A few pearls regarding pacing a patient with an unstable bradycardia:
If the patient has an implanted pacemaker (which isn't working properly), the transcutaneous pacing pads should be placed at least 10 cm away from the implanted PM pulse generator.
Placement of a transvenous pacemaker is absolutely contraindicated if the patient has a prosthetic tricuspid valve.
Neither transcutaneous or transvenos pacing is likely to work in the setting of severe acidosis or severe hypothermia. Severely hypothermic patients, in fact, have very irritible myocardial tissue and therefore attempts at pacing may produce ventricular dysrhythmias.
