CVPR 04-03-14 09-10am Myocarditis and Cardiomyopathy - Horwitz Flashcards
Acute myocarditis – defn
An inflammatory disease of the myocardium that usually attacks a healthy child or adult and is often viral in origin
Acute myocarditis – presentation
Wide range: Often presents w/in 2 wks after a URI or flu-like syndrome w/fever & chills or GI symptoms…… If concurrent pericarditis is present, pts may have chest pain and ECG changes as well…. Adult cases often present w/HF with or without cardiogenic shock….. Arrhythmias w/palpitations or syncope are sometimes the presenting symptoms & may cause sudden death.
Causes of myocarditits
Many viruses cause myocarditis…..Hypersensitivity to drugs (anthracyclines & other chemo agents most common)…..Systemic inflammatory diseases (SLE) ….. Certain bacterial, fungal or other infectious diseases are among less common causes
Peripartum cardiomyopathy
Begins the last month of pregnancy or w/in 5 months after pregnancy….. Poorly understood…..Often resolves but may proceed to a serious cardiomyopathy.
Mechanism of virally-induced cardiomyopathy
In cases of viral etiology, an immune-related process rather than direct damage from the actual pathogen may be the major mechanism of injury…… Certain viruses (like Coxsackie B) have a relatively high incidence of myocarditis; However, in any viral epidemic only a very small % of victims are afflicted by clinically detectable myocarditis for an unknown reason (genetic predisposition?)
Myocarditis & Autoimmunity
Myocarditis is often an autoimmune reaction….. Certain viruses (coxsackie B) have regions (epitopes) immunologically similar to cardiac myosin.
Physical findings in Myocarditis
S3…Pulmonary congestion or peripheral edema…If cardiac dilation is present, mitral or tricuspid insufficiency murmurs…..Increased troponins ressembling findings in acute MIs may be present
ECG changes in Myocarditis
A variety of nonspecific ECG changes may occur, including patterns suggestive of pericarditis or acute MI…..
Echocardiograms in Myocarditis
Often demonstrate global or diffuse ventricular dysfunction & are very useful in confirming that a myocardial process is present
Biopsies in Myocarditis
Rarely done, but show focal or diffuse necrosis & myocyte swelling w/inflammatory changes.
Asymptomatic Myocarditis
A large % of myocarditis cases w/minimal or absent symptoms (other than evidence of an acute viral infection) probably go unrecognized…… Some such cases may eventually develop a dilated cardiomyopathy
Myocarditis w/HF - outcomes
Myocarditis cases presenting w/heart failure may resolve w/out apparent injury, may proceed rapidly downhill to death or may evolve into a chronic dilated cardiomyopathy.
Myocarditis w/HF - therapy
If HF is present, usual methods for this condition are applicable to treatment, esp. diuresis, low dose BBs & ACE-Is (and occasionally inotropic agents)
Nonviral Infectious Myocarditis - treatment
If non-viral infections are involved, appropriate antimicrobial agents are used.
Steroids to treat Myocarditis
In diseases in which steroids are known to effective (such as SLE), they are useful…. However, in viral or idiopathic cases steroids are controversial.
Three types of cardiomyopathy
- Most common = Dilated Cardiomyopathy….. 2. Rare = Hypertrophic cardiomyopathy….. 3. Rare = Restrictive cardiomyopathy
Dilated cardiomyopathy
Left ventricle is always involved, but often all 4 heart chambers are dilated…..Mild hypertrophy w/increased cardiac mass is usual (may be same thickness as normal, but now covers more area b/c of dilation, so more total mass)
Hypertrophic cardiomyopathy
Left ventricle is hypertrophied but not dilated, and there often is disproportionate hypertrophy of the septum….. may cause obstruction & problems w/diastolic filling
Restrictive cardiomyopathy
Infiltration or fibrosis of the ventricles, usually without dilatation.
Causes of dilated cardiomyopathy
Clinical distinction often made between “ischemic” (due to CAD) and “nonischemic” dilated cardiomyopathy….. Dilation may be present w/out development of HF in mild cases or early stages of the disease.
Dilated cardiomyopathy – Clinical manifestations
- Most common to detect this condition when severe Heart Failure is present (Cardiomegaly on chest films, ECHO: Dilated ventricles w/impaire systolic function & low EF = confirm the Dx)….. 2. Arrhythmia (injury, fibrosis, dilation; may cause sudden death)….. 3. Thromboembolism (dilation, poor contraction, abnormal surface)
Dilated cardiomyopathy – Presentation
HF w/large silent [i.e., asymptomatic] heart w/impaired systolic function
Dilated cardiomyopathy – Etiology
Usually idiopathic…. Also: Ischemia, Familial, Viral, Alcohol abuse, etc.
Dilated cardiomyopathy – Treatment
- Treatment of HF: Usually diuretics, ACE-Is, & BBs (BBs once stabilized/decongested); Also, digoxin, spironolactone, vasodilators, inotropes, biventricular pacing if refractory ventricular asynchrony present (often due to left bundle branch block)….. 2. Anticoagulation to prevent emboli (esp. if A fib present)….. 3. Anti-arrhythmic agents – drugs & implantable defibrillators (to prevent sudden death)….. 4. Last resorts: Implantable left ventricular devices (LVADs) or Heart transplant
Hypertrophic cardiomyopathy - presentation
Left ventricle is hypertrophy (often eccentric) but NOT dilated… Disorganized muscle fibers & collagen matrix, esp. in septum (which is often disproportionately thickened)….. Predominant diastolic disfunction, w/normal or enhanced systolic function….. Septal thickening + hyperdynamic contraction may cause aortic outflow tract obstruction (LV pressure»Aortic pressure )
Hypertrophic obstructive cardiomyopathy – symptoms/outcomes
Dyspnea (increase LV filling pressure)….. Angine (hyprtrophic lV, increase systolic LV pressure)…..Especially w/obstruction, sudden death may occur w/exertion (arrhythmias), esp. common cause of sudden death in athletes
Hypertrophic cardiomyopathy – etiology
Relatively rare & usually familial - Strong genetic component – Autosomal dominant inheritance
Treatment of hypertrophic cardiomyopathy
If obstructive component present: 1. Decrease contractility may decrease outflow tract obstruction - If drugs (BBs, Verapamil) ineffective, surgical resection or percutaneous alcohol septal ablation in the outflow tract often relieves obstruction….. 2. Avoid extreme exertion (may prevent sudden death)….. 3. Ventricular pacing (ICD) may occasionally be useful for relief of obstruction or arrhythmia control
Restrictive cardiomyopathy – presentation
Impaired ventricular filling due to stiff (non-compliant) ventricles….. Systolic function often normal & ventricles usually NOT dilated
Restrictive cardiomyopathy – Dx & Treatment
Dx via echocardiography w/Doppler assessment of ventricular filling….No real treatment
Restrictive cardiomyopathy – prognosis & etiology
Rare & w/poor prognosis (Intractable failure and fatal arrhythmias may occur)….. An infiltrative disease, most commonly due to amyloidosis & sarcoidosis
Brain natriuretic peptide (BNP) test
To decide if there is HF or not (very good at ruling out HF): If BNP low (500, usually in 1000s), probably is HF….. Also useful in monitoring therapy for HF pt
