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Adult Patient 2 > Cardiac Physiology and Failure > Flashcards

Cardiac Physiology and Failure Flashcards

1
Q

How is mean arterial pressure calculated?

A

MAP approximates to diastolic + 1/3 pulse pressure

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2
Q

What is the pulse pressure?

A

The difference between the systolic and diastolic blood pressures

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3
Q

What is the difference in right and left ventricular pressures?

A

LV systolic 120mmHg

RV systolic 25 mmHg

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4
Q

What is the right atrial pressure equivalent to?

How is this seen clinically?

A

Central Venous Pressure

Jugular Venous Pulse

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5
Q

What cardiac events are associated with the first heart sound (S1)?

A

Closure of mitral and tricuspid valves

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6
Q

What cardiac events are associated with the second heart sound (S2)?

A

Closure of the aortic and pulmonary valves

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7
Q

Why does a stenotic valve produce a murmur?

A

Stiff/narrowed valve doesn’t open completely
Blood is forced through the narrowed opening
(ejection murmur)

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8
Q

Why does a regurgitant valve produce a murmur?

A

Valve edges are scarred
Valve doesn’t close completely
Backflow of blood

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9
Q

What is the Ejection Fraction?

A

The proportion of LVEDV that is ejected

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10
Q

Why is left sided heart failure more common?

A

Higher workload

More pressure on the left side

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11
Q

How do you get right sided heart failure?(2)

A

Secondary - progressed from left sided - most common
Prolonged left ventricular failure can progress to right sided failure – biventricular or congestive cardiac failure

Primary - right side alone
Right ventricular failure usually happens because of a raised pulmonary vascular resistance

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12
Q

What are the two aspects of left ventricular pressure-volume relationship?

A

Filling - diastolic compliance

Ejecting - systolic contraction

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13
Q

What does the Frank-Starling relationship assume?

What factors explain this?

A

Assumes after load is constant

Greater contact of actin/myosin interaction
Greater sensitivity of myofibrils to calcium ions from the sarcoplasmic reticulum

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14
Q

Whats is the influence on ejection fraction of heart failure resulting from diastolic dysfunction?
Why is this the result?

A

Heart failure with preserved ejection fraction

Impaired myocardial relaxation

Heart cannot fill properly

Stiff, fibrotic ventricle - LVEDP rises - reduced stroke volume

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15
Q

Whats is the influence on ejection fraction of heart failure resulting from systolic dysfunction?
Why is this the result?

A

Heart failure with reduced ejection fraction

Impaired myocardial relaxation

Heart cannot empty properly

Weak ventricle - reduced stroke volume

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16
Q

What is the upstream effect of heart failure, why does this occur and what are the effects of this?

A

Increased upstream pressure in the circulation

Inability to keep up with the returning venous blood

The rise in hydrostatic pressure in heart failure leads to loss of fluid from the circulation - OEDEMA
In the lungs, the fluid accumulates in the alveoli – PULMONARY OEDEMA

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17
Q

What is the downstream effect of heart failure? What does this have a particular influence on?

A

Reduced perfusion of vital organs

Especially the kidneys

18
Q

How is the kidney affected in heart failure?

A

reduces perfusion of the junta-glomerular cells

aldosterone released - sodium and water retention
angiotensin II released - vasoconstriction

19
Q

What is the result of an increase in SVR(afterload) resulting from vasoconstriction?

A

reduced stroke volume
greater systolic contraction required
worsens an already failing heart

20
Q

In what direction does the hydrostatic pressure cause fund to move?

A

Out of the blood vessel into the interstitial space

21
Q

In what direction does the osmotic gradient cause fluid to move?

A

Pulls fluid into the blood vessel from the interstitial space

22
Q

What are the main features affected in right sided heart failure?

A

JVP, Liver, Peripheries - oedema

23
Q

What are the main features affected in left sided heart failure?

A

Lungs - pulmonary oedema

Kidneys - reduced renal function

24
Q

What are some possible causes of heart failure?(8)

A 
Ischaemic heart disease
Valvular disease 
Intra-Cardiac shunts
Arrhythmias
Drugs
Hypertension
Cardiomyopathy
Fluid overload
25
Q

What is cardiomyopathy?

A

Diseases of the heart muscle

Becomes enlarged, think or rigid

26
Q

How is myocardial ischaemia worsened in terms of coronary blood flow?

A

A rising wall tension from cardiac failure (especially LV in diastole) will worsen coronary flow / myocardial ischaemia
- coronary arteries occluded during ventricular contraction, most perfusion occurs during diastole

Tachycardia will worsen it further by reducing total diastolic time

27
Q

What is the mortality of heart failure after diagnosis?

A

10% within 30 days
30% within 1 year
50% within 5 years

28
Q

What are the typical symptoms of heart failure?

A

Breathlessness - on exertion, at rest, on lying flat (orthopnoea), nocturnal cough, or waking from sleep (paroxysmal nocturnal dyspnoea).

Fluid retention (ankle swelling, bloated feeling, abdominal swelling, or weight gain).

Fatigue, decreased exercise tolerance, or increased recovery time after exercise.

Light headedness or history of syncope.

29
Q

What are the risk factors for hear failure?

A

Coronary artery disease including previous history of myocardial infarction, hypertension, atrial fibrillation, and diabetes mellitus.

Drugs, including alcohol.

Family history of heart failure or sudden cardiac death under the age of 40 years.

30
Q

What do you examine for if you suspect heart failure?

A

Tachycardia (heart rate over 100 beats per minute) and pulse rhythm.

A laterally displaced apex beat, heart murmurs, and third or fourth heart sounds (gallop rhythm).

Hypertension.

Raised jugular venous pressure.

Enlarged liver (due to engorgement).

Respiratory signs such as tachypnoea, basal crepitations, and pleural effusions.

Dependent oedema (legs, sacrum), ascites.

Obesity.

31
Q

How do you manage suspected heart failure?

A

Reduce or stop any drugs that could be worsening it

If symptoms are sufficiently severe, start a loopdiuretic such as:
Furosemide 20-40 mg daily.
Bumetanide 0.5-1.0 mg daily.
Torasemide 5-10 mg daily.

32
Q

What is being assessed when testing cardiac function?

A

structure of the muscle
competency of the valves
rate and rhythm

33
Q

What methods are used for physiological stress testing?

A

treadmill
bicycle ergonometer - patient stays still - less ECG interruption
can measure VO2 max

34
Q

6 principle mechanisms of cardiac dysfunction

A

Pump failure: weak systole or poor diastolic relaxation

Flow obstruction: e.g. plaque in vessel, or prevention of valve opening or ↑ ventricular chamber pressure (aortic valvular stenosis, systemic hypertension, aortic coarctation - CHD)

Regurgitant flow: backward flow through incompetent valve

Shunted flow: blood diverted (e.g. congenital defects or acquired post MI)

Disorders of cardiac conduction: uncoordinated transmission of electrical impulses (arrythmias)

Rupture of heart or major vessel: aortic dissection & exsanguination

35
Q

What does an Echocardiogram measure?

A

Chamber size
Muscle contractility
Valve function

done at rest

36
Q

What are the portions for a focus assessed transthoracic echo?

A

position 1 - subcostal
position 2 - apical 4 chamber
position 3 - parasternal long axis
position 4 - pleural scanning

37
Q

What is the first-line investigation for cardiac sounding chest pain?

A

CT coronary angiogram

38
Q

What is used for 24hr ambulatory heart monitoring?

A

Holter ECG

39
Q

What is ARVC and how is it managed?

A

Arrhythmogenic right ventricular cardiomyopathy

scar tissue replaces normal tissue

CMR

Implantable cardioverter-defibrillator

40
Q

What is restrictive cardiomyopathy?

A

idiopathic
impaired ventricular filling during diastole
primary disease in ventricular compliance

Adult Patient 2 (4 decks)

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