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Double-chambered Left Ventricle: Submitral Accessory Valvular Tissue Causing Inlet and Outlet Obstruction
Double-chambered Left Ventricle: Submitral Accessory Valvular Tissue Causing Inlet and Outlet Obstruction Mario Albertucci, MD, Roberto M. Lang, MD, Robert B. Karp, MD, Richard H. Marcus, MD, and Duane Follman, MD, Chicago, Illinois
We report a patient with a large submittal ridge of muscular and fibrous tissue that divides the left ventricle into two distinct chambers causing inlet and outlet obstruction. Doppler echocardiography revealed obstruction to both filling and ejection. Echocardiography demonstrated that the obstruction was in series with the mitral apparatus. Surgery was done with resection of much of this ring of tissue. Subsequent studies revealed morphologic and hemodynamic improvement. ( J AM Soc EcHOCARDIOGR 1994;7:67-71.)
Subdivision of the left ventricle into two distinct chambers is a rare cardiac anomaly that usually takes the form of a diverticulum attached to the main left ventricular chamber. 1 Less commonly, a distinct mid ventricular muscular obstruction separating the left ventricular cavity into two chambers has been de scribed. We report a double-chambered left ventricle caused by "in series" duplication of the mitral ap paratus. Case Report A 21-year-old female college student had progressive shortness of breath and fatigue on exercise. Cardiac auscultation revealed normal first and second heart sounds, a grade 4/6 crescendo-decrescendo systolic murmur over the precordium, and an early 1 I 4 apical diastolic rumble. The hemoglobin level was 13 gm/dl, the hematocrit level was 41%, and the oxygen saturation 98% on room air. On chest roentgenogram, heart size was at the upper limits of normal with left ventricular prominence. An azygos pseudolobe was present, but the lung fields were clear. The electrocardiogram showed normal sinus rhythm at a rate of 80 beats/min, left axis deviation, and a left bundle branch block. Transthoracic and transesophageal echocar diography demonstrated a two-chambered left ventricle (Figure 1) comprising a large proximal chamber separated
from a small thick-walled distal chamber by a fibromuscular ridge projecting from the bases of the papillary muscles. The mean systolic gradient (from distal to proximal cham ber) was calculated to be of 64 mm Hg while color flow imaging disclosed a mushroom-shaped jet similar to that observed across stenotic aortic valves (Figure 2, top, and Figure 3). A diastolic gradient of 14 mm Hg between the two chambers (from proximal to distal chamber) was de tected by continuous wave Doppler (Figure 3) while color flow imaging during diastole revealed a candle-flame jet similar in appearance to that seen across stenotic mitral valves (Figure 2, bottom). Ultrafast computed tomography (cine-CT) clearly delineated the submittal accessory val vular tissue causing inlet and outlet obstruction (Figure 4). Left ventriculography demonstrated an incomplete in traventricular membrane at the level of the papillary mus cles, which divided the ventricle into proximal and distal chambers. Dye flowed freely between the two chambers via a channel in the anterior superior portion of the ven tricle. A dynamic systolic pressure gradient was demon strated between the distal and proximal left ventricular chambers across the fibromuscular ring by use of a two sensor micromanometer with its tip in the distal chamber. Peak systolic pressures in the distal and proximal chambers were 225 mm Hg and 165 mm Hg, respectively. There was no pressure gradient across the aortic valve and no mitral regurgitation.
From the Departments of Cardiac Surgery and Cardiology, The Universiry of Chicago. Reprint requests: Robert B. Karp, MD, Section of Cardiac Sur gery, The University of Chicago, MC 5040, 5841 S. Maryland Ave., Chicago, IL 60637. Copyright © 1994 by the American Society ofEchocardiography. 0894-7317/94 $1.00 + .10 27/1149512
Operation Surgery was undertaken to relieve the midventricular obstruction. Median sternotomy was performed and car diopulmonary bypass was established. The heart was of normal size. The lateral aspect of the left ventricle was thickened midway between the atrioventricular groove and the apex. A standard left atriotomy was performed. The mitral valve and its chordae appeared normal but the pap
67
68 Albertucci et al.
Journal of the American Society of Echocardiography January-February 1994
Figure 1 A, Transthoracic and B, Transesophageal echocardiographic studies demonstrated a two-chambered left ventricle_ Distal and proximal left ventricular chambers are divided by what appears to be a fibromuscular ridge (arrow), which extends from the bases of the papillary muscles_ Distal chamber cavity size appears to be smaller and have relatively thicker walls than the proximal chamber. LA, Left atrium; MV, mitral valve; RV, right ventricle; LV, left ventricle.
illary muscles were thickened. Below the normal mitral valve apparatus, attached to the thickened papillary mus cles, was a discrete muscular ledge, supporting a fibrous structure that resembled a rudimentary mitral valve. This fibromuscular tissue impinged on the ventricular cavity, dividing the left ventricle into two separate chambers con nected by a channel l2 to 15 mm in diameter (Figure 5). Additional chordae tendineae were attached to the fibro muscular ridge. Four radial incisions from the central portion laterally
were made to open the passage from the mitral annulus to the apex. The radial incisions were then connected by re secting the intervening muscle and chordae tendineae. This maneuver relieved the obstruction to left ventricular out flow and allowed free flow of blood from the mitral valve toward the apex. The resection was limited by the attach ment of the mitral valve to the thickened and confluent papillary muscle. The mitral valve was found to be com petent when tested. After closure of the left atrium and deairing, cardiopulmonary bypass was weaned without dif
Journal of the American Society of Echocardiography Volume 7 Number l
Albertucci et al.
69
Figure 2 Top) Still-frame of two-dimensional echocardiogram of the left ventricle obtained from apical four-chamber view. Color flow imaging from apical view in systole shows a mush room-shaped jet similar to that observed in aortic stenosis. Note that jet has a mosaic appearance due to the high-velocity turbulent flow. Bottom) Color flow imaging in diastole demonstrates a candle flame appearance of the jet similar to that observed in mitral stenosis. Jet has a central blue wne due to color reversal from aliasing of high velocities. Peripheral wne is orange yellow, representing turbulence.
ficulty. Intraoperative transesophageal echocardiographic study revealed no systolic or diastolic gradient. Histologic diagnosis of the resected tissue indicated normal cardiac muscle with focal fibrosis and thickened valvular tissue. The postoperative course was unremarkable. Two months after surgery the patient was asymptomatic and resumed regular activities withouit limitations.
DISCUSSION
Subdivision of the right ventricle, which under nor mal conditions is divided into inlet and outlet por tions by the muscular ridge of the crista supraven tricularis and the trabecula septomarginalis, is more
Journal of the American Society of Echocardiography January-February 1994
70 Albertucci et al.
ECG
DIASTOLIC GRADIENT between proximal and distal . chambers
CW
DOPPLER SYSTOLIC GRADIENT between ,....____ distal and proximal chambers
11 i11 taa, 'I", "'I
"'
:!'u,,, , 'rt
,. 1sec I
,
.;
I
I
,
I
I
I
I
,
,
"' ,
1111 , 11 ,
1
u11
I ,
",·,
Figure 3 Continuous-wave (CW) Doppler tracing from the apical four-chamber view of antegrade (diastolic) and retrograde (systolic) "transmembrane flow." The mean transmembrane diastolic gradient (from proximal to distal chamber) was estimated to be 14 mm Hg. The mean systolic gradient (from distal to proximal chamber) was calculated to be 64 mm Hg.
Figure 4 Systolic frame ofan ultrafast computed tomographic scan obtained at the ventricular level clearly delineating the submittal accessory valvular tissue causing inlet and outlet obstruc tion. Note the narrow passage connecting the two left ventricular chambers (white arrowhead).
common than double-chambered left ventricle. 1 Left ventricular subdivision in this case was due to du plication of the mitral valve apparatus. The abnor mality consisted of an accessory papillary muscle and
chordae that bridge the middle of the left ventricle from the ventricular septum to the anterior papillary muscle. This anatomic arrangement caused a dia stolic flow gradient as well as significant dynamic
Journal of the American Society of Echocardiography Volume 7 Number l
Albertucci et al.
7l
Figure 5 Intraoperative photograph of the mitral valve and subvalvular structures exposed through a standard left atriotomy. The anterior papillary muscle and the large muscular ledge are visualized (arrow).
systolic obstruction. The mitral valve appeared to be normal. Brenner et al. 2 have described the echocardiogra phic features of left ventricular bands in infants and children. These false tendons or bands are fibromus cular structures that traverse the ventricular cavity. Occasionally, false tendons are extremely prominent and may attach to the septum by a small accessory papillary muscle, resulting in an "hourglass left ven tricle" deformity that does not result in significant systolic obstruction. In contrast, duplication of the mitral valve apparatus is rare. All previously described duplications have been in parallel, in the same plane as the annulus. 3· 5 This case appears to be the first case of mitral duplication "in series" causing inflow and outflow obstruction relieved by muscular resection. We Jould like to thank Lynn Weinert for her important contribution towards the preparation of the figures of this manuscript. The staff ofthe Non-Invasive Cardiac Imaging Laboratory and Cardiac Catheterization Laboratory are all
thanked for their contributions. In addition we would like to thank Daniel J. Murphy, Jr., MD, Jack L. Titus, MD, PhD, A.D. Pacifico, MD, and A.J. Tajik, MD, for sharing with us their expert opinions on the diagnosis and treat ment of this case.
REFERENCES l. Gearless LM, Partridge JB, Fiddler GI, Williams G, Scott 0. Two chambered left ventricle. Three new varieties. Br Heatt J 1981;46:278-84. 2. Brenner JI, Baker K, Ringel RE, Berman MA. Echocardio graphic evidence of left ventricular bands in infants and chil dren. JAm Coli Cardiol1984;3:1515-20. 3. Reed GE, Cortes LE, Clauss RH, Reppert EH. The surgical repair of duplication of the mitral orifice. Ann Thorac Surg 1970;9:81-5. 4. Schraft WC Jr, Lisa JR. Duplication of the mitral valve: case report and review of the literature. Am Heatt J 1950;39: 136 40. 5. Wigle ED. Duplication of the mitral valve. Br Heart J 1957;19:296-300.
We report a patient with a large submittal ridge of muscular and fibrous tissue that divides the left ventricle into two distinct chambers causing inlet and outlet obstruction. Doppler echocardiography revealed obstruction to both filling and ejection. Echocardiography demonstrated that the obstruction was in series with the mitral apparatus. Surgery was done with resection of much of this ring of tissue. Subsequent studies revealed morphologic and hemodynamic improvement. ( J AM Soc EcHOCARDIOGR 1994;7:67-71.)
Subdivision of the left ventricle into two distinct chambers is a rare cardiac anomaly that usually takes the form of a diverticulum attached to the main left ventricular chamber. 1 Less commonly, a distinct mid ventricular muscular obstruction separating the left ventricular cavity into two chambers has been de scribed. We report a double-chambered left ventricle caused by "in series" duplication of the mitral ap paratus. Case Report A 21-year-old female college student had progressive shortness of breath and fatigue on exercise. Cardiac auscultation revealed normal first and second heart sounds, a grade 4/6 crescendo-decrescendo systolic murmur over the precordium, and an early 1 I 4 apical diastolic rumble. The hemoglobin level was 13 gm/dl, the hematocrit level was 41%, and the oxygen saturation 98% on room air. On chest roentgenogram, heart size was at the upper limits of normal with left ventricular prominence. An azygos pseudolobe was present, but the lung fields were clear. The electrocardiogram showed normal sinus rhythm at a rate of 80 beats/min, left axis deviation, and a left bundle branch block. Transthoracic and transesophageal echocar diography demonstrated a two-chambered left ventricle (Figure 1) comprising a large proximal chamber separated
from a small thick-walled distal chamber by a fibromuscular ridge projecting from the bases of the papillary muscles. The mean systolic gradient (from distal to proximal cham ber) was calculated to be of 64 mm Hg while color flow imaging disclosed a mushroom-shaped jet similar to that observed across stenotic aortic valves (Figure 2, top, and Figure 3). A diastolic gradient of 14 mm Hg between the two chambers (from proximal to distal chamber) was de tected by continuous wave Doppler (Figure 3) while color flow imaging during diastole revealed a candle-flame jet similar in appearance to that seen across stenotic mitral valves (Figure 2, bottom). Ultrafast computed tomography (cine-CT) clearly delineated the submittal accessory val vular tissue causing inlet and outlet obstruction (Figure 4). Left ventriculography demonstrated an incomplete in traventricular membrane at the level of the papillary mus cles, which divided the ventricle into proximal and distal chambers. Dye flowed freely between the two chambers via a channel in the anterior superior portion of the ven tricle. A dynamic systolic pressure gradient was demon strated between the distal and proximal left ventricular chambers across the fibromuscular ring by use of a two sensor micromanometer with its tip in the distal chamber. Peak systolic pressures in the distal and proximal chambers were 225 mm Hg and 165 mm Hg, respectively. There was no pressure gradient across the aortic valve and no mitral regurgitation.
From the Departments of Cardiac Surgery and Cardiology, The Universiry of Chicago. Reprint requests: Robert B. Karp, MD, Section of Cardiac Sur gery, The University of Chicago, MC 5040, 5841 S. Maryland Ave., Chicago, IL 60637. Copyright © 1994 by the American Society ofEchocardiography. 0894-7317/94 $1.00 + .10 27/1149512
Operation Surgery was undertaken to relieve the midventricular obstruction. Median sternotomy was performed and car diopulmonary bypass was established. The heart was of normal size. The lateral aspect of the left ventricle was thickened midway between the atrioventricular groove and the apex. A standard left atriotomy was performed. The mitral valve and its chordae appeared normal but the pap
67
68 Albertucci et al.
Journal of the American Society of Echocardiography January-February 1994
Figure 1 A, Transthoracic and B, Transesophageal echocardiographic studies demonstrated a two-chambered left ventricle_ Distal and proximal left ventricular chambers are divided by what appears to be a fibromuscular ridge (arrow), which extends from the bases of the papillary muscles_ Distal chamber cavity size appears to be smaller and have relatively thicker walls than the proximal chamber. LA, Left atrium; MV, mitral valve; RV, right ventricle; LV, left ventricle.
illary muscles were thickened. Below the normal mitral valve apparatus, attached to the thickened papillary mus cles, was a discrete muscular ledge, supporting a fibrous structure that resembled a rudimentary mitral valve. This fibromuscular tissue impinged on the ventricular cavity, dividing the left ventricle into two separate chambers con nected by a channel l2 to 15 mm in diameter (Figure 5). Additional chordae tendineae were attached to the fibro muscular ridge. Four radial incisions from the central portion laterally
were made to open the passage from the mitral annulus to the apex. The radial incisions were then connected by re secting the intervening muscle and chordae tendineae. This maneuver relieved the obstruction to left ventricular out flow and allowed free flow of blood from the mitral valve toward the apex. The resection was limited by the attach ment of the mitral valve to the thickened and confluent papillary muscle. The mitral valve was found to be com petent when tested. After closure of the left atrium and deairing, cardiopulmonary bypass was weaned without dif
Journal of the American Society of Echocardiography Volume 7 Number l
Albertucci et al.
69
Figure 2 Top) Still-frame of two-dimensional echocardiogram of the left ventricle obtained from apical four-chamber view. Color flow imaging from apical view in systole shows a mush room-shaped jet similar to that observed in aortic stenosis. Note that jet has a mosaic appearance due to the high-velocity turbulent flow. Bottom) Color flow imaging in diastole demonstrates a candle flame appearance of the jet similar to that observed in mitral stenosis. Jet has a central blue wne due to color reversal from aliasing of high velocities. Peripheral wne is orange yellow, representing turbulence.
ficulty. Intraoperative transesophageal echocardiographic study revealed no systolic or diastolic gradient. Histologic diagnosis of the resected tissue indicated normal cardiac muscle with focal fibrosis and thickened valvular tissue. The postoperative course was unremarkable. Two months after surgery the patient was asymptomatic and resumed regular activities withouit limitations.
DISCUSSION
Subdivision of the right ventricle, which under nor mal conditions is divided into inlet and outlet por tions by the muscular ridge of the crista supraven tricularis and the trabecula septomarginalis, is more
Journal of the American Society of Echocardiography January-February 1994
70 Albertucci et al.
ECG
DIASTOLIC GRADIENT between proximal and distal . chambers
CW
DOPPLER SYSTOLIC GRADIENT between ,....____ distal and proximal chambers
11 i11 taa, 'I", "'I
"'
:!'u,,, , 'rt
,. 1sec I
,
.;
I
I
,
I
I
I
I
,
,
"' ,
1111 , 11 ,
1
u11
I ,
",·,
Figure 3 Continuous-wave (CW) Doppler tracing from the apical four-chamber view of antegrade (diastolic) and retrograde (systolic) "transmembrane flow." The mean transmembrane diastolic gradient (from proximal to distal chamber) was estimated to be 14 mm Hg. The mean systolic gradient (from distal to proximal chamber) was calculated to be 64 mm Hg.
Figure 4 Systolic frame ofan ultrafast computed tomographic scan obtained at the ventricular level clearly delineating the submittal accessory valvular tissue causing inlet and outlet obstruc tion. Note the narrow passage connecting the two left ventricular chambers (white arrowhead).
common than double-chambered left ventricle. 1 Left ventricular subdivision in this case was due to du plication of the mitral valve apparatus. The abnor mality consisted of an accessory papillary muscle and
chordae that bridge the middle of the left ventricle from the ventricular septum to the anterior papillary muscle. This anatomic arrangement caused a dia stolic flow gradient as well as significant dynamic
Journal of the American Society of Echocardiography Volume 7 Number l
Albertucci et al.
7l
Figure 5 Intraoperative photograph of the mitral valve and subvalvular structures exposed through a standard left atriotomy. The anterior papillary muscle and the large muscular ledge are visualized (arrow).
systolic obstruction. The mitral valve appeared to be normal. Brenner et al. 2 have described the echocardiogra phic features of left ventricular bands in infants and children. These false tendons or bands are fibromus cular structures that traverse the ventricular cavity. Occasionally, false tendons are extremely prominent and may attach to the septum by a small accessory papillary muscle, resulting in an "hourglass left ven tricle" deformity that does not result in significant systolic obstruction. In contrast, duplication of the mitral valve apparatus is rare. All previously described duplications have been in parallel, in the same plane as the annulus. 3· 5 This case appears to be the first case of mitral duplication "in series" causing inflow and outflow obstruction relieved by muscular resection. We Jould like to thank Lynn Weinert for her important contribution towards the preparation of the figures of this manuscript. The staff ofthe Non-Invasive Cardiac Imaging Laboratory and Cardiac Catheterization Laboratory are all
thanked for their contributions. In addition we would like to thank Daniel J. Murphy, Jr., MD, Jack L. Titus, MD, PhD, A.D. Pacifico, MD, and A.J. Tajik, MD, for sharing with us their expert opinions on the diagnosis and treat ment of this case.
REFERENCES l. Gearless LM, Partridge JB, Fiddler GI, Williams G, Scott 0. Two chambered left ventricle. Three new varieties. Br Heatt J 1981;46:278-84. 2. Brenner JI, Baker K, Ringel RE, Berman MA. Echocardio graphic evidence of left ventricular bands in infants and chil dren. JAm Coli Cardiol1984;3:1515-20. 3. Reed GE, Cortes LE, Clauss RH, Reppert EH. The surgical repair of duplication of the mitral orifice. Ann Thorac Surg 1970;9:81-5. 4. Schraft WC Jr, Lisa JR. Duplication of the mitral valve: case report and review of the literature. Am Heatt J 1950;39: 136 40. 5. Wigle ED. Duplication of the mitral valve. Br Heart J 1957;19:296-300.