[Cardiac pacemakers and implantable cardioverter-defibrillators in the perioperative phase]

Recent developments have changed the techniques and indications for different methods of temporary cardiac pacing. Temporary transvenous pacing involves endocardial right ventricular stimulation by a bipolar electrode, introduced directly via a vein, or through a "paceport" pulmonary artery catheter. A "multipurpose" pulmonary artery catheter permits both atrial and ventricular sensing and pacing. Noninvasive transcutaneous cardiac pacing is safe, fast, and easily applicable. However, pain and discomfort from cutaneous nerve or muscle stimulation may be intolerable for unsedated patients. Transoesophageal cardiac pacing is usually successful only for atrial stimulation, e.g., in sinus node bradycardia, but is not indicated in patients with impaired AV-conduction. In patients with implanted pacemakers, temporary cardiac pacing can both impair or improve the haemodynamic situation. Implanted pacemakers should always be checked following surgery involving electrocautery. Preoperatively, rate-responsive pacemakers should be re-programmed so as to avoid activation of the rate-responsive function. Automatic implantable cardioverter-defibrillators should be deactivated to avoid delivery of inappropriate shocks. In patients with implanted epicardial patch electrodes, transthoracic defibrillation can be difficult with routine defibrillation protocols and may require positioning of the paddles on the lateral chest wall. However, emergency noninvasive transcutaneous cardiac pacing is possible in such patients with normal thresholds.