Myocarditis/cardiomyopathy

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myocarditis
-inflammation of the myocardial cell, interstitial, and/or vascular elements
-commonly caused by viruses, toxic and autoimmune etiologies with subsequent myocardial destruction and myocyte necrosis
-no blockage of coronary arteries
MCC of myocarditis in US
-viral infection: coxsackie V adenovirus virus, influenzaa, CMV, poliomyoelitis, EBV, HIV, viral hep, mumps, rubella, varicella, vaccinia, arbovirus, RSV, HSV, yellow fever, rabies parvovirus
second MCC of myocarditis in US
-medication related
-ex: drug sensitivity reactions: PCN, HCTZ, methyldopa, sulfonamides, doxorubicin, streptomycin, cyclophosphamide, phenytoin, cyclophosphamide
Worldwide MCC of myocarditis
diptheria
MCC of myocarditis in south america
Chagas disease (also lyme disease, acute rheumatic fever)
other causes of myocarditis
-infections (rickettsia: rocky mtn spotted fever, q fever; bacteria: diptheria, TB, strep, meningococci, brucellosis, clostridia, staph, m pneumo, psittacosis; spirochete: syphilis, leptospirosis, lyme; invasive fungi, protozoa (chagas, toxoplasmosis, malaria, helminths)
-illicit drugs: amphetamines, cocaine
-chemicals: hydrocarbons, CO, arsenic, lead, mercury, cobalt, radiation
-bites, stings: scorpion venom, snake venom, black widow spider, wasp, tick paralysis
-autoimmune/ connective tissue disorders: giant cell myocarditis, sarcoidosis, SLE, RA, scleroderma, kawasaki disease, IBD, dermatomyositis
pathophysiology of myocarditis
-direct cellular damage to cell or presence of toxin and body attacks heart cells
acute phase of myocarditis
< 2 weeks
-myocytes take up viral RNA and there is a cytotoxic cell mediated necrosis with rapid cell death (within 1-2 days)
-surviving cells infiltrated by macrophages
-NK cells target myocardium expressing viral Rna and continue myocyte necrosis
-inflammatory mediators (TNF) are in circulation leading to neg ionotropic effect
-virus is cleared by PMNs, cytotoxic T cells, and neutralizing antibodies
chronic phase of myocarditis
> 2 weeks
-continuing myocyte destruction is autoimmune
-abnormal expression of HLA, persistence of the viral genome in myocardium
-over or under active immune response may lead to dilated cardiomyopathy/heart failure
-in pts where virus is not cleared
clinical manifestations of myocarditis
-highly variable
-usually manifests in otherwise healthy person
-no hx of cardiac dysfunction
-50% will have an antecedent viral prodrome (1-2 weeks ago)
-asymptomatic (focal myocarditis): incidental finding at autopsy: may not be related to death: inflammation in small localized areas, not near conductors
-systematic illness: fatigue, dyspnea, myalgias, few cardiac signs
-cardiac presentation: myopericarditis: chest pain in 35% of pts: pleuritic sharp, stabbing, squeezing precordial/substernal pain, friction rub: fever, sweats, chills, dyspnea
-fulminant CHF: DOE/at rest, orthopnea, PND, palpitations, tachycardia, gallop (S3,S4), mitral regurg, JVD, edema
clinical manifestations of myocarditis
-focal myocarditis: features of an acute MI: syncope may signal high grade AV block or risk of sudden death
-arrhythmia: occasionally with sudden death due to underlying ventricular arrhythmia or AV block (especially in giant cell myocarditis) (small and focal areas of inflammation in electrically sensitive areas) (forms clots so common to this is pulm or systemic embolism
other clues to myocarditis
-sarcoid myocarditis: LAD, arrhythmias, sarcoid involvement in other organs (up to 70%)
-rheumatic fever: affects heart in 50-90%, erythema marginatum, polyarthralgia, chorea, SQ nodules (joan's criteria)
-hypersensitive/eosinophilic myocarditis: pruritic maculopapular rash and hx of using offending drug (sulfonamide)
fulminant myocarditis
-follows viral prodrome
-distinct onset of illness consisting of severe cardiovascular compromise with ventricular dysfunction and multiple foci of active myocarditis
-either resolves spontaneously or results in death
acute myocarditis
-less distinct onset of illness
-established ventricular dysfunction
-may progress to dilated cardiomyopathy
chronic active myocarditis
-less distinct onset of illness with clinical and histologic relapses
-development of ventricular dysfunction associted iwth chronic inflammatory changes (including giant cells)
chronic persistent myocarditis
-less distinct onset of illness
-persistent histologic infiltrate with foci of myocyte necrosis but without ventricular dysfunction (despite sxs of chest pain, palpitations)
EKG findings of myocarditis
-sinus tachycardia: ST elevation without reciprocal depression, decrease in QRS amplitude
-transitory Q wave development
-20% AV block
diagnosis of myocarditis
-cardiac enzymes: troponin elevated
-ESR, CRP: elevated in 60% of pts
-PMNs may be elevated
-CXR: may reveal normal or enlarged heart and/or signs of pulm venous htn
-echo: impaired LV systolic and diastolic function, wall motion abnormalitis, decreased EF
-viral antibody titers: greater than 4 fold increase with gradual fall during convalescence
-antimyosin scintigraphy, gallium scan, MRI, PET scan: assess degree of myocardial inflammation
-cardiac angiography: r/o caoronary ischemia as cause of new onset of CHF, especially in presentation of acute MI
gold standard diagnosis for myocarditis
-endomyocardial biopsy
-recommended in acute deterioration of heart function of unknown origin that is not responding to medical tx
-sensitivity increases with more biopsies
-use if do not know what it is and not responding to tx
treatment for myocarditis
-decrease congestion and improving hemodynamics
-supportive: rest, cardiac monitoring, supplemental O2, fluid electrolyte management
-Tx CHF: ACEI, CCB, diuretics, digitalis, B blockers (avoid in decompensated/fulminant myocarditis)
-consider: anticoagulation, if there is inflammation in electrically sensitive areas give anti arrhythmic meds, if there is an AV block consider trans venous pacing
-immunosuppression has not been demonstrated to change the natural hx of infectious myocarditis
-cardiac transplant
prognosis of myocarditis
-mild sxs recover completely with no residual cardiac dysfunction
-1/3 pts will develop dilated cardiomyopathy
-peds pts: 92% survival
-in study, pts with giant cell myocarditis, 89% of pts either died or underwent transplantation with median survival from sx onset to death or transplantation being only 5.5 months
cardiomyopathies
-group of diseases that affect the heart muscle itself and are not a result of htn, congenital or acquired valvular, coronary or pericardial abnormalities
-heart muscle is diseased or abnormal for no reason
dilated cardiomyopathy
-MC
-the ventricular walls become thin or are normal
-ventricular chambers become large so heart not very good at systolic function
hypertrophic cardiomyopathy
-walls of ventricles become very thick
-not a concentric thickness
-chambers are small
-impaired diastolic function (later)
-pts are hyperkinetic
restrictive cardiomyopathy
-rare
-systolic and diastolic dysfunction-chambers are normal or slightly small
-walls are normal or slightly thick
-sometime infiltrated muscle to make it slightly stiff
characterstics of dilated cardiomyopathy
-ventricular chamber enlargement and dilation (may also affect atria)
-accompanied by an alteration in systolic pump function-results in clinical sundrome of CHF
-usually left ventricle but could be both or atria
-diffuse myocardial damage leads to dilation secondary increase residual volume caused by decreased ejection fraction
-partially compensate: frank starling mechanism: to improve cardiac contractility need to stretch heart more
-compensation: decrease CO/GFR activates RAA system, increase vasopressin and ANP (volume expansion)
-pressure buildup : regurgitation of mitral and tricuspid valve
etiology of dilated cardiomyopathy
-genetics/familial
-secondary to otehr cardiovascular disease (ischemia, htn, valvular disease)
-tachycardia induced
-infectious
-metabolic (thyroid/parathyroid disease, DM, electrolyte imbalance of K/ Mg)
decrease in phosphate (burns, prolonged respiratory alkalosis, DKA tx-reversible with replenishment)
-nutritional : beriberi, protein deficiencty
-toxic: poison, food, ALCOHOL
-medications: litium, cyclophosphamide, DOXORUBICIN (chemo), metamphetamines
-CVD
-infiltrative (hemochromatosis, amyloidosis, sarcoidosis)
-radiation, electric shock, peri-partium
-immunologic: post vaccine, serum sickness, transplant rejection
characteristics of hypertrophic cardiomyopathy
-inappropriate myocardial LV hypertrophy, often asymmetrical
-frequently involves the septum and may or may not be a result in obstruction of flow through the left ventricular outflow tract
-MC in males: 20-30. 60s
-leading cause of sudden cardiac death in children: 6%, die of v fib
-used to be called IHSS: segmental hypertrophy occurs anywhere, not just septum and can present w.o LV outflow obstruction
-obstructive: due to mid-systolic obstruction of flow through the LV outflow tract as a result of a bernoulli effect induced systolic anterior mitral valve movement toward the septum
-non-obstructive
characteristics of hypertrophic cardiomyopathy
-interventricular septum is more massively hypertrophied than LV free wall causing dynamic systolic outflow obstruction
-mitral rergitation in 90% of obstructive pts
-degree of LV outflow obstruction increases by decreased preload, afterload or increased contractility or heart rate
-etiology: genetic, familial (defect in genes encoding sarcomeric proteins, abnormal calcium kinetics
-complications: CHF, arrhythmias, infective endocarditis, A fib, sudden cardiac death
characteristics of restrictive cardiomyopathy
-rigidity, restrictive filling -decreased diastolic volume of either or both ventricles
-normal or near normal systolic function, LV chamber size, and wall thickness
-increase interstitial fibrosis
-decrease systolic function as disease progresses
-thickening and rigidity of ventricular wall
etiology: idiopathic, infiltrative or fibrotic disease (MCC : amyloidosis), can be tx induced
-severe prolonged eosinophilia of any cause can infiltrate myocardium (loeffler endocarditis)
-valves spared
-need to r/o: constrictive pericarditis: pericrdial calcifications adn thickening, pericardial effusion, normal sized ventricles
-clinical manifestations of restrictive cardiomyopathy
-determine the severity and possible causes
-hx of HTN, angina, CAD, anemia or thyroid disease
-personal cancers (drugs, metastasis, radiation)
-previous CHF or myocardial injury, med hx, drugs use (cocaine, sympathomimetics, amphetamines, alcohol consumption)
-genetics, familial
-congestive heart failure: peripheral edema, pulm edema, weight gain, JVD, DOE, enlarged heart, gallop, cardiomegaly, fatigue
extra clinical manifestations of hypertrophic cardiomyopathy
-murmur is increased with valsalva or standing bc of decreased preload
-feel LV heave or lift
-double apical impulse: forceful left atrial contraction against a highly noncompliant LV, common in adults
-triple apical impulse: late systolic bulge when heart is almost empty and is performing near isometric contraction
-double carotid arterial pulses: first arterial pulse is light, second is stronger
-systolic ejection crescendo-decrescendo murmur
-holosystolic murmur at apex: mitral regurgitation
-association with wolff parkinson white syndrome
-many children are asymptomatic: 6% mortality rate
diagnosis of cardiomyopathy
-include CBC, metabolic panel, thyroid funciton, cardiac biomarkers, BNP, CXR, echo, cardiac MRI, EKG, urine toxicology, cardiac cateherization (assess co-existing coronary artery, valvular disease, evalutate therapeutic intervention)
-radionuclide angiography: accurate assessment of ejection fraction, wall motion abnormalities
-ca
dilated cardiomyopathy findings
-CXR: cardiomegaly, enlargement of all chambers
-EKG: sinus tachycardia, interventicular conduction delays, decrease QRS voltage, bi ventricular/ bi atrial enlargement
-echo: increase LV chamber size, normal or decreased LV wall thickness, decrease LV contractility and ejection fraction, moderate mitral/ tricuspid regurgitation
hypertrophic cardiomyopathy findings
-CXR: normal, maybe cardiomegaly, decrease in LV chamber size
-EKG: LVH, left atrial hypertrophy, LAD, diffuse non specific ST-T changes, increase in QRS voltage because lots of muscle, AV blocks, deep narrow dagger like Q waves
-echo: LV wall/interventricular septum thickened, LVH, LAH, decrease in LV chamber size, impaired diastolic filling, abnormal systolic anterior leaflet motion of mitral valve, MVP, and MR
restrictive cardiomyopathy findings
-CXR: atrial dilation
-EKG: sinus tachycardia, decrease QRS voltage, bundle branch or AV blocks
-echo: non dilated, non hypertrophied LV, marked dilation of both atria, impaired diastolic function, moderate mitral/tricuspid regurgitation
diagnosis of restrictive cardiomyopathy
-CBC for eosinophilia
-myocardial biopsy for histological id
-amyloidosis is MCC (demonstrates apple green direfringence, stained with congo red, viewed under polarizing microscope
treatment for dilated cardiomyopathy
-vasodilators: decrease preload and afterload, decrease wall tension, decrease oxygen demand (ACEI are first line/ARB: IV nitroprusside, sublingual, oral nitrates, hydralazine)
-catecholamines: potent beta adrenergic effects (dopamine, dobutamine)- advanced refractory CHF
-digitalis, diuretics: loop diuretics: helpful in pts with renal insufficiency
-beta blockers: favorable for long term effect (carvediol)
-cardiac transplantation: young pts with advanced myocardial damage regfractory to medical therapy
treatment for hypertrophic cardiomyopathy
-want good preload
-improve sxs and LV complicance, decrease outlfow obstruction, decrease arrhythmias, and prevent major complications
-cardiac drugs: beta and calcium channel blockers
-do not give ionotropes, diuretics, sympathomimetics, nitrates, ACEI
-surgery: transaortic ventriculomyotomy or ventriculomyectomy
-pt education: athletes are most increased risk of sudden death, no competitive sports, implantable cardiac defibrillator
treatment for restrictive cardiomegaly
-decrease venous pressure without significantly decreasing CO and BP (sensitive to alteriations in LV volume)
-beta and cardio selective CCB (verapamil, dilitiazem) to increase LV filling time, improve ventricular relaxation, decrease compensatory sympathetic stimulation
-diuretics: decrease preload: symptomatic relief
-no benefits from vasodilators
-want moderate tachycardia
-poor prognosis for this disease and rapidly deterioration: surgical resection
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