clinical tx of arrhythmias 2

Question 1

Bradyarrhythmias: below AV node

Answer 1

(infranodal/His Purkinje system)

1. Mobitz II 2nd degree AV block
2. complete heart block

Question 2

The 3rd level of bradyarrhythmia is located:

Answer 2

below the AV node, or infranodal

Question 3

Second-Degree AV Block – Mobitz II

Answer 3

1. Intermittently dropped ventricular beats preceded by constant PR intervals.
2. The infranodal (His bundle) tissue is most commonly the site of Mobitz II block.

Question 4

To differentiate Mobitz I from Mobitz II,

Answer 4

the PR interval in the beats preceding and following the dropped beat.
If a difference between these two PR intervals is more than 0.02 seconds (20 msec), then it is Mobitz I.
If the difference is less than 0.02 seconds, then it is Mobitz II.

Question 5

When should you be concerned?

Answer 5

1. When the patient is symptomatic, no matter which part of the conduction system is affected.
2. When the rhythm is infranodal (below the AV node).

Question 6

Acute treatment for unstable patient:

Answer 6

1. beta-agonists
   (dopamine or isoproterenol)
2. transcutaneous pacing
3. temporary transvenous pacing.

Question 7

offending medications examples:

Answer 7

1. antiarrhythmics
2. clonidine
3. lithium

Question 8

reversible causes: examples:

Answer 8

1. ischemia/infarction,
2. hypothyroidism
3. neurologic causes
4. Lyme disease

Question 9

Implanting a pacemaker is a minor surgery with the generator placed

Answer 9

in the shoulder region underneath the skin and it is connected to 1 or 2 leads that are guided via the venous system into the heart at the atrial and/or ventricular level, where sensing of the heart rhythm and pacing occurs.

Question 10

Bradyarrhythmia Take Home Points

Answer 10

1. Determine level of block responsible for bradycardia: sinus node, AV node, infranodal
2. Symptoms and infranodal disease, which can progress to unreliable heart rhythms, should dictate treatment.
3. Treat potential reversible causes.
4. Acutely stabilize patients.
5. Only long-term treatment is a permanent pacemaker.

Question 11

tachyarrhythmias types:

Answer 11

1. Supraventricular Tachycardias (SVT)
2. Ventricular Tachycardia
   Ventricular Fibrillation

Question 12

multifocal atrial tachycardia:

Answer 12

3 or more p waves

Question 13

Regular SVT

Answer 13

1. there is a 1:1 P to QRS relationship can be divided into a variety of tachycardias.
2. sometimes you can’t see the p wave

Question 14

For the irregular SVTs, use:

Answer 14

antiarrhythmics, or cardiovert them to control rate

Question 15

For regular SVTs, the first step is

Answer 15

both a diagnostic and treatment option, which is to use adenosine, a drug that blocks the AV node very transiently.

Question 16

adenosine functions by

Answer 16

blocking the AV node and allowing visualization of the p waves to assess the mechanism of the tachycardia.

Furthermore, as some of these tachycardias are dependent on the AV node to maintain their circuit, adenosine can also terminate the tachycardia.