18) Cardiomyopathies - classification, pathophysiology, diagnosis and management.

Question 1

what are the different types of cardiomyopathy

Answer 1

Dilated cardiomyopathy (DCMP)

 Hypertrophic cardiomyopathy (HCMP)

 Restrictive cardiomyopathy

 Arrhythmogenic right ventricle cardiomyopathy

Question 2

what is the etiology of dilated cardiomyopathy ?

Answer 2

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

Question 3

what is the pathophysiology of dilative cardiomyopathy ?

Answer 3

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

Question 4

what are the signs and symptoms of dilative cardiomyopathy ?

Answer 4

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

Question 5

what are the physical findings of dilative cardiomyopathy

Answer 5

auscultations
mitral valve regurgitation or triscipid valve regurgitative - holosystolic murmur

S3 GALLOP

left ventricular impulse displaced

rales over both lung fields

Question 6

how do we diagnose dilative cardiomyopathy ?

Answer 6

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

Question 7

what is the treatment for dilative cardiomyopathy ?

Answer 7

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

Question 8

what are the different types of hypertrophic cardiomyopathy

Answer 8

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

Question 9

HCM is one of the most frequent causes of?

Answer 9

sudden cardiac death in young patients, especially young athletes.

along side myocarditis

Question 10

etiology of hypertrophic cardiomyopathy ?

Answer 10

Autosomal dominant 
with varying penetration
mutations of the sarcomeric protein genes - beta myosin heavy chain, 
myosin binding protein C 
cardiac troponin t

Question 11

pathophysiology of hypertrophic cardiomyopathy

Answer 11

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

Question 12

what is the mechanism of obstruction in hypertrophic cardiomyopathy ?

Answer 12

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

Question 13

what are the clinical features of hypertrophic cardiomyopathy ?

Answer 13

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

Question 14

what re the physical findings in hypertrophic cardiomyopathy ?

Answer 14

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

==============

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

Question 15

what is the diagnostic criteria for hypertrophic cardiomyopathy ?

Answer 15

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

Question 16

what are the modes of diagnosis in hypertrophic cardiomyopathy ?

Answer 16

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

============
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

===========

genetic testing +cardiac biopsy

Question 17

what is the treatment management of hypertrophic cardiomyopathy in all patients ?

Answer 17

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

=======

medical therapy

=====

invasive procedures

Question 18

what is the treatment management for symptomatic hypertrophic cardiomyopathy ?

Answer 18

always , first line for this is
BETA BLOCKERS-

second line if beta blockers not suitable - NDHP
verapamil

low dose oral diuretics

dysopyramide - in obstructive

Question 19

what are the invasive therapy recommended in hypertrophic cardiomyopathy ?

Answer 19

refectory to medical therapy

= septal reduction - septal myectomy preferred
or
trans coronary alcohol ablation of septal hypertrophy

= dual chamber pace maker

= heart transplant

Question 20

what medical therapies are contraindicated in hypertrophic cardiomyopathy ?

Answer 20

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

Question 21

what are the major complications of hypertrophic cardiomyopathy

Answer 21

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.

Question 22

what are the causes for restrictive cardiomyopathy ?

Answer 22

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 ,

Question 23

what is the pathophysiology of restrictive cardiomyopathy ?

Answer 23

decrease elasticity of the myocardium - decrease ventricular fill-in - decrease end diastolic volume - atrial congestion - atrial enlargement - venous congestion

Question 24

what are the clinical features of restrictive cardiomyopathy ?

Answer 24

dyspnea

right heart failure symptoms :
jVD 
peripheral edam 
ascitis 
hepatomegaly 
kussmaul sign - elevation of jugular pressure on inspiration

Question 25

what are the different diagnostics to restrictive cardiomyopathy ?

Answer 25

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)

Question 26

treatment of restrictive cardiomyopathy ?

Answer 26

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)

Question 27

what is the pathophysiology of arythmogenic right ventricular cardiomyopathy ?

Answer 27

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

Question 28

what are the clinical features of arrhythmogenic right ventricular cardiomyopathy ?

Answer 28

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)

Question 29

how do we diagnose arrhythmogenic right ventricular cardiomyopathy

Answer 29

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)

Question 30

what are the ECG finings in arrhythmogenic right ventricle hypertrophy ?

Answer 30

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

Question 31

what are the Echo finings in arrhythmogenic right ventricle hypertrophy ?

Answer 31

RV enlargement- reduced thickness
RV wall motion abnormalities
↓ RV EF

Question 32

what is the treatment management of arthmogenic right ventricular cardiomyopathy ?

Answer 32

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)

Question 33

what is the cause of arrythmogenic right ventricular cardiomyopathy ?

Answer 33

mutation of various gene - autosomal recessive or dominant