CRM11: Revision and intro to EP

Question 1

Function of leads

Answer 1

-Main function: act as a conductor
-Delivers electrical stimuli from impulse generator to myocardium
-Carries intrinsic signals from heart to impulse generator
-In ICD forms part of the shock vector (high energy leads)

Question 2

What type of battery is used in a pacemaker?

Answer 2

-Lithium iodide

Question 3

Advantages of lithium iodide battery?

Answer 3

-High electrochemical potential
-High energy density
-Predictable discharge
-Impedance rise as it ages

Question 4

Answer 4

Question 5

Features of silicone

Answer 5

+Soft and flexible
+Chemically inert
+Biocompatible
+Biostable

-High friction coefficient (sticky)
-Prone to nicks and cuts
-Larger in diameter

Question 6

Features of polyurethane

Answer 6

+Low friction coefficient (slippery)
+Thinner leads
+Biocompatible
+Firmer and stiffer than silicone

-Not chemically inert
-Not biostable
-Metal ion oxidation and stress due to movement causes cracking

Question 7

What is an epicardial lead?

Answer 7

-Placed directly on the heart on the epicardium, requires thoracotomy

Question 8

What is a transvenous lead?

Answer 8

-Introduced to the RV or RA via a vein - cephalic, subclavian

Question 9

What is a bipolar lead?

Answer 9

-Incorporates two poles on the body of the lead:
-Proximal pole RING which is positive
-Distal pole TIP which is negative

Question 10

What is a unipolar lead?

Answer 10

-Circuit is established using a negative pole located at the tip of the lead
-With the can as the positive pole

Question 11

Is this normal function?

Answer 11

-Normal upper rate behaviour
-P wave falls in refractory period

Question 12

Describe DDI pacing

Answer 12

-You can have a paced AV delay
-If it doesn’t see a P wave, pace atrium, pace ventricle
-You can’t have a sensed AV delay
-If it sees a P wave/QRS, it inhibits atrial/ventricular pacing

Question 13

What rhythm is DDI good for?

Answer 13

-Atrial fibrillation

Question 14

Give 2 examples of a non-metabolic rate-response sensor?

Answer 14

-An accelerometer and a piezoelectric crystal

Question 15

What are the 2 physiological functional effects of the rate adaptive delay algorithm in a dual chamber pacemaker?

Answer 15

B

Question 16

Answer 16

C

Question 17

Answer 17

B

Question 18

Which chambers does coronary sinus run between?

Answer 18

-Left atrium and left ventricle
-Signals on CS lead are left atrial and left ventricular signals

Question 19

What type of tachycardia is shown here?

Answer 19

Re-entry:
V -> A -> His

Question 20

What type of ablation is shown here?

Answer 20

WPW

Question 21

What type of ablation is this?

Answer 21

-PVI ablation for AF
-Left atrium