Outline your approach to the evaluation and treatment of a cardiac surgical patient who returns to your Intensive Care Unit with temporary atrial epicardial pacing wires and problems with atrial pacing.
Evaluation of problems with atrial pacing requires careful evaluation of the rhythm strip (and/or ECG), and systematic examination of pacing leads (from patient to pacemaker, including ensuring atrial wires are connected to atrial port of pacemaker). Specific problems to be excluded include:
· excessive sensitivity to electrical activity (resulting in inappropriate/excessive inhibition of atrial pacing). Excessive sensitivity is usually due to settings on the pacemaker, and may be confused with return of spontaneous atrial activity (including AF). Treatment is to increase the absolute value of sensitivity (making it harder to inhibit).
· relative insensitivity to electrical activity (resulting in atrial pacing when not appropriate). Insensitivity is due to the specific setting of sensitivity (including deliberate setting of AOO mode). Treatment is to decrease absolute value of sensitivity (making it easier to inhibit).
· inability to capture (resulting in no atrial activation). Inability to capture is usually due to some specific mechanical problem including: wires no longer connected to atrium [potentially activating ventricle, diaphragm or nothing at all], wires not tightly connected to cable, cable not connected to correct port, or setting of output too low relative to requirements. Treatment is to tighten and confirm all external connections, then increase output if possible. Bipolar leads may be tried in reverse positions, or attempt to convert to unipolar pacing. Positioning of patient may also facilitate capture (short term solution). Other specific treatments to be considered include treatment of underlying arrhythmias/bradycardias with appropriate medications.
It is difficult to say precisely what ones management would be if the college doesn't specify what "problems" there are with the atrial pacing.
A guide to troubleshooting the pacemaker circuit is offered elsewhere.
1) Start with the box.
Ok, so the hardware is intact. if there is output failure, its not because of the leads or the battery. Move on to the software.
2) Check the sensor threshold.
Crank the sensitivity setting up to double the sensor threshold.
This should take care of oversensing as a cause of pacing failure.
3) Now, check the output threshold.
Crank the output to double the capture threshold.
4) Still not working?