The Heart
Terms
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- Where do the coronary arteries originate?
- In or directly above the SINUSES OF VALSALVA of the aortic valve.
- Describe the LEFT coronary artery.
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Bifurcates within 1 cm into the LEFT ANTERIOR DESCENDING (LAD) and the LEFT CIRCUMFLEX coronary arteries.
LAD supplies: anterior left ventricle, anterior right ventricle, anterior 2/3 of interventricular septum, ventricles circumferentially at the apical region.
left circumflex supplies: lateral wall of the left ventricle. - What does the RIGHT coronary artery supply?
- Remainder of the right ventricle, posteroseptal region of the left ventricle, including the posterior 1/3 of the interventricular septum at the base of the heart.
- How is DOMINANCE determined?
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By the coronary artery that contributes most of the blood to the posterior descending coronary artery.
10% = left dominant pattern. - What is the most prominent feature of heart failure?
- The abnormally high atrial filling pressure relative to stroke volume.
- What is the most common type of heart disease responsible for cardiac failure?
- Ischemic heart disease -- accounts for >80% of deaths from heart disease.
- Define Congenital Heart Disease.
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Reflects faulty embryonic development, which is expressed either as misplaced structures ro as an arrested progression of a normal structure from an early stage to a more advanced one.
1% of all live births.
Combo. of multifactorial genetic factors and environmental influences-- increased risk among siblings.
Intrauterine influence: maternal infection with ruberlla virus during 1st trimester.
Also maternal use of drugs during early prenancy-- thalidomide syndrome --> 10% incidence of CHD. - Ventricular Septal Defect (Roger Disease)
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MOST COMMON of all congenital heart defects (25-30%).
The most common ventricular septal defect is related to failure of the membranous portion of the septum to form, either in whole or in part.
The higher pressure in the left ventricle leads to a left-to-right shunt --> increased pulmonary flow --> increased pulmonary vascular resistance --> shunt is reverse to right-to-left = EISENMENGER COMPLEX --> right ventricular hypertrophy and right-sided CHF. - Name the congenital heart diseases that are "initial left-to-right shunt"
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1) Ventricular septal defect (Roger Disease)
2) Atrial septal defect
3) Patent ductus arteriosus
4) Persistent truncus arteriosus
5) Anomalous pulmonary venous drainage - Describe the embryological development of the atrial septum.
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The septum primum extends downward to join with the endocardial cushions, closing the ostium primum. Before the closure is complete, the midportion of the septum primum develops an ostium secundum, so that the right-to-left flow continues. The septum secundum develops to the right of the septum primum-- this leaves a foramen ovale.
Adults: fossa ovalis - List the different types of atrial septal defects (6)
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1) Patent foramen ovale: incomplete seal of the foramen ovale.
2) Atrial Septal defect, ostium secundum type
3) Lutembacher Syndrome: combination of mitral stenosis and an ostium secundum type
4) Sinus Venosus Defect: occurs in the UPPER PORTION of the atrial septum
5) Atrial Septal defect, ostium primum type: infolves the region adjacent to the endocardial cushion; usually celfts in the anterior leaflet of the mitral valve and septal leaflet of the tricuspid valve.
6) persistent common atrioventricular canal: fully developed, combined atrial and ventircular septal defects- common in DS patients. - Patent Ductus Arteriosus (PDA)
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The ductus arteriosus in the FETUS connects the descending aortic arch with the pulmonary artery.
Esp. frequent in infants whose mothers were infected with rubella virus early during pregnancy. - Truncus Arteriosus
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A common trunk for the origin of the aorta, pulmonary arteries, and coronary arteries.
Results from an absent or incomplete partitioning of the fetal truncus arteriosus by the spiral septum.
Most infants have a torrential pulmonary blood flow --> heart failure + recurrent respiratory tract infections --> death. - Tetralogy of Fallot (Dominant Right-to-Left Shunt)
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Most common cyanotic congenital heart disease in older children and adults, representing 10% of all congenital heart disease.
Boot-shaped heart.
Patent ductus arteriosus is protective.
Right ventricular blood is shunted through the ventricular septal defect and into the aorta --> arterial desaturation --> cyanosis --> dyspnea on exertion --> squatting position.
Marked polycythemia (many RBC's) --> cerebral thromboses - What are the 4 antomic changes that define the tetralogy of Fallot?
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1) pulmonary stenosis
2) ventricular septal defect (involves membranous septum region)
3) dextroposition of the aorta, so that it overrides teh ventricular septal defect
4) right ventricular hypertrophy - Transposition of the Great Arteries
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A situation in which the aorta arises from the right ventricle and the pulmonary artery from the left ventricle = 2 indepdent and parallel blood circuits.
All have an atrial septal defect, 1/2 have a ventricular septal defect, and 2/3 have a PDA.
Incompatible with life but 90% survival rate with an arterial switch operation. - Coarctation of the aorta
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A local constriction of the aorta that almost always presents immediately below the origin of the left subclavian artery at the site of the ductus arteriosus.
Males> females
Hallmark: discrepancy between the BP in the upper extremities (hypertension) and lower extremities (hypotension --> weakness and coldness)
Radiologic exam: notching of inner surfaces of the ribs owing to pressure from the dilated intercostal arteries. - Valvular Aortic Stenosis
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males > females 4:1
usually features the fusion of 2 of the 3 semilunar cusps.
Hypoplastic left heart syndrome is characterized by hypoplasia of the left ventricle, ascending aorta, and mitral valve. - Subvalvular Aortic Stenosis
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Results from abnormal development of a band of subvalvular fibroelastic tissue or a muscular ridge. The stenosis is caused by a membranous diaphragm or fibrous ring that surrounds the left ventricular outflow tract immediately below the aortic valve.
Males>females 2:1 - Ebstein Malformation
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A downward displacement of an abnormal tricuspid valve into an underdeveloped right ventricle. This divides the ventricles into 2 separate parts- the "atrialized" ventricle and the functional right ventricle.
Leads to heart failure, R ventricular dilatation, arrhythmias, sudden death. - Endocardial Fibroelastosis (EFE)
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Condition characterized by fibroelastic thickening of the endocardium of the left ventricle, which may also affect the valves.
Secondary (more common): occurs in association with underlying CV anomalies that leads to left ventricular hypertrophy during an inability to meet the increased oxygen demands of the myocardium. The endocardium of the L V displays irregular, white opaque thickened patches.
Primary EFE: unknown cause, absence of any associated lesion. L V very dilated; bad prognosis; infants develop progressive heart failure; need cardiac transplant. - Dextrocardia
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An inverted position of the heart, which represents a mirror image of the normal, left-sided location and configuration.
Heart is normal if the positioning of the visceral organs is also abnormal = situs inversus. - What is the most common symptom of ischemic heart disease?
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ANGINA PECTORIS = pain in the chest.
Symptomatic only when the luminal cross-sectional area is reduced by >75%.
Unstable angina. - sudden death
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The initial manifestation of ischmic heart disease may be unexpected ventricular fibrillation, which results in suddent death.
CORONARY ATHEROSCLEROSIS underlies most cases of sudden cardiac death. - What are the major elements that predispose a person to coronary artery disease? (3)
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1) elevated blood cholesterol level
2) hypertension
3) cigarette smoking - Location of transmural infarcts (3)
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1) right coronary artery: occlusion here produces an infarct of the posterior basal basal region of the left ventricle and the posterior 1/3 of the interventricular septum.
2) LAD coronary artery: lccusion here produces an infarct of the apiral, anterior, and anteroseptal walls of the left ventricle.
3) left circumflex coronary artery: occlusion here leads to an infarct of the lateral wall of the left ventricle. - Subendocardial infarction generally results from....
- hypoperfusion of the heart in disorders such as aortic stenosis or hemorrhagic shock or from hypoperfusion during the course of cariopulmonary bypass.
- Clinical diagnosis of acute myocardial infarction.
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Sudden onset with severe crushing pain.
1/4-1/2 occur without any symptoms and the infarcts are identified later by electrocardiographic changes or at autopsy.
Dx confirmed by electrocardiography and appearnace of increased levels of certain enzymes in the serum, particularly in the isoenzymes of lactic dehydrogenase and creatine kinase. - Complications of myocardial infarction
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Arrhythmias
Left ventricular failure & cardiogenic shock
Extension of the infarct
Rupture of the free wall of the mycoardium.
Septal perforation.
Rupture of a portion of a papillary muscle.
Aneurysms
Mural Thrombosis & embolism
Pericarditis - Define infarct expansion
- localized thinning and stretching of the ventricular wall in the region of a healing myocardial infarct-- actually an EARLY aneurysm. Composed of necrotic myocardium and collagenous tissue that expands with each contraction of the heart.
- Define false aneurysm.
- Results from rupture of a portion of the left ventricle that has been walled off by pericardial scar tissue. The wall is made of pericardium and scar tissue and NOT of left ventricular myocardium.
- Postmyocardial infarction syndrome (Dressler syndrome)
- a delayed pericarditis, which develops 2-10 weeks after infarction.
- Therapeutic Interventions that limit infarct size (3)
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Need RESTORATINO OF ARTERIAL BLOOD FLOW.
1) Thrombolytic enzymes: tissue-plasminogen activator or streptokinase- intravenously or directly into an obstructed coronary artery.
2) percutaneous transluminal coronary angioplasty- produces dilatation of narrowed coronary artery by inflation of a balloon catheter.
3) coronary artery bypass grafting: can restore the flow of blood to the distal segment of a coronary arteyr with a proximal occlusion. - Patients with ISCHEMIC CARDIOMYOPATHY:
- patients who present with left ventricular failure and in whom cardiac dysfunction occurs WITHOUT tissue necrosis.
- How does the WHO define systemic hypertension?
- persistent elevation of blood pressure to greater than 160 mmHg systolic, greater than 90 mmHg diastolic, or both.
- What is the most common cause of death in patients with hypertension?
- Congestive heart failure
- Define cor pulmonale
- Right ventricular hypertrophy and dilatation secondary to pulmonary hypertension.
- Acute cor pulmonale
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sudden occurrence of pulmonary hypertension, most commonly as a result of sudden, massive pulmonary embolizatoin.
Cuases acute right-sided heart failure and is a medial emergency. - Chronic cor pulmonale
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Caused by any pulmonary disease that intereferes with ventrilatory mechanics or gas exchange or that obstructs the pulmonary vasculature.
Most common causes: pulmonary fibrosis and chronic obstructive pulmonary disease. - Rheumatic heart disease
- Encompasses myocarditis during acute rheumatic fever, which is a sequel to group A streptococcal infection, and residusla chronci valvular deformities.
- Aschoff body
- The typical lesion of rheumatic myocarditis. Consists of a perivascular focus of swollen eosinophlic collagen surrounded by lymphocytes, plasma cells, and mac's. It is eventually replaced by a nodule of scar tissue.
- ACUTE Rheumatic Fever
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A complication of an acute streptococcal infection, which is almost always a pharyngitis.
LEADING CAUSE OF DEATH from heart disease in people between 5-25 in less-developed regions.
A pancarditis (inflammation of the entire heart) involving all 3 layers of the heart.
-myocarditis
-pericarditis
-endocarditis - CHRONIC Rheumatic Heart Disease
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The mitral valve is the most commonly and severely affect valve. Aortic valve is second most commonly involved valve.
Chronic mitral valvulitis: irregular thickening and calcification of the leaflets --> valve can't close properly --> mitral regurgitation.
A severe stenotic mitral valve has a narrowed orifice that looks like a "fish mouth" - Complications of chronic rheumatic heart disease (4)
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1) bacterial endocarditis
2) mural thrombi
3) congestive heart failure
4) cor pulmonale - Lupus Erythematosus
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(collagen vascular disease)
Endocarditis is the most striking cardiac lesion of SLE - verrucous (wartlike) vegetations occur on the endocardial surfaces and are called LIBMAN-SACKS ENDOCARDITIS. Most common on the mitral valves. No functional deficit and no scarring. - Scleroderma
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(collagen vascular disease)
The myocardium has intimal sclerosis of the small arteries, which leads to small infarcts and patchy fibrosis. - Acute endocarditis
- An infection of a NORMAL cardiac valve by suppurative organisms, typically Staph aureus and Strep pyogenes.
- Subacute endocarditis
- Less virulent organisms colonized DEFORMED VALVES that had been damaged by rheumatic heart disease.
- What is the most common predisposing condition for bacterial endocarditis in CHILDREN?
- Congenital heart disease
- What is the most frequent basis for bacterial endocarditis in ADULTS?
- Mitral valve prolapse and congenital heart disease.
- Wat is the most common serious complication of bacterial endocarditis?
- congestive heart failure, usually as a result of a destruction of a valve.
- Nonbacterial thrombotic endocarditis (NBTE)
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vegetations on apparently normal cardiac valves, almost always in association with cancer or some other wasting disease.
affects mitral and aortic valves equally- doesn't destory the valve; no inflammation and no microorganisms.
AKA marantic endocarditis
Principal danger: embolization to distant organs. - Define calcific aortic stenosis
- A narrowing of the aortic valve lumen as a result of the deposition of calcium in the cusps and valve ring.
- Calcific aortic stenosis occurs in which situations? (4)
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-elderly patients as a degenerative process involving a normal aortic valve.
-in an aortic valve scarred as a result of rheumatic fever.
-congenital bicuspid aortic valve becomes calcified with age.
-severe atherosclerosis of the aorta may be associated. - Mitral valve prolapse (MVP)
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A situation in which redundent mital valve leaflets fail to approximate during systole, resulting in mitral regurgitation.
caused by a variety of conditions, all of which have in common excessive mobility of the mitral valve leaflets.
Has a hereditary component- autosomal dominant trait.
Myxomatous proliferation may involve the mitral valve leaflets and the annulus and chordae tendineae. - Carcinoid Heart Disease
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Patients with carcinoid tumors that have metastasized to the liver often display changes in the endocardium of the right side of the heart.
The endocardial lesions probably result from high concentrations of tumor-produced SEROTONIN and other tumor products which are metabolized in the lung.
Left side of heart SPARED. - Name the 3 metabolic diseases of the heart.
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1) Hyperthyroid heart disease: tachycardia and increased cardiac workload --> angina pectoris and high output failure.
2) Hypothyroid heart disease: decreased cardiac output + reduced heart rate + impaired myocardial contractility.
3) Thiamine deficiency(Beriberi) heart disease: seen in the Orient; inadequate vitamin B1 for at least 3 months; US - alcoholics; similar to hyperthyroidism. - Define CARDIOMYOPATHY.
- PRIMARY disease of the myocardium (therefore exludes myocardial disease caused by ischemia, hypertension, etc.)
- Idiopathic Dilated Cardiomyopathy (DCM)
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Suggested that it results from an autoimmune disorder--
1) common observation of a focal or mild lymphocyte infiltrate in the myocardium
2) presence of heart-specific autoantibodies in some patients
3) occasional abnormalities of cellular immunity
genetic factors now very importent. - Secondary dilated cardiomyopathy
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A common pathway for the effects of virtually any toxic, metabolic, or infectious disorder causing widespread degenerative changes in the myocardium.
Alcohol abuse, hypertension, pregnancy, and viral myocarditis predispose. - Toxic cardiomyopathy
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-ethanol
-catecholamines
-anthracyclines (potent chemotherapeutic agents)
-cocaine - Restrictive Cardiomyopathy
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A group of disease in which myocardial or endocardial abnormalities limit diastolic filling while allowing contractile function to remain relatively normal.
-amyloidosis
-endomyocardial disese
-storage diseases - List the 4 causes of restrictive cardiomyopathy.
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1) interstitial infiltration of amyloid, metastatic carcinoma, or sarcoid granulomas
2) endomyocardial disease
3) storage disaeses
4) a marked increase in interstitial fibrous tissue - Amyloidosis
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(restrictive cardiomyopathy)
-amyloid infiltration results in cardiac enlargement without significant ventricular dilatation.
Symptoms predominantly referable to the RIGHT side of the heart.
Senile cardiac amyloidosis: the deposition of a protein closely related to prealbumin in the hearts of elderly patients. - Endomyocardial Disease (EMD)
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(restrictive cardiomyopathy)
1) Endomyoardial Fibrosis: equatorial Africa.
2) Eosinophilic EMD (Loffler Endocarditis): temperate regions; hyper-eosinophilia; men in 50's, rash.
Suspected to result from myocardial injury produced by eosinophils. - Storage Diseases (4)
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1) Glycogen storage disease
2) Mucopolysaccharidoses (GAG's)
3) Sphingolipidoses- Fabry disease: accumulation of glycosphingolipids.
4) Hemochromatosis: excessive iron deposition in many tissues and is caused by a genetic defect of iron metabolism. - Cardiac Myxoma
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Most common primary tumor of the heart.
Usually sporadic but sometimes associated with familial autosomal dominant syndromes.
Most arise in the LEFT ATRIUM.
Glistening, gelatinous, polypoid mass. - Rhabdomyoma
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Most common primary cardiac tumor in infants/children, forming nodular masses in the myocardium.
May actually be a HAMARTOMA instead of a neoplasm?
Almost all are multiple and involve both L and R ventricles and sometimes the atria.
Pale masses; cells have fibrillar processes that radiate to the margin of the cell - "spider cell"
Often occur with tubrous sclerosis. - Metastatic Tumors
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Derive from cancer of the lung, breast, and GI tract.
Many malignant MELANOMAS metastasize to the heart.
Can result in manifestations of RESTRICTIVE CARDIOMYOPATHY. - Name 3 cardiac tumors.
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Cardiac myxoma
Rhabdomyoma
Metastatic Tumors - Name 4 manifestations of Pericardial Effusion.
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1) Serous pericardial effusion - increased ECF volume; fluid has a low protein content and few cellular elements.
2) chylous effusion (fluid-containing chylomicrons)
3) hemopericardium
4) cardiac tamponade - Acute pericarditis can be classified as:
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Fibrinous (frequent cause: uremmia)
Purulent (cause: bacterial infection)
Hemorrhagic
Chest pain DOESN'T radiate down left arm. - Constrictive Pericarditis
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A chronic, fibrosing disease of the pericardium that compresses the heart and restricts inflow.
Radiation therapy and cardiac surgery; also follows a purulent or TB infection (TB major cause in underdeveloped regions). - Hypertrophic Cardiomyopathy
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An uncommon condition in which cardiac hypertrophy is out of proportion to the hemodynamic load on the heart.
1/2 of cases: mutations in the cardiac beta-myosin heavy chain gene on chromosome 14.
All defects involve SARCOMERIC PROTEINS.
Few symptoms; Dx made at screening of the family of a patient with symptomatic HCM. - What is the most notable histologic feature of hypertrophy cardiomyopathy?
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Myofiber diarray- most extensive in the interventricular septum.
Characterized by oblique, often perpendicular orientation of adjacent hypertrophic myocytes. - What are the main differences between left-sided and right-sided heart failure?
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Left:
⬢ More common
⬢ Consequences are in the lung
Right:
⬢ Less common alone, but often complicates left
⬢ Consequences are massive edema not in the lungs - Define myocardial infarction.
- a discrete focus of ischemic necrosis in the heart.
- What is the main significance to dentists of rheumatic heart disease?
- patients with it must be protected from bacteremia following dental procedures
- What percentage of nonfatal myocardial infarcts are asymptomatic and diagnosed after the even by electrocardiographic changes or at autopsy?
- 1/4-1/2
- What is the underlying factor in MOST cases of sudden death?
- coronary atherosclerosis, often occurring during the 1st hour after the onset of symptoms.
- compensatory mechanisms seen in congestive heart failure (4)
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⬢ Hypertrophy
⬢ Catecholamines
⬢ Vasoconstriction
⬢ Fluid retention - What is the cause of rheumatic fever?
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beta-hemolytic Streptococcus (pyogenes)
it is a complication of an acute streptococcal infection, which is almost always a pharyngitis. - What is the key diagnostic symptom for rheumatic heart disease?
- mitral murmur
- triggers for an angina pectoris attack (4)
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⬢ Eating
⬢ Environment
⬢ Emotion
⬢ Exercise - diseases associated with bacterial endocarditis in adults (3)
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⬢ Rheumatic heart disease
⬢ Streptococcus infections
⬢ Staphylococcus infections - The thrombus composed of aggregated platelets and clotted blood is made unstable by activation of which fibrinolytic enzyme?
- plasmin
- What is the importance of cardiac troponin?
- earliest test that shows myocardial infarction
- When changing from the resting state to the aerobic state, by how much must the coronary circulation increase?
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4-fold
(or from 5% to 20% of total cardiac output) - streptococcal diseases that involve the heart (5)
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⬢ Rheumatic heart disease
⬢ Strep throat
⬢ Bacterial endocarditis
⬢ Glomerulonephritis
⬢ Scarlet fever - Compare rheumatic fever and rheumatic heart disease.
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⬢ Rheumatic fever: Caused by beta-hemolytic strep infection, an acute disease
⬢ Rheumatic heart disease: Caused by post-strep immune reaction, a chronic disease - tests that can be used to confirm a diagnosis of myocardial infarct (6)
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⬢ ECG
⬢ Troponin I or II
⬢ AST
⬢ ALT
⬢ CPK
⬢ LDH - disease that may predispose a patient to develop rheumatic heart disease (4)
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⬢ Strep throat
⬢ Glomerulonephritis
⬢ Rheumatic fever
⬢ Scarlet fever - subtypes of non-small cell carcinoma (2)
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⬢ Squamous cell carcinoma
⬢ Adenocarcinoma - What is the five year survival rate for a myocardial infarct?
- 50%
- What are inverted T waves an indication of?
- myocardial infarction
- disorders requiring antibiotic premedication for periodontal scaling (3)
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⬢ Rheumatic heart disease
⬢ Ventricular septal defect
⬢ Atrial septal defect - What is the most frequent cause of bacterial infective endocarditis?
- dental manipulation