Idiopathic Hypertrophic Subaortic Stenosis in Pregnancy ALBERT J. KOLIBASH,
M.D.,
DANIEL E. RUIZ, M.D., and RICHARD P. LEWIS, M.D.,
F.A.C.P.,
Columbus, Ohio
The coexistence of pregnancy and idiopathic hypertrophic subaortic stenosis is a potentially dangerous combination. We report a 23-year-old white woman with idiopathic hypertrophic subaortic stenosis and pregnancy who presented with severe symptoms (Class IV) and modest outflow obstruction associated with marked mitral regurgitation. After delivery, the evidence for significant mitral regurgitation regressed, while the outflow obstruction seemed unchanged. However, she returned to Functional Class II. We review the mechanisms by which pregnancy and labor may alter the hemodynamics of idiopathic hypertrophic subaortic stenosis and we discuss recommendations for the management of these patients during pregnancy, labor, and the immediate postpartum period. We conclude that despite increasing symptoms, most women with idiopathic hypertrophic subaortic stenosis can tolerate pregnancy and a vaginal delivery.
IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS is charac-
terized by dynamic changes in left ventricular outflow obstruction and a variable degree of mitral regurgitation. Although not described until 16 years ago ( 1 , 2 ) , it is now being recognized with increasing frequency ( 3 ) . Nevertheless, there are few reported cases describing idiopathic hypertrophic subaortic stenosis in pregnancy, when it may present a difficult diagnostic and therapeutic problem (4-7). We present the clinical and hemodynamic findings in such a patient and discuss the management of idiopathic hypertrophic subaortic stenosis in pregnancy. Case Report
A 23-year-old white pregnant woman near term was admitted to the Ohio State University Hospital because of severe dyspnea in March 1973. The patient had noted exertional dyspnea since childhood. At age 19, while taking amphetamines for weight reduction, the dyspnea worsened. In December 1971, a right heart catheterization showed normal right heart and pulmonary capillary wedge pressures. Left atrial enlargement was diagnosed by angiography and a diagnosis of mild mitral insufficiency was made. She became pregnant in July 1972, and subsequently her symptoms worsened. Three weeks before admission, an episode of paroxysmal nocturnal dyspnea, chest pain, Hianhnresis. and svnmnp. nrpm'nitated an admission to a • From the Division of Cardiology, Department of Medicine, The Ohio State University College of Medicine, Columbus, Ohio. Annals of Internal Medicine 82:791-794, 1975
Downloaded from https://annals.org by Tulane University user on 12/08/2018
community hospital. Pulmonary edema was diagnosed, and digitalis therapy was begun. The patient stated that digitalis "made her heart pound." One day before transfer, the patient again developed pulmonary edema. She was transferred to the Ohio State University Hospital with a diagnosis of ruptured chordae tendineae. Her family history was of interest because her mother, who was known to have a heart murmur, died suddenly at age 42. Retrospective review of her mother's medical records suggested that she died of idiopathic hypertrophic subaortic stenosis. Physical examination showed a thin, pale young woman in mild respiratory distress. Her weight was 56 kg, blood pressure, 100/70 mm Hg, pulse, 98 per minute, respirations, 23 per minute, temperature, 37 °C [98.6 °F]. The jugular venous pressure was normal, but prominent Awaves were visible. The carotid pulse had a rapid upstroke but was not bifid. There was a palpable S3 gallop at the apex. A systolic thrill was present at the apex and left sternal border. P-2 was increased in intensity, and a loud S3 gallop was heard without an audible S4. A grade 5/6 harsh systolic ejection murmur was heard best at the apex and transmitted to the axilla and left sternal border. The lungs were clear. The abdomen had an enlarged uterus near term. The chest X-ray showed gross enlargement of the heart, with marked left atrial enlargement. Comparison with old films showed that this had occurred during the pregnancy (Figure 1). The electrocardiogram showed left ventricular hypertrophy and left atrial enlargement. During the first 2 hospital days, the patient continued to have chest pain and resting dyspnea. Systolic time intervals, indirect carotid pulse tracing, phonocardiogram, apexcardiogram, and echocardiogram were compatible with the diagnosis of idiopathic hypertrophic subaortic stenosis (812) (Figure 2). A retrograde left heart catheterization was done. The resting left ventricular end-diastolic pressure was 34 mm Hg, and there was a resting peak gradient of 38 mm Hg across the left ventricular outflow tract. After premature ventricular beats, the gradient increased to 80 mm Hg. Left ventricular cineangiography showed massive hypertrophy of the inferior and the high septal portions of the left ventricular wall, with obliteration of the cavity in systole. Ventricular contraction was vigorous, and massive mitral regurgitation was evident. The left ventricular end-diastolic volume seemed normal. These findings were consistent with the angiographic appearance of the left ventricle in idiopathic hypertrophic subaortic stenosis (13). The coronary arteries were normal. After cardiac catheterization, the patient spontaneously 791
Figure 1, Left. Chest X-ray 14 months before delivery. Overall heart size is normal, and double density suggests left atrial enlargement. Center. One week before delivery, striking cardiomegaly with left atrial enlargement is shown. Right. Six weeks after delivery, the overall heart size is much decreased.
began labor which lasted 17 hours. Throughout labor she was maintained on propranolol, 2 mg intravenously, every 3 hours. Demerol® was administered for pain, and intravenous oxytocin was administered during the last 4 hours of labor. Her vital signs remained stable throughout. The second stage of labor lasted 20 minutes. A 2.7 kg boy was delivered with the application of low forceps under Penthrane® and local Xylocaine® anesthesia. The baby received an Apgar score of 10. After delivery, two more doses of propranolol were given. Blood loss was not significant. Propranolol was withdrawn on the first postpartum day because of a severe vasovagal episode, and subsequently her condition remained stable. She noted an immediate improvement in her dyspnea after delivery and was discharged on the fourth postpartum day. At 6 weeks postpartum the clinical exam suggested
idiopathic hypertrophic subaortic stenosis with outflow obstruction and minimal mitral regurgitation. The murmur was less loud, clearly midsystolic, and only a faint thrill was present. The murmur increased in intensity with standing and lessened slightly with squatting. A palpable S4 gallop had appeared, and the S3 gallop was greatly diminished (Figures 1 and 2). The chest X-ray showed marked decrease in left atrial size. Since discharge the patient had experienced no syncope or chest pain and she showed continued improvement in her dyspnea. The systolic time intervals and echocardiogram were compatible with significant left ventricular outflow obstruction (9-12). The left ventricular ejection time was abnormally prolonged, and the echocardiogram showed marked systolic anterior motion of the mitral valve. In view of this, the patient was restarted on propranolol, 40 mg daily.
Figure 2. Indirect carotid tracings (ICT), apexcardlograms (ACG), and phonocardlograms (PCQ) before (A) and after (B) delivery. Both ICT are typical of Idiopathic hypertrophic subaortic stenosis (IHSS). Prepartum there Is a loud S3 and prominent rapid filling wave (RFW), an ejection sound (ES), and no S4. Postpartum the S3 and RFW are less prominent, and there Is a loud S4. The ACQ shows a prominent "A" wave and a late systolic bulge typical of IHSS. 792
June 1975 • Annals of Internal Medicine • Volume 82 • Number 6
Downloaded from https://annals.org by Tulane University user on 12/08/2018
At 3 months postpartum the patient reported further increased exercise tolerance relative to her prepartum state. Her physical exam and echocardiogram were not obviously changed, but her systolic time intervals showed normalization of the left ventricular ejection time compatible with lessening of left ventricular outflow obstruction (11, 12). In addition, there was prolongation of electromechanical systole consistent with beta blockade (14). Subsequently, her propranolol dosage has been increased to 80 mg daily, and the patient remains a Functional Class II-B. Discussion
The physiologic alterations that accompany pregnancy are potentially dangerous for patients with idiopathic hypertrophic subaortic stenosis. Indeed, limited experience suggests that significant worsening of symptoms is the rule in these patients (5). Nevertheless, there have been no deaths recorded (4-7). The degree of outflow obstruction and mitral regurgitation in idiopathic hypertrophic subaortic stenosis is largely determined by the interplay of three variables. These include the left ventricular end-diastolic volume, the inotropic state of the left ventricle, and systemic vascular impedance (3, 15-17). Pregnancy may unfavorably or favorably alter any one or all of these variables. During pregnancy, increased blood volume (18, 19) increases left ventricular end-diastolic volume, and outflow obstruction should diminish. This effect is counteracted by the fall in systemic arterial resistence accompanying the increase in cardiac output characteristic of the latter half of pregnancy. Uterine obstruction of the inferior vena cava occurs when these patients are supine (20) and may produce a decrease in venous return (21), resulting in worsening of left ventricular outflow obstruction. Finally, increased adrenergic activity resulting from pain and emotional stress accompanying the last few weeks of pregnancy could aggravate outflow obstruction. From the above considerations, we conclude that prenatal management of the patient with idiopathic hypertrophic subaortic stenosis should include the following: [1] digitalis or sympathomimetic medications are contraindicated; [2] the lateral decubitus position is preferred to the supine; and [3] excessive diuresis or drugs that decrease systemic vascular resistance should be avoided. Labor is associated with additional hemodynamic changes. The central blood volume increases about 500 ml during uterine contraction (22). This induces a rise in cardiac output and in mean arterial pressure that should improve outflow obstruction. However, the Valsalva maneuver used for bearing down could potentially increase outflow obstruction. Oxytocin does not seem to be contraindicated and indeed may lessen outflow obstruction. Stage two of labor should be shortened by the use of forceps, but Caesarean section seems reserved for obstetrical indications only. NeoSynephrine® and immediate blood replacement should be available should hypotension occur during delivery. Antibiotic coverage with penicillin and streptomycin is indicated because of the inherent risk of infective endocarditis (4, 23,24).
In our patient no significant changes in blood pressure or pulse were observed during the second stage of labor, at which time she was receiving intravenous propranolol. Others have used propranolol intramuscularly (7). We feel that the intravenous route is more desirable for these reasons: [1] the time course of blockade of the inotropic effect of beta adrenergic stimulation is known only for the intravenous administration (25), and furthermore [2], there is variation in the bioavailability of oral drugs (26). This patient presented with massive mitral regurgitation and only mild-moderate left ventricular outflow obstruction. Evidence of marked mitral regurgitation disappeared immediately after delivery. Thus, despite the multiple possibilities that the interplay of the hemodynamic effects of pregnancy can have on the outflow gradient and mitral regurgitation in idiopathic hypertrophic subaortic stenosis, the net effect in this patient was to markedly increase the mitral regurgitation. At present, she seems to have moderate outflow obstruction with minimal mitral regurgitation. The physiologic explanation for the apparent predominant worsening of mitral regurgitation during pregnancy in this patient is not clear. The observation is of interest because almost all patients with idiopathic hypertrophic subaortic stenosis experience increased symptoms during pregnancy (4), but it is not clear whether this is usually due to increased mitral regurgitation or to increased outflow obstruction. ACKNOWLEDGMENTS: Grant support: in part by training grant number 5 T01 HL05968, National Institutes of Health. Doctor Kolibash was the recipient of a Central Ohio Heart Chapter of the American Heart Association fellowship during the duration of this project. Received 16 September 1974; revision accepted 20 December 1974. • Requests for reprints should be addressed to Albert Kolibash, M.D., Division of Cardiology, The Ohio State University Hospitals, 466 W. Tenth Avenue, Columbus, OH 43210. References 1. TEARE D: Asymmetrical hypertrophy of the heart in the heart in young adults. Br Heart J 20:1-8, 1958 2. BROCK R: Functional obstruction of the left ventricle (acquired aortic subvalvular stenosis). Guys Hosp Rep 106:221-238, 1957 3. BRAUNWALD E, LAMBREW CT, ROCKOFF SD, et al: Idiopathic
hypertrophic subaortic stenosis: I. A description of the disease based upon an analysis of 64 patients (abstract). Circulation 30 (suppl4):3, 1964 4. GOODWIN JF, OAKLEY DM: The cardiomyopathies. Br Heart J
34:545-552, 1972 5. SWAN DA, BELL B, OAKLEY CM, et al: Analysis of symptomatic
course and prognosis and treatment of hypertrophic obstructive cardiomyopathy. Br Heart J 33:671-685, 1971 6. BROWN AK, DOUKAS N, RIDING WD, et al: Cardiomyopathy and
pregnancy. Br Heart J 29:387-393, 1967 7. TURNER GM, OAKLEY CM, DIXON HG: Management of preg-
nancy complicated by hypertrophic obstructive cardiomyopathy. Br Med J 4:281-284, 1968 8. LINDGREN KM, EPSTEIN SE: Idiopathic hypertrophic subaortic
stenosis with and without mitral regurgitation. Br Heart J 34:191-197,1972 9. HENRY WL, CLARK CE, EPSTEIN SE: Asymmetric septal hyper-
trophy: Echocardiography identification of the pathognomonic anatomic abnormality of IHSS. Circulation 47:225-233, 1973 10. SHAH PM, GRAMIAK R, ADELMAN AG: Role of echocardiography
in diagnostic and hemodynamic assessment of hypertrophic subaortic stenosis. Circulation 46:891-898, 1971 11. SALZMAN SH, WOLFSON S, JACKSON B, et al: Epinephrine infu-
sion in man (standardization, normal response, and abnormal response in idiopathic hypertrophic subaortic stenosis). Circulation 47:137'-144, 1971 Ko/ibash et a/. • Idiopathic Hypertrophic Subaortic Stenosis
Downloaded from https://annals.org by Tulane University user on 12/08/2018
793
12. WIGLE ED, AUGER P, MARQUIS Y: Muscular subaortic stenosis
(the direct relation between the intraventricular pressure difference and the left ventricular ejection time). Circulation 46:3644, 1967 13. SIMON AL, ROSS JJ, GAULT JH: Angiographic anatomy of the
left ventricle and mitral valve in idiopathic hypertrophic subaortic stenosis. Circulation 36:852-867, 1967 14. LEWIS RP, BOUDOULAS H, FORESTER WF, et al: Shortening of
electromechanical systole as a manifestation of excessive adrenergic stimulation in acute myocardial infarction. Circulation 46:856-862, 1972 15. WIGLE ED, DAVID PR, LABRASSE CJ, et al: Muscular subaortic
stenosis. Am J Cardiol 15:761-772, 1965 16. LEWIS RP, BRISTOW JD, FARREHI C, et al: Idiopathic left ven-
tricular hypertrophy. Am J Med 38:842-852, 1965 17. WIGLE ED, ADELMAN AG, AUGER P: Mitral regurgitation in
muscular subaortic stenosis. Am J Cardiol 24:698-706, 1969 18. PRITCHARD JA: Changes in the blood volume during pregnancy and delivery. Anesthesiology 26:393-399, 1965 19. PRITCHARD J A, ADAMS RH: Erythrocyte production and destruc-
794
June 1975 • Annals of Internal Medicine • Volume 82 • Number 6
Downloaded from https://annals.org by Tulane University user on 12/08/2018
tion during pregnancy. Am J Obstet Gynecol 79:750-757, 1960 20. SCOTT DB, KERR MG: Inferior vena cava pressure in late pregnancy. / Obstet Gynaecol Br Commonw 70:1044-1049, 1963 21. LEES MM, TAYLOR SH, SCOTT OB, et al: The circulatory effects
of recumbent postural change in late pregnancy. Clin Sci 32: 453-465, 1967 22. ADAMS
JQ, ALEXANDER
AM:
Alterations
in
cardiovascular
physiology during labor. Obstet Gynecol 12:542-549, 1958 23. VECHT RJ, OAKLEY CM: Infective endocarditis in three patients with hypertrophic obstructive cardiomyopathy. Br Med 7 2:455459, 1968 24. BOITEAU GM, ALLENSTEIN BJ: Hypertrophic subaortic stenosis. Am J Cardiol 8:614-623, 1961 25. ROBINSON JL, RICH JM, WEISSLER AM: Differential effects of
propranolol on the chronotropic and inotropic response to isoproterenol in man (abstract). Am J Cardiol 31:155, 1973 26. SHAND DG, NUCKOLLS MS, OATES JA: Plasma propranolol levels
in adults with observations in four children. Clin Pharmacol Ther 11:112-120, 1970
M.D.,
DANIEL E. RUIZ, M.D., and RICHARD P. LEWIS, M.D.,
F.A.C.P.,
Columbus, Ohio
The coexistence of pregnancy and idiopathic hypertrophic subaortic stenosis is a potentially dangerous combination. We report a 23-year-old white woman with idiopathic hypertrophic subaortic stenosis and pregnancy who presented with severe symptoms (Class IV) and modest outflow obstruction associated with marked mitral regurgitation. After delivery, the evidence for significant mitral regurgitation regressed, while the outflow obstruction seemed unchanged. However, she returned to Functional Class II. We review the mechanisms by which pregnancy and labor may alter the hemodynamics of idiopathic hypertrophic subaortic stenosis and we discuss recommendations for the management of these patients during pregnancy, labor, and the immediate postpartum period. We conclude that despite increasing symptoms, most women with idiopathic hypertrophic subaortic stenosis can tolerate pregnancy and a vaginal delivery.
IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS is charac-
terized by dynamic changes in left ventricular outflow obstruction and a variable degree of mitral regurgitation. Although not described until 16 years ago ( 1 , 2 ) , it is now being recognized with increasing frequency ( 3 ) . Nevertheless, there are few reported cases describing idiopathic hypertrophic subaortic stenosis in pregnancy, when it may present a difficult diagnostic and therapeutic problem (4-7). We present the clinical and hemodynamic findings in such a patient and discuss the management of idiopathic hypertrophic subaortic stenosis in pregnancy. Case Report
A 23-year-old white pregnant woman near term was admitted to the Ohio State University Hospital because of severe dyspnea in March 1973. The patient had noted exertional dyspnea since childhood. At age 19, while taking amphetamines for weight reduction, the dyspnea worsened. In December 1971, a right heart catheterization showed normal right heart and pulmonary capillary wedge pressures. Left atrial enlargement was diagnosed by angiography and a diagnosis of mild mitral insufficiency was made. She became pregnant in July 1972, and subsequently her symptoms worsened. Three weeks before admission, an episode of paroxysmal nocturnal dyspnea, chest pain, Hianhnresis. and svnmnp. nrpm'nitated an admission to a • From the Division of Cardiology, Department of Medicine, The Ohio State University College of Medicine, Columbus, Ohio. Annals of Internal Medicine 82:791-794, 1975
Downloaded from https://annals.org by Tulane University user on 12/08/2018
community hospital. Pulmonary edema was diagnosed, and digitalis therapy was begun. The patient stated that digitalis "made her heart pound." One day before transfer, the patient again developed pulmonary edema. She was transferred to the Ohio State University Hospital with a diagnosis of ruptured chordae tendineae. Her family history was of interest because her mother, who was known to have a heart murmur, died suddenly at age 42. Retrospective review of her mother's medical records suggested that she died of idiopathic hypertrophic subaortic stenosis. Physical examination showed a thin, pale young woman in mild respiratory distress. Her weight was 56 kg, blood pressure, 100/70 mm Hg, pulse, 98 per minute, respirations, 23 per minute, temperature, 37 °C [98.6 °F]. The jugular venous pressure was normal, but prominent Awaves were visible. The carotid pulse had a rapid upstroke but was not bifid. There was a palpable S3 gallop at the apex. A systolic thrill was present at the apex and left sternal border. P-2 was increased in intensity, and a loud S3 gallop was heard without an audible S4. A grade 5/6 harsh systolic ejection murmur was heard best at the apex and transmitted to the axilla and left sternal border. The lungs were clear. The abdomen had an enlarged uterus near term. The chest X-ray showed gross enlargement of the heart, with marked left atrial enlargement. Comparison with old films showed that this had occurred during the pregnancy (Figure 1). The electrocardiogram showed left ventricular hypertrophy and left atrial enlargement. During the first 2 hospital days, the patient continued to have chest pain and resting dyspnea. Systolic time intervals, indirect carotid pulse tracing, phonocardiogram, apexcardiogram, and echocardiogram were compatible with the diagnosis of idiopathic hypertrophic subaortic stenosis (812) (Figure 2). A retrograde left heart catheterization was done. The resting left ventricular end-diastolic pressure was 34 mm Hg, and there was a resting peak gradient of 38 mm Hg across the left ventricular outflow tract. After premature ventricular beats, the gradient increased to 80 mm Hg. Left ventricular cineangiography showed massive hypertrophy of the inferior and the high septal portions of the left ventricular wall, with obliteration of the cavity in systole. Ventricular contraction was vigorous, and massive mitral regurgitation was evident. The left ventricular end-diastolic volume seemed normal. These findings were consistent with the angiographic appearance of the left ventricle in idiopathic hypertrophic subaortic stenosis (13). The coronary arteries were normal. After cardiac catheterization, the patient spontaneously 791
Figure 1, Left. Chest X-ray 14 months before delivery. Overall heart size is normal, and double density suggests left atrial enlargement. Center. One week before delivery, striking cardiomegaly with left atrial enlargement is shown. Right. Six weeks after delivery, the overall heart size is much decreased.
began labor which lasted 17 hours. Throughout labor she was maintained on propranolol, 2 mg intravenously, every 3 hours. Demerol® was administered for pain, and intravenous oxytocin was administered during the last 4 hours of labor. Her vital signs remained stable throughout. The second stage of labor lasted 20 minutes. A 2.7 kg boy was delivered with the application of low forceps under Penthrane® and local Xylocaine® anesthesia. The baby received an Apgar score of 10. After delivery, two more doses of propranolol were given. Blood loss was not significant. Propranolol was withdrawn on the first postpartum day because of a severe vasovagal episode, and subsequently her condition remained stable. She noted an immediate improvement in her dyspnea after delivery and was discharged on the fourth postpartum day. At 6 weeks postpartum the clinical exam suggested
idiopathic hypertrophic subaortic stenosis with outflow obstruction and minimal mitral regurgitation. The murmur was less loud, clearly midsystolic, and only a faint thrill was present. The murmur increased in intensity with standing and lessened slightly with squatting. A palpable S4 gallop had appeared, and the S3 gallop was greatly diminished (Figures 1 and 2). The chest X-ray showed marked decrease in left atrial size. Since discharge the patient had experienced no syncope or chest pain and she showed continued improvement in her dyspnea. The systolic time intervals and echocardiogram were compatible with significant left ventricular outflow obstruction (9-12). The left ventricular ejection time was abnormally prolonged, and the echocardiogram showed marked systolic anterior motion of the mitral valve. In view of this, the patient was restarted on propranolol, 40 mg daily.
Figure 2. Indirect carotid tracings (ICT), apexcardlograms (ACG), and phonocardlograms (PCQ) before (A) and after (B) delivery. Both ICT are typical of Idiopathic hypertrophic subaortic stenosis (IHSS). Prepartum there Is a loud S3 and prominent rapid filling wave (RFW), an ejection sound (ES), and no S4. Postpartum the S3 and RFW are less prominent, and there Is a loud S4. The ACQ shows a prominent "A" wave and a late systolic bulge typical of IHSS. 792
June 1975 • Annals of Internal Medicine • Volume 82 • Number 6
Downloaded from https://annals.org by Tulane University user on 12/08/2018
At 3 months postpartum the patient reported further increased exercise tolerance relative to her prepartum state. Her physical exam and echocardiogram were not obviously changed, but her systolic time intervals showed normalization of the left ventricular ejection time compatible with lessening of left ventricular outflow obstruction (11, 12). In addition, there was prolongation of electromechanical systole consistent with beta blockade (14). Subsequently, her propranolol dosage has been increased to 80 mg daily, and the patient remains a Functional Class II-B. Discussion
The physiologic alterations that accompany pregnancy are potentially dangerous for patients with idiopathic hypertrophic subaortic stenosis. Indeed, limited experience suggests that significant worsening of symptoms is the rule in these patients (5). Nevertheless, there have been no deaths recorded (4-7). The degree of outflow obstruction and mitral regurgitation in idiopathic hypertrophic subaortic stenosis is largely determined by the interplay of three variables. These include the left ventricular end-diastolic volume, the inotropic state of the left ventricle, and systemic vascular impedance (3, 15-17). Pregnancy may unfavorably or favorably alter any one or all of these variables. During pregnancy, increased blood volume (18, 19) increases left ventricular end-diastolic volume, and outflow obstruction should diminish. This effect is counteracted by the fall in systemic arterial resistence accompanying the increase in cardiac output characteristic of the latter half of pregnancy. Uterine obstruction of the inferior vena cava occurs when these patients are supine (20) and may produce a decrease in venous return (21), resulting in worsening of left ventricular outflow obstruction. Finally, increased adrenergic activity resulting from pain and emotional stress accompanying the last few weeks of pregnancy could aggravate outflow obstruction. From the above considerations, we conclude that prenatal management of the patient with idiopathic hypertrophic subaortic stenosis should include the following: [1] digitalis or sympathomimetic medications are contraindicated; [2] the lateral decubitus position is preferred to the supine; and [3] excessive diuresis or drugs that decrease systemic vascular resistance should be avoided. Labor is associated with additional hemodynamic changes. The central blood volume increases about 500 ml during uterine contraction (22). This induces a rise in cardiac output and in mean arterial pressure that should improve outflow obstruction. However, the Valsalva maneuver used for bearing down could potentially increase outflow obstruction. Oxytocin does not seem to be contraindicated and indeed may lessen outflow obstruction. Stage two of labor should be shortened by the use of forceps, but Caesarean section seems reserved for obstetrical indications only. NeoSynephrine® and immediate blood replacement should be available should hypotension occur during delivery. Antibiotic coverage with penicillin and streptomycin is indicated because of the inherent risk of infective endocarditis (4, 23,24).
In our patient no significant changes in blood pressure or pulse were observed during the second stage of labor, at which time she was receiving intravenous propranolol. Others have used propranolol intramuscularly (7). We feel that the intravenous route is more desirable for these reasons: [1] the time course of blockade of the inotropic effect of beta adrenergic stimulation is known only for the intravenous administration (25), and furthermore [2], there is variation in the bioavailability of oral drugs (26). This patient presented with massive mitral regurgitation and only mild-moderate left ventricular outflow obstruction. Evidence of marked mitral regurgitation disappeared immediately after delivery. Thus, despite the multiple possibilities that the interplay of the hemodynamic effects of pregnancy can have on the outflow gradient and mitral regurgitation in idiopathic hypertrophic subaortic stenosis, the net effect in this patient was to markedly increase the mitral regurgitation. At present, she seems to have moderate outflow obstruction with minimal mitral regurgitation. The physiologic explanation for the apparent predominant worsening of mitral regurgitation during pregnancy in this patient is not clear. The observation is of interest because almost all patients with idiopathic hypertrophic subaortic stenosis experience increased symptoms during pregnancy (4), but it is not clear whether this is usually due to increased mitral regurgitation or to increased outflow obstruction. ACKNOWLEDGMENTS: Grant support: in part by training grant number 5 T01 HL05968, National Institutes of Health. Doctor Kolibash was the recipient of a Central Ohio Heart Chapter of the American Heart Association fellowship during the duration of this project. Received 16 September 1974; revision accepted 20 December 1974. • Requests for reprints should be addressed to Albert Kolibash, M.D., Division of Cardiology, The Ohio State University Hospitals, 466 W. Tenth Avenue, Columbus, OH 43210. References 1. TEARE D: Asymmetrical hypertrophy of the heart in the heart in young adults. Br Heart J 20:1-8, 1958 2. BROCK R: Functional obstruction of the left ventricle (acquired aortic subvalvular stenosis). Guys Hosp Rep 106:221-238, 1957 3. BRAUNWALD E, LAMBREW CT, ROCKOFF SD, et al: Idiopathic
hypertrophic subaortic stenosis: I. A description of the disease based upon an analysis of 64 patients (abstract). Circulation 30 (suppl4):3, 1964 4. GOODWIN JF, OAKLEY DM: The cardiomyopathies. Br Heart J
34:545-552, 1972 5. SWAN DA, BELL B, OAKLEY CM, et al: Analysis of symptomatic
course and prognosis and treatment of hypertrophic obstructive cardiomyopathy. Br Heart J 33:671-685, 1971 6. BROWN AK, DOUKAS N, RIDING WD, et al: Cardiomyopathy and
pregnancy. Br Heart J 29:387-393, 1967 7. TURNER GM, OAKLEY CM, DIXON HG: Management of preg-
nancy complicated by hypertrophic obstructive cardiomyopathy. Br Med J 4:281-284, 1968 8. LINDGREN KM, EPSTEIN SE: Idiopathic hypertrophic subaortic
stenosis with and without mitral regurgitation. Br Heart J 34:191-197,1972 9. HENRY WL, CLARK CE, EPSTEIN SE: Asymmetric septal hyper-
trophy: Echocardiography identification of the pathognomonic anatomic abnormality of IHSS. Circulation 47:225-233, 1973 10. SHAH PM, GRAMIAK R, ADELMAN AG: Role of echocardiography
in diagnostic and hemodynamic assessment of hypertrophic subaortic stenosis. Circulation 46:891-898, 1971 11. SALZMAN SH, WOLFSON S, JACKSON B, et al: Epinephrine infu-
sion in man (standardization, normal response, and abnormal response in idiopathic hypertrophic subaortic stenosis). Circulation 47:137'-144, 1971 Ko/ibash et a/. • Idiopathic Hypertrophic Subaortic Stenosis
Downloaded from https://annals.org by Tulane University user on 12/08/2018
793
12. WIGLE ED, AUGER P, MARQUIS Y: Muscular subaortic stenosis
(the direct relation between the intraventricular pressure difference and the left ventricular ejection time). Circulation 46:3644, 1967 13. SIMON AL, ROSS JJ, GAULT JH: Angiographic anatomy of the
left ventricle and mitral valve in idiopathic hypertrophic subaortic stenosis. Circulation 36:852-867, 1967 14. LEWIS RP, BOUDOULAS H, FORESTER WF, et al: Shortening of
electromechanical systole as a manifestation of excessive adrenergic stimulation in acute myocardial infarction. Circulation 46:856-862, 1972 15. WIGLE ED, DAVID PR, LABRASSE CJ, et al: Muscular subaortic
stenosis. Am J Cardiol 15:761-772, 1965 16. LEWIS RP, BRISTOW JD, FARREHI C, et al: Idiopathic left ven-
tricular hypertrophy. Am J Med 38:842-852, 1965 17. WIGLE ED, ADELMAN AG, AUGER P: Mitral regurgitation in
muscular subaortic stenosis. Am J Cardiol 24:698-706, 1969 18. PRITCHARD JA: Changes in the blood volume during pregnancy and delivery. Anesthesiology 26:393-399, 1965 19. PRITCHARD J A, ADAMS RH: Erythrocyte production and destruc-
794
June 1975 • Annals of Internal Medicine • Volume 82 • Number 6
Downloaded from https://annals.org by Tulane University user on 12/08/2018
tion during pregnancy. Am J Obstet Gynecol 79:750-757, 1960 20. SCOTT DB, KERR MG: Inferior vena cava pressure in late pregnancy. / Obstet Gynaecol Br Commonw 70:1044-1049, 1963 21. LEES MM, TAYLOR SH, SCOTT OB, et al: The circulatory effects
of recumbent postural change in late pregnancy. Clin Sci 32: 453-465, 1967 22. ADAMS
JQ, ALEXANDER
AM:
Alterations
in
cardiovascular
physiology during labor. Obstet Gynecol 12:542-549, 1958 23. VECHT RJ, OAKLEY CM: Infective endocarditis in three patients with hypertrophic obstructive cardiomyopathy. Br Med 7 2:455459, 1968 24. BOITEAU GM, ALLENSTEIN BJ: Hypertrophic subaortic stenosis. Am J Cardiol 8:614-623, 1961 25. ROBINSON JL, RICH JM, WEISSLER AM: Differential effects of
propranolol on the chronotropic and inotropic response to isoproterenol in man (abstract). Am J Cardiol 31:155, 1973 26. SHAND DG, NUCKOLLS MS, OATES JA: Plasma propranolol levels
in adults with observations in four children. Clin Pharmacol Ther 11:112-120, 1970
