Lecture 12: Cardiomyopathy Flashcards
Define cardiomyopathy.
- disorders characterized by morphologically and functionally abnormal myocardium in absence of any other disease that could cause the observed “phenotype” (presentation i assume).
- Excludes cardiac dysfunction caused by structural heart disease.
Structural HD: CAD, primary valve disease, and HTN
What are the 3 classifications of cardiomyopathy?
- Dilated
- Hypertrophic
- Restrictive
- Arrhythmogenic RV CM/dysplasia (ARVC/D)
- unclassified CM
can be further broken into: intrinstic v extrinsic. primary v. secondary. ischemic v nonischemic.
What part of the heart is primarily affected in cardiomyopathy?
LV function
causes dysfunction in systole/diastole or both. presentation varies from asymptomatic to CHF and cardiac arrest
What is the initial imaging modality for cardiomyopathy?
Echocardiography
can also get nuclear imaging, coronary angiography w left ventriculography, and cardiac MRI.
What does systolic dysfunction eventually lead to?
- Decease in myocardial contractility and reduction in LVEF
- Compensatory LV enlargement
- compensatory Higher stroke volume
- HF develops once this fails
What characterizes systolic dysfunction?
- Decreases in myocardial contractility
- Reduction in LVEF
- Heart will compensate by enlarging LV.
What characterizes diastolic dysfunction?
- Abnormal LV relaxation and filling
- Elevated filling pressures
- Can occur with/without systolic dysfunction.
- However, if there is systolic dysfunction, it will always occur.
difficult to quantify on echo therefore often missed or underestimated
What is myocarditis?
- Inflammatory, infiltrative process of myocardium due to both infectious and non-infectious causes.
- results in Necrosis and/or degeneration of myocytes
- Leads to myocardial dysfunction and dilated cardiomyopathy.
may be acute, subacute, or chronic
What are the two main mechanisms by which myocarditis occurs?
- Host-mediated: direct cytotoxic effect of the causative agent.
- Autoimmune-mediated: secondary immune response.
What occurs in the acute phase of myocarditis?
- First 2 weeks
- Myocyte death due to causative agent.
What occurs in the chronic phase of myocarditis?
- After 2 weeks
- Result of inappropriate, overactive immune response.
What are the primary viral causes of myocarditis?
- Adenovirus
- Coxsackie B virus
- CMV
- COVID-19
What are the primary toxins that cause myocarditis?
- Alcohol
- Anthracyclines
- Cocaine
Who is myocarditis MC in?
20-50 y/o men
men have higher mortality rate with this too. frequency of myocarditis is poorly defined d/t variability of clinical presentation
What typically precipitates infective myocarditis?
- Acute febrile illness/respiratory infection
Will develop a few days or weeks after.
no known underlying cardiac pathology
What are the classic symptoms associated with infective myocarditis?
- SOB
- Pleural/pericardial chest pain
- Fever/chills
- HF
- Arrhythmias (palps, syncope, sudden death)
can be gradual or abrupt with decreased CO, shock and severely depressed LV systolic fxn
What PE findings are we looking for in infective myocarditis?
- Pericardial friction rub
- S3/S4
- Mitral or tricuspid regurg murmur
- Volume overload
What are the important initial diagnostic tests to order for suspected infective myocarditis?
- EKG - sinus tach, dysrhythmias, PVCs, ST-T changes
- Cardiac Biomarkers (elevated troponins)
- CXR (non-specific but could see cardiomeg,pulm edema, pleural effusion)
- Transthoracic echo - CRITICAL
What labs are appropriate to order for suspected infective myocarditis?
- CRP
- ^ESR
- CBC (eosinophilia)
- +/- Rheumatology workup
- Serum viral antibody titers
- BNP (probs >100)
what other imaging can be used in suspected infective myocarditis
cardiac MRI
helps assess extent od inflammation, myocyte necrosis and scarring. also shows ventricular size/shape, wall motion abnormalities, and pericardial effusion
Can suggest myocarditis, but sensitivity and specificity are limited and time-dependent
How is infective myocarditis concretely diagnosed?
Histologic evidence via endomyocardial biopsy.
Only do this if there is a high probability it will change management.
rarely used because seldom changes management
according to the AHA/ACC when is a EMB reccomended and when is it suggested
What is the primary treatment for myocarditis?
- Consult cardiology
- LVEF <40% = ACEI and BB
- NSAIDS for pain (colchicine)
- arrhythmic management
trials using immunosuppression, steroids, IVIG and antivirals have shown no benefit
what are typical causes of noninfective myocarditis
- medications
- illicit drugs
- toxic substances
What is the primary treatment for noninfectious myocarditis?
If LVEF >40%, Monitor until HF symptoms start occurring.
Once HF symptoms occur, refer to cardiology.
What is the #1 reason for heart transplant?
Dilated cardiomyopathy
What is dilated cardiomyopathy?
- LVEF < 40%
- No CAD or valvular disease
- Dilation and impaired contraction of one or both ventricles, predominantly the LV
Regurgitation may occur due to the stretch of mitral/aortic valves.
Who is dilated cardiomyopathy MC in?
3x more common in Black patients
once symptoms manifest, mortality rate is 50% at 5 years
What is the primary cause of dilated cardiomyopathy?
Idiopathic!!
could also be:
* infectious
* excessive alcohol
* genetic
* systemic disorders
* peripartum
* endocrinopathies
* tachycardia induced
* arrhythmia associated
what viruses can be infectious causes of dilated cardiomyopathy
- Parvo B19
- herpes
- coxsackievirus
- influenza
- adenovirus
- CMV
- HIV
What are the two main diseases that can lead to DCM?
- Chagas disease (protozoan infection. leading cause of DCM in central and south america)
- Lyme disease (manifests as conduction abnormality. may cause myocardial dysfunction d/t myocarditis)
Trypanosoma cruzi
What are the 3 main bacterial causes of DCM?
- TB
- Meningococcal
- Pneumococcal
What is the main genetic inheritance of DCM?
- Autosomal Dominant
- involves antibodies to a variety of cardiac proteins
what systemic disorders can lead to DCM
- sarcoidosis
- SLE
- Celiac
- Scleroderma
- RA
what endocrine disorders can lead to DCM
- thryoid dysfunction
- pheochromocytoma
- cushings
- GH excess/deficiency
what are the arrhythmia associated etiologies for DCM
- PVC-mediated (>15% burden)
- RV-paced rhythm
When specifically does peripartum CM occur?
Late pregnancy or early postpartum.
Early treatment can resolve it within 2-3 months.
presents as SCA or CHF
what are tachycardia induced etiologies for DCM? how does this cause DCM?
- afib, SVT, AVNRT
- HR correlates with LV dysfunction
- Causes reduced myocyte contractility
- LV dysfunction can occur w/o dialtion
What is the DCM etiology mnemonic?
- Alcohol Abuse
- Beriberi (wet) Vit B1 (thiamine) deficiency
- Coxsackie B myocarditis
- Chronic cocaine use
- Chagas’ disease
- Doxorubicin toxicity
ABCCCD
A Bunch of stuff Can Cause Cardiac Disease
what would the PE show in DCM
- rales
- elevated JVP
- S3 gallop
- murmur o mitral or tricuspid regurg
- peripheral edema
- ascites
What EKG findings can be seen in DCM?
- Tachycardia
- Pulsus alternans
- LBBB
What symptom would prompt us to order a BNP or NT-proBNP for DCM? Why do we order these?
Dyspnea
tests are ordered for prognosis and disease severity
what is the purpose of an echo in DCM diagnosis
excludes valvular disease and confirms ventricular dilation, LVsystolic fxn or pulm HTN
what is the treatment plan for dilated cardiomyopathy
- treat underlying source (commonly resolves LV dysfunction)
- CHF management
- Prevention of SCA
- Heart transplant
What characterizes restrictive cardiomyopathy?
- Nondilated ventricle with impaired filling
- Fibrosis or infiltration of the ventricular wall
- Diastolic dysfunction
- Biatrial enlargement
Most uncommon type.
What are the primary causes of restrictive cardiomyopathy?
- Infiltrative disorders (amyloidosis, sarcoidosis, fatty infiltration)
- Storage Disease (Hemochromatosis, Fabry’s)
- Radiation, chemo, carcinoid heart disease, hypereosinophilic syndrome
MCC is chemo in the US.
How is restrictive cardiomopathy diagnosed
echo or cardiac MRI
Endomyocardial biopsy may be considered
How do we treat restrictive cardiomyopathy?
- Treat underlying causes
- Diuretics (edema and congestion)
Most likely bc it backs up into the lungs since filling gets back up due to poor diastolic function.
What characterizes hypertrophic cardiomyopathy?
- LV hypertrophy (occasionally RV involved)
- Interventricular septum dysfunction most commonly involved as myocytes build up.
- NOT due to HTN or valvular issues.
- Diastolic dysfunction
How is HCM typically inherited? what does this genetic mutation cause?
Autosomal dominant - this genetic mutation causes mutations of sarcomere genes
What valve is at risk in HCM?
Aortic valve, since it sits above the interventricular septum.
What does Hypertrophic cardiomyopathy lead to
can lead to LV outflow obstruction, MI, and/or mitral regurg
How does HCM typically present?
- Fatigue
- CP
- CHF
- Syncope
- SCA
- Carotid pulses bisferiens d/t mimicked AS
- increased risk for arrhythmias
What murmur may occur in HCM?
- Mid-systolic, harsh, 3rd-4th intercostal that is louder with valsalva
- Quieter on squatting.
What is the usual EKG change seen in HCM?
LVH
What is the diagnostic modality of choice for HCM?
Echocardiogram - this will show LV wall >1.5 cm thick
What medications are we advised to AVOID in HCM treatment?
- Diuretics
- Vasodilators
We do not want lowering of preload.
What medications are indicated for HCM?
- BBs
- Verapamil specifically (relaxes contractility)
What procedures may help with HCM?
- Septal myectomy
- Alcohol septal ablation
What screening is recommended for any 1st degree relative with HCM?
- Annual echo until 20
- Q5years afterwards
What is the MCC of HF in the US?
Ischemic cardiomyopathy
results from death/damage/hibernation of myocardium d/t reduced O2.
What is the typical cause of ischemic cardiomyopathy?
CAD
but can be from any source of ischemia such as cocaine, vasospasm, thrombus ect.
What characterizes ischemic cardiomyopathy?
- Systolic dysfunction
- LV involvement primarily but can involve RV or both ventricles
- presents as CHF (edema, dyspnea, JVD)
What would an EKG and CXR show in ischemic cardiomyopathy
- EKG - Possible Q waves
- CXR - may see pulm edema
What should appear on echo for ischemic cardiomyopathy?
- Decreased LVEF
- Regional wall motion abnormality
What diagnostic study after an echo may help with ischemic cardiomyopathy?
Coronary angiography - especially if LV dysfunction cause is unknown
How do we manage ischemic cardiomyopathy?
- Revascularization via PCI or CABG
- Nuclear viability study to check to determine if myocardial dysfunction is d/t hibernation or scarring
- CHF management
How do we prevent SCA?
- External wearable defibrillator (Lifevest)
- ICD
What characterizes arrhythmogenic RVCM?
- Ventricular arrhythmias + specific myocardial pathology
- RV free wal myocardium replaced by fibrous/fatty tissue leading to RV dilation and abnormal function of RV
- Causes sudden death in young adults in Europe primarily
How does arrhythmogenic right ventricular cardiomyopathy present
- Chest pain
- Palpitations
- Syncope
- SCA
How do we diagnose ARVCM
Echo and Cardiac MRI
How do we manage arrhythmogenic RVCM?
- Diuretics for systemic congestion
- Anitarrhythmics, ablation, or ICD for ventricular arrhythmias.
What is Left ventricular noncompaction cardiomyopathy?
- rare Congenital cardiomyopathy
- Altered myocardial wall d/t intrauterine arrest of compaction of loose interwoven meshwork
How does LV concompaction present
- CHF
- Thromboembolism
- Ventricular arrhythmias
DX CONFIRMED W CARDIAC MRI
How do we treat Left ventricular noncompaction cardiomyopathy?
Heart transplant
What is takotsubo cardiomyopathy?
- Stress-induced/broken heart syndrome
- Causes ACS due to high catecholamine surge
MC in postmenopausal women.
Result of intense psychological or physical stress
How is takotsubo diagnosed?
LV apical ballooning on Echo or LV angiography
How is takotsubo’s treated?
BBs for a year