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 Table of Contents  
INTERESTING CASE REPORT
Year : 2018  |  Volume : 2  |  Issue : 3  |  Page : 179-181

Submitral aneurysm: A rare cause of complete heart block


Department of Cardiology, TNMC and BYL Nair Charitable Hospital, Mumbai, Maharashtra, India

Date of Web Publication10-Dec-2018

Correspondence Address:
Dr. Meghav M Shah
303 Mahesh Apts., Plot No. 90, Shrimad Rajchandra Road, Ghatkopar East, Mumbai - 400 077, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jiae.jiae_8_18

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  Abstract 

Subvalvular left ventricular (LV) aneurysms are rare and are of two types – subaortic and submitral. More commonly, they are submitral in position. Submitral aneurysms (SMAs) are most commonly located below posterior mitral leaflet (PML), whereas subaortic aneurysms are present below intermediate portion of the left aortic sinus. SMA was first described by Corvisart in 1812, and since then, only about 100–120 cases have been described worldwide. Aneurysmal dilatation in submitral position behind PML that communicates with left ventricle helps in making the diagnosis. Color Doppler echocardiography reveals the severity of mitral regurgitation. Transesophageal echocardiography and contrast-enhanced computed tomography (CT) are helpful in diagnosis in cases of acute rupture of SMA, and contrast-enhanced CT helps in evaluation of coronaries. Surgical resection is the definitive treatment for these aneurysms. Our special case presented with complaints of giddiness and presyncope and was diagnosed as complete heart block on electrocardiogram and was then diagnosed as having a large SMA on two-dimensional echocardiogram with LV dysfunction. Usually, SMAs present with dyspnea, pansystolic murmurs due to mitral regurgitation, fever secondary to infective endocarditis, or as thromboembolism. However, this patient presented symptoms of complete heart block. To conclude, SMA should be considered in differential diagnosis of mitral regurgitation with LV dysfunction and heart failure in young patients. Although complete heart block is uncommon in these patients, it should be kept in mind.

Keywords: Complete heart block, giddiness and presyncope, left ventricular dysfunction, severe mitral regurgitation, submitral aneurysm-Type II


How to cite this article:
Nawale JM, Chavan RV, Shah MM, Chaurasia AS, Nalawade D. Submitral aneurysm: A rare cause of complete heart block. J Indian Acad Echocardiogr Cardiovasc Imaging 2018;2:179-81

How to cite this URL:
Nawale JM, Chavan RV, Shah MM, Chaurasia AS, Nalawade D. Submitral aneurysm: A rare cause of complete heart block. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2018 [cited 2019 Jan 16];2:179-81. Available from: http://www.jiaecho.org/text.asp?2018/2/3/179/247033




  Introduction Top


Subvalvular left ventricular (LV) aneurysms are rare and are of two types – subaortic and submitral. More commonly, they are submitral in position.[1] Submitral aneurysms (SMAs) are most commonly located below posterior mitral leaflet (PML), whereas subaortic aneurysms are present below intermediate portion of the left aortic sinus.[2] SMA was first described by Corvisart in 1812, and since then, only about 100–120 cases have been described worldwide.[3] First case series was reported from Nigeria by Abrahams et al. in 1962.[4]

Subvalvular LV aneurysms occurring in intimate relationship to the mitral and aortic valves have been also described in the South African Bantu[5],[6] and the American Negro.[7],[8] About 15 cases of SMA have been reported from India as of 2004.[9],[10]

Most of the cases of subvalvular LV aneurysms described in the literature are due to congenital weakness of the fibromuscular annuli. Chesler et al. postulate that a dehiscence of the fibromuscular union will result in aneurysm formation.[1],[2],[6]

Du Toit et al. classified SMA into 3 types, namely

  • Type I: Single localized neck
  • Type II: Multiple necks (separate distinct openings)
  • Type III: Involvement of the entire mitral annulus.[11]



  Clinical Presentation Top


A 20-year-old male patient presented to our hospital with chief complaints of giddiness for 4 days with one episode of presyncope and recurrent vomiting. There was no past history of similar complaints or a significant family history of heart diseases. His pulse rate was 44 beats/min irregularly irregular, with blood pressure being 100/50 mmHg and an elevated mean jugular venous pressure of 6 cm above sternal angle. Apex impulse was felt in 5th intercostal space, hyperdynamic in nature. First heart sound was variable but soft, and the second heart sound was normal, with the presence of LV S3. A pansystolic murmur with Grade 3/6 intensity with high pitch was heard in the apical region with radiation to the axilla. His routine blood investigations (complete blood count, liver function test, renal function test, and arterial blood gas) were within normal limits. An electrocardiogram was done which revealed complete heart block. Chest X-ray was suggestive of cardiomegaly, and 2D echocardiography showed evidence of outpouching in the left atria proximal to mitral valve suggestive of SMA with multiple necks [Figure 1] and [Figure 2] with severe mitral regurgitation with eccentric jet along PML [Figure 3] and severe LV systolic dysfunction and severe pulmonary hypertension. Temporary pacing wire was inserted in the patient in view of slow ventricular rate. For confirmation and further surgical ease, cardiac magnetic resonance imaging (MRI) and CT were done. Cardiac CT and MRI revealed a 7.8 cm × 4.0 cm × 7.6 cm SMA with multiple necks with compression of the left atria, distal superior vena cava, and right main pulmonary artery.
Figure 1: Parasternal short axis view at basal level showing the large neck of submitral aneurysm opening into the left ventricle

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Figure 2: Parasternal short axis view of submitral aneurysm and left ventricle. Size of submitral aneurysm is comparable to the left ventricle

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Figure 3: Apical 4-chamber view showing severe mitral regurgitation with evidence of large pouch on the lateral aspect of the left atria and ventricle suggestive of submitral aneurysm

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The patient was treated with diuretics and digoxin in addition to temporary pacemaker, with relief of symptoms over a period of 3–4 days. Surgical resection of aneurysm was planned with epicardial pacing. The patient was taken up for surgery but unfortunately succumbed to the same.


  Discussion Top


SMA should be considered in differential diagnosis of mitral regurgitation with LV dysfunction and heart failure in young patients. Although thrombus inside SMA is very common, very few episodes of thromboembolism have been reported due to small ostial neck.[12] Widespread use of echocardiography has made diagnosis early and easy. It helps in determination of size, mitral regurgitation, and rupture. Blood enters the SMA from the left ventricle during systole and exits from the cavity during diastole. Real-time three-dimensional (3D) echocardiography helps in determining relation of the aneurysm with other structures surrounding it. Rupture in left atrium should be suspected whenever there is a paravalvular leak across the mitral valve. Transesophageal echocardiography is most useful in confirmation for the same. Computed tomography (CT) can also be useful in this regard. Differential diagnosis includes false aneurysms caused by myocardial necrosis due to infective endocarditis, tuberculosis, syphilis, trauma, polyarteritis nodosa, and takayasu arteritis.[12],[13],[14]

Typical absence of coronary artery disease and its typical location confirms the diagnosis. Initial medical stabilization includes diuretics and afterload reducing agents. This should be followed by early surgery, which is the only definitive surgery.

Approach

Definitive surgery includes pericardial patch repair with or without mitral valve repair/replacement under cardiopulmonary bypass. Approach to surgery depends on its relation to left circumflex artery (LCX). When the neck is superior to LCX, then left atrium or intracardiac approach is warranted as neck is in contact with floor of left atrium. Advantage of this approach is that mitral valve can be tested and assessed for competence but with the disadvantage of removing larger aneurysms which extend below the floor of the left atria. Other surgery is extracardiac approach where SMA is opened from epicardial side. Its disadvantage is that there is inadequate exposure to mitral annulus and there can be residual mitral regurgitation and also the adhesions can cause operative difficulties.[3],[15],[16]

Sometimes, combined approach is required depending on size, degree of mitral regurgitation, and extent of involvement of posterior mitral annulus. Simultaneous mitral ring annuloplasty helps in decreasing postoperative mitral regurgitation, whereas mitral valve replacement is required when leaflets are damaged and nonrepairable.

Failure to identify multiple necks and inadequate closure of aneurysm with lack of support to mitral annulus can lead to repeated aneurysm. Mortality is high in nonoperated cases. Postoperative cure is dependent on the size of aneurysm, the severity of LV dysfunction, and the degree of residual mitral regurgitation.


  Conclusion Top


SMA should be considered in differential diagnosis of mitral regurgitation with LV dysfunction and heart failure in young patients. Although complete heart block is uncommon in these patients, it should be kept in mind. It could be presumed due to compression of the atrioventricular node by the SMA per se or its extension into the atrioventricular groove. Secondarily, it could be hypothesized as concomitant congenital heart block presenting along with the SMA which would not have been diagnosed earlier. Aneurysmal dilatation in submitral position behind PML that communicates with left ventricle helps in making the diagnosis. Color Doppler echocardiography reveals the severity of mitral regurgitation. Transesophageal echocardiography and contrast-enhanced CT are helpful in diagnosis in cases of acute rupture of SMA, and contrast-enhanced CT helps in evaluation of coronaries. Surgical resection is the definitive treatment for these aneurysms.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Chesler E, Tucker RB, Barlow JB. Subvalvular and apical left ventricular aneurysms in the Bantu as a source of systemic emboli. Circulation 1967;35:1156-62.  Back to cited text no. 1
    
2.
Chesler E, Mitha AS, Edwards JE. Congenital aneurysms adjacent to the annuli of the aortic and/or mitral valves. Chest 1982;82:334-7.  Back to cited text no. 2
    
3.
Janeira LF, Talit U, Parker R, Hughes CE, Tuna IC. Surgical management of ventricular tachycardia in subannular left ventricular aneurysm. Ann Thorac Surg 1995;60:438-40.  Back to cited text no. 3
    
4.
Abrahams DG, Barton CJ, Cockshott WP, Edington GM, Weaver EJ. Annular subvalvular left ventricular aneurysms. Q J Med 1962;31:345-60.  Back to cited text no. 4
    
5.
Lurie AO. Left ventricular aneurysm in the African. Br Heart J 1960;22:181-8.  Back to cited text no. 5
    
6.
Chesler E, Joffe N, Schamroth L, Meyers A. Annular subvalvular left ventricular aneurysms in the South African Bantu. Circulation 1965;32:43-51.  Back to cited text no. 6
    
7.
Burn CG, Hollander AG, Crawford JH. Rare cardiac aneurysm in a child. Amer Heart J 1943;26:415-18.  Back to cited text no. 7
    
8.
Bertnard, CA, Cooley RN. Congenital aneurysm of the left ventricle: A case report. Ann Intern Med 1955;43:426-34.  Back to cited text no. 8
    
9.
Chockalingam A, Gnanavelu G, Alagesan R, Subramaniam T. Congenital submitral aneurysm and sinus of valsalva aneurysm. Echocardiography 2004;21:325-8.  Back to cited text no. 9
    
10.
Ruhela M, Kumar D, Meena CB, Bagarhatta R. Submitral Aneurysm: A Rare congenital anomaly. Am J Med Case Rep 2014;6:114-6.  Back to cited text no. 10
    
11.
Du Toit HJ, Von Oppell UO, Hewitson J, Lawrenson J, Davies J. Left ventricular sub-valvar mitral aneurysms. Interact Cardiovasc Thorac Surg 2003;2:547-51.  Back to cited text no. 11
    
12.
Gao C, Xiao C, Li B. Mitral valve aneurysm with infective endocarditis. Ann Thorac Surg 2004;78:2171-3.  Back to cited text no. 12
    
13.
Sharma S, Daxini BV, Loya YS. Profile of submitral left ventricular aneurysms in Indian patients. Indian Heart J 1990;42:153-6.  Back to cited text no. 13
    
14.
Rose AG, Folb J, Sinclair-Smith CC, Schneider JW. Idiopathic annular submitral aneurysm associated with takayasu's aortitis. A report of two cases. Arch Pathol Lab Med 1995;119:831-5.  Back to cited text no. 14
    
15.
Sutorius DJ, Helmsworth JA, Majeski JA, Miller SF. Repair of a subvalvular left ventricular aneurysm following mitral valve replacement. Ann Thorac Surg 1981;32:92-6.  Back to cited text no. 15
    
16.
Almeida-Filho OC, Schmidt A, Sgarbieri R, Marin-Neto JA, Maciel BC. Large submitral left ventricular aneurysm associated with mitral valve aneurysm. Echocardiography 2002;19:391-3.  Back to cited text no. 16
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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