Troubleshooting transvenous pacing

1. Intermittent loss of capture must be addressed urgently, as sudden and complete loss of capture will likely result in hemodynamic instability or collapse. Consider in-flight diversion if possible or a communication patch to a Cardiologist.

2. Immediately prepare to transcutaneous pace while troubleshooting.

3. Check to ensure electrodes are properly inserted and attached to pacer box.

4. Ensure the pacer box has battery power.

5. Assess the patient for landmarks on the TVP catheter wire.

a. May also utilize point of care ultrasound to evaluate wire position.

6. Consider switching to asynchronous mode (e.g. DOO, VOO).

7. Evaluate systematically:

a. EMI from aircraft (pacemaker will be inhibited from firing and ECG will look like electrocautery or perhaps even VF)

i. Switch to asynchronous mode, but ensure rate is greater than the patient’s intrinsic rate to avoid R on T phenomenon.

1. DOO for 3rd degree heart block without atrial fibrillation

2. VOO for 3rd degree heart block with atrial fibrillation

b. Failure to pace due to output failure (pacing spikes absent or heart rate not reaching set value)

i. Increase mA (20mA atria and 25mA ventricle) and decrease sensitivity (if in VVI) while observing cardiac monitor to ensure there is electrical capture

ii. Switch to an asynchronous mode to prevent oversensing (DOO, VOO)

c. Failure to capture (visible pacing spikes on ECG but lack of mechanical capture – pulse, arterial line wave form pulsation)

i. Increase output

ii. Check connections, rule out mechanical issue

iii. May also be due to drug interaction (anti-arrhythmics) or post cardiac defibrillation

d. Failure to sense (producing pacing spikes inappropriately)

i. Decrease absolute value of sensing (therefore making it easier to inhibit)

e. Oversensing (inhibited pacing)

i. Large P or T waves may be sensed as intrinsic atrial activity

ii. Increase sensitivity (therefore making it hard to inhibit) or switch to asynchronous mode (DOO, VOO)

f. AV dyssynchrony – loss of atrial kick causing hypotension (SBP usually falls at least 20 points)

i. Ensure both leads are properly capturing and pacer is in dual chamber mode.

Transvenous pacing: Other points to consider

- CXR should be performed after TVP placement and before flight to rule out pneumothorax and confirm wire placement
  - If x-ray is not available, point of care ultrasound can be utilized to verify lung sliding and examine the RV for wire and balloon location
- If possible, 12-lead ECG should be performed to confirm capture
- Document TVP placement depth in case of dislodgement or failure to capture in route.
- All patients with TVPs should have external (transcutaneous) pads applied and an appropriate pacing device available
- All patients with TVPs should ideally have an additional pacer box if possible, and at the least, additional batteries
- Ensure the TVP is secure appropriately and the dressing changed prior to transport; do not change en route
- After all patient movement, reassess all lead connections, TVP depth and ensure there is both electrical and mechanical capture
- Prepare for electromagnetic interference (EMI) from aircraft electronics