MYOCARDITIS & INFLAMMATORY CARDIOMYOPATHY
Transcript of MYOCARDITIS & INFLAMMATORY CARDIOMYOPATHY
MYOCARDITIS MYOCARDITIS & &
INFLAMMATORY CARDIOMYOPATHYINFLAMMATORY CARDIOMYOPATHY
BY Fellow: Hung Hung ChungLiehChungLieh
MYOCARDITISMYOCARDITIS: Cardiac Inflammation
Etiology1. Infectious process (Most commonly)2. Radiation3. Chemicals/Drugs 4. Physical agents5. Idiopathic (Giant-cell myocarditis)
MYOCARDITISChemicals/DrugsAnthracyclines (450-550 mg/m2)Anthracyclines combined Trastuzumab
(Anti-HER-2 receptor AB)Cocaine (Vasoconstrictor)Drug-Induced Allergic Myocarditis
(Eosinophilic infiltrate in myocardium)
VIRAL MYOCARDITISEPIDEMIOLOGY
Post mortem studies suggested myocarditis is a major cause of sudden, unexpected death (20%) in adults less than 40 years, young athlets, US Air Force Recruits..etcProspective & retrospective studies: Myocardial inflammation in 1 to 9% of routine postmortem examinationsVariable incidence due to differences in methods of diagnostic evaluation
VIRAL MYOCARDITISEPIDEMIOLOGYDallas Criteria (Histological diagnosis introduced in 1986)
Use tools of Light Microscopy in endomyocardial-biopsy specimensActive Myocarditis - Infiltrating lymphocytes and myocytolysisBorderline/Ongoing Myocarditis - Infiltrating lymphocytes (+), and myocytolysis (-)Negative - Infiltrating lymphocytes (-), and myocytolysis (-)
Probably underestimate the true incidence of myocarditis due to large intraobserver variability
VIRAL MYOCARDITISMOST COMMON INFECTIVE VIRUS
Coxsackievirus B (Enterovirus)Adenoviruses in A Recent Report
VIRAL MYOCARDITISCLINICAL MANIFESTATIONS
Asymptomatic StateECG Changes (Transient Electrocardiographic ST-T-Wave Abnormalities)
ArrhythmiasFulminant Condition with ArrhythmiasHeart FailureDeath
VIRAL MYOCARDITISFULMINANT MYOCARDITIS
Rapid Progressive Cardiogenic Shock (LOS) Life-Threatening Arrhythmia (LTA)A Prominent Cause of Sudden, Unexpected deathOften Within Hours to Several Days Following A Flu-Like Illness
VIRAL MYOCARDITISPOSSIBLE PHYSICAL EXAMINATIONS
Often NormalMuffled First Heart SoundThird Heart Sound Murmur of Mitral RegurgitationPericardial Friction Rub (Associated with Pericarditis)
VIRAL MYOCARDITISDIFFERENTIAL DIAGNOSIS
Acute Myocardial InfarctionChest painECG ChangesElevated Cardiac Enzymes
VIRAL MYOCARDITISDIAGNOSIS
A 4-FOLD RISE IN NEUTRALIZING ANTIBODY TITERS IN PAIRED SERA
(over A 2 to 4-Week Period):Generally Believed to Establish A Viral PathogenesisENDOMYOCARDIAL BIOPSY:Remains The Best Standard for Diagnosis of Myocarditis
VIRAL MYOCARDITISDIAGNOSIS
DIAGNOSIS SHOULD NOT BE BASED ON HISTOLOGIC FINDINGS ALONE
1. The potential discord between clinical and histologic features of myocarditis;
2. Inherent limitation of histologic diagnosis;3. Newer, less invasive modalities of diagnosing
myocarditis in develop.
VIRAL MYOCARDITISTHERAPEUTIC STRATEGY (For Patients with CHF, Arrhythmias)
Swan-Ganz Catheter CxR, ECG, ECHOABG, Blood Count, & BCS
FULMINANT MYOCARDITIS
AOYAMA & COLLEAGUES (2001)52 Patients with Fulminant Myocarditis PCPS UsageInitial Symptoms (Flu-Like); Cardinal SymptomsSevere Myocardial Disorders, Heart Failure, Arrhythmia, Conduction System Disorders, & Cardiogenic Shock
FULMINANT MYOCARDITISCLINICAL FINDINGS ON ADMISSION (1)
VITAL SIGNS: Systolic blood pressure <90 mmHg (50%), tachycardia, or bradycardia (60%).CHEST X-RAY: Slight dilatation (increased cardiothoracic ratio: 55%), congestion (70%).
FULMINANT MYOCARDITISCLINICAL FINDINGS ON ADMISSION (2)
ECG: Sinus tachycardia (40%), complete atrioventricular block (C-AVB) (35%), ST-T abnormality (100%), abnormal Q wave (80%), low voltages (60%), poor r-wave progression (95%).ECHO: Diffuse left ventricular hypokinesis (90%), slight hypertrophy (65%), pericardial effusion (90%), nondilated left atrium (85%) or left ventricle (90%).
FULMINANT MYOCARDITISCLINICAL FINDINGS ON ADMISSION (3)
ABG: Respiratory compensation of metabolic acidosis (50%).BLOOD CELLS: Leukocytosis (60%).BIOCHEMICAL EXAMINATION: Elevation of creatine kinase (90%), renal dysfunction (55%), hyponatremia (60%), elevated C-reactive protein (CRP) (95%).
FULMINANT MYOCARDITIS
MORGERA & COLLEAGUES (1992) : POOR PROGNOSIS in ECG
Abnormal QRS Complexes Left Bundle Branch Block
FULMINANT MYOCARDITISFELKER & COLLEAGUES (2000) :
TYPICAL ECHO FINDINGS
Non-dilated Left Ventricular (LV) ChambersThickened Myocardium (Suggestive of Myocardial Edema) Decreased Fractional Shortening
FULMINANT MYOCARDITISPROGNOSTIC SEROLOGIC MARKERS
Serum Levels of Soluble Fas (sFas) & Soluble Fas Ligand (sFasL) (Fuse et al, 2000)Cardiac Isoform of Troponin-I (cTnI) (Briassoulis et al, 2000)CRP (Kaneko et al, 2000)
VIRAL MYOCARDITISTREATMENTFulminant MyocarditisShort-Term PCPS (VADs/ECMO) Indications:
Duncan and colleagues/Aoyama and colleagues (2001)
Cardiogenic Shock induced by LOS or LTA despite maximal medical therapy (Drugs & IABP)Increasing Inotropic Requirements: Unlikely
VIRAL MYOCARDITISTREATMENTFulminant MyocarditisECMO: Acker (2001)
Circulatory CollapseCardiac ArrestSevere Pulmonary Failure with HypoxemiaBridged to VADs from ECMO if Necessary
VIRAL MYOCARDITISTREATMENTFulminant MyocarditisPCPS Tapper: Duncan and colleagues (2001)
Creatinine Liver enzymesSerum Lactate
(End Organ Perfusion Marker/Perfusion Marker)
VIRAL MYOCARDITISTREATMENTFulminant Myocarditis
High-Dose Immunoglobulin Therapy: Takeda and colleagues (1998)
VIRAL MYOCARDITISPROGNOSISFulminant MyocarditisShort Term Prognosis
Aoyama and Colleagues (2001): 32 (57.5%) of 52 treated with PCPS survived and returned
to normal life
Acker (2001):Overall success rates of 50-70% with mechanical
ventricular support
VIRAL MYOCARDITISPROGNOSISFulminant MyocarditisLong Term Prognosis
McCarthy and Colleagues (2000):93% were alive without having received a heart transplant
11 years after biopsy
Aoyama Colleagues (2001): Readmission rate of 10%, an exacerbation rate 3.3%, and
mortality of 10% during the follow-up period of 962 ±780 days post PCPS
BACTERIAL MYOCARDITISETIOLOGY
UncommonA Complication of Bacterial Endocarditis (Staphylococcus Aureus and Enterococci)Myocardial Abscess Formation (Valve Rings & IVS)Diphtheritic Myocarditis in 1/4 Diphtheritic Infections
BACTERIAL MYOCARDITISMECHANISM OF CARDIAC DAMAGE
Liberation of Toxin:1. Inhibits protein synthesis; 2. Leads to a dilated, flabby, hypocontractile heart.Conducting System:
Frequently involved as well.
BACTERIAL MYOCARDITISPROGNOSIS & TREATMENT
Cardiomegaly & Severe Congestive Heart Failure: Typically appear after the first week of illness;Prompt therapy with antitoxin is crucial; Antibiotic therapy is also indicated but is of less urgency.
CHAGAS' MYOCARDITISEPIDEMIOLOGYPathogen: Trypanosoma Cruzi (Transmitted
By An Insect Vector)Course: Extensive Myocarditis Typically
Evident Years after The Initial InfectionMost Common: In Central and South
America
CHAGAS' MYOCARDITISCLINICAL MANIFESTATION
Acute IllnessOnly About 1%Acute MyocarditisMyocardial Damage Years Later in About 1/3
CHAGAS' MYOCARDITISCLINICAL MANIFESTATION
Chronic IllnessDilatation of several cardiac chambersFibrosis and thinning of the ventricular wallAneurysm formation (especially at the left ventricular apex)Mural thrombiChronic progressive heart failure is the rule with poor survival
CHAGAS' MYOCARDITISCLINICAL MANIFESTATION
ECG FINDINGS1. Abnormal in most patients with cardiac
involvement2. Typically shows RBBB and LAFB3. May progress to complete AV block
CHAGAS' MYOCARDITISCLINICAL MANIFESTATION
ECHO FINDINGS1. A unique pattern of hypokinesis of the
posterior left ventricular wall2. Relatively preserved septal wall motion
CHAGAS' MYOCARDITISPROGNOSIS
Ventricular arrhythmias are common (especially during and after exertion) Cause of death:
Intractable congestive heart failureArrhythmiaA minority of patients dying from embolic phenomena.
CHAGAS' MYOCARDITISTREATMENT
Oral Amiodarone appears to be particularly effective in treating VTsCHF treatment strategy
HIV MYOCARDITISMany cardiac disease has also been associated with HIV-1HIV-I RNA has been detected in heart tissue from patients with AIDSDCM was evident in 80% of a large group of asymptomatic HIV-Positive patients, 83% of whom had myocarditis Overt clinical involvement is seen in 10% of HIV patients Most common finding is left ventricular dysfunction
HCV MYOCARDITIS
HCV also is able to replicate in myocardiumBoth HCV positive & negative-strand RNA was noted in DCM
HIV MYOCARDITISSome cases appears to be due to infiltration of the myocardium by the virus itselfIn others, heart is affected by opportunistic
infections common in AIDS, such as toxoplasmosis, or cardiac metastases in Kaposi's sarcoma, other 2nd viral myocarditis from CMV, Adenovirus
FROM MYOCARDITIS TO CARDIOMYOPATHY
Higher incidence of neutralizing antibodies to CVB in patients with cardiomyopathy (than in age-, sex-, race-, and living district-matched control subjects) has prompted the theory of a viral cause underlying the pathogenesis of cardiomyopathy
(From Myocarditis to Cardiomyopathy: Circulation. 1999;99:1091-1100)
FROM MYOCARDITIS TO CARDIOMYOPATHY
Host Factors That Influence Susceptibility to Viral Myocarditis
Murine viral infection is increased by:MalnutritionExerciseSex & sex hormonesAgeGenetic factors (Immune States)
FROM MYOCARDITIS TO CARDIOMYOPATHY
Host Factors That Influence Susceptibility to Viral Myocarditis
Susceptibility to viral infection may be regulated primarily by:1. MHC2. H-2 complex,
in each strain of inbred mice.
FROM MYOCARDITIS TO CARDIOMYOPATHY
Sequential Pathological Changes in Murine Viral Infection (EMCV or CVB)
After inoculation of mice with a virus, 2 principal pathogenic mechanisms are implicated in the destruction of myocardial tissue:
1. The direct viral mechanism;2. Immunocyte-mediated pathogenic mechanism.
FROM MYOCARDITIS TO CARDIOMYOPATHY
Sequential Pathological Changes in Murine Viral Infection
Acute Phase of Viral Myocarditis (Days 0 to 3)Subacute Phase of Viral Myocarditis (Days 4 to 14)Chronic Phase of Viral Myocarditis (Days 15 to 90)
Flow diagram indicating temporal changes in murine myocytes inoculated with virus covering days 0 to 90. Large solid arrow indicates beneficial effect; dashed arrow, detrimental effect; small solid arrow, induced, produced, or activated; and NT, neutralizing antibody titer.
FROM MYOCARDITIS TO CARDIOMYOPATHYAcute Phase of Viral Myocarditis (Days 0 to 3)
1. Virus-Induced Cytotoxicity (Focal Necrotic Myofibers in the absence without inflammatory cells infiltrate)
2. Cytokine mRNA (IL-1ß, TNF-α, IFN-γ) already induced 3 days after inoculation
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)1. NK Cells: The first wave of infiltrating cells in the
heart2. Cytokine mRNA (IL-1ß, TNF-α, IFN-γ, IL-2) are
produced and persisted as long as 80 days after inoculation: Beneficial VS Deleterious Effects
3. Circulating levels of cytokines also elevated in patients with Acute myocarditis, DCM, CHF
4. The role of NO
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)NK Cells, Perforin, & IFN
1. NK Cells (IL-2 Activated) have protective effects against viral invasion by limiting replication
2. Perforin Molecules Formation with Myocardial Injury (NK-like large granular lymphocytes, GM1 Positive cells)
3. NK also damage virus-infected myofibers
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)NK Cells, Perforin, & IFN
NK Cells, PerforinIFN administration (Exogenous) before, immediately
with, or within 24 hours of inoculation with EMCV or CVB3 can be effective in viral myocarditis
Native IFN is not fully protectiveNO induced by IFN is important in enterovirus
infection
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)NK Cells, Perforin, & IFN
IFNNK Cells, Perforin, & IFN IL-1ß, TNF-α, IFN-γ
each induce inducible NO Synthase (iNOS)IL-1ß + IFN-γ: Contractile dysfunction in the
presence of insulin in adult rate ventricular myocytes
TGF-ß decreases iNOS activity, protein content, and mRNA at cardiac microvascular endothelial cells
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Viral Titers & Neutralizing Antibody (AB)Viral titers in the myocardium were maximal on day 4 after
EMCV inoculation in NALB/c mice, but rapidly decreased & disappeared after day 10
Neutralizing ABs elevated rapidly on day 8 & 10 & reached the highest level on day 14
Infiltrating mononuclear cells (NK, Macrophage), which appear in the heart 5 to 10 days after viral infection, also play a definite role in suppressing viral infection
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Cell-Mediated Immune PathogenicityInfiltrating T lymphocytes are seen in the myocardium
as the 2nd wave of cells, important in:Limiting viral replicationIn eliminating infected myocardial cells
They peaked on day 7 to 14 after viral inoculation, coinciding the most severe acute pathological damage in the myocardium
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Cell-Mediated Immune Pathogenicity
Lyt 1-positive cells (helper/inducer): In the same extent as they were in the peripheral blood & the spleenLyt 2-positive cells (suppressor/cytotoxic): Greatly increased in the myocardium on days 7 to 14
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Cell-Mediated Immune Pathogenicity
B lymphocytes (10-20% of infiltrating lymphocytes) in the myocardium on day 7-14Thereafter, they increased gradually with reciprocal T cells counts drop over 1-3 months
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Cell-Mediated Immune PathogenicityCell-Mediated immune mechanisms play a pivotal role
in the ongoing destruction of cardiac tissueCytotoxic T lymphocytes have been shown to lyse virus-infected myocytes in vitro (Figure 4)Recent study raises the possibility that: 1. Anti-TCR Abs or; 2. Vaccine with synthetic TCR V-regionpeptides to prevent T-cell-mediated myocardial damage after viral infection
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Cell-Mediated Immune PathogenicityPerforin Particles on Virus-specific CTLs caused
myocardial injuryMechanism
Cellular ContactAdhesion of Myocytes (ICAM-1 by TNF-α, IFN-γ, CD40, B7-1, B7-2 ) to T Lymphocytes (CD40L, CD28)
OutcomeViral MyocarditisDCM
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Myocardial Injury in T-Cell-Depleted MiceMonoclonal ABS, Antithymocyte serum:
Induced marked reduction in myocardial damage (CVB3 in Mice)
BALB/c-nu/nu (T-cell-depleted Mice): Less prominent myocardial pathological changes
BALB/c-nu/+ :Markedly severe, prominent mononuclear cells infiltration, cavity enlargement
FROM MYOCARDITIS TO CARDIOMYOPATHYSubacute Phase of Viral Myocarditis (Days 4 to 14)Myocardial Injury in T-Cell-Depleted MiceNo Significant Virus Titrations in Myocardium &
Serum Abs:Viral clearance from the myocardium is controlled by B lymphocytesT cell Lymphocytes mediated the severity & development of myocarditis
FROM MYOCARDITIS TO CARDIOMYOPATHY
Chronic Phase of Viral Myocarditis (Days 15 to 90)Persistent Evolutional Myocardial InjuryLV Cavity Dimentions Enlargement, Myocardial
Fibrosis (Inner 2/3 of LV Wall)No Inflammatory Cells Infiltration In This StageIL-1 Associated?Absence of Culturable Virus/Viral Capsid Proteins
NotedCell-Mediated Autoimmune Mechanism Possible
FROM MYOCARDITIS TO CARDIOMYOPATHYChronic Phase of Viral Myocarditis (Days 15 to 90)Persistent Viral RNAIn situ hybridization & PCR: viral RNA detection in
heart 3 weeks later EMCV-inoculationT-cell lymphocytes hypothesis
Altered Manner or Restricted Manner in viral replication possible?Carrier State Infection (Extracardiac Organ in Immunocompromised status)?Hepatitis C Role?
FROM MYOCARDITIS TO CARDIOMYOPATHY
Chronic Phase of Viral Myocarditis (Days 15 to 90)Persistent Viral RNAHCV Involvement
FROM MYOCARDITIS TO CARDIOMYOPATHY
Chronic Phase of Viral Myocarditis (Days 15 to 90)Persistent Viral RNA
Heart specific autoantibodies (Anti-sarcolemma Abs in CVB-Induced Murine myocarditis)Cross-Reactivity to CVB3 Capsid Proteins (40% Identity shared with Myosin in Amino Acid Sequence )Myocardiogenic Epitopes located in the cardiac myosin rod or in the head portion
FROM MYOCARDITIS TO CARDIOMYOPATHY
Chronic Phase of Viral Myocarditis (Days 15 to 90)Apoptosis
Early shrinkage, Disintegration of nucleolus, Rapid phagocytosis, Total absence of InflammationJames et al (Arrhythmias including sudden unexpected death, cardiomyopathy, arrhythmogenic right ventricular dysplasia Uhl’s anomaly..etc)Partial role from acute viral myocarditis to DCMVirus triggered mechanism
FROM MYOCARDITIS TO CARDIOMYOPATHY
From Myocarditis to CardiomyopathyMechanism
1. Direct Virus-induced Myocytes Injury2. Immune-mediated Mechanism3. Persistent Viral RNA in Myocardium4. Apoptosis
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Hemodynamic PortionSupportive care is the first line of therapyCHF Stage:
Diuretics..To lower ventricular filling pressuresACEI..To decrease vascular resistanceß-Blocker..Once clinical stability achievedPotent IVD Vasodilators..Esp. in severe filling pressures
Aggressive control of vascular filling pressures might minimize immune activation by preventing endotoxin in the gut
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Hemodynamic PortionMicrovascular Spasm Theory?-> Calcium Blocker/α1-Blocker: Also effectiveAmlodipine
Inhibit NO productionProlonged survival and reduced myocardial damageImproved survival of patients with non-ischemic DCM
AmiodaroneBeneficialInhibition of TNF- α, IL-6
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Antiviral AgentsRibavirin (Virazole), synthetic nucleoside analogue:
Against RNA, DNA VirusesHuman amnion study in vitro/ Mice myocardial study is beneficial
Recombinant human leukocyte IFN- α A/D:Inhibit viral replication/Reduce inflammatory process in Mice modelIt should be used before or simultaneously used with viral inoculation
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Antiviral AgentsCombined Usage of Ribavirin/ IFN- α:
May decreased the effective dosageMinimize side effectsSynergic effects ….in Mice model
FROM MYOCARDITIS TO CARDIOMYOPATHYTHERAPY-Immunosuppressive AgentsSteroids:Inhibits ABs synthesisAggravated the course of Murine MyocarditisWorth further study
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsCyclosporine:Preferentially inhibit helper T-cell functionsInhibition of IL-2 productionGreater mortality/CHF when administered early/later
during myocarditis in MurineDecreased Thy 1.2+ (pan T) & L3T4+ (activated helper
T) in blood/thymusNo reduction in serum neutralizing ABs titers
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsFK-506At least 10-fold stronger than Cyclosporine in vivoAlmost total depletion of T- & B-cell functions in
MiceHigher mortality rate, higher virus titer & low serum
ABs
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsCyclophosphamideInhibit mainly the B-cell region in lymphoid organs
at low dose (30 mg. kg-1.d-1)Total cellular depletion of the B/T-cell regions (300
mg. kg-1.d-1)High dose in the early stage resulted in an increased
mortalityTreatment in the late stage had no effect
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsSUMMARYThe importance in the ABs production in the host for
the treatment of viral myocarditisABs production is not affected by the absence of T
cellsNo distinct benefit for patients with myocarditis in
Prednisolone with either Cyclosporine/ Azathioprine in recent biopsy –proven trials
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsAnti-Monoclonal ABs (Against total T cells) in Mice model
Decreased mortality during the viremic stage Less myocardial cellular infiltration & necrosisNo significant changes in ABs titers/virus replications
High-dose Immunoglobulin/γ-GlobulinEffective in the treatment of Mice/Human myocarditis
High-dose γ-GlobulinEffective in myocarditis 2nd to Kawasaki Dz
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsLevamisole (In Mice Study)
A promising immunopotentiating drugIncreased the number of myocarditis lesions
Recombinant human TNFMore severe myocarditis in Mice
Exogenous IL-1 or IL-2Restored myocarditis susceptibility in Mice
FROM MYOCARDITIS TO CARDIOMYOPATHY
THERAPY-Immunosuppressive AgentsAnti-B7-1 Monoclonal AB Alone or Combined with
Anti-CD40L Monoclonal ABObviously suppressed myocardial injuries in Murine
viral myocarditis