Troubleshooting

Question 1

What are the common causes of undersensing?

Answer 1

Lead dislodgement, insulation failure, lead fracture, change in signal, lead maturation, improperly programmed sensitivity, change in signal, electrolyte imbalance, sensing circuit failure or drug effects.

Question 2

What are the common causes of oversensing?

Answer 2

EMI, lead fracture, inappropriate sensitivity, myopotential inhibition, improperly programmed sensitivity, far-field oversensing, T wave oversensing, crosstalk, poor connection to header, or circuit failure.

Question 3

Common causes of loss of capture.

Answer 3

Lead dislodgment, intrinsic competition, too low amplitude/pulse width, ischemic or dead tissue, electrolyte imbalance, lead issue (isulation or conductor), connector problem, or circuit failure.

Question 4

What is the issue if you see a strip that has no pacing spikes on it where it should?

Answer 4

No output. Common causes: connector block issue, polarity programmed incorrectly, lead issue, circuit failure, battery depletion.

Question 5

What is the normal variance to be expected for lead impedances?

Answer 5

<30%, (300-2000 ohms)

Question 6

What is the impedance when a lead has been fractured?

Answer 6

High

Question 7

What is the impedance when insulation is breached?

Answer 7

Low

Question 8

Signs of a lead fracture:

Answer 8

High impedance, current too low to be effective.

Question 9

Signs of an insulation break:

Answer 9

Decreased impedance, current drain, possible LOC, rapid battery depletion