to rupture. The location of the aneurysm created a possible complication not usually encountered with similar lesions of the aortic arch.5 Because of its posterior position and the anomalous origin of the left subclavian artery, the aneurysm compressed the vessel and .almost occluded it. Since the narrowing was upstream to the origin of the vertebral artery, the hemodynamic basis for the subclavian “steal” was created, a possible pathway of collateral flow to the distal left subclavian artery coursing through the right vertebral and basilar arteries, and down the left vertebral artery. Although this mechanism was not documented, such an acquired subclavian steal may have accounted for some of the patient’s vertigo and mental changes. Acknowledgment We gratefully acknowledge the valuable advice and comments of Dr. Lotte Strauss and the assistance of Dr. Benedicto, Mr. Norman Katz and Ms. I. Weinstock.
References Stewart JR, Kincald OW, Edwards JE: An Atlas of Vascular Rings and Related Malformations of the Aortic Arch System. Springfield, Ill., Charles C Thomas, 1984 Hudson REB: Cardiovascular Pathology, vol 2. Baltimore, Williims & Wilkins, 1965. p 2088-2092 D’Cruz IA, Talot C, Namln EP, el al: Right sided aorta. Part II. Right aortlc arch, right descending aorta, and associated anoma-
lies. Br Heart J 28:725-739, 1988 4. Crawford ES, DeBakey ME, Cooley DA, et al: Surgical considerations of aneurysms and atherosclerotic occlusive lesions of the aorta and major arteries. Postgrad Med 29:151-183, 1961 5. Bradley WG: Congenital aortic-arch abnormalities with the “subclavian-steal” pattern of blood flow. Br Heart J 28:718-720, 1966
August 1974
The Amerfcan Journal of CARDIOLOGY
Volume 34
249
Right Aortic Arch with Ruptured Aneurysm of Anomalous Left Subclavian Artery
STEVEN
H. DIKMAN,
MURRAY ALVIN
BARON,
MD
MD,
J. GORDON.
FACC
MD
New York, New York
An aneurysm In the anomalous left subciavian artery developed in an elderly woman with a right aortic arch and an aberrant left subclavian artery (lefl ligamentum arteriosum connected to the left common carotid artery). The aneurysm gradually enlarged, eventually rupturing with exsanguination. A progressive increase in the size of this aneurysm was associated with symptoms and anatomic findings consistent with the subclavian “steal” syndrome.
Aortic arch anomalies associated with an aberrant subclavian artery have been found with various anatomic and embryologic configurations’ and with diverse clinical presentations.2 In this report an unusual variant of this anomaly is described in an elderly woman who had been followed up by one of us for 24 years until her death. An aberrant left subclavian artery was the seat of an aneurysm that gradually enlarged and eventually ruptured with exsanguination. Moreover, a progressive increase in size of this aneurysm was associated with symptoms and anatomic findings consistent with the subclavian “steal” syndrome. Case Report
From the Mount Sinai Hospital and the Mount Sinai School of Medicine of the City University of New York, New York, N. Y. Manuscript accepted September 5, 1973. Address for reprints: Steven H. Dikman, MD. Deoartrnent of Patholoov. Mount Sinai Hospital. 5th’ Ave. and 100th St..-iew York, N. Y. 10629.’
This 77 year old woman was first seen at the age of 53 because of a sensation of heaviness in the substernal region that was fairly constant but seemed to be aggravated at meals. There was no actual pain or dysphagia and no cough or sputum production. Occasional transient hoarseness was noted. Physical examination was normal except for some diffuse enlargement of the thyroid gland. Blood pressure was 140/100 mm Hg and equal in both arms, the heart was not enlarged and there were no murmurs. A chest X-ray film (Fig. 1) revealed a right aortic arch that produced a sharp indentation on the posterior aspect of the esophagus, which indicated the presence of a posterior aortic diverticulum. This diverticulum represented the vestige of a left aortic arch. Over the ensuing years the patient had only minor nonspecific symptoms. At age 73 years an adenocarcinoma of the rectosigmoid was resected. Her chest X-ray film at this time revealed aneurysmal enlargement of the aortic diverticulum (Fig. 2A). During the next year she had symptoms suggestive of angina, and ST-T changes in the precordial leads indicative of myocardial ischemia. She also experienced intermittent hoarseness associated with paralysis of the right vocal cord. The right radial pulse was stronger than the left; the blood pressure in the right arm was 125/90 and in the left arm 110/90 mm Hg. At age 75 years she began to have spells of vertigo, sometimes accompanied by vomiting, that came on suddenly and subsided after 15 to 30 minutes. Neurologic examination was normal except for evidence of an organic mental syndrome. Although the aneurysm of the aorta was progressively enlarging (Fig. 2B), resection was not advised because of her mental status. Her symptoms remained essentially the same over the next 2 years until she died suddenly at home at age 77 years.
AugusllQ74
The Amorkan
Journal of CARDIOLOGY
Volume 34
245
ANEURYSM
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
FIGURE 1. Chest roentgenograms. 1947. A, in the frontal projection, the barium-filled esophagus and the trachea are displaced to the left by a right-sided aortic arch. The prominence in the region usually occupied by a normal aortic knob is caused by a diverticulum of the aortic arch that extends to the left behind the esophagus and protrudes beyond the bounds of the superior mediastinum (arrow). B. in the right anterior oblique view, the anterior displacement and the compression of the esophagus indicate the presence of a retroesophageal mass. This deform&y in conjunctiin with a right aortic arch is characteristic of a posterior aortic diverticulum. Although the diverticulum is large, it is within “normal limits” and does not I,epresent an aneurysm.
FIGURE 2. Chest roentgenograms. A, 1967. Over a 20 year period, the aottic diierticulum has gradually undergone aneurysmal dilatation. The wall of the aneurysm is calcified. The shadow of the descending aorta along the right side of the rnedttstinum (arrow) has not changed slgniflcantty in this time. B, 1969. Two years later, the aneurysm appears considerably larger, thereby indicating an accelerated growth and suggesting impending rupture.
246
August 1974
The Am&can
Jeurnat of CARDIOLOGY
Votume 34
ANEURYSM
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
FIGURE 3. Specimen of heart and major vessels wlth aneurysm of aberrant left subclavian artery (see text for explanation). A, anterior view. B, posterior view. Arrow points to site of rupture. A = aneurysm; AA = ascending aorta; AV = aberrant vessel: H = heart; LCA = left caroffl artery; LSA = left subcfavian artery: RCA = right carotid artery; RDA = right descending aorta; RSA = right subclavian artery; VA = vertebral artery.
Necropsy Findings The left pleural cavity contained 1,000 cc of blood. The heart weighed 290 g, and all chambers were dilated. The valves were normal. The base of the aorta, the ascending aorta and the coronary ostia were in normal position. The aorta arched over the right main bronchus and descended to the right of the midline until just above the diaphragm, where it crossed in front of the vertebral bodies to pass through a normal left-sided hiatus in the diaphragm (Fig. 3A). Four major branches emerged from the aortic arch (Fig.
3, A and B). The left common carotid artery was the most proximal branch and arose from the ascending aorta 6 cm from the root and slightly to the left of the midline. A well defined ligamenturn arteriosum connected this vessel with the left pulmonary artery (not shown in accompanying illustrations). Remnants of a right-sided ductus arteriosus were not found. The right common carotid artery originated 1.5 cm distal to the left carotid artery. The right subclavian artery, the third branch of the aortic arch, arose 1.5 cm distal to the right common carotid artery and coursed over the first rib into the right arm. The right vertebral ar-
FIGURE 4. Narrow opening (arrow) into aneurysm (A) from aberrant vessel.
August 1974
The American Journal of CARDIOLOGY
Volume 34
247
ANEURYSM
OF SUBCLAVIAN
ARTERY-OIKMAN
ET AL.
tery, thyrocervical trunk and internal mammary artery were all in their normal locations. The fourth branch of the aortic arch arose from its left posterior aspect 2 cm distal to the right subclavian artery, and coursed to the left behind the esophagus, displacing it anteriorly (Fig. 3B). The large aberrant artery (4 cm in diameter and 3.5 cm in length) entered a large saccular aneurysm (8 by 6.5 by 5
TRACHEt \ RCC
ESOPHAGUS I. )
cm) through a small (0.8 cm) opening (Fig. 3 and 4). The aneurysm occupied the apex of the left thoracic cavity and was partially covered by the collapsed upper pulmonary lobe. Portions of the wall were severely atherosclerotic and partially calcified. The aneurysm was almost completely occluded by extensive recent and old thrombi. An irregular 2 cm tear was found in an attenuated portion of the poste-
8
LCC
R
DORSAL AORTIC ROOT - SECHENTS 3 to 7
VENTRAL AGRTIC ROOT BETWEEN ARCHES IV L VI
FIGURE 5. Schematic drawings of anatomy. A, ventral view of Edwards’ hypothetic double arch and bilateral ductus arteriosi. The ascending and descending aorta are each depicted in the midline. A diagonal line indicates site of interruption to produce Figure 5C. B, normal conflluration. C, configuration in present case with right aortic arch, aberrant retroesophageal left subclavian artery showing ruptured aneurysm. A ligamentum arteriosum connects the left common carotid artery to the left pulmonary artery. A = aneurysm; LA = liimentum arteriosum: LCC = teft common carotid artery; LPA = left pulmonary artery; LS = Ieft subcfavtan artery; PT = pulmonary trunk; ACC = right common carotid artery; RPA = right pulmonary artery; RS = right subclavlan artery; V = vertebral artery; 8.9 = 8th and 9th dorsal intersegmental arteries. Figure 5A modified from Stewart et al.’ courtesy of authors and Charles C Thomas, Springfield, Ill.
248
Auguef 1974
The Amerken
Journal of CARDIOLOGY
Vdume 34
ANEURYSM
rior wall of the aneurysm (Fig. 3B). Through this opening, the aneurysm communicated with the large left hemothorax. The superior aspect of the aneurysm was fixed to the apex of the parietal pleura by fibrous adhesions. The left subclavian artery arose from the aneurysm near its junction with the aberrant aortic vessel (Fig. 3). As the subclavian artery coursed toward the left arm, it was draped over and partially incorporated into the wall of the aneurysm. The lumen of the subclavian artery was almost totally obliterated by compression from the aneurysm and by thrombi near its orifice. The vertebral artery was patent and appeared to be the major vessel .communicating with the left subclavian artery distal to the obstruction. The remainder of the thoracic and abdominal aorta showed moderate atheromatous change. The major branches of the descending aorta were normally located. The major venous systems within the thorax and abdomen were within normal limits.
Discussion Embryology: In the developing embryo, the fourth aortic arches are paired, one arch going to the left of the trachea and one to the right (Fig. 5A). Normally, the right arch disappears almost entirely, its remnant forming a portion of the right subclavian artery (Fig. 5B). If, instead, the left fourth arch regresses, and the right persists, the result is a right aortic arch. Depending on where the interruption of the left arch occurs, two different configurations can result. In the first, the branching of the great vessels is essentially a mirror image of the normal left arch. This type of right aortic arch is commonly associated with tetralogy of Fallot or a persistent truncus arteriosus.3 In the second type of right aortic arch, a portion of the embryonic left dorsal aorta persists as an aberrant vessel extending toward the left (Fig. 32). In this situation the left subclavian artery usually arises from remnants of the left dorsal aorta and appears as the fourth branch of the adult aortic arch. This type of right aortic arch is not associated with congenital heart disease and is almost always asymptomatic Although the aberrant vessel does indent the posteri-
OF SUBCLAVIAN
ARTERY-DIKMAN
ET AL.
or wall of the esophagus, dysphagia usually does not occur because of the mobility of the esophagus. The ductus arteriosus has been described in various locations when associated with a right aortic arch.’ In our case, the ductus connected the left common carotid artery with the left pulmonary artery. Since both vessels were in front of the trachea, a vascular ring did not result. Aortic aneurysm and subclavian “steal” syndrome: This case documents the .natural history of an aortic aneurysm. A life expectancy of less than 5 years is usually quoted for these aneurysms.4 However, a narrow orifice to a saccular aneurysm is unusual. In this case the narrowing may represent a coarctation that arose during the development of the left dorsal aorta. Degenerative changes in an intact vessel wall or in vestigial remnants of the proximal left aortic arch resulted in an aneurysm at this location. Despite the the relatively slow development of the lesion, the patient’s death was due to rupture. The location of the aneurysm created a possible complication not usually encountered with similar lesions of the aortic arch.5 Because of its posterior position and the anomalous origin of the left subclavian artery, the aneurysm compressed the vessel and .almost occluded it. Since the narrowing was upstream to the origin of the vertebral artery, the hemodynamic basis for the subclavian “steal” was created, a possible pathway of collateral flow to the distal left subclavian artery coursing through the right vertebral and basilar arteries, and down the left vertebral artery. Although this mechanism was not documented, such an acquired subclavian steal may have accounted for some of the patient’s vertigo and mental changes. Acknowledgment We gratefully acknowledge the valuable advice and comments of Dr. Lotte Strauss and the assistance of Dr. Benedicto, Mr. Norman Katz and Ms. I. Weinstock.
References Stewart JR, Kincald OW, Edwards JE: An Atlas of Vascular Rings and Related Malformations of the Aortic Arch System. Springfield, Ill., Charles C Thomas, 1984 Hudson REB: Cardiovascular Pathology, vol 2. Baltimore, Williims & Wilkins, 1965. p 2088-2092 D’Cruz IA, Talot C, Namln EP, el al: Right sided aorta. Part II. Right aortlc arch, right descending aorta, and associated anoma-
lies. Br Heart J 28:725-739, 1988 4. Crawford ES, DeBakey ME, Cooley DA, et al: Surgical considerations of aneurysms and atherosclerotic occlusive lesions of the aorta and major arteries. Postgrad Med 29:151-183, 1961 5. Bradley WG: Congenital aortic-arch abnormalities with the “subclavian-steal” pattern of blood flow. Br Heart J 28:718-720, 1966
August 1974
The Amerfcan Journal of CARDIOLOGY
Volume 34
249