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Cyanosis in Uncomplicated Atrial Septal Defect with Normal Right Cardiac and Pulmonary Arterial Pressures
ring in our patient, he still had beats with normal intraventricular conduction when the A-H interval increased from 200 to 350 msec (after scanning of the right atrium), an event that can be characteristically diagnosed as a dual intranodal pathway. 3 Therefore, the normalization of ventricular activation through the normal pathway occurred when the slow pathway was utilized, with a V 2 - V 3 interval of 330 msec, probably higher than the absolute refractory period of the left bundle. When there was left bundle-branch block, the V 2-V3 interval was 250 msec. The reported authors•-• always obtained beats with left bundle-branch block because their patients probably did not have three atrioventricular pathways placed in parallel and because the conduction along the atrioventricular junction always reached the left bundle in the absolute refractory phase. Although it might be obtained with drugs, the normalization of the ventricular activation, in spite of being arti6cial, can help us to recognize electrocardiographic changes such as regions of necrosis, cardiac hypertrophies, disturbances in conduction, and ischemic abnormalities, which are usually obscured by preexcitation. The reciprocal atrial beat in this patient only occurred after ventricular activation by normal atrioventricular conduction, with retrograde conduction along the accessory pathway. Due to the delay in atrioventricular conduction, it becomes impossible for an extrastimulus to be conducted anterogradely by Kent's bundle and retrogradely by the normal pathway, since the His bundle is chronologically activated after the ventricular depolarization. In these cases, the low refractoriness of the accessory bundle "protects" against the development of paroxysmal tachycardia, because it keeps the ventricles in the refractory phase. The tachyarrhythmia can only be elicited through marked intranodal delays, but this is difficult to observe spontaneously, so that explains why this patient has three atrioventricular pathways and never showed a crisis of tachycardia. The references to multiple atrioventricular pathways have been frequent, but this seems to be the &rst recording of double ventricular activation with normal intraventricular conduction due to the delay in the slow pathway.
REFERENca 1 Scherlag BJ, Lau SH, Helfant RH, et al: Catheter technique for recording His bundle activity in man. Circulation 39:13-18, 1969 2 Damato AN, Lau SH, Patton RD, et al: A study of atrioventricular conduction in man using premature atrial stimulation and His bundle recordings. Circulation 40:6169, 1969
3 Denes P, Wu D, Dhingra R, et al: Demonstration of dual AV nodal pathways in patients with paroxysmal supraventricular tachycardia. Circulation 48:549-555, 1973 4 Grouleau R, Puech P, Cabasson J, et al: Particularites de Ia conduction auriculo-ventriculaire dans un syndrome de Wolff-Parkinson-White. Arch Mal Coeur 67:13-22, 1974 5 Neuss H, Schlepper M, Spies HF: Double ventricular response to an atrial extrasystole in a patient with WPW syndrome type B. Eur J Cardiol2:175-179, 1974 6 Josephson ME, Seides SF, Damato AN: Wolff-ParkinsonWhite syndrome with 1:2 atrioventricular conduction. Am J Cardiol37:1094-1096, 1976
•
CIAFONE ET AL
Cyanosis in Uncomplicated Atrial Septal Defect with Normal Right Cardiac and Pulmonary Arterial Pressures* RusseU A. CUI/one, M.D.; Julian M. Aroesty, M.D.; Ronald M. Weintraub, M.D.; Paul]. LaBa1a, M.D.; tmd S1>en Paulin, M.D. A patient with cyanosis In an uncomplieated ostium seenndum atrial septal defeet'wltbont pnlmonary hypertension Is deserlhed. There were no anatonde abnormalities In right-sided cardiae valves or venons retnrn and no evidence of rlaht ventrlenlar hypoplasia or hypertrophy; however, the dlastolle pressnre enrve snaestecl a decreased compliance. We 111111e1t that this nnusaal finding may be a resnlt of lntrlnsleally abnormal right ventricular eompllanc:e. { t is not generally recognized that cyanosis can occur
in patients with atrial septal defects in the absence of pulmonary hypertension or anatomic abnormalities in right-sided cardiac valves or venous return. Such a case is presented. The right-to-left shunt may be due to abnormal right ventricular compliance. In uncomplicated atrial septal defects, previous reports of cyanosis explained by abnormal right ventricular compliance all dealt with patients with hypoplastic right ventricles or with patients following pulmonic valvuloplasty for pulmonic stenosis. Our patient successfully underwent surgical repair, emphasizing that an atrial septal defect with cyanosis is not necessarily an inoperable condition. In large series1 •1 of patients with atrial septal defects, cyanosis has been a relatively unusual occurrence, usually noted after the development of pulmonary hypertension. There have been isolated reports of cyanosis in atrial septal defects with normal pulmonary arterial and right ventricular pressures8 ·• associated with anomalies in venous return of the superior and inferior vena cavae, 1 - 7 hypoplasia of the right ventricle,s,e or pulmonic stenosis.10 We present a case of cyanosis in an adult with an uncomplicated ostium secundum atrial septal defect, normal right-sided cardiac pressures, and no other associated anomalies. CASE REPoRT
A 27-year-old man had had a cardiac murmur since birth. He had had an inactive childhood but was without dyspnea, fatigue, or cyanosis. In November 1975, he developed persistent fatigue following an influenza-like illness and was hospitalized for further study. The blood pressure was 140/90 mm Hg, and the pulse
•From the Thorndike Laboratory and the Departments of Medicine, S~, and Radiology, Harvard Medical School and Beth Israel HOSJ!ital, Boston. Supported in part by grant HL 5909 from the National Heart, Lung, and Blood Institute. .Rsprint n~qf16818: Dt. Aroe.dt/, 330 Brookline AQft'MUI, L-340,
Boston 02215
CHEST, 74: 5, NOVEMBER, 1978
F':tGtmB I. Chest roentgeoograms. Posteroanterior view ( ls/f) and lateral view ( righl) ue within normal limits.
rate was 80 beats per minute. The patient was an asthenic short man with perioral cyanosis and marked clubbing of fingers and toes. The pulses and pulse contour were normal The lUDgS were clear. There was no right ventricular lift. The first and second heart sounds were normal, and there was no gallop rhythm. There was a grade 3/6 systolic ejection murmur along the left sternal border. The hemoglobin level was 18.0 gm/100 mi. and the hematocrit reading was 53 percent. The chest :r:-ray fl1m (Fig 1) was normal, as were the results of a cardiac series with fluoroscopic e:r:amination. The electrocardiogram (Fig 2) showed peaked P waves suggestive of right atrial. enlarge-
ment and nonspecific abnormalities of the T waves. The phonocardiogram demonstrated a short systolic murmur and a flmd split leCOild heart sound with an fnterval of 0.03 second. The echocardiogram demonstrated normal septal motion. an enlarged right ventricular cavity, and normal mitral, tricuspid, and aortic valves. Arterial blood obtained with the patient breathing room air revealed an arterial o:r:ygen pressure (Pa01 ) of 50 mm Hg, an arterial carbon dio:r:ide tensiOD of !8 mm Hg, and an arterial pH of 7.52. When the patient squatted, his systolic pressure rose 20 mm Hg, and his Pa01 rose to 57 mm Hg. The results of tests of pulmonary function were normal.
F'lc1JBE 2. Standard IS-lead ECG, abowfng linus arrhythmias, peaked P waves suggestive of right atrial enlargemeat, and DOIIIP8CI8o ab1101'11lalities of T waWL
CHEST, 74: S, NOVEMBER, 1978
CYAII- IN UNCOIIPUCATED ATRIAL SEPTAL DEFECT 587
Table I -Data frorn Catlaeteri..,on • Saturation, percent
Data Superior vena cava
66
Inferior vena cava
74
Pressure, mmHg**
Right atrium High Middle Low
75
Right ventricle
76
16/8t
Pulmonary artery
78
16/10 (12)
Pulmonary vein
99
Left atrium
89
6
Left ventricle
89
120/8
Aorta
85
120/70 (90)
Pulmonary capillary wedge
92
7
73
6
80
*Oxygen carrying capacity was 24.1 volumes percent. **Numbers within parentheses are means. tAtrial pressure was 10 mm Hg. Right and left cardiac catheterization, left and right ventriculograms, a left atrial angiogram, and an inferior venacavogram were perfonned. The systemic flow of blood was 3.8 L/min/sq m (Fick's method). The blood pressures and oxygen saturations of the various cardiac chambers are shown in Table 1. Of note was the marked step-up from the vena cavae to the middle of the right atrium and the marked step.. down from the highly saturated ( 99 percent) pulmonary venous blood to that in the left atrium. This signifies a bidirectional shunt with a right-to-left shunt of 2.7 L/min and a left-to-right shunt of 1.7 L/min. There was no evidence of tricuspid stenosis or insufBciency or of pulmonary hypertension. The pulmonary vascular resistance was low ( 15 dynes • sec • em-s); however, the right ventricular diutolic pressure curve was unusual (Fig 3), manifesting an early diastolic dip followed by a pressure plateau of 6 to 8 mm Hg. The "a" wave was prominent at 10 to 14 mm Hg. The left ventriculogram rewaled a normal, posteriorly lying systemic ventricle, with a decreased ejection fraction ( 48 percent). The right ventricle was uormal in location and size. Left and right atrial angiograms revealed obvious mixture at
the atrial level but nonnal vena cavae, mitral valve, and tricuspid valve. At operation, the right and left ventricles appeared normal in size and shape. The mitral and tricuspid valves were nonnal. A large ostium secundum atrial septal defect was found in the superior septum, with multiple smaller perforations below the large superior defect. The inferior vena cava and superior vena cava were nonnal in position, and there were no abnormal systemic venous connectioDs. The defect was enlarged by excising the perforated septum and was closed with a Dacron patch. Before discharge from the hospital, the PaO~ was 85 mm Hg (hemoglobin level, 10.6 gm/100 ml) with the patient breathing room air. DISCUSSION
It is generally accepted that the direction of the shunt in atrial septal defect is a function of the relative resistance to filling of the two ventricles.1 Somerville• speculated that an increased resistance to right ventricular filling from impaired distensibility could lead to reversal of the shunt and cyanosis in atrial septal defects without elevated right-sided pressures. We believe that this hypothesis may apply in this case. It is of interest that · when afterload and systemic resistance were increased by squatting, thus favoring right ventricular diastolic &Ding, the patient's hypoxia lessened. Oakley et al10 reported four cases of cyanosis in patients with atrial septal defects after the successful relief of pulmonic stenosis. These investigators10 concluded that the persistent cyanosis was due to continuing impairment of right ventricular distensibility. Three reports attributed cyanosis in patients with atrial septal defects to hypoplastic right ventricles.a,e,u The other possible cause for the right-to-left shunt is the streaming of blood from the vena cava through the atrial septal defect. Uncomplicated atrial septal defects may have inconsequential streaming of blood from the vena cava through the defect; however, fl.ve cases have been reJ!Orted in which the anatomy of the inferior vena cava, the eustachian valve, or the septal defect allowed for marked right-to-left streaming and cyanosis. Reid et al12 presented cases where the defect was unusually low in position, and Winters et al8 reported a case of an atrial septal defect with cyanosis after a pneumonectomy
two
EKG 20 16 mmHg
12
8
4 0~---L--~----~--~--~--~
RIGHT VENTRICLE
RIGHT VENTRICLE
FIGURE 3. Right ventricular pressure tracing obtained at catheterization. Left panel is recorded at paper speed of 25 mm/sec, with one-second markings. IUght pGfiBl is recorded at 75 mm/sec, with 0.04-second markings. Note early diastolic dip, with diastolic plateau of 6 to 8 mm Hg. The "a" wave ( tJfTOWheads) is prominent, ranging from 10 to 16 mm Hg. Right ventricular enddiastolic pressure ranged from 8 to 12 mm Hg.
598 CIAFONE ET AL
CHEST, 74: 5, NOVEMBER, 1978
had caused rotation of the heart, with resultant emptying of the iuferior vena cava into the septal defect. Other cases of supposed simple atrial septal defects with cyanosis without pulmonary hypertension have been reported, but these have excluded pulmonary hypertension on the basis of an autopsy alone,• have failed to rule out connections between the superior vena cava and left abium,• or did not exclude significant pulmonary venous hypoxia becatise of primary pulmonary disease.1,7 The presence of cyanosis in a patient with an uncomplicated ostium secundum atrial septal defect does not preclude the presence of normal pulmonary arterial pressure and normal pulmonary vascular resistance. This finding conBrms the importance of cardiac catheterization to establish the underlying physiologic processes.
REFDEN'CES 1 Dexter L: Atrial septal defect. Br Heart J 18:209-225, 1956 2 Zaver AG, Nadas AS: Atrial septal defect-secundum type. Circulation32 (suppl3):W-24-ill-32, 1965 3 Selzer A, Lewis AE: The occurrence of chronic cyanosis in cases of atrial septal defect. Am J Med Sci 213:516524,1949 . 4 Somerville W: Atrial septal defect: Reversed shunt with
CHEST, 74: 5, NOVEMBER, 1978
5
6
7
8 9 10
11
12
normal pulmonary vascular resistance. Br J Med 20:265266,1958 Reghib G, Ruttenberg HD, Anderson RC, et al: Termination of left superior vena cava in left atrium: Atrial septal defect and abeence of ClOfODal)' sinus. CircaJatfon 31:908918,1965 Winters WL Jr, Cortes F, McDonough M, et al: Venoarterial shunting from inferior vena cava to left atrium in atrial septal defects with normal right heart pressures. Am J Cardiol19:293-300, 1967 Maillfs MS, Cheng TO, Meyer JF, et al: Cyanosis in patients with atrial septal defect due to systemic venous drainage into left atrium. Am J Cardiol 33:674-678, 1974 Haworth SG, Shineboume EA, Miller AH: Right-to-left intra-atrial shunting with normal right ventricular pressure. Br HeartJ 37:386-391, 1975 Durrani F, Hope RR: Cyanosis and unrecognized atrial septal defect in children. NZ Med J 81:481-482, 1975 Oalcley CM, Braimbridge MV, Bentall HM, et al: Reversed interatrial shunt following complete relief of pulmonary valve stenosis. Br Heart J 26:662-670, 1964 Sackner MA, Robinson MJ, Helwig J Jr, et al: Isolated right ventricular hypoplasia with atrial septal defect: Occurrence in three members of a family. Circulation 22:803,1960 Reid JM, McGuiness JB, Welsh TM: An unusual cause of cyanosis in atrial septal defect of secundum type. Scott Med J 10:384-388, 1965
CYANOSIS IN UNCOMPLICATED ATRIAL SEPfAL DEFECT •
REFERENca 1 Scherlag BJ, Lau SH, Helfant RH, et al: Catheter technique for recording His bundle activity in man. Circulation 39:13-18, 1969 2 Damato AN, Lau SH, Patton RD, et al: A study of atrioventricular conduction in man using premature atrial stimulation and His bundle recordings. Circulation 40:6169, 1969
3 Denes P, Wu D, Dhingra R, et al: Demonstration of dual AV nodal pathways in patients with paroxysmal supraventricular tachycardia. Circulation 48:549-555, 1973 4 Grouleau R, Puech P, Cabasson J, et al: Particularites de Ia conduction auriculo-ventriculaire dans un syndrome de Wolff-Parkinson-White. Arch Mal Coeur 67:13-22, 1974 5 Neuss H, Schlepper M, Spies HF: Double ventricular response to an atrial extrasystole in a patient with WPW syndrome type B. Eur J Cardiol2:175-179, 1974 6 Josephson ME, Seides SF, Damato AN: Wolff-ParkinsonWhite syndrome with 1:2 atrioventricular conduction. Am J Cardiol37:1094-1096, 1976
•
CIAFONE ET AL
Cyanosis in Uncomplicated Atrial Septal Defect with Normal Right Cardiac and Pulmonary Arterial Pressures* RusseU A. CUI/one, M.D.; Julian M. Aroesty, M.D.; Ronald M. Weintraub, M.D.; Paul]. LaBa1a, M.D.; tmd S1>en Paulin, M.D. A patient with cyanosis In an uncomplieated ostium seenndum atrial septal defeet'wltbont pnlmonary hypertension Is deserlhed. There were no anatonde abnormalities In right-sided cardiae valves or venons retnrn and no evidence of rlaht ventrlenlar hypoplasia or hypertrophy; however, the dlastolle pressnre enrve snaestecl a decreased compliance. We 111111e1t that this nnusaal finding may be a resnlt of lntrlnsleally abnormal right ventricular eompllanc:e. { t is not generally recognized that cyanosis can occur
in patients with atrial septal defects in the absence of pulmonary hypertension or anatomic abnormalities in right-sided cardiac valves or venous return. Such a case is presented. The right-to-left shunt may be due to abnormal right ventricular compliance. In uncomplicated atrial septal defects, previous reports of cyanosis explained by abnormal right ventricular compliance all dealt with patients with hypoplastic right ventricles or with patients following pulmonic valvuloplasty for pulmonic stenosis. Our patient successfully underwent surgical repair, emphasizing that an atrial septal defect with cyanosis is not necessarily an inoperable condition. In large series1 •1 of patients with atrial septal defects, cyanosis has been a relatively unusual occurrence, usually noted after the development of pulmonary hypertension. There have been isolated reports of cyanosis in atrial septal defects with normal pulmonary arterial and right ventricular pressures8 ·• associated with anomalies in venous return of the superior and inferior vena cavae, 1 - 7 hypoplasia of the right ventricle,s,e or pulmonic stenosis.10 We present a case of cyanosis in an adult with an uncomplicated ostium secundum atrial septal defect, normal right-sided cardiac pressures, and no other associated anomalies. CASE REPoRT
A 27-year-old man had had a cardiac murmur since birth. He had had an inactive childhood but was without dyspnea, fatigue, or cyanosis. In November 1975, he developed persistent fatigue following an influenza-like illness and was hospitalized for further study. The blood pressure was 140/90 mm Hg, and the pulse
•From the Thorndike Laboratory and the Departments of Medicine, S~, and Radiology, Harvard Medical School and Beth Israel HOSJ!ital, Boston. Supported in part by grant HL 5909 from the National Heart, Lung, and Blood Institute. .Rsprint n~qf16818: Dt. Aroe.dt/, 330 Brookline AQft'MUI, L-340,
Boston 02215
CHEST, 74: 5, NOVEMBER, 1978
F':tGtmB I. Chest roentgeoograms. Posteroanterior view ( ls/f) and lateral view ( righl) ue within normal limits.
rate was 80 beats per minute. The patient was an asthenic short man with perioral cyanosis and marked clubbing of fingers and toes. The pulses and pulse contour were normal The lUDgS were clear. There was no right ventricular lift. The first and second heart sounds were normal, and there was no gallop rhythm. There was a grade 3/6 systolic ejection murmur along the left sternal border. The hemoglobin level was 18.0 gm/100 mi. and the hematocrit reading was 53 percent. The chest :r:-ray fl1m (Fig 1) was normal, as were the results of a cardiac series with fluoroscopic e:r:amination. The electrocardiogram (Fig 2) showed peaked P waves suggestive of right atrial. enlarge-
ment and nonspecific abnormalities of the T waves. The phonocardiogram demonstrated a short systolic murmur and a flmd split leCOild heart sound with an fnterval of 0.03 second. The echocardiogram demonstrated normal septal motion. an enlarged right ventricular cavity, and normal mitral, tricuspid, and aortic valves. Arterial blood obtained with the patient breathing room air revealed an arterial o:r:ygen pressure (Pa01 ) of 50 mm Hg, an arterial carbon dio:r:ide tensiOD of !8 mm Hg, and an arterial pH of 7.52. When the patient squatted, his systolic pressure rose 20 mm Hg, and his Pa01 rose to 57 mm Hg. The results of tests of pulmonary function were normal.
F'lc1JBE 2. Standard IS-lead ECG, abowfng linus arrhythmias, peaked P waves suggestive of right atrial enlargemeat, and DOIIIP8CI8o ab1101'11lalities of T waWL
CHEST, 74: S, NOVEMBER, 1978
CYAII- IN UNCOIIPUCATED ATRIAL SEPTAL DEFECT 587
Table I -Data frorn Catlaeteri..,on • Saturation, percent
Data Superior vena cava
66
Inferior vena cava
74
Pressure, mmHg**
Right atrium High Middle Low
75
Right ventricle
76
16/8t
Pulmonary artery
78
16/10 (12)
Pulmonary vein
99
Left atrium
89
6
Left ventricle
89
120/8
Aorta
85
120/70 (90)
Pulmonary capillary wedge
92
7
73
6
80
*Oxygen carrying capacity was 24.1 volumes percent. **Numbers within parentheses are means. tAtrial pressure was 10 mm Hg. Right and left cardiac catheterization, left and right ventriculograms, a left atrial angiogram, and an inferior venacavogram were perfonned. The systemic flow of blood was 3.8 L/min/sq m (Fick's method). The blood pressures and oxygen saturations of the various cardiac chambers are shown in Table 1. Of note was the marked step-up from the vena cavae to the middle of the right atrium and the marked step.. down from the highly saturated ( 99 percent) pulmonary venous blood to that in the left atrium. This signifies a bidirectional shunt with a right-to-left shunt of 2.7 L/min and a left-to-right shunt of 1.7 L/min. There was no evidence of tricuspid stenosis or insufBciency or of pulmonary hypertension. The pulmonary vascular resistance was low ( 15 dynes • sec • em-s); however, the right ventricular diutolic pressure curve was unusual (Fig 3), manifesting an early diastolic dip followed by a pressure plateau of 6 to 8 mm Hg. The "a" wave was prominent at 10 to 14 mm Hg. The left ventriculogram rewaled a normal, posteriorly lying systemic ventricle, with a decreased ejection fraction ( 48 percent). The right ventricle was uormal in location and size. Left and right atrial angiograms revealed obvious mixture at
the atrial level but nonnal vena cavae, mitral valve, and tricuspid valve. At operation, the right and left ventricles appeared normal in size and shape. The mitral and tricuspid valves were nonnal. A large ostium secundum atrial septal defect was found in the superior septum, with multiple smaller perforations below the large superior defect. The inferior vena cava and superior vena cava were nonnal in position, and there were no abnormal systemic venous connectioDs. The defect was enlarged by excising the perforated septum and was closed with a Dacron patch. Before discharge from the hospital, the PaO~ was 85 mm Hg (hemoglobin level, 10.6 gm/100 ml) with the patient breathing room air. DISCUSSION
It is generally accepted that the direction of the shunt in atrial septal defect is a function of the relative resistance to filling of the two ventricles.1 Somerville• speculated that an increased resistance to right ventricular filling from impaired distensibility could lead to reversal of the shunt and cyanosis in atrial septal defects without elevated right-sided pressures. We believe that this hypothesis may apply in this case. It is of interest that · when afterload and systemic resistance were increased by squatting, thus favoring right ventricular diastolic &Ding, the patient's hypoxia lessened. Oakley et al10 reported four cases of cyanosis in patients with atrial septal defects after the successful relief of pulmonic stenosis. These investigators10 concluded that the persistent cyanosis was due to continuing impairment of right ventricular distensibility. Three reports attributed cyanosis in patients with atrial septal defects to hypoplastic right ventricles.a,e,u The other possible cause for the right-to-left shunt is the streaming of blood from the vena cava through the atrial septal defect. Uncomplicated atrial septal defects may have inconsequential streaming of blood from the vena cava through the defect; however, fl.ve cases have been reJ!Orted in which the anatomy of the inferior vena cava, the eustachian valve, or the septal defect allowed for marked right-to-left streaming and cyanosis. Reid et al12 presented cases where the defect was unusually low in position, and Winters et al8 reported a case of an atrial septal defect with cyanosis after a pneumonectomy
two
EKG 20 16 mmHg
12
8
4 0~---L--~----~--~--~--~
RIGHT VENTRICLE
RIGHT VENTRICLE
FIGURE 3. Right ventricular pressure tracing obtained at catheterization. Left panel is recorded at paper speed of 25 mm/sec, with one-second markings. IUght pGfiBl is recorded at 75 mm/sec, with 0.04-second markings. Note early diastolic dip, with diastolic plateau of 6 to 8 mm Hg. The "a" wave ( tJfTOWheads) is prominent, ranging from 10 to 16 mm Hg. Right ventricular enddiastolic pressure ranged from 8 to 12 mm Hg.
598 CIAFONE ET AL
CHEST, 74: 5, NOVEMBER, 1978
had caused rotation of the heart, with resultant emptying of the iuferior vena cava into the septal defect. Other cases of supposed simple atrial septal defects with cyanosis without pulmonary hypertension have been reported, but these have excluded pulmonary hypertension on the basis of an autopsy alone,• have failed to rule out connections between the superior vena cava and left abium,• or did not exclude significant pulmonary venous hypoxia becatise of primary pulmonary disease.1,7 The presence of cyanosis in a patient with an uncomplicated ostium secundum atrial septal defect does not preclude the presence of normal pulmonary arterial pressure and normal pulmonary vascular resistance. This finding conBrms the importance of cardiac catheterization to establish the underlying physiologic processes.
REFDEN'CES 1 Dexter L: Atrial septal defect. Br Heart J 18:209-225, 1956 2 Zaver AG, Nadas AS: Atrial septal defect-secundum type. Circulation32 (suppl3):W-24-ill-32, 1965 3 Selzer A, Lewis AE: The occurrence of chronic cyanosis in cases of atrial septal defect. Am J Med Sci 213:516524,1949 . 4 Somerville W: Atrial septal defect: Reversed shunt with
CHEST, 74: 5, NOVEMBER, 1978
5
6
7
8 9 10
11
12
normal pulmonary vascular resistance. Br J Med 20:265266,1958 Reghib G, Ruttenberg HD, Anderson RC, et al: Termination of left superior vena cava in left atrium: Atrial septal defect and abeence of ClOfODal)' sinus. CircaJatfon 31:908918,1965 Winters WL Jr, Cortes F, McDonough M, et al: Venoarterial shunting from inferior vena cava to left atrium in atrial septal defects with normal right heart pressures. Am J Cardiol19:293-300, 1967 Maillfs MS, Cheng TO, Meyer JF, et al: Cyanosis in patients with atrial septal defect due to systemic venous drainage into left atrium. Am J Cardiol 33:674-678, 1974 Haworth SG, Shineboume EA, Miller AH: Right-to-left intra-atrial shunting with normal right ventricular pressure. Br HeartJ 37:386-391, 1975 Durrani F, Hope RR: Cyanosis and unrecognized atrial septal defect in children. NZ Med J 81:481-482, 1975 Oalcley CM, Braimbridge MV, Bentall HM, et al: Reversed interatrial shunt following complete relief of pulmonary valve stenosis. Br Heart J 26:662-670, 1964 Sackner MA, Robinson MJ, Helwig J Jr, et al: Isolated right ventricular hypoplasia with atrial septal defect: Occurrence in three members of a family. Circulation 22:803,1960 Reid JM, McGuiness JB, Welsh TM: An unusual cause of cyanosis in atrial septal defect of secundum type. Scott Med J 10:384-388, 1965
CYANOSIS IN UNCOMPLICATED ATRIAL SEPfAL DEFECT •