last authored: May 2016, Natalie Lapointe
last reviewed: May 2016, Colin McCabe
Introduction
Pacemakers are used to apply repeated electrical stimulation to the heart, predominantly during cases of bradycardia where medications have failed to provide a sufficient increase in heart rate, and where the patient remains symptomatic or unstable.
Pacers can be temporary or permanent.
Transcutaneous Pacing
pacing pads, courtesy of PhilippN
Transcutaneous pacing (TCP) is used during advanced cardiac life support (ACLS) for treatment of symptomatic bradycardia with poor perfusion. TCP shocks the heart through electrodes placed on the skin, normally by a manual monitor/defibrillator.
It is used in situations of:
- hemodynamically unstable bradycardia
- acute myocardial infarction, with sick sinus syndrome, Mobitz II second-degree AV block, third-degree AV block, or new bundle branch block
- bradycardia with symptomatic ventricular escape rhythms
In order to begin TCP:
- describe the procedure to the patient, obtaining verbal consent
- initiate procedural sedation (i.e., benzodiazepines and opioids) if possible
- dry the chest and remove excess hair, if necessary
- apply pacing pads and monitor leads, if not yet in place
- set the monitor to ‘pacer mode’
- set the heart rate to 70-80 bpm
- gradually increase the amplitude until ECG evidence of an increased heart rate (capture). Current should be set at 2mA above dose at which consistent capture is observed for safety.
- confirm mechanical capture should be assessed via the radial pulse. Do not use the carotid pulse, as muscle activation caused by the pacing may mimic a pulse.
Ensure you become familiar with your institution’s device and it’s controls.
Contraindications to pacing include:
- severe hypothermia
- asystole
- chest trauma
- spinal injury
Transvenous Pacing
Transvenous pacing may be instituted if transcutaneous pacing fails, or if it needs to be continued for a length of time prior to placement of a permanent pacemaker.
Using sterile conditions, and normally at the bedside with conscious sedation, the pacer is introduced into a vein and ‘floated’ to either the right atrium or ventricle. Confirmation of placement using X ray or other means is imperative.
Complications that may occur with temporary transvenous pacemakers (TTVP) include:
- bleeding
- infection
- pneumothorax
- arrhythmias
- myocardial infarction (MI)
- electrode displacement
- hematoma at insertion site
- perforation of right ventricle
Permanent Pacemaker
Implantable Cardioverter-Defibrillator, courtesy of Gregory Marcus
If the bradycardia appears permanent, or recurrent, a permanent pacemaker, or an implantable cardioverter-defibrillator, should be inserted. Further details on the options available, and the procedure for insertion, are beyond the scope of this topic.
Complications are not common with permanent pacemakers, but may include:
- bleeding
- pneumothorax
- arrhythmias
- air embolism
- thrombosis
ECG Findings of Pacemakers
A pacer spike may show up as a long line, or may be a little blip. To adequately perform a systematic strip analysis, one must determine whether the type of pacemaker is:
- atrial (spike prior to the P wave)
- ventricular (spike prior to the R wave)
- both atrial AND ventricular (dual-chamber pacemaker)
Next, the rate of the rhythm is to be calculated. Any intrinsic rhythm must also be identified.
It is also vital to assess for any sign of pacemaker malfunction.
Atrial and ventricular pacing; courtesy of Life in the Fast Lane