Valvular Disease, Endocarditis, Tumors of the Heart and Cardiomyopathies Flashcards
What is Stenosis? What is insufficiency?
Stenosis means failure of valve to open completely.
Insufficiency is failure to close completely allowing reversed flow.
Abnormalities can be genetic or acquired. 2/3 of acquired valvular diseases are stenosis of mitral and aortic valves.
What is Aortic valve calcification ?
Most common of valvular abnormalities. It is a degenerative age related process that is a consequence of hyperlipidemia, hypertension, inflammation etc. Leads to deposition of hydroxyapatite.
Morphology : The hallmark is mounded calcified masses within the cusps which prevent opening. The calcification process begins in the fibrosa the outermost layer.
Clinically is causes a decrease in exercise tolerance, syncope, angina, dyspnea, HF and LV hypertrophy.
What is Mitral Annular Calcification?
Calcific deposits in the fibrous annulus. They appear as irregular, stony hard, occasionally ulcerated nodules at the base of the leaflets. Usually does not affect valvular function. In exceptional cases can lead to regurgitation, stenosis and may provide site for thrombus formation and increased risk of endocarditis.
What is Mxomatous Degeneration of the Mitral Valve ?
Mitral Valve Prolapse (MVP), one or both leaflets flop and prolapse into the LA during systole.
Morphology : The affected leaflets are enlarged, thick and rubbery. The tendinous cords may be elongate, thin or even ruptured The key histological change is the thickening of the spongiosa layer with deposition of mucoid (myxomatous) material.
Clinically it is characterized by chest pain mimicking angina, dyspnea and fatigue. Rare complications include infective endocarditis, mitral insufficiency, CHF, chordal rupture etc.
What is Acute Rheumatic Fever?
Acute Rheumatic Fever (ARF) is a non infectious acute multi system post inflammatory autoimmune response related to the M protein antigens of group A Streptococcus following a pharyngitis infection. Antibodies and CD4+ T cells directed streptococcal M proteins can recognize cardiac self antigens. Therefore damage to the heart may be caused by a combination of antibody and T cell mediated reactions.
Distinctive lesions occur in the heart, called Aschoff bodies, consisting of foci of T lymphocytes, occasional plasma cells, and plump activated macrophages called Anitschkow cell
diffuse inflammation and Aschoff bodies may be found in any of the three layers of the heart, resulting in pericarditis, myocarditis, or endocarditis. Inflammation of the endocardium and the left-sided valves typically results in fibrinoid necrosis within the cusps or tendinous cords. Overlying these necrotic foci and along the lines of closure are small vegetations, called verrucae. Subendocardial lesions, perhaps exacerbated by regurgitant jets, can induce irregular thickenings called mccallum plaques.
What is Rheumatic Heart Disease?
It is a chronic progressive process in patients with antecedent ARF, characterized by scarring and deformity of valve. In other words it is the remaining heart damage after an episode of ARF.
What is Endocarditis?
It is a microbial infection of the heart valves or the mural endocardium that leads to the formation of vegetations made by thrombotic debris and organisms. The aorta, aneurysms and other blood vessels can also become infected.
Pathogenesis
Endocarditis is caused in 50% to 60% of cases by Streptococcus Viridans. S. Aureus is responsible for 20% to 30% of cases. Other bacterial cases include enterococci.
Morphology : The vegetations are bulky, destructive lesions containing fibrin, inflammatory cells and bacteria. Aortic and mitral valves are the most common sites of infection. The vegetations can be single or multiple and may involve more than one valve they may erode the myocardium and produce an abscess. They are prone to embolization.
Clinically a patient has rapidly developing fever, chills and weakness. Murmurs are present in 90% of patients with left sided IE.
What is the difference between Acute and Subacute IE?
• Acute IE : Infection by highly virulent organism that rapidly produces necrotizing and destructive lesions. usually difficult to treat with antibiotics alone, require surgery most of the time. Despite treatment death can ensue within days or weeks.
• Subacute IE : Infection by organism with lower virulence that cause less destruction. Cure can be achieved with antibiotics.
What is Non Bacterial Thrombotic Endocarditis?
It can also be non infectious and most commonly characterized by a deposition of small thrombi without inflammation fo the leaflets. The vegetations are made of blood, platelets and fibrin. It often occurs in debilitated patients with cancers and other valve diseases. There is a striking association with pancreatic mucinous adenocarcinoma because of the procoagulant effects of tumor derived mucin.
What is Iiebman Sacks Disease?
It is an endocarditis occasionally encountered in systemic lupus erythematosus characterized by mitral and tricuspid valvulitis with small vegetations. Lesions are small, 1 to 4 mm, single or multiple pink verrucous appearance.
What are cardiomyopathies?
They are heterogenous group of diseases associated with mechanical and/or electrical dysfunction that exhibit inappropriate ventricular hypertrophy or dilatation. Mechanical failure can lead to CHF and an electric failure can lead to life threatening arrhythmias.
Primary cardiomyopathies can be genetic or acquired while secondary cardiomyopathies have a myocardial involvement as a component of a systemic multi organ disorder.
What is a Dilated Cardiomyopathy?
It is characterized morphologically and functionally by progressive cardiac dilation and contractile (systolic) dysfunction, with concomitant hypertrophy.
Pathogenesis : DCM is familial in 30% to 50% of cases. It is caused by more than 20 genes encoding proteins in the cytoskeleton, sarcolemma and nuclear envelope. In particular TTN, a gene that encode titin. In genetic cases it is autosomal dominant is the predominant pattern. Myocarditis can progress to DCM as well. Alcohol and other toxins.
Morphology : The heart is enlarged, heavy and loose. Mural thrombi are common. Histologically most muscle cells are hypertrophied with enlarged nuclei. Interstitial and endocardial fibrosis is also present.
Clinically DCM can occur at any age, it presents with dyspnea, fatigue, poor exertions capacity. Death occurs from progressive heart failure or arrhythmias.
What is Arrhythmogenic Right Ventricular Cardiomyopathy?
Inherited disease of myocardium causing RV failure and rhythm disturbances with sudden death. The disease has been associated to defective cell adhesion proteins in the desmosome that link adjacent cardiac myocytes. The RV is severely thinned due to loss of monocytes.
What si Hypertrophic Cardiomyopathy?
HCM is a common, heterogenous genetic disorder characterized by myocardial hypertrophy, poorly compliant LV leading to abnormal filling and intermittent ventricular outflow obstruction.
Pathogenesis : In most cases it is genetic. The transmission pattern is autosomal dominant. Caused by mutations in sarcomeric proteins mostly found in the gene encoding beta myosin heavy chain.
Morphology : The heart is thick, heavy and hyper contracting in contrast to the loose heart in DCM. It results in diastolic dysfunction. There is massive myocardial hypertrophy, classically a disproportionate thickening of the ventricular septum in relation to the LV free wall. The LV outflow tract exhibits fibrous endocardial plaque.
Clinically the reduced abnormality is reduces stroke volume due to impaired diastolic filling. In addition 25% of patients have dynamic obstruction to LV outflow. During auscultation harsh systolic ejection.
Therapy : Most patients can be helped with pharmacological intervention to decrease HR and contractility. In cases that are unresponsive heart transplant is the only treatment left.
What is Restrictive Cardiomyopathy ?
It is characterized by a primary decrease in ventricular compliance resulting in impaired ventricular filling during diastole. It can be idiopathic or associated with other disease that affect the myocardium like amyloidosis and sarcoidosis. Morphological features are not distinctive. Microscopically there may be only patchy or diffuse interstitial fibrosis.
