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Sem2: MDSA30160: Cardiorespiratory Disease > L6 Cardiac Failure, Cardiomyopathies, Myocarditis > Flashcards

L6 Cardiac Failure, Cardiomyopathies, Myocarditis Flashcards

1
Q

___________: The volume of blood pumped by the left ventricle in one heart beat.

Influenced by?

A

Stroke Volume: The volume of blood pumped by the left ventricle in one heart beat

SV is controlled/influenced by:

  • Preload
  • myocyte contractility
  • afterload
  • number and size of myocytes
  • heart architecture
  • synchronous function of the atrias and ventricles
    • arrythmias will cause abnormal atrial/ventricular filling
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2
Q

__________: the volume of blood pumped by the heart in one minute

A

Cardiac Output: the volume of blood pumped by the heart in one minute

Cardiac Output (CO) = Stroke Volume (SV) x Heart Rate (HR)

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3
Q

The amount of ventricular stretch at the end of the diastole.

A

Preload: left ventricular end-diastolic pressure (LVEDP)

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4
Q

Amount of resistance the left ventricle must overcome to open the aortic valve and push the blood volume out into the systemic circulation

A

Afterload: AKA systemic vascular resistance (SVR)

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5
Q

State in which the heart is unable to pump blood at the required rate

A

CONGESTIVE CARDIAC FAILURE (CCF)

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6
Q

Causes of Congestive Heart Faiulre

A
  • Causes:
    • Damaged myocardium
      • severe ischemia/infarct
    • Obstruction to flow
      • Aortic stenosis (blockage)
      • hypertension
    • Regurgitant flow
      • mitral or aortic valve regurgitation
    • Cardiac conduction disorders (Heart block or arrhythmias)
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7
Q

Systolic vs. Diastolic Dysfunction contributing to Congestive Heart Failure

A
  • Systolic dysfunction: Forward direction failure
    • insufficient blood volume is being pumped forward
    • poor organ perfusion → Hypoxia
  • Diastolic dysfunction: Backward direction failure
    • insufficient blood volume enters the ventricle during diastole
    • Vascular congestion
      • Pulmonary and peripheral Congestion
        • Pulmonary and peripheral Edema (excess of watery fluid in the cavities or tissues)
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8
Q

In most cases of heart failure, patients present with _______________.

A

In most cases of heart failure, patients present with combined both right and left-sided heart failure with the clinical and morphological features of each

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9
Q

Common Clinical Features of Left Sided Heart Failure?

A
  • Common Clinical Features of Left Sided Heart Failure:
    • Dyspnea
    • Orthopnea (shortness of breath while lying flat)
    • Paroxysmal nocturnal dyspnea (PND) - dyspnea only at night
    • Pulmonary Congestion/ Oedema (crackles/crepitation on chest auscultation)
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10
Q

Common Clinical Features of Right Sided Heart Failure?

A
  • Common Clinical Features of Right-Sided Heart Failure
    • Peripheral Oedema (ankle -, leg, sacral oedema, due to increased hydrostatic pressure)
    • Pleural Effusion (Hydrothorax)
      • Accumulation of excessive fluid in the pleural space that surrounds each lung
    • Jugular venous distention and elevated jugular venous pulse
    • Splanchnic congestion (Hepatosplenomegaly)
    • Ascites- Abdominal Fluid accumulation
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11
Q

Adaptive Mechanisms to Heart Failure?

A
  • Myocardial Hypertrophy
  • Frank-Starling mechanism:
    • Increased preload (dilation) leads to increased contractility
      • Increased volume stretches the myocardial wall causing more forceful contractions (Frank-Starling mechanism)
        • Increases calcium sensitivity of myofibers
        • Causes a greater number of actin-myosin cross-bridge formation
      • Greater contractility => Increased stroke volume
  • Neurohumoral systems activation:
    • Release of norepinephrine/noradrenaline (increases HR and augments contractility)
    • Renin-angiotensin-aldosterone system activation
    • Release of atrial natriuretic peptide
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12
Q

Describe the Frank-Starling Mechanism?

A
  • Frank –Starling mechanism:
    • Increased preload (dilation) leads to increased contractility
    • STARLING’S LAW: Stroke volume of heartincreasesin response to anincreasein the volume of blood filling the heart at the end of diastole
      • The increased volume stretches the myocardial wall causing more forceful contractions (Frank-Starling mechanism)
        • Increases calcium sensitivity of myofibers
        • Causes greater number of actin-myosin cross bridge formation
      • Greater contractility => Increased stroke volume
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13
Q

STARLING’S LAW: Stroke volume of heart ________ in response to an ________ in the volume of blood filling the heart at the end of _______

A

STARLING’S LAW: Stroke volume of heartincreasesin response to anincreasein the volume of blood filling the heart at the end ofdiastole

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14
Q

Distal effects of left cardiac failure are seen most prominently in ______

Clinical Symptoms?

A
  • Lungs:
    • Backward/retrograde pressure from left heart/pulmonary vein
    • Perivascular transudate (discharge)
      • Widening of institution space
      • Edema fluid enters alveolar sacs
      • Pleural effusion
  • Clinical signs & symptoms of above:
    • Dyspnoea
    • Cough
    • Orthopnoea (shortness of breath when laying down)
    • paroxysmal nocturnal dyspnoea
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15
Q

Left sided heart failure effects seen in _______________ due to lack of forward push/decreased cardiac output

A
  • Kidneys:
    • Deceased renal perfusion→ Activation of renin-angiotensin-aldosterone system →induces water/salt retention
    • → expansion of the blood volume and the interstitial fluid volume
      • promotes pulmonary congestion/oedema!
  • Brain:
    • Changes seen in severe/advance state:
      • decreased cerebral perfusion
      • cerebral hypoxia
      • confusion
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16
Q

Right Sided Cardiac Failure is also known as _________

A

Right-Sided Cardiac Failure is also known as ‘Venous Congestion Syndrome’

left-sided cardiac failure tends to cause right-sided cardiac failure → increased pulmonary circulation pressure causes increased right heart pressure

17
Q

Rights sided Cardiac failure is associated with what kind of congestion?

Symptoms?

A

Minimal pulmonary congestion (and thus minimal respiratory symptoms) but massive systemic congestion

Symptoms:

  • Liver/portal system:
    • Slight increase in size/weight of liver to congestion of the liver tissue.
    • Surface looks like Nutmeg
      • Spleen:
    • Increased size, feels tense, marked sinusoidal dilatation.
  • Subcutaneous tissues:
    • Peripheral oedema/swelling
    • especially lower limb (ankles/pre-tibial area) sacral region
  • Pleural & pericardial effusions
  • Ascites: Fluid within abdominal/peritoneal cavity
18
Q

_____________: Manifests due to the right ventricle being burdened by pressure due to increased resistance of the pulmonary circulation. Leads to right ventricular _______ and ____

A

Pure Right Sided Cardiac Failure –COR PULMONALE**: Manifests due to the right ventricle being burdened by pressure due to increased resistance of the pulmonary circulation. Leads to right ventricular **dilation** and **hypertrophy

19
Q

________________;

  • Massive pulmonary embolism
    • right ventricle cannot pump blood into the occluded pulmonary arteries
    • right ventricle dilates until it can’t contract
  • Immediate cause of death in massive PE.
A

Acute Cor Pulmonale:

  • Massive pulmonary embolism
    • right ventricle cannot pump blood into the occluded pulmonary arteries
    • right ventricle dilates until it can’t contract
  • Immediate cause of death in massive PE.
20
Q

________________:

  • Due to chronic severe pulmonary hypertension.
  • Disorders?
A

Chronic Cor Pulmonale:

  • Due to chronic severe pulmonary hypertension.
  • Disorders include:
    • COPD
    • emphysema
    • Pulmonary interstitial fibrosis
    • PE
    • Pulmonary arteritis
    • cystic fibrosis
    • neuromuscular disorders affecting chest movement
    • disorders inducing pulmonary vascular constriction
21
Q

Primary vs. Secondary Cardiomyopathy

A

Cardiomyopathy: Disease of heart muscle

  • Primary: congenital or no known cause)
  • Secondary: have known causes, i.e. ischemic, hypertension).
22
Q

Characteristics/Causes of Dilated Cardiomyopathy?

A

CHARACTERISTICS

  • Most common cardiomyopathy
  • Characterized by cardiac hypertrophy, dilatation, and CONTRACTILE/SYSTOLIC DYSFUNCTION
  • Stasis: Mural thrombi: Source for systemic thrombo-emboli
  • Valves are anatomically normal but dilation of ventricle can lead to mitral regurgitation as valves too far to properly close

CAUSES:

  • Idiopathic
  • Myocarditis
  • Alcohol
  • Pregnancy/Peripartum: Occurs in third trimester or post-partum.
  • Genetic
23
Q

Most Common Cardiomyopathy?

A

Dialated

24
Q

Characteristics/Causes/Signs of Hypertrophic Obstructive Cardiomyopathy

A

Characteristics

  • Typically septal/left ventricular hypertrophy
  • Characterized by impaired ventricular compliance & impaired diastolic filling = DIASTOLIC DYSFUNCTION
  • associated with severe disease & high incidence of sudden death.

Cause:

  • Genetic: About 50% cases are familial autosomal dominant,
    • beta-myosin heavy chain gene mutation
  • Clinical/morphologic/prognostic features vary greatly

Signs

  • Exertional dyspnea: Due to decreased cardiac output & secondary increase in pulmonary pressure
  • Harsh systolic ejection murmur: ventricular outflow tract obstruction
  • Angina type pain

Major problems:
· Atrial fibrillation with mural thrombi formation (risk of systemic emboli)
· cardiac failure
· arrhythmias

25
Q

Characteristics/Causes of Restrive Cardiomyopathy

A
  • Decrease in ventricular compliance → impaired ventricular filling during diastole → DIASTOLIC DYSFUNCTION.
    • Contractile function not affected
    • The relaxation of the heart muscle is abnormal
  • CAUSES:
    • Primary/idiopathic
    • Secondary to Radiation treatment (myocardial fibrosis)
    • Amyloidosis (deposition of amyloid in the myocardium),
    • Sarcoidosis (non-caeseating granulomas in the myocardium),
    • Metastatic tumour
    • Loeffler endomyocarditis (endomyocardial fibrosis & eosionophilia & large mural thrombi)
  • Gross Pathology:
    • Ventricles are NOT dilated
    • Myocardium is FIRM & STIFF
    • Both Atrial cavities are dilated
26
Q

Primary Cardiomyopathies (4)

A

Primary cardiomyopathies include:

1. Dilated

2. Hypertrophic Obstructive (HOCM)

3. Restrictive

4. Arythmogenic right ventricular dysplasia (ARVD); Fibro-fatty infiltrate of right ventricle with interstitial fibrosis. Genetic basis

27
Q

What is MYOCARDITIS?

A
  • A primary inflammatory process of myocardium
  • Can occur at any age
28
Q

Causes of Myocarditis?

A
  • INFECTIOUS: Most common cause
    • Viruses (majority of cases) with infants
      • Frequently implicated viruses are Coxsackie A & B, ECHO virus, influenza A & B
      • Occurs days/weeks after a primary viral infection elsewhere, such as an upper RTI
      • Mechanisms of myocyte damage:
        • Direct viral cytotoxicity
        • The virus induces cell-mediated immune reaction that attacks myocytes harboring virus/viral antigens
    • immunosuppressed susceptible to bacteria, fungi, protozoa
  • IMMUNE-MEDIATED REACTIONS:
    • Post streptococcal infections/Rheumatic fever
    • Drugs/Medications
      • hypersensitivity reaction to a drug {penicillin)
      • direct drug toxicity to the heart {e.g. doxorubicin}
  • PHYSICAL AGENTS: Radiation
  • SARCOIDOSIS
    • disease involving abnormal collections of inflammatory cells that form lumps known as granulomata
29
Q

Signs/Symptoms of Myocarditis?

A
  • Vary from extremes of asymptomatic to sudden onset of Cardiac Failure
    • Shortness of Breath
    • Palpitations
    • Fatigue
    • Precordial discomfort
    • mild fever (if cause is infectious)
  • Patients can recover without any long term sequelae
  • sudden death also possible due to
    • Arrhythmia
    • CCF (from dilated cardiomyopathy)
30
Q

Gold Standard of Myocarditis Diagnosis?

A

Endomyocardial biopsy is the gold standard to diagnose myocarditis

  • Myocarditis is a focal disease so four to five biopsy samples must be obtained from more than one area of the right ventricular (RV) septum
31
Q

For a diagnosis of myocarditis both _____________ and _________ need to be present. _____________ is also an indicator

A

For a diagnosis of myocarditis, both inflammatory cells & myocyte necrosis are needed to be present.

Tropinin is a sign of myocardial injury

32
Q

______ is a sign of myocardial injury

A

Tropinin is a sign of myocardial injury

Sem2: MDSA30160: Cardiorespiratory Disease (24 decks)

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