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The use of the Valsalva maneuver to differentiate fixed-orifice aortic stenosis from muscular subaortic stenosis
The use of the Valsalva differentiate fixed-orifice muscular
subaortic
maneuver to aortic stenosis
from
stenosis
Frank I. Marcus, M.D.* Robert C. Jones, M.D., F.A.C.P.** Washington, D. C.
P
atients with muscular hypertrophy of the left ventricular outflow tract commonly present with signs and symptoms simulating fixed valvular aortic stenosis. The points of differentiation favoring muscular subaortic stenosis are the apical location of the systolic murmur, the quick rising or double-peaked peripheral pulse contour, the absence of an aortic ejection sound, and the lack of a diastolic murmur of aortic insufficiency.‘v2 In the chest roentgenogram of the patient with muscular subaortic stenosis, aortic valvular calcification will not be present, and poststenotic dilatation of the aorta will seldom be seen. Nevertheless, it is often difficult to be certain of the type of left obstruction ventricular outflow after thorough clinical evaluation. Laboratory procedures used to differentiate muscular subaortic stenosis from fixed-orifice aortic stenosis include left ventricular angiocardiography3v4 as well as a decrease in the amplitude of the peripheral pulse after a premature beat.5 One of us (F. I. M.) observed that the Valsalva maneuver serves to accentuate the degree of outflow obstruction in patients with muscular subaortic stenosis.6 It was suggested that in patients with fixed-
orifice aortic stenosis the Valsalva maneuver should not cause an increase in the degree of obstruction.6 Rather, with a diminished flow across the valve, the left ventricular-aortic systolic gradient should decrease. Thus, the difference in hemodynamic response should differentiate these two conditions. Similar observations were made by Braunwald and associates,’ and their data were in agreement with this hypothesis. It is the purpose of this paper to present our experience based on simultaneously recorded pressures in the left ventricle and in a peripheral artery in patients with fixed-orifice and muscular subaortic stenosis, in order to verify further that the hemodynamic response is of aid in differential diagnosis. Case selection
From Jan 1, 1963 to Jan. 1, 1964, the response to the Valsalva maneuver was recorded in 1.5 patients undergoing left heart catheterization for suspected aortic outflow obstruction. Ten with fixed stenosis and 3 with muscular subaortic stenosis were encountered. Of those with fised-orifice stenosis, 3 have undergone surgery. Two had valvular
Received for publication June 6. 1964. *Markle Scholar in Medical Science; Assistant Professor of Medicine, Georgetown University School of Medicine; of Cardiology, Georgetown University Medical Division. District of Columbia General Hospital, Washington, **Assistant Chief of Cardiology, Walter Reed Army Medical Center. Washington, D. C.
473
Chief D. C.
.‘It rest
During
Valsnicu wzat2wwr ~_-_-_-.-
____~--_--
Patient
L v systolic pressure (mm.
HE)
Arterial systolic presswe (mm. Hg)
/ j :
Peak L1’ arterial systolic gradied
1 (mm.
! LV
systolic
pressure
Hg)
(mm.
Hg)
Arteriui / systolic
j ~ Change irt i L V systolic
i pressure
/
1 (mm.
j (mm.
Ng)
pressure
--..--Ckuw@! irt artekial : systolic 1
Hg)
pressure
I (mm.
Muscular Subaortic R. H. A. H. M. B.
Stenosis 118 158 184
118 1.58 104
0 0 SO
133 200 214
99 125 92
+15 +42
Fixed-Orifice Aortic M. A. R. W. R. B. H. E. D. E. I’. G. G. c. c. J. F. I<. R. S. IL D. A. N. s. G.
Stenosis 110 172 143 15.5 172 17.5 160 lil 220 240
106 150 115 117 130 129 96 100 140 9.5
4 22 28 38 42 46 64 71 80 14.5
104 160 123 130 127 180 130 120 185 17.5
95 147 98 88 113 145 7% 80 108 95
-6-l -12 -20 -25 -45 +5 -30 -51 -35 -65
-18 -20 -32 -30
No Left Ventricular s. c. D. A.
Outflow 135 120
0 0
102 7%
102 7%
-33 -42
-33 -47
Obstruction 135 125
lesions, and one had a subvalvular diaphragm. Seven others with fixed-orifice obstruction had clinical and hemodynamic findings in accord with this type of lesion. All but one (Patient E. D.) had either an aortic ejection sound, an aortic diastolic murmur, or poststenotic aortic dilatationfindings exceedingly uncommon in patients with muscular subaortic stenosis. The pulse pressure after the premature beat increased in all of the patients with fixed-orifice stenosis. Two of the 3 subjects with muscular subaortic stenosis (A. H. and R. H.) had diagnostic left ventricular angiocardiograms. Patient A. H. was the subject of a previous report.6 In the third patient the diagnosis was verified by the reproducible decline in the pulse pressure after the premature beat. Two patients presented clinically with features that were suggestive of muscular subaortic stenosis. They illustrate the response of the Valsalva maneuver in the individual without left ventricular out-
Hg)
-19 -33 -12
$30
-2 -3 -17 -29 -17
+I6
flow obstruction, since a left ventricularaortic systolic gradient could not be demonstrated at rest, nor could obstruction be elicited after the inhalation of amyl nitrite8 or by the infusion of isoproterenol at a rate of 3 I*g per minute.g-*l Methods The patients mere studied in either the cardiovascular laboratories of the District of Columbia General Hospital or the Walter Reed Armv Medical Center.* Left heart catheterization was performed by the retrograde femoral or by the transseptal technique. Simultaneous left ventricular and arterial pressures were inscribed on an Electronics for Medicine recorder, using P23Db Statham strain gauges. The Valsalva maneuver was performed with the patient in the supine position. In children under 10 years of age, increased intrathoracic pressure was produced by *Patient M. B. was catheterized by Georgetown University Hospital.
Dr.
M.
Criscitiello
at
Volume
Number
69
Use of Valsalva maneuver to differentiate
4
the anesthetist exerting pressure on the breathing bag for 15 to 20 seconds. Although intrapleural pressures were not measured, the degree of straining was adequate as indicated by the rise in ventricular end-diastolic pressure.12 The systolic pressures were measured immediately prior to straining, during peak Valsalva effect when the brachial arterial pulse pressure showed maximum decline, and after release of straining. It was noted that during performance of the Valsalva maneuver the patient may move or tense the muscles of the extremities sufficiently to alter the position of the arterial needle and cause interference with adequate transmission of the pressure. The damped arterial pulse pressure recorded will read erroneously low and lead to the interpretation of an increase in the systolic gradient when no increase exists. This pitfall may be avoided by instructing the patient to avoid tension of the muscles of the extremities during straining, and by observation of the needle in the peripheral vessel while the test is being performed.
BEFORE V&SALVA
WRING VAlSALVA
PREGGu~IE GRADIENT In mm tlg
60
40
20
Fig. 1. Change in left ventricular-arterial systolic gradient before and during the Valsalva maneuver. The striking increase in gradient observed in patients with muscular subaortic stenosis contrasts with the unchanged or decreased gradient in those with fixed-orifice aortic stenosis.
types of stenosis
475
Results
The data, summarized in Fig. 1 and Table I, indicate that the hemodynamic response in the patients with muscular subaortic stenosis differs from that observed in patients with fised-orifice aortic stenosis. In the 3 patients with muscular obstruction, there was an increment of 15 to 42 mm. Hg in left ventricular systolic pressure during peak Valsalva effect. In contrast, the patients with fixed-orifice stenosis, with one exception (Patient G. C.), demonstrated a decline in left ventricular systolic pressure. Characteristic responses are illustrated in Figs. 2 and 3. In patients in all categories, excluding Patient G. C., the arterial systolic pressure fell. The divergence in left ventricular and arterial pressures in the group with muscular subaortic stenosis resulted in an increase in the left ventricular outflow pressure gradient (Fig. 1). With fixed-orifice stenosis, the left ventricular and brachial arterial systolic pressures were altered in parallel. Usually, the left ventricular systolic pressure declined more than the arterial pressure, and the systolic gradient diminished. Discussion
The response to the Valsalva maneuver was observed to differ in subjects with fixedorifice aortic stenosis as compared to those with muscular subaortic stenosis. In the presence of fixed-orifice aortic stenosis the decrease in venous filling of the heart during straining results in a marked decrease in stroke output.? As flow diminishes across the fixed obstruction, both left ventricular and aortic systolic pressures fall. Usually, left ventricular pressure falls disproportionately since the relationship of gradient to flow is such that, as the flow is halved, the gradient will fall to one fourth of the original value.13 The unique response of Patient G.’ C. deserves comment. This patient with stenosis of the tricuspid, mitral, and aortic valves responded to straining by an increase in both left ventricular and brachial arterial systolic pressures. This “squarewave” response has been described in patients with congestive heart failure, as well as in those with large atria1 septal defects.14s15Since the “square-wave” response
AC3RTtC VALVULAR
STENOStS
Fig. 2. I,eft \.entricular (L. I’. i and brachial arterial (B.-4.) pressure pulsesrecorded sinlultaneously during the performance of the Valsalva test in Patient E. I’. G. with aortic stenosis and insufficimcy. Sote the concomitant fall in both pressures. There is a disappearance of the bisferiens pulse in the brarhinl arterial pressure tracing. Paper speed of 25 mm. per second.
Fig. 3. Circulatory response to straining in Patient R. H. with muscular subaortic stenosis. The characteristic. brachial arterial (B.A.) pressure pulse contour was elicited at peak Valsalva response. /,. V.: Left ventriculnr pressure pulse. Paper speed of 2.5 mm. per second.
can be reproduced in normal individuals after rapid infusion of whole blood, or abolished in patients with congestive heart failure when cuffs are inflated on the ertremities, it is thought to be related to a large central blood volume or increased total intravascular volume.15Jfi Although the left ventricular systolic pressure increased xvith straining in this patient with valvular aortic stenosis, both the left ventricular and arterial systolic pressures rose concomitantly. There was a decrease of 11 111111. Hg in the gradient. Therefore, the square-wave response in a patient with fixed-orifice aortic stenosis can readily- be differentiated from the divergent left ventricular and arterial pressures observed during straining in patients with muscular subaortic stenosis. The increased obstruction seen in the presence of muscular subaortic stenosis during straining may be explained by a diminution in venous return, which result-s in a decrease in cardiac dimensions and :I
further approximation of the already narrowed outflow track6 It would be anticipated that left ventricular systolic pressures would rise during the Valsalva maneuver, as a consequence of increased obstruction, and this was observed in the 3 patients with this condition. However, this response may be modified by other factors, such as the contractile properties of the myocardium in response to the vagal stimulation induced by straining, as well as by the degree of change in the peripheral resistance. This may be the esplanation for the variable response of the left ventricular systolic pressure during peak Valsalva effect observed by others.’ Nevertheless, the disproportionate fall in arterial pressure that yields an increased systolic gradient has been a consistent finding. The characteristic hemodynamic responses to the Valsalva maneuver as described in this paper and by others7 have been consistent- and should, therefore, IKJ
Use oj Valsalva maneuver to diferentiate
useful in differentiating muscular subaortic from fixed-orifice aortic obstruction. , In previous publications it was demonstrated that the Valsalva test was of aid in establishing the diagnosis of muscular subaortic stenosis in a patient who did not have a left ventricular-brachial artery systolic gradient during the control period.6,7 This was confirmed in Patient R. H., in whom a diagnostic gradient was induced during straining. (Fig. 3). In this patient, as in Patient A. H., the subject previously reported on,6 there was an increase in the peripheral pulse pressure after the premature beat at rest, but a decrease just after release from straining. This observation demonstrated that the “paradoxical” decrease in the pulse pressure after the premature beat, although characteristic of the response seen in patients with muscular subaortic stenosis, may not be present when the patient is in the control state, because of the variable degree of outflow obstruction. During the performance of the Valsalva maneuver it is instructive to study the contour of the peripheral pulse as the amplitude decreases. In the patient with fixed valvular aortic stenosis, the dicrotic notch is lowered and disappears as it reaches the diastolic pressure. In patients with valvular aortic stenosis and aortic insufficiency, the second peak of the bisferiens pulse diminishes and eventually disappears as the amplitude of the pulse decreases57 (Fig. 2). In contrast, in patients with muscular subaortic stenosis, the doublepeaked contour remains, or may appear at the height of the Valsalva test (Fig. 3). The relative position of the dicrotic notch is not significantly changed during straining. These observations suggest that evidence of muscular subaortic stenosis can be obtained by the direct recording of the peripheral pulse at rest and during the Valsalva maneuver in a patient suspected of having this entity. Currently, the protocol used to diagnose muscular subaortic stenosis is as follows: Left ventricular and peripheral pulse pressures are recorded simultaneously. If a systolic gradient is present, premature ventricular beats are induced. If the pulse pressure after the premature beat is diminished, the diagnosis of muscular sub-
types of stenosis
477
aortic stenosis is established. The type of outflow obstruction is further verified by the response to the Valsalva maneuver. If a gradient is not observed, the patient inhales amyl nitrite, and the left ventricular and peripheral pulses are continuously recorded.8 If no gradient is induced, it is considered unlikely that left ventricular outflow obstruction is present, since this provocative test has been observed to be more sensitive than either isoproterenol or straining in evoking a gradient.‘* If a systolic gradient is seen, it is interpreted as evidence of outflow obstruction of undetermined type, since a similar response is observed in fixed-orifice aortic stenosis. The response to the Valsalva maneuver is then used in order to differentiate fixedorifice aortic stenosis from muscular subaortic stenosis. Further verification of the nonfixed nature of the obstruction may be obtained by observing the response after the premature beat during the height of amyl-nitrite effect. Intravenous isoproterenol may also be used to induce a gradient in muscular subaortic stenosis,g-ll but amvl nitrite is preferred since the latter drug ‘ls less likely to induce ventricular ectopic beats, and since it is probably more sensitive than isoproterenol in eliciting evidence of left ventricular obstruction. Nitroglycerin ma) be substituted for amyl nitrite.7 However, amyl nitrite is preferred to nitroglycerin since the left ventricular-systolic arterial gradient induced by amyl nitrite is of short duration. With nitroglycerin, an unespectedly long effect, sometimes accompanied by chest pain, has been observed. During the peak effect of the drugs employed, inspection of the contour of the peripheral pulse adds confirmation with regard to the type of outflow obstruction. Summary
The response to the Valsalva maneuver was observed in 10 patients with fised-orifice aortic stenosis and 3 patients with muscular subaortic stenosis. In the patients a-ith fixed-orifice aortic stenosis the peak systolic gradient either remained essentially unchanged or decreased. This was due to a decrease in left ventricular systolic pressure equal to or greater than the decline in arterial pressure.
In the subjects with muscular subaortic stenosis the peak systolic gradient increased with straining, an effect caused b>a rise in left ventricular systolic pressure while arterial systolic pressure declined. The mechanism for the difference in the responses was discussed. The peripheral pulse tracing during the Valsalva maneuver n-as found to differ in contour in the two groups studied. The conclusion is that the response to the Valsalva maneuver is of aid in the hemodynamic differentiation of fixed-orifice aortic stenosis from tmuscular subaortic stenosis. \Vc wish to thank Dr. Modes&o Criscitiello, Assistant Professor of Medicine, Georgetown ITni\-ersity School of Medicine, for permission to publish the data on Patient M. B., and Dr. Joseph K. I’erloff, Assistant Professor of Medicine, Georgetown Irnversity School of Medicine, for his critical review of the manuscript. We are also grateful for the sec.retarial assistance of Mrs. Helen S. Sharp. REFERENCES 1.
Calvin, J. L., Perloff, J. K., Conrad, P. W., and Hufnagel, C. .q. : Idiopathic hypertrophic subaortic stenosis, AM. HEART J. 63:477, 1962. 2. Menges, H., Jr., Brandenburg, R. O., and Brown, A. L.: The clinical, hemodynamic and pathological diagnosis of muscular subvalvular stenosis, Circulation 24:1126, 1961. aortic 3. Braunwald. E.. Morrow. A. G.. Cornell. W. I’.. Aygen, M.’ M.1 and Hiibish, ,?. F.: Idiopathid hypertrophic subaortic stenosis, Lqnl. J. Med. 29:924, 1960. 4. Cohen, J., Effat, H., Goodwin, J. F., Oakley, C. M., and Steiner, R. E.: Hypertrophic obstructive cardiomyopathy, Brit. Heart J. 26:16, 1964. 5. Brockenbrough E. C., Braunwald, E., and Morrow, A. G.: A hemodynamic technic for the detection of hypertrophic subaortic stenosis, Circulation 23:189, 1961. 6. Marcus, F. I., Westura, E. E., and Summa, J. The hemodynamic effect of the Valsalva ma-
neurer
111 muscular suhaortic s1enosih. .\M. J. 67:324, 1961. (‘.ibstract) Clill. Req. 12:28, 1964. 7. Braunwa!d, E., Oldham, H. N.. Jr., lions. J., Tr.. Linhart. 1. W. Mason. I>.. and Fort. I,.. iI1:. &xlatory responsk of pat&its . The . with ldlopathx hypertrophlc subaortic stenosis to nitroglycerin and to the \‘alsalva maneu\‘er, Circulation 29:422, 1961. 8. Marcus, F. I., Perloff, J. K., and DeLeon, A. C. The use of amyl nitrite in the hemodynamic assessment of aortic valvular and muscular subaortic stenosis, Am. IIEART J. 68:448, 1964. 9. Braunwald, E., and Ebert, P. .\.: Hemodynamic alterations in idiopathic hypertrophic subaortic stenosis induced by sympathomimetic drugs, Am. J. Cardiol. 10:489, 1962. 10. Whalen, R. E., Cohen, :I. I., Sumner, Ii. G., and McIntosh, H. D.: Demonstration of the dynamic nature of idiopathic hypertrophic subaortic stenosis. Am. T. Cardiol. 114.196.1. 11. Krasnow, N., Roiett, E”.. Hood, L%‘. B., Yurchak, I’. M., and Gorlin, R.: Reversible obstruction of the x-entriculnr outflow tract, Am. J. Cardiol. ll:l, 1963. 12. Lauson, H. D.. Bloomlield, R. .1., and Cournand, A.: The influence of the respiration on the circulation in man, r1m. J. Med. 1:315, 1946. Ii., and Gorlin, S. G.: Hydraulic form13. Gorlin, ula for calculation of the area of the stenotic mitral valve, other cardiac valves, and central circulatorvshunts. I.. AM. HEART 1. 41:1, 1951. 14. Gorlin, R:, Knowles,’ J. H., and Storey, C. F. The Valsalva maneuver as a test of cardiac function, Am. J. Med. 22:197, 1957. E. W., Oliver, G. C., Swanson, M. 15. Hancock, I., and Hultgren. H. N.: Valsalva’s maneuver ;n atria1 septal defect, All. HEART J. 65:50, 1963. . J. D., and i\?lkins, 16. Judson, W. I:., Hatcher, R. W.: Blood Dressure responses to the \‘a]salva maneuve; in cardiacpatients with and without congestive failure, Circulation 11:889, 1955. A. E., and Neilson, G. H.: The Valsalva 17. Doyle, maneuver in aortic valve disease, Brit. Heart J. 19:525, 1957. 18. Massumi, R. : Personal communication HEART
subaortic
maneuver to aortic stenosis
from
stenosis
Frank I. Marcus, M.D.* Robert C. Jones, M.D., F.A.C.P.** Washington, D. C.
P
atients with muscular hypertrophy of the left ventricular outflow tract commonly present with signs and symptoms simulating fixed valvular aortic stenosis. The points of differentiation favoring muscular subaortic stenosis are the apical location of the systolic murmur, the quick rising or double-peaked peripheral pulse contour, the absence of an aortic ejection sound, and the lack of a diastolic murmur of aortic insufficiency.‘v2 In the chest roentgenogram of the patient with muscular subaortic stenosis, aortic valvular calcification will not be present, and poststenotic dilatation of the aorta will seldom be seen. Nevertheless, it is often difficult to be certain of the type of left obstruction ventricular outflow after thorough clinical evaluation. Laboratory procedures used to differentiate muscular subaortic stenosis from fixed-orifice aortic stenosis include left ventricular angiocardiography3v4 as well as a decrease in the amplitude of the peripheral pulse after a premature beat.5 One of us (F. I. M.) observed that the Valsalva maneuver serves to accentuate the degree of outflow obstruction in patients with muscular subaortic stenosis.6 It was suggested that in patients with fixed-
orifice aortic stenosis the Valsalva maneuver should not cause an increase in the degree of obstruction.6 Rather, with a diminished flow across the valve, the left ventricular-aortic systolic gradient should decrease. Thus, the difference in hemodynamic response should differentiate these two conditions. Similar observations were made by Braunwald and associates,’ and their data were in agreement with this hypothesis. It is the purpose of this paper to present our experience based on simultaneously recorded pressures in the left ventricle and in a peripheral artery in patients with fixed-orifice and muscular subaortic stenosis, in order to verify further that the hemodynamic response is of aid in differential diagnosis. Case selection
From Jan 1, 1963 to Jan. 1, 1964, the response to the Valsalva maneuver was recorded in 1.5 patients undergoing left heart catheterization for suspected aortic outflow obstruction. Ten with fixed stenosis and 3 with muscular subaortic stenosis were encountered. Of those with fised-orifice stenosis, 3 have undergone surgery. Two had valvular
Received for publication June 6. 1964. *Markle Scholar in Medical Science; Assistant Professor of Medicine, Georgetown University School of Medicine; of Cardiology, Georgetown University Medical Division. District of Columbia General Hospital, Washington, **Assistant Chief of Cardiology, Walter Reed Army Medical Center. Washington, D. C.
473
Chief D. C.
.‘It rest
During
Valsnicu wzat2wwr ~_-_-_-.-
____~--_--
Patient
L v systolic pressure (mm.
HE)
Arterial systolic presswe (mm. Hg)
/ j :
Peak L1’ arterial systolic gradied
1 (mm.
! LV
systolic
pressure
Hg)
(mm.
Hg)
Arteriui / systolic
j ~ Change irt i L V systolic
i pressure
/
1 (mm.
j (mm.
Ng)
pressure
--..--Ckuw@! irt artekial : systolic 1
Hg)
pressure
I (mm.
Muscular Subaortic R. H. A. H. M. B.
Stenosis 118 158 184
118 1.58 104
0 0 SO
133 200 214
99 125 92
+15 +42
Fixed-Orifice Aortic M. A. R. W. R. B. H. E. D. E. I’. G. G. c. c. J. F. I<. R. S. IL D. A. N. s. G.
Stenosis 110 172 143 15.5 172 17.5 160 lil 220 240
106 150 115 117 130 129 96 100 140 9.5
4 22 28 38 42 46 64 71 80 14.5
104 160 123 130 127 180 130 120 185 17.5
95 147 98 88 113 145 7% 80 108 95
-6-l -12 -20 -25 -45 +5 -30 -51 -35 -65
-18 -20 -32 -30
No Left Ventricular s. c. D. A.
Outflow 135 120
0 0
102 7%
102 7%
-33 -42
-33 -47
Obstruction 135 125
lesions, and one had a subvalvular diaphragm. Seven others with fixed-orifice obstruction had clinical and hemodynamic findings in accord with this type of lesion. All but one (Patient E. D.) had either an aortic ejection sound, an aortic diastolic murmur, or poststenotic aortic dilatationfindings exceedingly uncommon in patients with muscular subaortic stenosis. The pulse pressure after the premature beat increased in all of the patients with fixed-orifice stenosis. Two of the 3 subjects with muscular subaortic stenosis (A. H. and R. H.) had diagnostic left ventricular angiocardiograms. Patient A. H. was the subject of a previous report.6 In the third patient the diagnosis was verified by the reproducible decline in the pulse pressure after the premature beat. Two patients presented clinically with features that were suggestive of muscular subaortic stenosis. They illustrate the response of the Valsalva maneuver in the individual without left ventricular out-
Hg)
-19 -33 -12
$30
-2 -3 -17 -29 -17
+I6
flow obstruction, since a left ventricularaortic systolic gradient could not be demonstrated at rest, nor could obstruction be elicited after the inhalation of amyl nitrite8 or by the infusion of isoproterenol at a rate of 3 I*g per minute.g-*l Methods The patients mere studied in either the cardiovascular laboratories of the District of Columbia General Hospital or the Walter Reed Armv Medical Center.* Left heart catheterization was performed by the retrograde femoral or by the transseptal technique. Simultaneous left ventricular and arterial pressures were inscribed on an Electronics for Medicine recorder, using P23Db Statham strain gauges. The Valsalva maneuver was performed with the patient in the supine position. In children under 10 years of age, increased intrathoracic pressure was produced by *Patient M. B. was catheterized by Georgetown University Hospital.
Dr.
M.
Criscitiello
at
Volume
Number
69
Use of Valsalva maneuver to differentiate
4
the anesthetist exerting pressure on the breathing bag for 15 to 20 seconds. Although intrapleural pressures were not measured, the degree of straining was adequate as indicated by the rise in ventricular end-diastolic pressure.12 The systolic pressures were measured immediately prior to straining, during peak Valsalva effect when the brachial arterial pulse pressure showed maximum decline, and after release of straining. It was noted that during performance of the Valsalva maneuver the patient may move or tense the muscles of the extremities sufficiently to alter the position of the arterial needle and cause interference with adequate transmission of the pressure. The damped arterial pulse pressure recorded will read erroneously low and lead to the interpretation of an increase in the systolic gradient when no increase exists. This pitfall may be avoided by instructing the patient to avoid tension of the muscles of the extremities during straining, and by observation of the needle in the peripheral vessel while the test is being performed.
BEFORE V&SALVA
WRING VAlSALVA
PREGGu~IE GRADIENT In mm tlg
60
40
20
Fig. 1. Change in left ventricular-arterial systolic gradient before and during the Valsalva maneuver. The striking increase in gradient observed in patients with muscular subaortic stenosis contrasts with the unchanged or decreased gradient in those with fixed-orifice aortic stenosis.
types of stenosis
475
Results
The data, summarized in Fig. 1 and Table I, indicate that the hemodynamic response in the patients with muscular subaortic stenosis differs from that observed in patients with fised-orifice aortic stenosis. In the 3 patients with muscular obstruction, there was an increment of 15 to 42 mm. Hg in left ventricular systolic pressure during peak Valsalva effect. In contrast, the patients with fixed-orifice stenosis, with one exception (Patient G. C.), demonstrated a decline in left ventricular systolic pressure. Characteristic responses are illustrated in Figs. 2 and 3. In patients in all categories, excluding Patient G. C., the arterial systolic pressure fell. The divergence in left ventricular and arterial pressures in the group with muscular subaortic stenosis resulted in an increase in the left ventricular outflow pressure gradient (Fig. 1). With fixed-orifice stenosis, the left ventricular and brachial arterial systolic pressures were altered in parallel. Usually, the left ventricular systolic pressure declined more than the arterial pressure, and the systolic gradient diminished. Discussion
The response to the Valsalva maneuver was observed to differ in subjects with fixedorifice aortic stenosis as compared to those with muscular subaortic stenosis. In the presence of fixed-orifice aortic stenosis the decrease in venous filling of the heart during straining results in a marked decrease in stroke output.? As flow diminishes across the fixed obstruction, both left ventricular and aortic systolic pressures fall. Usually, left ventricular pressure falls disproportionately since the relationship of gradient to flow is such that, as the flow is halved, the gradient will fall to one fourth of the original value.13 The unique response of Patient G.’ C. deserves comment. This patient with stenosis of the tricuspid, mitral, and aortic valves responded to straining by an increase in both left ventricular and brachial arterial systolic pressures. This “squarewave” response has been described in patients with congestive heart failure, as well as in those with large atria1 septal defects.14s15Since the “square-wave” response
AC3RTtC VALVULAR
STENOStS
Fig. 2. I,eft \.entricular (L. I’. i and brachial arterial (B.-4.) pressure pulsesrecorded sinlultaneously during the performance of the Valsalva test in Patient E. I’. G. with aortic stenosis and insufficimcy. Sote the concomitant fall in both pressures. There is a disappearance of the bisferiens pulse in the brarhinl arterial pressure tracing. Paper speed of 25 mm. per second.
Fig. 3. Circulatory response to straining in Patient R. H. with muscular subaortic stenosis. The characteristic. brachial arterial (B.A.) pressure pulse contour was elicited at peak Valsalva response. /,. V.: Left ventriculnr pressure pulse. Paper speed of 2.5 mm. per second.
can be reproduced in normal individuals after rapid infusion of whole blood, or abolished in patients with congestive heart failure when cuffs are inflated on the ertremities, it is thought to be related to a large central blood volume or increased total intravascular volume.15Jfi Although the left ventricular systolic pressure increased xvith straining in this patient with valvular aortic stenosis, both the left ventricular and arterial systolic pressures rose concomitantly. There was a decrease of 11 111111. Hg in the gradient. Therefore, the square-wave response in a patient with fixed-orifice aortic stenosis can readily- be differentiated from the divergent left ventricular and arterial pressures observed during straining in patients with muscular subaortic stenosis. The increased obstruction seen in the presence of muscular subaortic stenosis during straining may be explained by a diminution in venous return, which result-s in a decrease in cardiac dimensions and :I
further approximation of the already narrowed outflow track6 It would be anticipated that left ventricular systolic pressures would rise during the Valsalva maneuver, as a consequence of increased obstruction, and this was observed in the 3 patients with this condition. However, this response may be modified by other factors, such as the contractile properties of the myocardium in response to the vagal stimulation induced by straining, as well as by the degree of change in the peripheral resistance. This may be the esplanation for the variable response of the left ventricular systolic pressure during peak Valsalva effect observed by others.’ Nevertheless, the disproportionate fall in arterial pressure that yields an increased systolic gradient has been a consistent finding. The characteristic hemodynamic responses to the Valsalva maneuver as described in this paper and by others7 have been consistent- and should, therefore, IKJ
Use oj Valsalva maneuver to diferentiate
useful in differentiating muscular subaortic from fixed-orifice aortic obstruction. , In previous publications it was demonstrated that the Valsalva test was of aid in establishing the diagnosis of muscular subaortic stenosis in a patient who did not have a left ventricular-brachial artery systolic gradient during the control period.6,7 This was confirmed in Patient R. H., in whom a diagnostic gradient was induced during straining. (Fig. 3). In this patient, as in Patient A. H., the subject previously reported on,6 there was an increase in the peripheral pulse pressure after the premature beat at rest, but a decrease just after release from straining. This observation demonstrated that the “paradoxical” decrease in the pulse pressure after the premature beat, although characteristic of the response seen in patients with muscular subaortic stenosis, may not be present when the patient is in the control state, because of the variable degree of outflow obstruction. During the performance of the Valsalva maneuver it is instructive to study the contour of the peripheral pulse as the amplitude decreases. In the patient with fixed valvular aortic stenosis, the dicrotic notch is lowered and disappears as it reaches the diastolic pressure. In patients with valvular aortic stenosis and aortic insufficiency, the second peak of the bisferiens pulse diminishes and eventually disappears as the amplitude of the pulse decreases57 (Fig. 2). In contrast, in patients with muscular subaortic stenosis, the doublepeaked contour remains, or may appear at the height of the Valsalva test (Fig. 3). The relative position of the dicrotic notch is not significantly changed during straining. These observations suggest that evidence of muscular subaortic stenosis can be obtained by the direct recording of the peripheral pulse at rest and during the Valsalva maneuver in a patient suspected of having this entity. Currently, the protocol used to diagnose muscular subaortic stenosis is as follows: Left ventricular and peripheral pulse pressures are recorded simultaneously. If a systolic gradient is present, premature ventricular beats are induced. If the pulse pressure after the premature beat is diminished, the diagnosis of muscular sub-
types of stenosis
477
aortic stenosis is established. The type of outflow obstruction is further verified by the response to the Valsalva maneuver. If a gradient is not observed, the patient inhales amyl nitrite, and the left ventricular and peripheral pulses are continuously recorded.8 If no gradient is induced, it is considered unlikely that left ventricular outflow obstruction is present, since this provocative test has been observed to be more sensitive than either isoproterenol or straining in evoking a gradient.‘* If a systolic gradient is seen, it is interpreted as evidence of outflow obstruction of undetermined type, since a similar response is observed in fixed-orifice aortic stenosis. The response to the Valsalva maneuver is then used in order to differentiate fixedorifice aortic stenosis from muscular subaortic stenosis. Further verification of the nonfixed nature of the obstruction may be obtained by observing the response after the premature beat during the height of amyl-nitrite effect. Intravenous isoproterenol may also be used to induce a gradient in muscular subaortic stenosis,g-ll but amvl nitrite is preferred since the latter drug ‘ls less likely to induce ventricular ectopic beats, and since it is probably more sensitive than isoproterenol in eliciting evidence of left ventricular obstruction. Nitroglycerin ma) be substituted for amyl nitrite.7 However, amyl nitrite is preferred to nitroglycerin since the left ventricular-systolic arterial gradient induced by amyl nitrite is of short duration. With nitroglycerin, an unespectedly long effect, sometimes accompanied by chest pain, has been observed. During the peak effect of the drugs employed, inspection of the contour of the peripheral pulse adds confirmation with regard to the type of outflow obstruction. Summary
The response to the Valsalva maneuver was observed in 10 patients with fised-orifice aortic stenosis and 3 patients with muscular subaortic stenosis. In the patients a-ith fixed-orifice aortic stenosis the peak systolic gradient either remained essentially unchanged or decreased. This was due to a decrease in left ventricular systolic pressure equal to or greater than the decline in arterial pressure.
In the subjects with muscular subaortic stenosis the peak systolic gradient increased with straining, an effect caused b>a rise in left ventricular systolic pressure while arterial systolic pressure declined. The mechanism for the difference in the responses was discussed. The peripheral pulse tracing during the Valsalva maneuver n-as found to differ in contour in the two groups studied. The conclusion is that the response to the Valsalva maneuver is of aid in the hemodynamic differentiation of fixed-orifice aortic stenosis from tmuscular subaortic stenosis. \Vc wish to thank Dr. Modes&o Criscitiello, Assistant Professor of Medicine, Georgetown ITni\-ersity School of Medicine, for permission to publish the data on Patient M. B., and Dr. Joseph K. I’erloff, Assistant Professor of Medicine, Georgetown Irnversity School of Medicine, for his critical review of the manuscript. We are also grateful for the sec.retarial assistance of Mrs. Helen S. Sharp. REFERENCES 1.
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