Cardiomyopathies Flashcards
Define preload and afterload xx [2]
Preload: cardiac myocytes in ventricles are filling with blood and stretching. Creates end diastolic volume
Afterload: force or pressure need to contract to eject blood out of aortic valve
Define cardiomyopathies
Group of diseases of the myocardium that affect the mechanical or electrical function of the heart because the walls of the heart chambers have become stretched, thickened or stiff. This effects the hearts ability to pump blood around the body
Which of the following is dilated cardiomyopathy?
A
B
C
D
Which of the following is dilated cardiomyopathy?
A
B
C
D
Which of the following is restricted cardiomyopathy?
A
B
C
D
Which of the following is restricted cardiomyopathy?
A
B
C
D
Which of the following is hypertrophic cardiomyopathy?
A
B
C
D
Which of the following is hypertrophic cardiomyopathy?
A
B
C
D
Cardiomyocytes are subdivided into which type of cells? [3]
pacemaker cells [1]
atrial cardiomyocytes [1] (force producing)
ventricular cardiomyocytes [1] (force producing)
What can be 3 consequences of cardiomyopathies? [3]
Thrombus / PE [1]
Arrhthymias [1]
Heart failure [1]
What are the three types of cardiomyopathies? [3]
1. Dilated cardiomyopathy: dilated left ventricle which contracts poorly/has thin muscle.
2. Restricted cardiomyopathy: Impaired relaxation due to stiff wall making it difficult to stretch
3. Hypertrophic cardiomyopathy: ventricular thickening causing disorganied muscle mass and reduced volume in ventricles
Which of the following is the most common?
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Restricted cardiomyopathy
Which of the following is the most common?
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Restricted cardiomyopathy
Name 5 symptoms of cardiomyopathies [5]
Extreme fatigue
Shortness of breath
Dizziness
Chest pain / Angina
Heart palpitations
Peripheral oedema
Ascites
Fluid in flungs
Difficulty sleeping
Weight gain
Early stages: May not present with signs or symptoms – need mutli modal investigations
But as the condition advances, signs and symptoms usually appear as severity increases
Why would cardiomyopathy cause:
i) chest pain? [1]
ii) breathlessness? [1]
Why would cardiomyopathy cause:
i) chest pain? [1]
reduced o2
ii) breathlessness? [1]
pulmonary oedema
Dilated cardiomyopathy carries what type of inheritance pattern? [1]
Autosomal dominant
What are features of dilated cardiomyopathy? [1]
What are the physiological consequences of dilated cardiomyopathy? [3]
Left or biventricular dilation & systolic dysfunction in absence of CAD, hypertension valvular disease or congenital heart disease. Dilated left ventricle which contracts poorly/has thin muscle
Causes:
- Reduced stroke volume and therefore CO
- Disordered myocytes: impaired ventricular filling
- Increase in preload / end diastolic pressure
How does the heart compensate for a reduction in CO due to dilated cardiomyopathy? [2]
Frank Starling Mechanism:
- Sympathetic nervous system activates increase in HR and contractility
- Subsequent activation of RAAS
What is the effect of increased aldosterone on blood potassium levels? [1]
Increasde aldosterone causes reduced potassoim levels in blood
What is the effect of increased aldosterone on blood potassium levels? [1]
Increasde aldosterone causes reduced potassoim levels in blood
Risk factors for dilated cardiomyopathy?
- Infection
- Pregnancy
- HTN
- Nutritional deficiences
- CAD
- Alchohol / substance abuse
- Valve disease
- Autoimmune disease
How would you diagnose dilated cardiomyopathy?
Screening?
Clinical history?
Physical exams?
Cardiac imaging?
Screening
* Family history
* Arrhthymias
* Heart failure symptoms
Cardiac history
* CAD
* HTN
* Valvular disease
* Autoimmune disease
Physical exam:
* Tachycardia
* Tachypnoea
* Displaced apex beat (move lower left)
* Peripheral oedema
Imaging
* CXR: cardiac enlargement
* ECG: tachycardia, arrhythmia and non-specific T wave changes
* Echo: shows dilated ventricles
Genetic testing !
Which drug classes would you treat dilated cardiomyopathy with? [4]
ACE I / ARBs: lower BP
Diuretics: reduce fluid built up
Anti-coagulants: reduce blood clot chances
Beta blockers: control HR
How would you treat arrhythmias caused by dilated cardiomyopathy? [3]
What is another treatment possibility? [1]
Medication to treat blood clots (anti coagulants)
Pacemaker: control rhythm of heart
ICD: shock heart if need to go into normal rhythm
Surgery: remove areas of heart muscle / whole heart transport
What are causes of hypertrophic cardiomyopathy?
- Arrthymias
- Interstitial fibrosis
- Increased LV thickness without abnormal loading conditions
- Caused by sarcomeric protein gene mutations e.g troponin T and B- myosin
- All in the absence of hypertension and valvular disease
- The hypertrophic, non-compliant ventricles impair diastolic filling
resulting in reduced stroke volume and thus cardiac output - Another issue with thick powerful heart is that there is a disarray of
cardiac myocytes so conduction is affected
Describe the pathology behind hypertrophic cardiomyopathy (HCM)
The hypertrophic, non-compliant ventricles impair diastolic filling resulting in reduced stroke volume and thus cardiac output
Septum can also be affected: causes left ventricular outflow tract obstruction or mitral valve dysfunction. Significant thickening of septum causes tightening of aortic valve – reduced ejection fraction
Causes a disarray of cardiac myocytes so conduction is affected
What is the genetic reason that HCM may occur?
Caused by sarcomeric protein gene mutations e.g troponin T and B- myosin
Mutations in β-myosin heavy chain gene (β-MyHC) cause 30% of all cases.
How would you diagnose dilated cardiomyopathy?
Screening?
Clinical history?
Physical exams?
Cardiac imaging?
Screening
* Family history
* Arrhthymias
* Heart failure symptoms
Cardiac history
* CAD
* HTN
* Valvular disease
* Autoimmune disease
Physical exam:
* Tachycardia
* Tachypnoea
* Displaced apex beat (move lower left)
* Peripheral oedema
Imaging
* CXR: cardiac enlargement
* ECG: tachycardia, arrhythmia and non-specific T wave changes
* Echo: shows dilated ventricles
Genetic testing !
How would you diagnose hypetrophic cardiomyopathy?
Screening?
Clinical history?
Physical exams?
Cardiac imaging?
Screening
* Family history
* Arrhthymias
* Heart failure symptoms
Cardiac history
* CAD
* HTN
* Valvular disease
* Autoimmune disease
Physical exam:
* Tachycardia
* Tachypnoea
* Displaced apex beat (move lower left)
* Raised JVP
Imaging
ECG: is abnormal and shows signs of left ventricular hypertrophy with
progressive T wave inversion and deep Q waves
* Echocardiogram: shows ventricular hypertrophy and a small left
ventricle cavity*
- Genetic analysis can confirm diagnosis since most cases are
autosomal dominant and familial
Genetic testing !
Is hypertrophic obstructive cardiomyopathy a disatolic or systolic pathology? [1]
Diastolic !
What ECHO findings would you find for HOCM? [3]
mitral regurgitation (MR)
systolic anterior motion (SAM) of the anterior mitral valve leaflet
asymmetric hypertrophy (ASH)
What ECG findings would you find for HOCM? [3]
left ventricular hypertrophy
non-specific ST segment and T-wave abnormalities, progressive T wave inversion may be seen
deep Q waves
(atrial fibrillation may occasionally be seen)
