L 56 & 57 Pathology of HF/Dysarrythmia Flashcards

1
Q

Patients may describe AF as…

A
  • Heart thumping out of chest

- Lightheaded and anxious feeling that resolves shortly after the heart symptoms

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2
Q

Is AF a vascular disease?

A

No, as no vessels are involved!

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3
Q

The action potential movement across the heart starts with the … and the…, and then the …. This short pause between … and … allows the … to fill as much as possible before contraction, optimising how much blood is going around the body

A

The action potential movement across the heart starts with the right atrium and the left atrium, and then the ventricles. This short pause between atria and ventricles allows the ventricles to fill as much as possible before contraction, optimising how much blood is going around the body

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4
Q

DVT occurs in a … and PE is in an …

A

DVT occurs in a vein and PE is in an artery

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5
Q

Median heart rate in adults is …

A

75 bpm

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6
Q

What are the 4 general steps of the hearts conduction system?

A
  1. Pacemaker cells generate action potentials (APs)
  2. APs travel along the conduction system resulting in depolarisation and contraction of cells
  3. APs travel to LA via Bachmann’s bundle and to the ventricles via the AV node.
  4. Cardiac cells repolarise and depolarise over 60 times per minute
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7
Q

Do the ventricles or atria depolarize first?

A

Atria!

Think of A coming first in the alphabet

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8
Q

m

A

m

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9
Q

What is dysrhythmia?

A

A disturbance in the rhythm or rate of cardiac muscle contractions

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10
Q

How are dysrhythmia’s defined/classified? x4

A
  1. By their site of origin (e.g supraventricular, ventricular, atrial)
  2. Mechanism of disturbance (e.g fibrillation)
  3. Rate of disturbance (e.g tachycardia, bradycardia)
  4. Electrocardiogram appearance (e.g long QT syndrome)
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11
Q

Are dysrhythmias acute or chronic?

A

Both acute and chronic

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12
Q

What is an example of a life threatening type of dysrhythmia?

A

Ventricular fibrillation (VFib)

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13
Q

What does ECG/EKG stand for?

What does it mean?

A

Electrocardiogram: a measure of the electrical activity of the heart rate and rhythm

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14
Q

What are the following:
P wave:
QRS:
T wave:

A

P wave: atrial depolarisation
QRS: ventricular depolarisation and atrial repolarisation
T wave: ventricular repolarisation

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15
Q

How long are the following:
PR interval:
QRS:
QT interval:

A

PR interval: <0.2 sec
QRS: <0.1 sec
QT interval: <0.4 sec

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16
Q

What % of people over 65 in NZ have AF?

A

5%

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17
Q

AF gives a 4-5 fold increase in … stroke risk

A

Ishcaemic stroke risk (ischaemic embolic stroke)

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18
Q

What is the mechanism of dysrhythmia?

A

An abnormal impulse formation with increased automaticity and triggered activity.
There is also abnormal conduction

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19
Q

What occurs in abnormal impulse? (x2 expand though)

A
  • Increased automaticity: cells outside SA node start firing spontaneously
  • Triggered activity: cells contract (depol) twice despite only being activated once. Caused by ‘after depolarisation’ due to electrical instability in the cell membrane.
20
Q

What occurs in abnormal conduction?

A

A conduction delay (signal could be cancelled or amplified)

Re-entry/multiple signals (e.g one from fast and one from slow pathway).

21
Q

When is abnormal conduction often seen?

A

Often seen with ischaemia/damage

22
Q

Types of dysrhythmia x5

A
Tachycardia
Bradycardia
Supraventricular dysrhythmias
Ventricular dysrhythmias
Bradyarrythmias
23
Q

Define the following:
Tachycardia:
Bradycardia:

A

Tachycardia: >100bpm
Bradycardia: <60bpm

24
Q

3x types of bradyarrhythmias

A

Sinus bradycardia
Sick sinus syndrome
Atrioventricular block

25
Q

What is sinus bradycardia?

Common in ….

A

Natural causes of bradycardia x5 (e.g non-drug)
A slow HR of <60bpm.
Common in athletes and elderly
Causes: increased vagal tone or stimulation, vomiting, MI, hypothyroid, hypothermia, increased intracranial pressure. (Vagus nerve stimulation!)

26
Q

Drug classes that can cause bradycardia x2

A
B blockers (slow the impulse generation in SA node)
Non-DHP CCBs (slow the conduction in SA/AV node)
27
Q

What is sick sinus syndrome?

What is it associated with?

A

A combination of bradycardia and tachycardia caused by sinus node dysfunction.
Associated with episodes of atrial tachyarrhythmias

28
Q

Drug causes of sick sinus syndrome

A

B blockers, CCBs, digoxin

29
Q

What is an atrioventricular block?
Give 2 examples of ways this can happen
What 3 drugs/classes can cause this?

A
Impairment in the impulses generated in the atria (signal is blocked).
Can occur by:
- Slowed conduction into the ventricle
- Partial or total signal blockage.
Drugs: B blockers, CCBs, Digoxin
30
Q

5 types of tachyarrhythmias

A
  1. Atrial flutter
  2. Atrial fibrillation
  3. Ventricular tachycardia
  4. Torsades de Pointes (TdP)
  5. Ventricular fibrillation
31
Q

What is atrial flutter?
What is the atrial rate?
What is the concern with atrial flutter?
What is the ECG described as?

A

Rapid and regular atrial depolarisation (Increased RATE but consistent/regular rhythm)
Atrial rate: 250-350bpm
Can result in ventricular tachycardia if atrial impulses are conducted to the ventricle.
ECG described as a saw tooth flutter

32
Q

What can occur with atrial flutter?

A

Since the atrial rate is high, AV block may occur to protect the heart from the atrial flutter.

33
Q

What is atrial fibrillation?

A

Irregularly conducted impulses across the atria, caused by re-entry circuit or ectopic foci, leading to fibrillation.

34
Q

What is the most common sustained dysrhythmia?

A

Atrial fibrillation

35
Q

What is the atrial rate of atrial fibrillation?
How would it increase?
What is the concern with this?

A

350-600bpm
When the AVnode irregularly filters/blocks the atrial impulses, an increased irregular ventricular rate occurs.
Concern: atrial thrombus formation due to stasis.

36
Q

Clinical features of atrial fibrillation x4

A

Fatigue, palpitation, syncope, worsening heart failure.

37
Q

Define syncope and how do you pronounce it?

A

Syncope (pronounced “sin ko pea”) is the medical term for fainting or passing out

38
Q

What do these classifications of atrial fibrillations mean?

  • First detected:
  • Paroxysmal:
  • Persistent:
  • Permanent:
A
  • First detected: only one diagnosed episode
  • Paroxysmal: recurrent episodes that stop on their own <7 days.
  • Persistent: Recurrent episodes that last > 7 days
  • Permanent: Ongoing long-term episodes
39
Q

What is ventricular tachycardia?
When is it considered sustained?
What does the ECG look like?

A

A rate of 100-250bpm.
Is considered sustained if tachycardia lasts over 30 seconds.
ECG: wide and rapid QRS complexes

40
Q

What are the 2 different types of ventricular tachycardia and what do they mean?

A
  1. Monomorphic: all QRS complexes are similar

2. Polymorphic: QRS complexes change in morphology, amplitude, polarity

41
Q

What is ventricular fibrillation?

What does it follow?

A

A chaotic ventricular dysrhythmia characterised by rapid irregular ventricular fibrillation waves.
It follows an ischaemic event

42
Q

What is the most frequent cause of sudden death?

A

Ventricular fibrillation

43
Q

What is the rate of ventricular fibrillation?

A

250-500bpm

44
Q

Causes/risk factors for dysrhythmia x8

A
Coronary artery disease
High blood pressure
Cardiomyopathy
Valve disorders
Electrolyte imbalances
Injury (e.g MI)
(Healing process after heart surgery)
Drugs
45
Q

Signs and symptoms of dysrhythmia

A
  • Asymptomatic
  • Palpitations
  • Feeling of a pause
  • Anxiety
  • Shortness of breath
  • Dizziness/loss of consciousness
  • Cardiac arrest
46
Q

Dysrhythmias are an …. … …
They can be acute or …, … or fatal
The common signs and symptoms are … and dizziness.
They can be caused by …, … and …
The most common dysrhythmia is …, and complications include stroke.

A

Dysrhythmias are an abnormal rate/rhythm
They can be acute or chronic, asymptomatic or fatal
The common signs and symptoms are palpitations and dizziness.
They can be caused by congenital abnormalities, IHD and drugs.
The most common dysrhythmia is AF, and complications include stroke.