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Nitroglycerin and methemoglobinemia
1004
LETTERS
102:1202-1208.
cross sectional echocardiography. Br Heart J 1983;
6. Mandelkorn IB. Wolf NM. SinnhS. Schechter IA, Kersh RI, Rodgkrs DM, Workman MB, Bentivoglio LG, La Porte SM, Meister SC. Intracoronary thrombusinnon-transmuralmyocardialinfarction and ili unstable angina pectoris. Am J Cordiol 1983;52:3-6.
50:421-431.
ment of the right ventricular (RV) outflow tract using a projection they define as “a new subcostal view.” This basic echocardiographic projection for studying the RV outflow tract in congential heart diseases is not new. In fact, it was previously reported by several other investigators.2-7 Terms that have been applied to thisview include “right NITROGLYCERIN ANDMETNEMOGLOBlNEMlA oblique subxiphoid view,“z,6 “subcostal RV inflow-apex-outflow plane”3 and “paracorThe recent report by Saxon and Silverman1 onalshort axis.‘14z5 Obviously the study of varconfirms our finding that intravenous nitroious malformations and .patients involves glycerin administered in standard doses is an slight variations of the same basic echocaruncommon cause of clinically significant elediographic scan plane. In particular, as vation of aiterial methemoglobin. However, shown by the illustrations in our articles,2,6J 2 points about this relation bear emphasizing. we routinely “elongated” the right oblique While there were no episodes of clinically subxiphoid view obtaining the ascending significant methemoglobinemia in our 50 paaorta as suggested by Isaaz et al.1 With these tients treated with intravenous nitroglycerin, right oblique cuts, in a series of 351 patients 20 patients had elevated arterial methemoyounger than 2 years, we visualized and reglobin levels (2 to 5%) on at least 1 occasion. ported6 not only the 4 types of RV outflow Our patients who received higher infusion tract recognized by Isaaz et al,’ but also a wide rates of intravenous nitroglycerin (average spectrum of malformations, including tricus290 f 13 rg/min or 4.1 pg/kg/min) for an pid atresia, pulmonary atresia with intact average of 7.1 f 0.5 days showed a positive ventricular septum, tetralogy of Fallot, doucorrelationbetweenthetotalamountofnitroble outlet right ventricle, transposition of glycerin infused and elevation of methemothe great arteries and single ventricle. Moreglobin. Second, we described a patient reover, we believe in agreement with other inceiving intravenous nitroglycerin who was vestigator@ that in the z-dimensional found to have a methemoglobin level of 12%. echocardiographic study of congenital heart This patient was also receiving phenazopyridisease, “rigid position of the transducer dine (Pyridium@], an aniline dye whose use was no longer necessary for proper orientahas been associated with methemoglobinetion of the echographic beam”8 and minimia. The combination of nitrates and phenamal variation of the same basic echocardiozophyridine was recently postulated to cause graphic plane does not constitute a “new an elevated arterial methemoglobin level in projection.” another patient.3 Although use of nitrates Bruno Marino, MD rarely leads to clinically significant metheRome, Italy moglobinemia, the potential should be conStephenP. Sanders,MD sidered in patients receiving large doses of Boston, Massachusetts nitrates, especially in combination withother 25 October 1985 oxidizing agents.
Kerry Kaplan,MD RichardDavison,MD Chicago, Illinois 21 October 1985
1. Isaaz K. Cloez JL, Danchin N, Marcon F, Worms AM, Pernot C. Assessment of right ventricular outflow tract in children by two-dimensional echocardiography using a new subcostal view. Angiographic and morphologic correlative study. Am 1Cardioi
1. Saxon SA. Silverman ME. Effects of continuous infusion of intravenous nitroglycerin on methemoglobin levels. Am J Cardiol 1985;56:461-464. 2. Kaplan KJ, Taber M, Teagarden JR, Parker M, DavisonR.Association of methemoglobinemia and intravenous nitroglycerin administration. Am 1 Cardiol1985;55:181-183. 3. Cooper JR, Keats AS. Methemoglobinemia diag-
2. Marino B, Ballerini L, Piva R, Marcelletti C, Catena G, Boldrini R, Pasquini L, DeSimone G. Proiezione obliqua anteriore destra nella Tetralogia di Fall&: correlazioni anatomo-eco-angiocardiografiche. Revista Latina de Cardiologia 1983;4:409-
Texas Heart Inst J 1985;32:103-106.
the right ventricular body: Two dimensionalechocardiographicfeatures.Am JCardiof 1983;51:1498-
1985;56:53&545.-
415.
nosedasaconsequenceofcardiopulmonarybypass. 3.Von Doenhoff LJ, Nanda NC. Obstruction within 1501.
4. Silove ED, DeGiovanni JV, Shiu MF, Yi MM. “NEW”PROJECTION IN PEDIATRIC Diagnosisofrightventricularoutflowobstructionin TWO-DIMENSIONAL ECHOCARDIOGRAPHY infants by cross sectional echocardiography. Br
In a recent article on Z-dimensional echocardiography, Isaaz et all describe the assess-
Heart J 1983;50:416-420. 5. Silverman NH, Hunter S, Anderson RH, Yen S. Sutherland GR, Davies MJ. Anatomical basis of
6. Marina B. Ballerini L. Marcelletti C. Piva R. Pasquini L, Zacche C, Giannico S, DeSimone k: Right obliquesubxiphoid view for two-dimensional echocardiographicvisualizationoftherightventritie in congenital heart disease. Am J Cardioll984; 54:1064-1068.
7. Marina 8, DeSimone G, Pasquini L, Giannico S, Marcelletti C, Ammirati A, Guccione P, Boldrini R, Ballerini L. Comolete transnosition of the great arteries: visualization of left hnd right’outfliw tract obstruction by oblique subcostal two-dimensional echocardiography. Am f Cardiol 1985;55:11401145.
8. Williams RG. Echocardiography in the neonate and young infant. JACC 1985;5:3OS-365.
THECORRECT TERM IS “CROSS-SECTIONAL,” NOT“TWO-DIMENSIONAL” I have noted with increasing concern the habit of most (but by no means all] of your contributors to refer to the echocardiographic technique that provides cross-sectional display of anatomy as “~-dimensional.” This practiceisbynomeansconfinedtoyourjournal, but I write to you since you are one of the few remaining American cardiologic journals which fosters the healthy feature of a correspondence column. It is certainly true that the cross-sectional format is indeed Zdimensional, but the purpose in using the term is to distinguish this format from the Mmode technique. Is one then to presume that the M-mode technique is l-dimensional? Certainly one has seen it described in that fashion. And there, sir, is the rub! I am reliably informed by those who have a more mathematical and philosophical background than I that structures can exist only in the abstract when they have but 1 dimension. The M-mode technique is certainly not l-dimensional. The second dimension is that of time and, in the printed display, this appears asthelengthofthetrace.Thus, theterm%D” does not distinguish the M-mode from the cross-sectional formats of display. From your excellent editorials, one cannot but infer that as an editor, you place great strength on accuracy within your pages. May I be so bold as to suggest that accuracy of description of echocardiographic techniques would, in the future, be enhanced by use of the terms “Mmode” and “cross-sectional” formats rather than the all-embracing and nondiscriminant phrase “&dimensional”? Robert Il. Anderson,MD London, England 29 October 1984
LETTERS
102:1202-1208.
cross sectional echocardiography. Br Heart J 1983;
6. Mandelkorn IB. Wolf NM. SinnhS. Schechter IA, Kersh RI, Rodgkrs DM, Workman MB, Bentivoglio LG, La Porte SM, Meister SC. Intracoronary thrombusinnon-transmuralmyocardialinfarction and ili unstable angina pectoris. Am J Cordiol 1983;52:3-6.
50:421-431.
ment of the right ventricular (RV) outflow tract using a projection they define as “a new subcostal view.” This basic echocardiographic projection for studying the RV outflow tract in congential heart diseases is not new. In fact, it was previously reported by several other investigators.2-7 Terms that have been applied to thisview include “right NITROGLYCERIN ANDMETNEMOGLOBlNEMlA oblique subxiphoid view,“z,6 “subcostal RV inflow-apex-outflow plane”3 and “paracorThe recent report by Saxon and Silverman1 onalshort axis.‘14z5 Obviously the study of varconfirms our finding that intravenous nitroious malformations and .patients involves glycerin administered in standard doses is an slight variations of the same basic echocaruncommon cause of clinically significant elediographic scan plane. In particular, as vation of aiterial methemoglobin. However, shown by the illustrations in our articles,2,6J 2 points about this relation bear emphasizing. we routinely “elongated” the right oblique While there were no episodes of clinically subxiphoid view obtaining the ascending significant methemoglobinemia in our 50 paaorta as suggested by Isaaz et al.1 With these tients treated with intravenous nitroglycerin, right oblique cuts, in a series of 351 patients 20 patients had elevated arterial methemoyounger than 2 years, we visualized and reglobin levels (2 to 5%) on at least 1 occasion. ported6 not only the 4 types of RV outflow Our patients who received higher infusion tract recognized by Isaaz et al,’ but also a wide rates of intravenous nitroglycerin (average spectrum of malformations, including tricus290 f 13 rg/min or 4.1 pg/kg/min) for an pid atresia, pulmonary atresia with intact average of 7.1 f 0.5 days showed a positive ventricular septum, tetralogy of Fallot, doucorrelationbetweenthetotalamountofnitroble outlet right ventricle, transposition of glycerin infused and elevation of methemothe great arteries and single ventricle. Moreglobin. Second, we described a patient reover, we believe in agreement with other inceiving intravenous nitroglycerin who was vestigator@ that in the z-dimensional found to have a methemoglobin level of 12%. echocardiographic study of congenital heart This patient was also receiving phenazopyridisease, “rigid position of the transducer dine (Pyridium@], an aniline dye whose use was no longer necessary for proper orientahas been associated with methemoglobinetion of the echographic beam”8 and minimia. The combination of nitrates and phenamal variation of the same basic echocardiozophyridine was recently postulated to cause graphic plane does not constitute a “new an elevated arterial methemoglobin level in projection.” another patient.3 Although use of nitrates Bruno Marino, MD rarely leads to clinically significant metheRome, Italy moglobinemia, the potential should be conStephenP. Sanders,MD sidered in patients receiving large doses of Boston, Massachusetts nitrates, especially in combination withother 25 October 1985 oxidizing agents.
Kerry Kaplan,MD RichardDavison,MD Chicago, Illinois 21 October 1985
1. Isaaz K. Cloez JL, Danchin N, Marcon F, Worms AM, Pernot C. Assessment of right ventricular outflow tract in children by two-dimensional echocardiography using a new subcostal view. Angiographic and morphologic correlative study. Am 1Cardioi
1. Saxon SA. Silverman ME. Effects of continuous infusion of intravenous nitroglycerin on methemoglobin levels. Am J Cardiol 1985;56:461-464. 2. Kaplan KJ, Taber M, Teagarden JR, Parker M, DavisonR.Association of methemoglobinemia and intravenous nitroglycerin administration. Am 1 Cardiol1985;55:181-183. 3. Cooper JR, Keats AS. Methemoglobinemia diag-
2. Marino B, Ballerini L, Piva R, Marcelletti C, Catena G, Boldrini R, Pasquini L, DeSimone G. Proiezione obliqua anteriore destra nella Tetralogia di Fall&: correlazioni anatomo-eco-angiocardiografiche. Revista Latina de Cardiologia 1983;4:409-
Texas Heart Inst J 1985;32:103-106.
the right ventricular body: Two dimensionalechocardiographicfeatures.Am JCardiof 1983;51:1498-
1985;56:53&545.-
415.
nosedasaconsequenceofcardiopulmonarybypass. 3.Von Doenhoff LJ, Nanda NC. Obstruction within 1501.
4. Silove ED, DeGiovanni JV, Shiu MF, Yi MM. “NEW”PROJECTION IN PEDIATRIC Diagnosisofrightventricularoutflowobstructionin TWO-DIMENSIONAL ECHOCARDIOGRAPHY infants by cross sectional echocardiography. Br
In a recent article on Z-dimensional echocardiography, Isaaz et all describe the assess-
Heart J 1983;50:416-420. 5. Silverman NH, Hunter S, Anderson RH, Yen S. Sutherland GR, Davies MJ. Anatomical basis of
6. Marina B. Ballerini L. Marcelletti C. Piva R. Pasquini L, Zacche C, Giannico S, DeSimone k: Right obliquesubxiphoid view for two-dimensional echocardiographicvisualizationoftherightventritie in congenital heart disease. Am J Cardioll984; 54:1064-1068.
7. Marina 8, DeSimone G, Pasquini L, Giannico S, Marcelletti C, Ammirati A, Guccione P, Boldrini R, Ballerini L. Comolete transnosition of the great arteries: visualization of left hnd right’outfliw tract obstruction by oblique subcostal two-dimensional echocardiography. Am f Cardiol 1985;55:11401145.
8. Williams RG. Echocardiography in the neonate and young infant. JACC 1985;5:3OS-365.
THECORRECT TERM IS “CROSS-SECTIONAL,” NOT“TWO-DIMENSIONAL” I have noted with increasing concern the habit of most (but by no means all] of your contributors to refer to the echocardiographic technique that provides cross-sectional display of anatomy as “~-dimensional.” This practiceisbynomeansconfinedtoyourjournal, but I write to you since you are one of the few remaining American cardiologic journals which fosters the healthy feature of a correspondence column. It is certainly true that the cross-sectional format is indeed Zdimensional, but the purpose in using the term is to distinguish this format from the Mmode technique. Is one then to presume that the M-mode technique is l-dimensional? Certainly one has seen it described in that fashion. And there, sir, is the rub! I am reliably informed by those who have a more mathematical and philosophical background than I that structures can exist only in the abstract when they have but 1 dimension. The M-mode technique is certainly not l-dimensional. The second dimension is that of time and, in the printed display, this appears asthelengthofthetrace.Thus, theterm%D” does not distinguish the M-mode from the cross-sectional formats of display. From your excellent editorials, one cannot but infer that as an editor, you place great strength on accuracy within your pages. May I be so bold as to suggest that accuracy of description of echocardiographic techniques would, in the future, be enhanced by use of the terms “Mmode” and “cross-sectional” formats rather than the all-embracing and nondiscriminant phrase “&dimensional”? Robert Il. Anderson,MD London, England 29 October 1984