Pacer Management

Postoperative conduction abnormalities result either from pre-existing conduction disease, or acquired from direct surgical trauma, mechanical inj ury (annular calcificat ion), ischemic inj ury, or are drug or electrolyte provoked.

Initiation of temporary pacing requires attachment of an electrode pair to the external pulse generator. Bipolar pacing uses pair ed myocardial electrodes. Where only a single myocardial electrode is attached, unipolar stimulation is achieved by using one intramyocardial electrode (cathode) with a second myocardial electrode passe d through the skin t o function as the s ubcutane ous ano de. Reversing polarity (anodal stimulation) is not recommended (higher risk ventricular arrhythmias), however may allow improved stimulation thresholds where high catho dal stimulation thresholds ar e encountered.

Temporary pacing generators use a 9 V battery source typically good for 14-16 days of pacing. Newer DDD temporary generators have a low battery indicat or displa y that ale rts at 1 day resid ual p ower. Gradually reducing the pacing r ate to 30 bpm often allows emergence of an escap e rhythm that will support the patient during the period of battery change. A new loaded pulse generator is switched rather than replacing the batt eries in the act ive generator.

Pace termination is most frequently use d for atrial fl utter (Table 37.1).

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