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Ascending aortic obstruction of retrograde coronary blood flow in aortic atresia
BRIEF COMIMUNICATIONS
Ascending retrograde atresia
aortic obstruction of coronary blood flow in aortic
Ronald L. van der Horst, M.D., and Alois R. Hastneiter, M.D. Chicago,
Ill.
Impairment of coronary arterial blood supply may be an important mechanism of early deatb in aortic atresia. To our knowledge, however, hemodynamic evidence of potential obstruction to coronary blood flow-i.e., the demonstration of a retrograde pressure gradient between the descending and ascending aorta-has not been previously described in aortic atresia. This hemodynamic phenomenon of “reversed coarctation” of the aorta appears to corroborate the high prevalence of anatomic obstruction reported by pathologists. While hemodynamic obstruction may be a frequent occurrence in aortic atresia, this requires further documentation. A 3.2 kg infant presented at 4% months of age with tachypnea since birth and a failure to thrive. At cardiac
From the Section Center.
of Pediatric
Cardiology,
University
Supported in part Medical Research
by the University of Illinois Grant (2-54-39-66-3-14).
of Illinois
Foundation
Medical
Goodenberger
Reprint requests: Ronald L. van der Horst, M.D., Pediatric Cardiology, University of Illinois Hospital, 840 S. Wood St., Chicago, IL 60612.
catheterization, there was marked increase in oxygen saturation from 52 per cent in the superior vena cava and right atrium to 72 per cent in the right ventricle, pulmonary artery, and descending aorta. A catheter inserted through the femoral artery was manipulated to the ascending aorta and was then pulled back. Pressure in the ascending aorta was 66/45 mm Hg and in the descending aorta it was 100/50 mm Hg: i.e., a 34 mm Hg “reversed” peak systolic pressure gradient was present between these two anatomic sites (Fig. 1). The pressures were identical in the main pulmonary artery and the descending aorta. Angiography confirmed the diagnosis of aortic valve atresia with hypoplasia of the ascending and transverse aortic arch, a normal mitral valve and left ventricle, and a large ventricular septal defect and patent ductus arteriosus. The infant rema.ined in intractable heart failure and died at 5% months of age. An autopsy was not performed. The uniformly fatal outcome of infants with aortic atresia still poses a challenge for palliation. While few infants have been operated upon’-’ and the use of prostaglandin E, to maintain ductal patency offers hope, the prognosis for survival has not yet been substantially improved. As suggested by Doty,G adequate coronary blood flow appears to be a critical feature for survival. Thus, recognition of possible obstruction to retrograde blood flow into the ascending aorta and coronary arteries is important. That obstruction exists between the transverse aortic arch and the descending aorta is well recog-
Fig. 1. Pull-back pressure tracing in an infant with aortic significantly lower than the descending aortic pressure. OOOZ-8703/81/030345
+ 02$00.20/O
0 1981
The
C. V. Mosby
Co.
atresia.
The ascending
aortic
pressure
is
345
346
Brief
communications
nized by angiography7 and pathology.’ It has been described in three fourths of autopsied specimens.* The obstruction usually consists of the presence of a ridge or medial curtain protruding toward the aortic lumen at the ductal or preductal level. In addition, infants with aortic atresia have a diminutive ascending aorta which is potentially obstructive; the average internal diameter at the aortic root is 2.3 mm.s Quantitative correlation of the aortic root caliber between pathologic studies and Mmode echocardiography has been poor thus far”; twodimensional echocardiography may show better agreement. There is as yet no clear evidence that the small caliber of the proximal aorta interferes with coronary artery perfusion. It has been suggested that the hypoplastic ascending aorta in aortic atresia may be an adequate channel to provide myocardial oxygen and nutritional requirements during fetal growth.“’ However, the presence of a long narrow high-resistance channel may interfere with coronary blood flow after birth. Reduction in coronary blood flow resulting from constriction of the ductus arteriosus and/or the increased resistance to retrograde ascending aortic blood flow is likely to influence myoeardial contractility and significantly impair the performance of the pressure and volume overloaded right ventricle in aortic atresia. Death. in our patient occurred at a considerably older age than is usual in aortic atresia. For this reason, the possibility of progression of obstruction at the coarcted site can be entertained. Since the usual catheterization of infants with aortic atresia does not include retrograde aortic catheterization, it is not known if severe aortic obstruction occurs at an earlier age. The present report supports the concept that the size of the ascending and transverse aorta resulting in obstruction to retrograde coronary arterial Aow may be crucial in the prognosis of infants with aortic atresia. Thus surgical palliation may require modified techniques to overcome impairment of coronary blood flow. REFERENCES 1.
2.
3.
4.
5.
6. 7.
Doty DB, Knott HW: Hypoplastic left heart syndrome. Experience with an operation to establish functionally normal circulation. J Thorac Cardiovasc Surg 74:624, 1977. Freedom RW, Dische MR, Rowe RD: Conal anatomy in aortic atresia, ventricular septal defect, and normally developed left ventricle. AM HEART J 94:689, 1977. Levitsky S, van der Horst RL, Hastreiter AR, Eckner FA, Bennett, EJ: Surgical palliation in aortic atresia. J Thorac Cardiovasc Surg 79:456, 1980. Mohri H, Horiuchi T, Haneda K, Sato S, Khato 0, Ohmi H, Isbizawa E, Kagawa Y, Fukuda M, Yoshida Y, Shima T: Surgical treatment for hypoplastic left heart syndrome. Case report. J Thorac Cardiovasc Surg 78:223. 1979. Norwodd WI, Kirklin JK, Semdeis SP: Hypoplastic left heart syndrome. Experience with palliative surgery. Am J Cardiol 45:87, 1980. Doty DB: Aortic atresia (Editorial). J Thorac Cardiovasc Surg 79:462, 1980. Farooki ZO, Henry JG, Green EW: Echocardiographic spectrum of the hypoplastic left heart syndrome. A clinico-
8.
9.
10.
pathologic correlation in 19 newborns. Am J Cardiol38:337, 1976. Van Rueden TJ, Knight L, Moller JH, Edwards JE: Coarctation of the aorta associated with aortic valve atresia. Circulation 52951, 1975. Bass JL, Ben-Shachar G, Edwards JE: Comparison of M-mode echocardiography and pathologic findings in the hypoplastic left heart syndrome.\m J Cardiol45:79, 1980. Rudolph AM: Congenital diseases of the beart. Chicago, 1974, Year Book Medical Publishers, Inc, p 559.
Myopotential inhibition of demand pacemakers: Detection by ambulatory electrocardiography Lawrence J. Jacobs, M.D., Jay S. Kerzner, Morton A. Diamond, M.D., and Charles L. Sprung, M.D. Hollywood, FZa.
M.D.,
Accurate interpretation of ambulatory electrocardicgrams (Holter monitors) requires an awareness of various potentially misleading artifacts. These range from easily recognizable technical disturbances to subtle distortions that may mimic arrhythmias. Among the latter, “pseudo” atria1 fibrillation, “pseudo” ventricular tachycardia, and “pseudo” atrioventricular block have been reported.’ Although artifacts often foster imprecise diagnosis, certain noncardiac signals may, on occasion, reflect true abnormalities. We report the unexpected recognition, on a Holter monitor, of pacemaker suppression by myopotentials, after we closely scrutinized an “artifact” that had been initially dismissed as serendipitous. Because of advanced atrioventricular block causing syncope, a 66-year-old man underwent implantation of a Med-Cor demand pacemaker with a unipolar endocardial lead (Model 3784). Lightheadedness recurred postoperatively, however, and was usually associated with activities involving arm exercise, such as lawn mowing or lifting packages. Twenty-four-hour ambulatory electrocardiography revealed intermittent ventricular asystole, coinciding with the patient’s dizzy spells. Each asystolic period was also associated with high-frequency baseline osciilations, at fit regarded as artifact (Fig. 1). On closer scrutiny, however, it was discerned that every period of pacemaker malfunction demonstrated these signals, but that these “artifacts” were not observed in other parts of the recording. The diagnosis of skeletal muscle-induced pacemaker inhibition was entertained and then confirmed when the patient performed isometric arm exercise under direct electrocardiographic monitoring. This precipitated faintness, reproduced the myopotential artifact, and inhibited the pacemaker (Fig. 2). The patient became From the Medicine.
Department
Reprint requests: FL 33021.
Lawrence
000%8703/81/030346
of Medicine, J. Jacobs,
+ 02$00.20/O
University M.D.,
of
Miami
4490 Sheridan
0 1981 The
School
of
St., Hollywood,
C. V. Mosby
Co.
Ascending retrograde atresia
aortic obstruction of coronary blood flow in aortic
Ronald L. van der Horst, M.D., and Alois R. Hastneiter, M.D. Chicago,
Ill.
Impairment of coronary arterial blood supply may be an important mechanism of early deatb in aortic atresia. To our knowledge, however, hemodynamic evidence of potential obstruction to coronary blood flow-i.e., the demonstration of a retrograde pressure gradient between the descending and ascending aorta-has not been previously described in aortic atresia. This hemodynamic phenomenon of “reversed coarctation” of the aorta appears to corroborate the high prevalence of anatomic obstruction reported by pathologists. While hemodynamic obstruction may be a frequent occurrence in aortic atresia, this requires further documentation. A 3.2 kg infant presented at 4% months of age with tachypnea since birth and a failure to thrive. At cardiac
From the Section Center.
of Pediatric
Cardiology,
University
Supported in part Medical Research
by the University of Illinois Grant (2-54-39-66-3-14).
of Illinois
Foundation
Medical
Goodenberger
Reprint requests: Ronald L. van der Horst, M.D., Pediatric Cardiology, University of Illinois Hospital, 840 S. Wood St., Chicago, IL 60612.
catheterization, there was marked increase in oxygen saturation from 52 per cent in the superior vena cava and right atrium to 72 per cent in the right ventricle, pulmonary artery, and descending aorta. A catheter inserted through the femoral artery was manipulated to the ascending aorta and was then pulled back. Pressure in the ascending aorta was 66/45 mm Hg and in the descending aorta it was 100/50 mm Hg: i.e., a 34 mm Hg “reversed” peak systolic pressure gradient was present between these two anatomic sites (Fig. 1). The pressures were identical in the main pulmonary artery and the descending aorta. Angiography confirmed the diagnosis of aortic valve atresia with hypoplasia of the ascending and transverse aortic arch, a normal mitral valve and left ventricle, and a large ventricular septal defect and patent ductus arteriosus. The infant rema.ined in intractable heart failure and died at 5% months of age. An autopsy was not performed. The uniformly fatal outcome of infants with aortic atresia still poses a challenge for palliation. While few infants have been operated upon’-’ and the use of prostaglandin E, to maintain ductal patency offers hope, the prognosis for survival has not yet been substantially improved. As suggested by Doty,G adequate coronary blood flow appears to be a critical feature for survival. Thus, recognition of possible obstruction to retrograde blood flow into the ascending aorta and coronary arteries is important. That obstruction exists between the transverse aortic arch and the descending aorta is well recog-
Fig. 1. Pull-back pressure tracing in an infant with aortic significantly lower than the descending aortic pressure. OOOZ-8703/81/030345
+ 02$00.20/O
0 1981
The
C. V. Mosby
Co.
atresia.
The ascending
aortic
pressure
is
345
346
Brief
communications
nized by angiography7 and pathology.’ It has been described in three fourths of autopsied specimens.* The obstruction usually consists of the presence of a ridge or medial curtain protruding toward the aortic lumen at the ductal or preductal level. In addition, infants with aortic atresia have a diminutive ascending aorta which is potentially obstructive; the average internal diameter at the aortic root is 2.3 mm.s Quantitative correlation of the aortic root caliber between pathologic studies and Mmode echocardiography has been poor thus far”; twodimensional echocardiography may show better agreement. There is as yet no clear evidence that the small caliber of the proximal aorta interferes with coronary artery perfusion. It has been suggested that the hypoplastic ascending aorta in aortic atresia may be an adequate channel to provide myocardial oxygen and nutritional requirements during fetal growth.“’ However, the presence of a long narrow high-resistance channel may interfere with coronary blood flow after birth. Reduction in coronary blood flow resulting from constriction of the ductus arteriosus and/or the increased resistance to retrograde ascending aortic blood flow is likely to influence myoeardial contractility and significantly impair the performance of the pressure and volume overloaded right ventricle in aortic atresia. Death. in our patient occurred at a considerably older age than is usual in aortic atresia. For this reason, the possibility of progression of obstruction at the coarcted site can be entertained. Since the usual catheterization of infants with aortic atresia does not include retrograde aortic catheterization, it is not known if severe aortic obstruction occurs at an earlier age. The present report supports the concept that the size of the ascending and transverse aorta resulting in obstruction to retrograde coronary arterial Aow may be crucial in the prognosis of infants with aortic atresia. Thus surgical palliation may require modified techniques to overcome impairment of coronary blood flow. REFERENCES 1.
2.
3.
4.
5.
6. 7.
Doty DB, Knott HW: Hypoplastic left heart syndrome. Experience with an operation to establish functionally normal circulation. J Thorac Cardiovasc Surg 74:624, 1977. Freedom RW, Dische MR, Rowe RD: Conal anatomy in aortic atresia, ventricular septal defect, and normally developed left ventricle. AM HEART J 94:689, 1977. Levitsky S, van der Horst RL, Hastreiter AR, Eckner FA, Bennett, EJ: Surgical palliation in aortic atresia. J Thorac Cardiovasc Surg 79:456, 1980. Mohri H, Horiuchi T, Haneda K, Sato S, Khato 0, Ohmi H, Isbizawa E, Kagawa Y, Fukuda M, Yoshida Y, Shima T: Surgical treatment for hypoplastic left heart syndrome. Case report. J Thorac Cardiovasc Surg 78:223. 1979. Norwodd WI, Kirklin JK, Semdeis SP: Hypoplastic left heart syndrome. Experience with palliative surgery. Am J Cardiol 45:87, 1980. Doty DB: Aortic atresia (Editorial). J Thorac Cardiovasc Surg 79:462, 1980. Farooki ZO, Henry JG, Green EW: Echocardiographic spectrum of the hypoplastic left heart syndrome. A clinico-
8.
9.
10.
pathologic correlation in 19 newborns. Am J Cardiol38:337, 1976. Van Rueden TJ, Knight L, Moller JH, Edwards JE: Coarctation of the aorta associated with aortic valve atresia. Circulation 52951, 1975. Bass JL, Ben-Shachar G, Edwards JE: Comparison of M-mode echocardiography and pathologic findings in the hypoplastic left heart syndrome.\m J Cardiol45:79, 1980. Rudolph AM: Congenital diseases of the beart. Chicago, 1974, Year Book Medical Publishers, Inc, p 559.
Myopotential inhibition of demand pacemakers: Detection by ambulatory electrocardiography Lawrence J. Jacobs, M.D., Jay S. Kerzner, Morton A. Diamond, M.D., and Charles L. Sprung, M.D. Hollywood, FZa.
M.D.,
Accurate interpretation of ambulatory electrocardicgrams (Holter monitors) requires an awareness of various potentially misleading artifacts. These range from easily recognizable technical disturbances to subtle distortions that may mimic arrhythmias. Among the latter, “pseudo” atria1 fibrillation, “pseudo” ventricular tachycardia, and “pseudo” atrioventricular block have been reported.’ Although artifacts often foster imprecise diagnosis, certain noncardiac signals may, on occasion, reflect true abnormalities. We report the unexpected recognition, on a Holter monitor, of pacemaker suppression by myopotentials, after we closely scrutinized an “artifact” that had been initially dismissed as serendipitous. Because of advanced atrioventricular block causing syncope, a 66-year-old man underwent implantation of a Med-Cor demand pacemaker with a unipolar endocardial lead (Model 3784). Lightheadedness recurred postoperatively, however, and was usually associated with activities involving arm exercise, such as lawn mowing or lifting packages. Twenty-four-hour ambulatory electrocardiography revealed intermittent ventricular asystole, coinciding with the patient’s dizzy spells. Each asystolic period was also associated with high-frequency baseline osciilations, at fit regarded as artifact (Fig. 1). On closer scrutiny, however, it was discerned that every period of pacemaker malfunction demonstrated these signals, but that these “artifacts” were not observed in other parts of the recording. The diagnosis of skeletal muscle-induced pacemaker inhibition was entertained and then confirmed when the patient performed isometric arm exercise under direct electrocardiographic monitoring. This precipitated faintness, reproduced the myopotential artifact, and inhibited the pacemaker (Fig. 2). The patient became From the Medicine.
Department
Reprint requests: FL 33021.
Lawrence
000%8703/81/030346
of Medicine, J. Jacobs,
+ 02$00.20/O
University M.D.,
of
Miami
4490 Sheridan
0 1981 The
School
of
St., Hollywood,
C. V. Mosby
Co.