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Yr 2 - Cardiology System > Complete Heart Block, DVT, Fallots Tetralogy > Flashcards

Complete Heart Block, DVT, Fallots Tetralogy Flashcards

1
Q

What occurs during complete heart block?

A

Complete failure of AV node (due to damage to AV node) to transmit electrical signals from atria to ventricles

Atria have electrical activity and contract independently of the ventricles which
develop their own pacemaker activity – usually at a much slower rate

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2
Q

What anatomical structure is affected during complete heart block?

A

AV node

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3
Q

What is normally physiology of electrical transmission in heart?

A

Transmission of electrical depolarisation wave from atria to ventricles

AV node induces a short delay in transmission – to allow atria to contract before ventricles contract

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4
Q

What is purpose of AV node inducing short delay?

A

Prevents both contracting together which would not allow tricuspid and mitral valves to open

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5
Q

What structural abnormalities of AV node are present in complete heart block?

A
  • Fibrosis of AV node

- Necrosis / infarction of AV node

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6
Q

What is fibrosis of AV node?

A

Replacement of some of the normal cells with fibrous tissue due to cell death due to age

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7
Q

What is necrosis / infarction of AV node?

A

Death of all or most of cells as a result of coronary artery disease

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8
Q

Who is at risk of complete heart failure?

A

Elderly patient who may have had a prior myocardial infarction; be taking betablocker or other rate lowering drugs (digoxin, verapamil) that act to block AV node

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9
Q

How can complete heart block present?

A
  • Gradually and in isolation (chronic complete heart block)

- Suddenly with other symptoms (acute)

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10
Q

What are symptoms of chronic complete heart block?

A

Tiredness and breathlessness with exercise

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11
Q

What are symptoms of acute complete heart block?

A

Light-headedness or

collapse with loss of consciousness

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12
Q

What is coronary artery disease?

A

Arteries that supply blood to heart muscle become hardened and narrowed due to build up of cholesterol and other material (atherosclerosis)

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13
Q

What are clinical signs of complete heart block relating to pulse/heart rate?

A

Pulse / heart rate – is slow (often much lower than 60 beats per minute)

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14
Q

What are clinical signs of complete heart block relating to blood pressure?

A

Often low

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15
Q

What may consciousness be like with patients with complete heart block?

A

Patient may be seen to suddenly lose consciousness for some seconds (called cardiac syncope)

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16
Q

What is medical/surgical intervention of complete heart block?

A

Ambulance / paramedic staff may administer atropine

A temporary pacemaker may be introduced immediately on arrival in hospital

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17
Q

What is purpose of atropine during complete heart block?

A

Blocks vagus nerve and acetyl

choline allowing the heart rate to rise

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18
Q

What does pacemaker do during complete heart block?

A

A wire is introduced into a vein and from there into the right ventricle – allowing a small
electrical impulse to be sent to stimulate the heart

Permanent pacemaker needed if complete heart block persists

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19
Q

What is DVT?

A

Blood clot forms in vein (thrombosis) located deep inside body (typically leg)

Usually first appears in calf (lower leg) but may extend above knee (femoral vein) and possibly into pelves (iliac veins) and abdomen (inferior vena cava)

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20
Q

What anatomical structures / physiology are affected by DVT?

A

Deep veins of leg (femoral and popliteal veins) and pelvis (iliac veins)

Return of deoxygenated block back to right side of heart (inferior vena cava) and then to the lungs (pulmonary artery)

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21
Q

How can DVT patients have hereditary thrombophilia?

A

Deficiencies in anticoagulation factors protein C, protein S, antithrombin, or mutations in the factor V and prothrombin genes

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22
Q

What is thrombophilia?

A

The tendency to develop thrombosis

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23
Q

How can recent surgery increase risk of DVT?

A

Blood vessels can be damaged in surgery which can lead to risk of clot.

Bed rest with little movement after surgery can lead to clot.

24
Q

What else can contribute to risk of DVT?

A

Age, obesity, infection, immobilisation, combined (oestrogen-containing) contraception, tobacco, air travel

25
Q

What do low-molecular-weight heparin (LMWH) treat?

A

Prevention of blood clots and treatment of DCT

26
Q

What are symptoms for DVT?

A
  • Swelling of right or left calf
  • Pain in calf
  • There may be no symptoms related to the leg – but sudden pulmonary embolus may occur
27
Q

What are clinical signs of DVT?

A
  • Swelling and redness of the leg and dilation of the surface veins
  • Tenderness over veins when applying gentle pressure
  • Physical examination is unreliable for excluding the diagnosis of deep vein
    thrombosis
28
Q

What would ultrasound of leg in DVT show?

A

Absence or reduction of venous flow and presence of thrombus within vein(s)

29
Q

Why would D-dimer levels be tested for in low-probability situations of DVT?

A

This is a cross-linked fibrin

degradation product - an indication that thrombosis is occurring, and that the blood clot is being dissolved by plasmin

30
Q

What is the immediate / 3 to 6 month treatment for DVT?

A

Immediate anticoagulation with low molecular weight heparin

3 to 6 month anticoagulation with Direct Oral Anticoagulant or Warfarin

Regular walking / exercise

31
Q

What is fallots tetralogy?

A

A combination of four congenital abnormalities –> ventricular septal defect (VSD), pulmonary valve stenosis, a misplaced aorta and a thickened right ventricular wall (right ventricular hypertrophy)

32
Q

What physiology is affected in fallots tetralogy?

A

Sequential flow of deoxy blood from right heart to lungs and oxy blood through left heart to body

33
Q

What are the 4 structural abnormalities in fallots tetralogy?

A
  1.  Ventricular Septal Defect (VSD) – a hole in the heart
  2. Pulmonary stenosis
  3. Overriding aorta
  4. Right ventricular hypertrophy
34
Q

What is pulmonary stenosis?

A

A narrowing of pulmonary valve

35
Q

What is overriding aorta?

A

Position is over right as well as left ventricle

36
Q

What is right ventricular hypertrophy?

A

More muscular due to high pressure

37
Q

How does fallots tetralogy result in low oxygenation of blood?

A

Mixing of oxygenated and deoxygenated in the left ventricle via the VSD

38
Q

Why is there preferential flow of this mixed blood in fallots tetralogy through the aorta? What is this known as?

A

Because of obstruction to flow through the pulmonary valve and overriding aorta. This is known as a right-to-left shunt.

39
Q

What are the prior events to fallots tetralogy?

A

Patients are born with this set of abnormalities with no recognisable prior events/causes

40
Q

What is primary symptom of fallots tetralogy?

A

Low blood oxygen saturation with or without cyanosis (blue appearance due to low level of oxygen in arterial blood)

41
Q

What are other symptoms of fallots tetralogy?

A
  • From birth (congenital) or developing in the first year of life
  • Difficulty in feeding
  • Failure to gain weight
  • Retarded growth and physical development
  • Dyspnoea on exertion
42
Q

What are the clinical signs of fallots tetralogy?

A
  • Heart murmur which may range from almost imperceptible to very loud
  • Clubbing of the fingers and toes
  • Polycythaemia (excess of red blood cell)
  • “Tet spells” characterized by a sudden, marked increase in cyanosis followed by syncope, and may result in hypoxic brain injury and death
  • Older children will often squat during a “tet spell” which increases systemic
    vascular resistance and allows for a temporary reversal of the shunt
43
Q

What is cyanosis?

A

Blue tinged skin due to low level of oxygen in arterial blood

44
Q

What would echocardiogram results be in fallots tetralogy?

A

Demonstrates abnormal anatomy and also a shunt of blood passing from left to right initially and later seen to shunt from right to left (Eisenmenger Complex)

45
Q

What is an echocardiogram?

A

Ultrasound of heart

46
Q

What is appearance of heart via chest x-ray in fallots tetralogy?

A

Abnormal ‘coeur-en-sabot’ (boot-like) appearance of heart

47
Q

What is a ‘tet spell’?

A

Sometimes, babies who have tetralogy of Fallot will suddenly develop deep blue skin, nails and lips after crying or feeding, or when agitated. These episodes are called tet spells and are caused by a rapid drop in the amount of oxygen in the blood.

48
Q

How are ‘tet spells’ treated?

A

Oxygen effective in treating ‘tet spells’

49
Q

Why is oxygen effective at treating ‘tet spells’?

A

It is a potent pulmonary vasodilator and systemic vasoconstrictor which allows more blood flow to the lungs

50
Q

What would surgery for early management of fallots tetralogy be for babies?

A

May involve forming an anastomosis (join) between the subclavian artery and the pulmonary artery to allow more blood to get to lungs

51
Q

What is curative heart surgery used to relieve in fallots tetralogy?

A

Designed to relieve the right ventricular outflow tract stenosis by careful removal of muscle and repair of the VSD

Despite surgery – patients remain at increased risk of sudden cardiac death and heart failure

52
Q

What is atropine?

A

Atropine is a medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate and to decrease saliva production during surgery

53
Q

How does acetyl choline affect heart rate?

A

Released by parasympathetic nerves at synapses with cardiac muscle cells. Binds to M2 muscarinic receptors, causing decrease in heart rate

54
Q

What is cardiac syncope?

A

Suddenly lose consciousness for a few seconds

55
Q

What is thrombophilia?

A

Thrombophilia (sometimes hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels)

Yr 2 - Cardiology System (25 decks)

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