History

Fact Explanation
Children with minor degrees of mitral regurgitation are asymptomatic[9] The nature and severity of symptoms in mitral regurgitation (MR) relates to[1], etiology, rate of onset and progression, left ventricle (LV) function, pulmonary artery pressure and presence of preexisting valvular/myocardial diseases Children with mild disease may be asymptomatic with out complications until the second or third decade of life.
Fatigue[1][2] In MR the blood in the left ventricle re enters to the left atrium during the systole through the incompetent mitral valve. This causes reduction of blood volume enters to the aorta causing low cardiac out put. This condition manifest as fatiguability. Thought fatigue may be reported in children they can tolerate more severe mitral regurgitation better than adults.
Dyspnoea[1][2] This is occur due to the pulmonary venous congestion. Due to the increased blood volume in left atrium( due to regurgitated blood) pressure in pulmonary circulation will increase.This can ultimately leads to pulmonary hypertension and once it develops, complaints such as dyspnoea with light activity become more prominent.
Palpitations[1] Palpitations can develop due to either increases stroke volume or if the MR is complicated with atrial fibrillation( due to the chronic atrial dilatation).
Orthopnoea[7] Pulmonary oedema with pulmonary venous congestion will develop this symptom. Number of pillows patient is using due to uncomfortably on lying down will give an idea of presence of this symptom.
Development of shortness of breath, swelling of feet and ankles, sensation of feeling the heart beat, fatigue, weakness, fainting Due to increased pressure in the pulmonary circulation right ventricular workload will increase resulting right heart failure with the time. This will give these symptoms together[6].
Growth and development of the child[8] With severe mitral regurgitation, children may experience limited growth and failure to thrive. This is due to the MR it self causing abnormalities in the circulation and may be due to the recurrent infections/ recurrent hospital admissions/ surgeries associated with the condition.
Past history of mitral valve disease Mitral valve prolapse is a diagnosed cause for the development of MR with the time[5]. So the early diagnosis of mitral prolapse will helpful in identifying the cause. Mitral valve prolapse is the most common valvular abnormality(affect 2-6%)
Past history of rheumatic heart disease or symptoms of joint swelling /pain, rash, fever Carditis caused by rheumatic heart disease can result in MR[4].
Past history of infective endocarditis or symptoms of fever for long duration, rash, passage of blood with urine, fatiguability, weakness with long term injections( if seek medical advice) Infective endocarditis[3] is an etiological factor for the development of MR.
References
  1. OTTO CM. Timing of surgery in mitral regurgitation Heart [online] 2003 Jan, 89(1):100-105 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767516
  2. GAHL K, SUTTON R, PEARSON M, CASPARI P, LAIRET A, MCDONALD L. Mitral regurgitation in coronary heart disease. Br Heart J [online] 1977 Jan, 39(1):13-18 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC483187
  3. DELAHAYE F, CéLARD M, ROTH O, DE GEVIGNEY G. Indications and optimal timing for surgery in infective endocarditis Heart [online] 2004 Jun, 90(6):618-620 [viewed 15 August 2014] Available from: doi:10.1136/hrt.2003.029967
  4. SECKELER MD, HOKE TR. The worldwide epidemiology of acute rheumatic fever and rheumatic heart disease Clin Epidemiol [online] :67-84 [viewed 15 August 2014] Available from: doi:10.2147/CLEP.S12977
  5. LEWIS RP, WOOLEY CF, KOLIBASH AJ, BOUDOULAS H. The mitral valve prolapse epidemic: fact or fiction. Trans Am Clin Climatol Assoc [online] 1987:222-236 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2279723
  6. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 15 August 2014] Available from: doi:10.4065/mcp.2009.0706
  7. ALTSCHULE MD, ZAMCHECK N, IGLAUER A. THE LUNG VOLUME AND ITS SUBDIVISIONS IN THE UPRIGHT AND RECUMBENT POSITIONS IN PATIENTS WITH CONGESTIVE FAILURE. PULMONARY FACTORS IN THE GENESIS OF ORTHOPNEA J Clin Invest [online] 1943 Nov, 22(6):805-812 [viewed 15 August 2014] Available from: doi:10.1172/JCI101454
  8. CORIN WJ, SWINDLE MM, SPANN JF JR, NAKANO K, FRANKIS M, BIEDERMAN RW, SMITH A, TAYLOR A, CARABELLO BA. Mechanism of decreased forward stroke volume in children and swine with ventricular septal defect and failure to thrive. J Clin Invest [online] 1988 Aug, 82(2):544-551 [viewed 15 August 2014] Available from: doi:10.1172/JCI113630
  9. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706

Examination

Fact Explanation
Vital signs, normal in mild regurgitation. Heart and respiratory rates increase with increasing severity Patients with mild disease will be asymptomatic and symptoms and signs will appear with the increasing severity of the MR[1].
Pulse characterized in severe disease as having a small volume with a sharp upstroke. Irregularly irregular pulse can be seen in atrial fibrillation[7] Rate, rhythm, volume and character of the pulse should be check as it gives and idea of peripheral circulation as well as cardiac function[8].
Cardiac apex[9] displaced to left and apical impulse can be felt Due to cardiomegaly a displaced hyperdynamic apex beat can be palpable[1]. Apical impulse, a left atrial lift is a second impulse resulting from the increased volume with regurgitated blood into the left atrium during systole. Second impulse should be felt with second heart sound. This sign is most helpful in thin children. In more advanced disease, a double impulse is felt.
Signs in heart sounds are normal/Soft first heart sound[5], splitting of second heart sound, presence of third heart sound and loud second heart sound[6] On auscultation first heart sound is found to be slightly diminished due to mitral valve incompetence. Splitting of second heart sound is due to volume over load in right ventricle causing delayed closure and reduced cardiac output from left atrium causing early closure of aortic valve. Severe will associated wit third heart sound is occur due to increased ventricular filling[4]. Pulmonary component of the second heart sound will be more prominent/ louder with development pulmonary hypertension (increased pressure in pulmonary circulation increases the pressure difference in between pulmonary artery and right ventricle).
Murmur is a pansystolyc murmur( blowing and high pitched) heard best at the apex and left sternal edge and it radiates to left axilla. First heart sound is merges with the murmur extending to the second heart sound. Murmur occurs due to the alteration in the blood flow with the valvular abnormality. little correlation is noted with intensity of murmur with severity of MR[2][3].
Lung auscultation for crepitations Pulmonary venous congestion causes crepitations in bilateral lung bases[10].
Bi lateral ankle oedema, elevated jugular venous pressure, tender hepatomegallly. These are signs of right heart failure[11].
References
  1. GAHL K, SUTTON R, PEARSON M, CASPARI P, LAIRET A, MCDONALD L. Mitral regurgitation in coronary heart disease. Br Heart J [online] 1977 Jan, 39(1):13-18 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC483187
  2. DESJARDINS VA, ENRIQUEZ-SARANO M, TAJIK AJ, BAILEY KR, SEWARD JB. Intensity of murmurs correlates with severity of valvular regurgitation. Am J Med [online] 1996 Feb, 100(2):149-56 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8629648
  3. O'ROURKE RA, CRAWFORD MH. Mitral valve regurgitation. Curr Probl Cardiol [online] 1984 May, 9(2):1-52 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/6375982
  4. NIXON PG. THE THIRD HEART SOUND IN MITRAL REGURGITATION Br Heart J [online] 1961 Nov, 23(6):677-689 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1017807
  5. LAKIER JB, FRITZ VU, POCOCK WA, BARLOW JB. Mitral components of the first heart sound. Br Heart J [online] 1972 Feb, 34(2):160-166 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC487112
  6. SUTTON G, HARRIS A, LEATHAM A. Second heart sound in pulmonary hypertension. Br Heart J [online] 1968 Nov, 30(6):743-756 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC487797
  7. RAWLES JM, ROWLAND E. Is the pulse in atrial fibrillation irregularly irregular? Br Heart J [online] 1986 Jul, 56(1):4-11 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1277379
  8. BAKR AF, HABIB HS. Combining pulse oximetry and clinical examination in screening for congenital heart disease. Pediatr Cardiol [online] 2005 Nov-Dec, 26(6):832-5 [viewed 15 August 2014] Available from: doi:10.1007/s00246-005-0981-9
  9. O'NEILL TW, BARRY M, SMITH M, GRAHAM IM. Diagnostic value of the apex beat. Lancet [online] 1989 Feb 25, 1(8635):410-1 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/2563789
  10. WATSON RD, GIBBS CR, LIP GY. Clinical features and complications BMJ [online] 2000 Jan 22, 320(7229):236-239 [viewed 15 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117436
  11. PAZOS-LóPEZ P, PETEIRO-VáZQUEZ J, CARCíA-CAMPOS A, GARCíA-BUENO L, DE TORRES JP, CASTRO-BEIRAS A. The causes, consequences, and treatment of left or right heart failure Vasc Health Risk Manag [online] 2011:237-254 [viewed 18 August 2014] Available from: doi:10.2147/VHRM.S10669

Differential Diagnoses

Fact Explanation
Aortic Regurgitation[1] Due to the weakness of the valve, blood flow from the aorta into the left ventricle occurs during diastole It gives symptoms of fatigue and weakness with exercise, shortness of breath on exertion, chest pain(discomfort or tightness) especially during exercise and fainting, It gives collapsing pulse and high pitched early diastolic murmur.
Aortic Stenosis[1] Aortic stenosis is obstruction to the out flow from the left ventricle to systemic circulation at aortic valve. It gives symptoms of angina, dyspnoea, dizziness and fainting. Signs are slow rising pulse with narrow pulse pressure, ejection systolic murmur.
Mitral Stenosis[1] This causes obstruction to the out flow tract from left atrium to left ventricle via mitral valve giving symptoms of dyspnoea, fatiguability, palpitation and chest pain. Signs are low volume pulse with rumbling mid diastolic murmur.
Ventricular Septal Defect[2] this is associated with pathological connection between left and right ventricles causing blood flow from left to right. This gives symptoms due to low cardiac out put and right heart failure with pulmonary hypertension. Pansystolic murmur will be present.
Mitral Valve Prolapse[3] In mitral valve prolapse there is valve slips backward due to the abnormal size/damage to the mitral valve. This condition is usually asymptomatic, but it can be associated with palpitations, shortness of breath(especially with exercise), dizziness, syncope, panic attacks and anxiety.
References
  1. BOON NA, BLOOMFIELD P. The medical management of valvar heart disease Heart [online] 2002 Apr, 87(4):395-400 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767079
  2. Ventricular Septal Defects Br Med J [online] 1964 Apr 18, 1(5389):998-999 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1814211
  3. LEWIS RP, WOOLEY CF, KOLIBASH AJ, BOUDOULAS H. The mitral valve prolapse epidemic: fact or fiction. Trans Am Clin Climatol Assoc [online] 1987:222-236 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2279723

Investigations - for Diagnosis

Fact Explanation
ECG[1] To see evidence of left atrial hypertrophy, left ventricular hypertrophy or evidence of atrial fibrillation.
Chest X ray[1] Enlargement of the left atrium and left ventricle can be seen. Pulmonary venous congestion can be seen around bilateral hilar areas. If patient present wit acute onset dyspnoea due to pulmonary oedema, it also visible.
Echocardiography[1] Will reveal the structure and function of the heart.It will show, dilated left atrium and left ventricle, dynamic left ventricle can be seen unless myocardial dysfunction is prominent. Stuctural abnormalities of the mitral valve can be seen if endocarditis is associated with vegitations can also be seen.
Doppler studies[2] This will assess the defects and quantities of the mitral regurgitation using the flow of the blood inside the heart.
Cardiac catherization[1] During cardiac catheterization, dilated left atrum and left ventricle and pulmonary hypertension can be seen.
References
  1. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706
  2. VEYRAT C, AMEUR A, BAS S, LESSANA A, ABITBOL G, KALMANSON D. Pulsed Doppler echocardiographic indices for assessing mitral regurgitation. Br Heart J [online] 1984 Feb, 51(2):130-138 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC481473

Investigations - Fitness for Management

Fact Explanation
Full Blood count(FBC) Full blood count useful in assessing the haemoglobin level[2] of the patient, as anaemia can worsen cardiac symptoms due to poor perfusion. WBC level will useful in assessing any coexisting infections which should be treated quickly. Platelet count[1] will be useful in assessing any bleeding tendency before invasive procedures like cardiac catheterisation.
APTT, PT, INR These tests which use for assessing the clotting profile[3] important before invasive procedures/ surgeries . If the patient has developed atrial fibrillation and he is on warfarin this is useful in adjusting the dose[4].
References
  1. WAN S, LAI Y, MYERS RE, LI B, HYSLOP T, LONDON J, CHATTERJEE D, PALAZZO JP, BURKART AL, ZHANG K, XING J, YANG H. Preoperative Platelet Count Associates with Survival and Distant Metastasis in Surgically Resected Colorectal Cancer Patients J Gastrointest Cancer [online] 2013 Sep, 44(3):293-304 [viewed 17 August 2014] Available from: doi:10.1007/s12029-013-9491-9
  2. GASCHE C, LOMER MC, CAVILL I, WEISS G. Iron, anaemia, and inflammatory bowel diseases Gut [online] 2004 Aug, 53(8):1190-1197 [viewed 17 August 2014] Available from: doi:10.1136/gut.2003.035758
  3. AKHTAR A, MACFARLANE RJ, WASEEM M. Pre-Operative Assessment and Post-Operative Care in Elective Shoulder Surgery Open Orthop J [online] :316-322 [viewed 17 August 2014] Available from: doi:10.2174/1874325001307010316
  4. KURUVILLA M, GURK-TURNER C. A review of warfarin dosing and monitoring Proc (Bayl Univ Med Cent) [online] 2001 Jul, 14(3):305-306 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1305837

Investigations - Followup

Fact Explanation
Echocardiography[1] This is useful in follow up to see the structure and function with the time, and to see the improvement after surgery.
Blood culture[2] This is useful if the aetiology is suspected as infective endocarditis to see the evidence of bacteraemia.
References
  1. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706
  2. HABIB G. Management of infective endocarditis Heart [online] 2006 Jan, 92(1):124-130 [viewed 17 August 2014] Available from: doi:10.1136/hrt.2005.063719

Investigations - Screening/Staging

Fact Explanation
Echocardiography[1] This can assess the level of MR( mild, moderate, severe) and progress of the condition with the time.
References
  1. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706

Management - General Measures

Fact Explanation
Dietary modifications If the patient is having chronic symptomatic MR/ left ventricular dysfunction, reduction of salt intake is recommended. And also need to take healthy diet with low fats. Too much caffeine will worsen the arrhythmia, so especially if the patient is having atrial fibrillation better to avoid caffeine containing foods like- coffee, soft drinks[1][2] .
maintaing ideal body weight according to the height and do regular physical exercise[5] As the obesity can cause symptoms like shortness of breath it can interfere the assessment of the MR.Obesity is also associated with several morbidity conditions. In a obese patient facing a surgery there can be, anaesthetic problems[4], wound healing[5] and post surgical complains like deep vein thrombosis[6] can occur, so maintaining ideal body weight is very important.
Prophylactic antibiotics for the prevention of recurrence shuld be given to patients[7]. Screen for rheumatic fever( if the primary cause is that) and prophylactically treat other siblings with penicillin to prevent rheumatic fever[7]. This is one of the most important steps in prevention.
Dental care and dental surgeries under antibiotic coverage[8] Dental hygiene should be maintain. Tooth brushing should be done correctly, at least twice a day, reduce sweet intake, after eating a sweet food wash the mouth, go to a dental surgeon at least once in 3 months and take early treatment for dental caries Do dental surgeries under prophylactic antibiotic coverage to prevent occurrence of infective endocarditis, as it can cause bacteraemia and can cause systemic embolization.
Regular follow up[1] regular follow up is needed by a cardiologist to look for any evidence of worsening symptoms and development of complications follow up frequency will be individualized according to the patients condition. Electrocardiogram is useful in follow up. If the patient is having high blood pressure or is in risk of developing hypertension need to do regular blood pressure monitoring should be done.
References
  1. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706
  2. KLATSKY AL, HASAN AS, ARMSTRONG MA, UDALTSOVA N, MORTON C. Coffee, Caffeine, and Risk of Hospitalization for Arrhythmias Perm J [online] 2011, 15(3):19-25 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3200095
  3. GLATTER KA, MYERS R, CHIAMVIMONVAT N. Recommendations Regarding Dietary Intake and Caffeine and Alcohol Consumption in Patients With Cardiac Arrhythmias: What Do You Tell Your Patients To Do or Not To Do? Curr Treat Options Cardiovasc Med [online] 2012 Oct, 14(5):529-535 [viewed 17 August 2014] Available from: doi:10.1007/s11936-012-0193-6
  4. DORITY J, HASSAN ZU, CHAU D. Anesthetic Implications of Obesity in the Surgical Patient Clin Colon Rectal Surg [online] 2011 Dec, 24(4):222-228 [viewed 17 August 2014] Available from: doi:10.1055/s-0031-1295685
  5. PENCE BD, WOODS JA. Exercise, Obesity, and Cutaneous Wound Healing: Evidence from Rodent and Human Studies Adv Wound Care (New Rochelle) [online] 2014 Jan 1, 3(1):71-79 [viewed 17 August 2014] Available from: doi:10.1089/wound.2012.0377
  6. FREEMAN AL, PENDLETON RC, RONDINA MT. Prevention of venous thromboembolism in obesity Expert Rev Cardiovasc Ther [online] 2010 Dec, 8(12):1711-1721 [viewed 17 August 2014] Available from: doi:10.1586/erc.10.160
  7. KEITH JD. Modern Trends in Acute Rheumatic Fever Can Med Assoc J [online] 1960 Oct 8, 83(15):789-796 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1938419
  8. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706

Management - Specific Treatments

Fact Explanation
medical management Diuretics[2] and Vasodilators[2] Patient should be given afterload-reducing agents (eg; vasodilators) as high afterload can worsen the degree of regurgitation. Angiotensin converting enzyme inhibitors can be used. Diuretics are helpful in maintaining the forward cardiac output in persons who are having MR with symptoms and LV dysfunction
medical management Digoxin[3], Beta-blockers[3], Calcium channel blockers[3] and Anticoagulants[4] If the patient's condition is complicated with atrial fibrillation digoxin, beta-blockers, calcium channel blockers( in maintaining the normal ventricular function) and anticoagulant, warfarin( to prevent clot formation and embolization) treatment will be helpful. Anticoagulation also useful following mitral valve replacement surgery.
medical management Antiboiotics If MR is due to infective endocarditis[5]/ rheumatic fever[7], primary cause should be treated with antibiotics. Also prophylaxis treatment[6] is useful prior to dental procedures.
Surgical treatment[1][8] Mitral valve repair and replacement In severe MR this is the treatment option especially if there is LV systolic dysfunction in severe MR with an ejection fraction of 60% or less, an end-systolic dimension of 40 mm or greater and development of other complications like pulmonary hypertension, atrial fibrillation
References
  1. MAGANTI K, RIGOLIN VH, SARANO ME, BONOW RO. Valvular Heart Disease: Diagnosis and Management Mayo Clin Proc [online] 2010 May, 85(5):483-500 [viewed 17 August 2014] Available from: doi:10.4065/mcp.2009.0706
  2. BOON NA, BLOOMFIELD P. The medical management of valvar heart disease Heart [online] 2002 Apr, 87(4):395-400 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767079
  3. KHAN MA, AHMED F, NEYSES L, MAMAS MA. Atrial fibrillation in heart failure: The sword of Damocles revisited World J Cardiol [online] 2013 Jul 26, 5(7):215-227 [viewed 17 August 2014] Available from: doi:10.4330/wjc.v5.i7.215
  4. BIONDI-ZOCCAI G, MALAVASI V, D'ASCENZO F, ABBATE A, AGOSTONI P, LOTRIONTE M, CASTAGNO D, VAN TASSELL B, CASALI E, MARIETTA M, MODENA MG, ELLENBOGEN KA, FRATI G. Comparative effectiveness of novel oral anticoagulants for atrial fibrillation: evidence from pair-wise and warfarin-controlled network meta-analyses HSR Proc Intensive Care Cardiovasc Anesth [online] 2013, 5(1):40-54 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3670724
  5. GOPALAKRISHNAN PP, SHUKLA SK, TAK T. Infective Endocarditis: Rationale for Revised Guidelines for Antibiotic Prophylaxis Clin Med Res [online] 2009 Sep, 7(3):63-68 [viewed 17 August 2014] Available from: doi:10.3121/cmr.2009.848
  6. GRAY JD. Prophylaxis for Infective Endocarditis Can Fam Physician [online] 1987 Apr:1011-1014 [viewed 17 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2218443
  7. ROBERTSON KA, VOLMINK JA, MAYOSI BM. Antibiotics for the primary prevention of acute rheumatic fever: a meta-analysis BMC Cardiovasc Disord [online] :11 [viewed 17 August 2014] Available from: doi:10.1186/1471-2261-5-11
  8. DE OLIVEIRA JM, ANTUNES MJ. Mitral valve repair: better than replacement Heart [online] 2006 Feb, 92(2):275-281 [viewed 17 August 2014] Available from: doi:10.1136/hrt.2005.076208