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| ==Overview== | | ==[[Papillary muscle rupture overview|Overview]]== |
| [[Papillary muscle]] rupture is an infrequent mechanical complication of [[acute myocardial infarction]]. Early diagnosis is important so that surgical repair can be performed. | |
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| ==Pathophysiology== | | ==[[Papillary muscle rupture pathophysiology|Pathophysiology]]== |
| The vascularization of the [[papillary muscle]]s shows many individual variations and depends in part on coronary artery anatomy and dominance. However, the posterior papillary muscle is vascularized by posterior left ventricular branches that may have origin in the right, left or both coronary arteries. The anterior [[papillary muscle]] is vascularized by branches from diagonal, circumflex or even acute marginal branches of the left coronary artery. [[Papillary muscle]] ischemia occurs along with ischemia of the adjacent ventricular wall.
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| *Acute mitral regurgitation (as may occur due to the sudden rupture of a [[chordae tendineae]] or [[papillary muscle]]) causes a sudden volume overload of both the [[left atrium]] and the [[left ventricle]].
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| *The left ventricle develops volume overload because with every contraction it now has to pump out not only the volume of blood that goes into the [[aorta]] (the forward [[cardiac output]] or forward [[stroke volume]]), but also the additional blood that regurgitated into the [[left atrium]] (the regurgitant volume).
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| *The combination of the forward stroke volume and the regurgitant volume is known as the total stroke volume of the [[left ventricle]].
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| *In the acute setting, the total stroke volume (i.e. the forward plus the regurgitant volume) is increased, but the forward cardiac output into the aorta is decreased because a proportion of the blood is going backward into the left atrium. The mechanism by which the total stroke volume is increased as a result of increased left ventricular filling is known as the [[Frank-Starling law of the heart|Frank-Starling mechanism]].
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| The regurgitant volume causes acute volume overload and pressure overload of the [[left atrium]] as shown in the figure below. The sudden increase in pressure in the [[left atrium]] is transmitted backward into the [[pulmonary vein]] which in turn reduces drainage of blood from the lungs via the [[pulmonary vein]]s and raises the [[pulmonary capillary sedge pressure]]. This causes [[congestive heart failure|pulmonary congestion]].
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| [[Image:MR pressure graph.jpg]]
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| ==Pathological Findings==
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| Images shown below are courtesy of Professor Peter Anderson DVM PhD and published with permission. [http://www.peir.net © PEIR, University of Alabama at Birmingham, Department of Pathology]
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 5.jpg|Papillary Muscle Infarct with Rupture: Gross, left ventricle opened partially to show infarct and ruptured muscle, an excellent example
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| Image:Papillary muscle rupture 2.jpg|Papillary Muscle Infarct with Rupture: Gross, very good example
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 3.jpg|Papillary Muscle Infarct: Gross, an excellent example
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| Image:Papillary muscle rupture 6.jpg|Papillary Muscle Infarct: Gross, an excellent example
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 4.jpg|Papillary Muscle Infarct with Rupture: Gross, horizontal section of left ventricle looking toward base of heart, a very good example with lateral wall transmural infarct and ruptured papillary muscle
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| Image:Papillary muscle rupture.jpg|Papillary Muscle Infarct with Rupture: Gross, an excellent example of ruptured papillary muscle
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 7.jpg|Papillary Muscle Infarct with Rupture
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| Image:Papillary muscle rupture 8.jpg|Papillary Muscle Infarct with Rupture: Gross, natural color, close-up, well shown
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 9.jpg|Papillary Muscle Infarct: Gross fixed tissue very well shown and typical papillary muscle infarct
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| Image:Papillary muscle rupture 10.jpg|Papillary Muscle Infarct: Gross, natural color, close-up view of longitudinally section. Papillary muscle with obvious infarct, a very good example. There is a large old infarct with aneurysm in the anterior wall. The infarcted papillary muscle is the posterior one.
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 11.jpg|Papillary Muscle Thinning: Gross, natural color, band-like anterior papillary muscles secondary to healed infarct which is present in picture (but not easily seen). An excellent example for papillary muscle change
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| Image:Papillary muscle rupture 12.jpg|Mitral Valve Prosthesis and Large Apical Infarct: Gross, natural color, caged plastic ball with complete steel struts. A large recent infarct at apex of heart, at base of posterior papillary muscles. Etiology not completely clear but looks like an iatrogenic lesion (good illustration)
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 13.jpg|Myocardial Hemorrhage Following Mitral Valve Replacement: Gross, natural color, horizontal section of left ventricle showing a large area of mural hemorrhage extending from anterior papillary muscle
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| Image:Papillary muscle rupture 14.jpg|Papillary Muscle Infarct with Rupture: Gross, natural color, a close-up view (very good example)
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 15.jpg|Papillary Muscle Infarct with Rupture: Gross, fixed tissue, a close-up view (quite good example)
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| Image:Papillary muscle rupture 16.jpg|Papillary Muscle Infarct with Rupture: Gross, fixed tissue, but good color. Horizontal slice of LV with posterior infarct that appears old and a ruptured papillary muscle head.
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| </gallery>
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| </div>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Papillary muscle rupture 17.jpg|Papillary Muscle Infarct with Rupture: Gross, fixed tissue, but good color. An outstanding photo of ruptured head of posterior papillary muscle with entangled chordae
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| Image:Papillary muscle rupture 18.jpg|Papillary Muscle Infarct with Rupture: Gross, fixed tissue, but good color. An outstanding photo of ruptured head of posterior papillary muscle with entwined chordae
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| Image:Papillary muscle rupture 19.jpg|Papillary Muscle Infarct with Rupture: Gross, fixed tissue, but good color. An outstanding photo of ruptured head of posterior papillary muscle with entwined chordae
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| </gallery>
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| </div>
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| ==Diagnosis== | | ==Diagnosis== |
| ===Symptoms===
| | [[Papillary muscle rupture history and symptoms|History and Symptoms]] | [[Papillary muscle rupture physical examination|Physical Examination]] | [[Papillary muscle rupture chest x ray|Chest X Ray]] | [[Papillary muscle rupture echocardiography|Echocardiography]] |
| The symptoms of an acutely elevated wedge pressure due to papillary muscle rupture include [[dyspnea]], [[PND]], and [[orthopnea]].
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| ===Physical Examination===
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| ====Vitals====
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| Tachycardia and hypotension are often present
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| ====Heart====
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| *A palpable [[thrill]] may be present
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| *A harsh, not a blowing murmur is often present throughout the precordium
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| ====Lungs====
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| [[Rales]] may be present
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| ===Echocardiographic Findings of Ruptured Papillary Muscle and Severe MR===
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| <youtube v=gUdegG0-Shc/>
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| ===Chest X Ray===
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| Pulmonary edema is present without enlargement of the heart.
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| ==Treatment== | | ==Treatment== |
| Acute mitral regurgitation secondary to left ventricular [[papillary muscle rupture]] or [[chordae tendineae rupture]], is a medical and surgical emergency. Patients may present with acute [[pulmonary edema]] or [[cardiogenic shock]] and most often the required and definitive treatment is valvular surgery. However, medical therapy may be needed to stabilize the patient until surgery can be performed.
| | [[Papillary muscle rupture medical therapy|Medical Therapy]] | [[Papillary muscle rupture surgery|Surgery]] |
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| ===Medical Therapy===
| | {{Circulatory system pathology}} |
| ====Normotensive patients====
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| [[Vasodilators]] may be of use to decrease the [[afterload]] and thereby decrease the regurgitant fraction. The [[vasodilator]] most commonly used is [[nitroprusside]] <ref name="pmid4744778">{{cite journal |author=Chatterjee K, Parmley WW, Swan HJ, Berman G, Forrester J, Marcus HS |title=Beneficial effects of vasodilator agents in severe mitral regurgitation due to dysfunction of subvalvar apparatus |journal=[[Circulation]] |volume=48 |issue=4 |pages=684–90 |year=1973 |month=October |pmid=4744778 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=4744778 |accessdate=2011-03-18}}</ref><ref name="pmid1180426">{{cite journal |author=Harshaw CW, Grossman W, Munro AB, McLaurin LP |title=Reduced systemic vascular resistance as therapy for severe mitral regurgitation of valvular origin |journal=[[Annals of Internal Medicine]] |volume=83 |issue=3 |pages=312–6 |year=1975 |month=September |pmid=1180426 |doi= |url= |accessdate=2011-03-18}}</ref>. [[ACE inhibitors]] may be useful as oral therapy.
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| ====[[Hypotensive]] patients====
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| Prior to the surgical procedure, an [[intra-aortic balloon pump]] may be placed in order to improve perfusion of the organs and to reduce afterload and thereby decrease the degree of mitral regurgitation <ref name="pmid18820172">{{cite journal |author=Bonow RO, Carabello BA, Chatterjee K, de Leon AC, Faxon DP, Freed MD, Gaasch WH, Lytle BW, Nishimura RA, O'Gara PT, O'Rourke RA, Otto CM, Shah PM, Shanewise JS |title=2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons |journal=[[Circulation]] |volume=118 |issue=15 |pages=e523–661 |year=2008 |month=October |pmid=18820172 |doi=10.1161/CIRCULATIONAHA.108.190748 |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=18820172 |accessdate=2011-03-18}}</ref>.
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| In patients with acute mitral regurgitation secondary to '''[[myocardial ischemia]]/[[infarction]]''', early coronary revascularization should be performed.
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| ===Surgical approach===
| | [[Category:Disease]] |
| Patients with rupture of the chordae tendineae or papillary muscle should undergo early [[mitral valve repair]] if possible which results in a better preservation of left ventricular function and long term survival in comparison to [[mitral valve replacement]] <ref>Society of Thoracic Surgeons National Cardiac Surgery Database. Available at : http://www.sts.org/documents/pdf/STSExecutiveSummaryFall2005.pdf. Accessed November 2005</ref>.
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| ==References==
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| {{Reflist|2}}
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| {{Circulatory system pathology}}
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| {{SIB}}
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| [[Category:Cardiology]] | | [[Category:Cardiology]] |
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