Abstract:
Pacemakers (PM) and implantable cardioverter defibrillators (ICDs) are likely to be encountered by anaesthetists in South Africa
in everyday practice because of increasing rates of implantation of these cardiac implantable electronic devices (CIEDs) for an
expanding group of conditions that qualify for their use. These devices are becoming increasingly sophisticated and anaesthetic
perioperative management is changing with these developments. Traditionally, PM functions have been changed preoperatively
to asynchronous modes because of the fear that electromagnetic interference (EMI) from the electrosurgical unit (ESU or
diathermy) may cause oversensing and loss of pacing in patients who are PM-dependent. ICDs have had their anti-tachyarrythmia
modes deactivated preoperatively to prevent inadvertent shocks delivered as a result of the misinterpretation of EMI as ventricular
tachycardia (v-tach) or ventricular fibrillation (v-fib). Programming these devices in this manner may result in patient harm due
to R-on-T phenomenon in PM set in asynchronous mode and in ICDs, undiagnosed v-tach and v-fib going untreated in patients
who have anti-tachyarrythmia therapies switched off. Depending on the site of surgery, PM-on and ICD-on strategies may be
acceptable. Magnet use intraoperatively can be used safely to change PM and ICD settings with the advantage that reversal to
normal settings can be achieved by removal of the magnet once EMI is no longer in use. Intraoperative magnet use mandates that
the device is interrogated preoperatively and that the results of magnet application are known to the anaesthetist in advance.
Where management protocols stated may be controversial, the American Society of Anesthesiologists (ASA) survey of an expert
consultant panel as well as member anaesthetists is published, as well as the Cardiothoracic Anaesthetic Society of South Africa
(CASSA) committee responses to these controversies.
