Heart Block Flashcards

1
Q

What is heart block?

A

HB = bradyarrhythmia caused by delay / interruption in electrical conduction between Atria + Ventricles

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2
Q

What are the causes of HB? (5 Cardiac, 4 Non-Cardiac, 4 Drug causes)

A

Cardiac: AV block / SA node dysf / Post MI / Inf End / Fibrosis w age

Non-Cardiac: Vasovagal / Hypothermia / Hypothyroidism / Raised ICP (bc HTN)

Drugs: Amiodarone / Beta blockers / Calcium Ch blockers / Digoxin (HF drugs)

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3
Q

How can a MI cause Heart Block?

A

AV node supplied by RCA

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4
Q

What is 1st Degree HB in simple terms?

A

Delayed conduction thru AV node

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5
Q

What is 2nd Degree HB in simple terms?

A

Progressive delayed conduction / intermittently blocked conduction

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6
Q

What is 3rd Degree HB in simple terms?

A

TOTAL interruption of conduction between Atria + Ventricles –> complete AV dissociation

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7
Q

What is seen on an ECG for 1st Degree HB?

A

CONSTANT PR prolongation (200+ ms)

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8
Q

What more srs conditions can 1st Degree HB be a sign of? (3 things)

A
  1. Inf End
  2. BBB
  3. Aortic Root Abscess
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9
Q

What are the 2 types of 2nd Degree HB?

A
  1. Mobitz Type 1 (Wenckebach)
  2. Mobitz Type 2
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10
Q

What is seen on an ECG of Mobitz Type 1 (Wenckebach)? (4 steps)

A
  1. Progressive lengthening of PR interval
  2. Followed by dropped beat (Wencke Wencke Wencke BACH)
  3. Followed by a normal conducted beat w shorter PR interval
  4. Cycle continues
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11
Q

What is seen on an ECG of Mobitz Type 2? (2 things)

A
  1. Constant PR interval
  2. Occasional missing QRS complex after P wave (naked P wave lol)
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12
Q

Why are there occasional missing QRS complexes after P waves in Mobitz Type 2?

A

Occasionally atrial conduction NOT transmitted to ventricles

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13
Q

What is a Fixed Ratio Block in Mobitz Type 2?

A

Fixed number of P waves each time before you get a QRS complex

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14
Q

How do you calculate the ratio of the Fixed Ratio Block in Mobitz Type 2?

A

Count number of P waves before QRS complex
e.g 2 P waves before every QRS complex = 2:1 Block

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15
Q

What is seen on an ECG of 3rd Degree Heart Block?

A
  1. Normal constant P waves
  2. Less + broad QRS complexes happening randomly (not linked w P waves bc complete AV dissociation)
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16
Q

Why are the QRS complexes not linked with P waves in 3rd Degree HB?

A

The atria and ventricles are not communicatin with each other

17
Q

Which HB’s are asymptomatic? (2 things)

A
  1. 1st Degree HB
  2. Mobitz Type 1 (Wenckebach)
18
Q

Which HB’s are symptomatic? (2 things)

A
  1. Mobitz Type 2
  2. 3rd Degree HB
19
Q

What are the symptoms of HB? (4 things)

A
  1. Syncope
  2. Shock: Hypotension, Sweating, Pale, Increased CRT
  3. SOB
  4. Chest Pain

(1st Degree + Mobitz 1 = asymptomatic)

20
Q

How is the diagnosis of HB made?

A

ECG

21
Q

What are the management options for ALL HBs?

A

Identify reversible causes aka Elec imb / Meds induced causes

22
Q

What HB’s don’t need treatment? (2 things)

A
  1. 1st Degree
  2. Asymptomatic Mobitz 1 Wenckebach
23
Q

What is the management options for ASYMPTOMATIC 1st Degree HB?

A

No treatment

24
Q

What is the management options for SYMPTOMATIC 1st Degree HB?

A

Pacemaker

25
Q

What is the management options for ASYMPTOMATIC Mobitz Type 1 (Wenckebach)?

A

No treatment

26
Q

What is the management options for SYMPTOMATIC Mobitz Type 1 (Wenckebach)? (3 things)

A
  1. Atropine
  2. Transcutaneous Pacing (if atropine doesn’t work)
  3. Pacemaker (if persistent + NO reversible causes)
27
Q

What is the management options for Mobitz Type 2? (4 things)

A
  1. Atropine
  2. Transcutaneous Pacing (if atropine doesn’t work)
  3. Pacemaker (if persistent + NO reversible causes)
  4. Continuous monitoring bc can progress to 3rd Degree HB
28
Q

What is the management options for 3rd Degree HB? (3 things)

A
  1. Atropine
  2. Transcutaneous Pacing (if atropine doesn’t work)
  3. Pacemaker (if persistent + NO reversible causes)
29
Q

What poem lets you remember HB ECG?

A