18) Cardiomyopathies - classification, pathophysiology, diagnosis and management. Flashcards
what are the different types of cardiomyopathy
Dilated cardiomyopathy (DCMP)
Hypertrophic cardiomyopathy (HCMP)
Restrictive cardiomyopathy
Arrhythmogenic right ventricle cardiomyopathy
what is the etiology of dilated cardiomyopathy ?
idiopathic - genetic predisposition
secondary causes :
ischimic heart disease
endocrine - thyroid gland diseases and diabetes
infection - coxsackie b virus , chagas , HIV
thiamine deficiency - wet berri berii
toxic substances :
cocaine
alcohol
doxorubicin med
what is the pathophysiology of dilative cardiomyopathy ?
Causative factors decrease the contractility of myocardium → compensatory mechanisms (Frank-Starling law) → ↑ end-diastolic volume (preload) → → eccentric hypertrophy → reduced myocardial contractility → systolic dysfunction and ↓ ejection fraction → heart failure
what are the signs and symptoms of dilative cardiomyopathy ?
left sided heart failure symptoms
dyspnea , orthopnea
paroxysmal nocturnal dyspnea
AND
right sided heart failure symptoms -ankle edema
ascitis
cold extremities
jugular venous distention
angina pectoris
palpitation
what are the physical findings of dilative cardiomyopathy
auscultations
mitral valve regurgitation or triscipid valve regurgitative - holosystolic murmur
S3 GALLOP
left ventricular impulse displaced
rales over both lung fields
how do we diagnose dilative cardiomyopathy ?
1) confirmation of the underlying secondary cause or idiopathic disease
2) assess the cardiac function
3) assess structural remodelling
lab
BNP is high - heart failure
troponin and comb tested to rule out infarction or coronary angiography
echo - dilation of ventricles and atrium
reduce LVEf
wall motion abnormality
chest x ray
cardiomegaly
pulmonary edema
ecg left v hypertrophy LBBB lack of r waves progression in precordial leads AF
in some cases biopsy
what is the treatment for dilative cardiomyopathy ?
underlying disease
- remove cardio toxic agents
abstain from alcohol
treat endocrine disorder such as hyperthyroidism with beta blockers
treat infection - chagas disease - benznidazole
treatment for heart failure
sodium restriction
ACE inhibitors , beta blockers , diuretics , digoxin
surgical treatment
if LVEF is less than 35 percent - Implanatble cardiodefib
or CRT considered
if medical therapy fails heart transplant
what are the different types of hypertrophic cardiomyopathy
obstructive hypertrophy - ventricular asymetrical septal hypertrophy = blocks the outflow through the aorta
Nonobstructive HCM: without obstruction of the left ventricular outflow tract (LVOT)
only ventricular hypertrophy
- asymmetrical septal hypertrophy
- symmetric hypertrophy
- apical hypertrophy
HCM is one of the most frequent causes of?
sudden cardiac death in young patients, especially young athletes.
along side myocarditis
etiology of hypertrophic cardiomyopathy ?
Autosomal dominant with varying penetration mutations of the sarcomeric protein genes - beta myosin heavy chain, myosin binding protein C cardiac troponin t
pathophysiology of hypertrophic cardiomyopathy
non obstructive type end diastolic volume is reduced reduced stroke volume reduced cardiac output HOWEVER EJECTION FRACTION IS PRESERVED ( the blood in the ventricles are pumped out)
obstructive -
same - reduced EDV
however there is outflow tract obstruction - all the blood in the ventricles is not pumped out
ejection fraction is low
what is the mechanism of obstruction in hypertrophic cardiomyopathy ?
systolic anterior motion (SAM) of the anterior leaflet towards the inter ventricular septum during mid to late systole
results in secondary mitral regurgitation of some of the blood in the atrium
or
muscular obstruction
hypertrophic septum
Hypertrophy of papillary muscles → increased left ventricular apical pressure → ↑ risk for development of apical ventricular aneurysms
or LVOT obstruction is dynamic
increase LV contractility , decrease preload and after load can cause an increase in the degree of obstruction
what are the clinical features of hypertrophic cardiomyopathy ?
symptoms worsens with exercise and use of certain drugs such as DIURETICS , HYDRALAZINE , ACEI / ARB, DIGOXIN
the non obstructive type is frequently asymptomatic
exertion dyspnea
tachycardia , palpitation
syncope , dizziness
chest pain
sudden cardiac death particularly in intense physical activity
what re the physical findings in hypertrophic cardiomyopathy ?
reversed split - expiration p2 then A2
late onset systolic ejection murmur - crescendo decrescendo in the obstructive type -at the apex of left sternal border
DOES NOT RADIATE
=apex or left sternal border
enhanced by valsalva
SAM - there is mitral valve regurgitation
S4 GALLOP
precordial lifting
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Pulsus bisferiens: LV outflow obstruction causes a sudden quick rise of the pulse followed by a slower longer rise
carotid artery spike and dome pulse
what is the diagnostic criteria for hypertrophic cardiomyopathy ?
both needed !
1) left ventricular concentric hypertrophy - more than 15mm in adults
2) absence of other cardiac or systemic diseases that would explain the hypertrophy - such as hypertension or aortic stenosis
what are the modes of diagnosis in hypertrophic cardiomyopathy ?
TTA with doppler
- thickening of ventricular wall and septum
if LV wall thickness is or more than 30mm = high risk of sudden cardiac death
systolic anterior motion of the mitral valve
mitral regurgitation
increase aortic pressure gradient
findings more specific to obstructive
- asymmetrical thickening of the inter ventricular septum
contact between the septum and mittal valve during systole
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ECG typical findings :
LVH sign
asymmetrical septal hypertrophy deep Q wave - inferior leads 2,3,avf and lateral 1 , avl and v4-v6
giant inverted t waves in PRECORDIAL LEADS
LBBB
associated arrhythmia - vtach , afib , atrial flutter
MOST HAVE ABNORMAL ECG
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genetic testing +cardiac biopsy
what is the treatment management of hypertrophic cardiomyopathy in all patients ?
AVOID DEHYDRATION
maintain good body weight
no alcohol intake
avoid strenuous exercise
automated implanatble cardioverter defibrillator = for the to prevent cardiac death
absolute indication = arrhythmia ,VT
relative - syncope , lv thickness are than 30mm
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medical therapy
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invasive procedures
what is the treatment management for symptomatic hypertrophic cardiomyopathy ?
always , first line for this is
BETA BLOCKERS-
second line if beta blockers not suitable - NDHP
verapamil
low dose oral diuretics
dysopyramide - in obstructive
what are the invasive therapy recommended in hypertrophic cardiomyopathy ?
refectory to medical therapy
= septal reduction - septal myectomy preferred
or
trans coronary alcohol ablation of septal hypertrophy
= dual chamber pace maker
= heart transplant
what medical therapies are contraindicated in hypertrophic cardiomyopathy ?
to those with acute complication such as heart failure or afib
medication t be avoided with obstruction = high dose diuretics digoxin spironolactone ACE and arb CCB nitrates
positive inotrope , afterload reducing , or preload reducing drugs are contraindicated in obstructive
to be avoided in non obstructive
digoxin
what are the major complications of hypertrophic cardiomyopathy
hypotension
- fluids and vasopresores with purely only vasoconstriction effect and no inotropic effect eg - phenylephrine
in severe with cardiogenic shock and pulmonary edema - beta blocker an vasopressors
heart failure
May require discontinuation of negative inotropic medication
,May require medications, e.g., ACEIs, that are typically avoided
Atrial fibrillation
Typically requires anticoagulation and either rate control or rhythm control
May also require medications, e.g., digoxin, that are typically avoided
Ventricular dysrhythmias
AICD placement
Some patients may benefit from antiarrythmic medication and radiofrequency ablation of arrhythmogenic foci.
what are the causes for restrictive cardiomyopathy ?
idiopathic
systemic infiltrative disease
amyloidosis - most common
sarcoidosis
hemochrombtosis
other:
löffler endocarditis
endocardial fibroelastosis - common occurrence in the first two years of life
endomyocardial fibrosis
radiationor post surgery
chemotherapy - doxorubicin ,
what is the pathophysiology of restrictive cardiomyopathy ?
decrease elasticity of the myocardium - decrease ventricular fill-in - decrease end diastolic volume - atrial congestion - atrial enlargement - venous congestion
what are the clinical features of restrictive cardiomyopathy ?
dyspnea
right heart failure symptoms : jVD peripheral edam ascitis hepatomegaly kussmaul sign - elevation of jugular pressure on inspiration
what are the different diagnostics to restrictive cardiomyopathy ?
auscultation
maybe an S3 or s4 gallop
rales
Echocardiography
Normal or decreased ventricular volume
Rapid early but reduced diastolic filling
Near normal or elevated EF
Atrial enlargement and dilation
Wall thickening is possible (usually symmetric ).
ECG Low voltage (especially in amyloidosis and sarcoidosis )
Left bundle branch block and other conduction disorders
CXR:
Signs of pulmonary congestion (e.g., pulmonary edema, pleural effusion)
Can reveal signs of underlying disease (e.g., hilar lymphadenopathy in sarcoidosis)
Endo/myocardial biopsy
Histology classically shows fibrosis.
Diagnosis of underlying cause if other tests are inconclusive (e.g., amyloid or iron depositions, eosinophilic infiltrates in Löffler endocarditis)
treatment of restrictive cardiomyopathy ?
limited and often palliative.
Treatment of underlying condition (e.g., phlebotomy for hemochromatosis or chelation )
corticosteroids in sarcoidosis
light chain amyloidosis
chemotherapeutic agent
Symptomatic treatment
Maintenance of sinus rhythm: beta blockers
↑ Ventricular filling time, ↓ sympathetic activity: cardioselective calcium channel blockers- verapamil and diltiazem
↓ Preload: ACE inhibitors, except in amyloidosis (ACEIs are poorly tolerated in amyloidosis)
For fluid overload: diuretics
Heart transplant (in patients with refractory symptoms)
what is the pathophysiology of arythmogenic right ventricular cardiomyopathy ?
Right ventricular myocardial cell death due to myocyte apoptosis, inflammation, and fatty/fibrotic tissue replacement → thinning of the right ventricular wall → dilation of the ventricle → ventricular arrhythmia and dysfunction
what are the clinical features of arrhythmogenic right ventricular cardiomyopathy ?
very variable Many patients remain asymptomatic.
Angina pectoris
Dyspnea
Peripheral edema, ascites, hepatic and splenic congestion
syncope, possibly sudden cardiac death (particularly during or after exercise)
how do we diagnose arrhythmogenic right ventricular cardiomyopathy
ARVC is diagnosed based on the AHA criteria :
1) Dysfunction and structural abnormalities of RV (can be revealed by echocardiography, MRI, or RV angiography)
2) Histological characteristics (require myocardial biopsy)
3) Abnormal repolarization (diagnosed with ECG)
4) Depolarization/conduction abnormalities (diagnosed with ECG)
5) Arrhythmias (diagnosed with ECG)
6) Family history (confirmation of ARVC in a relative either by criteria, pathological examination in surgery or autopsy, or by genetic testing)
what are the ECG finings in arrhythmogenic right ventricle hypertrophy ?
Repolarization disturbances in the right precordial leads (V1-3)
ECG
Possibly epsilon wave (at the end of a widened QRS complex)
Highly specific for ARVC but only occurs in ∼ ⅓ of patients
epsilon wave, is a marker of delayed activation of the RV free wal
Increased QRS duration
Ventricular tachycardia
Ventricular extrasystoles
what are the Echo finings in arrhythmogenic right ventricle hypertrophy ?
RV enlargement- reduced thickness
RV wall motion abnormalities
↓ RV EF
what is the treatment management of arthmogenic right ventricular cardiomyopathy ?
Avoid intense physical exertion.
Antiarrhythmic treatment
Pharmacologic: beta blockers (e.g., sotalol), amiodarone, calcium channel blockers
Invasive AICD implantation (in high-risk patients, e.g., patients with left ventricular involvement)
Heart transplant (in severe cases that are refractory to all other treatments)
what is the cause of arrythmogenic right ventricular cardiomyopathy ?
mutation of various gene - autosomal recessive or dominant
