Epicardial Pacing and Care
Epicardial pacing wires are commonly positioned on the epicardial (outer) surface of the heart after cardiac surgery to diagnose and treat arrhythmias, which may be caused by electrolyte imbalances, inflammation, injury, edema, and hypothermia. Depending on the needs of the patient, the surgeon usually places positive and negative electrodes on both the right atrium and the right ventricle. These electrodes are loosely sutured to the epicardial surface and brought out through the chest wall through small incisions.
In the event that pacing is required, epicardial pacing wires are connected to the pulse generator of a temporary pacemaker. When the patient becomes hemodynamically stable, the wires can be removed. Complications following epicardial pacing wire removal occur more frequently in patients with a history of heart failure and repeat heart surgery. Historically, only doctors or
physician assistants were allowed to remove epicardial pacing wires; however, specially trained critical care nurses can now safely remove them.
physician assistants were allowed to remove epicardial pacing wires; however, specially trained critical care nurses can now safely remove them.
Sensitivity and Stimulation Threshold Testing10
Sensitivity and stimulation threshold testing help determine the appropriate pacemaker rate and the amount of electrical current needed to initiate depolarization of the myocardium. Testing should occur on both chambers, as appropriate. Sensitivity threshold testing isn’t necessary if the patient has no intrinsic rhythm. In some facilities, critical care nurses are permitted to perform sensitivity and stimulation threshold testing; in other facilities, the doctor must perform the testing. Follow your facility’s policy regarding who can perform testing as well as the frequency of testing. Commonly, testing occurs at least every 24 hours to make sure that the pacemaker is functioning properly and that it isn’t delivering high levels of energy to the myocardium.
Performing Sensitivity Threshold Testing
Slowly turn the sensitivity dial counterclockwise to a higher setting until the sensing indicator light stops flashing; the light will stop flashing when the device no longer senses the patient’s intrinsic rhythm.
Gradually turn the sensitivity dial clockwise to a lower setting until the sensing light begins flashing with each complex and the pacing light stops flashing; this setting is the sensing threshold.
Set the sensitivity dial to the setting that’s half the value of the sensing threshold.
Performing Stimulation Threshold Testing
Set the pacing rate about 10 beats/minute above the patient’s intrinsic rate.
Beginning at 20 milliamperes, slowly decrease the output until capture is lost.
Gradually increase the milliamperes until you see a 1:1 capture and the pacing light flashes; this is the stimulation threshold.
Set the milliamperes at least two times higher than the stimulation threshold.
Equipment
For Insertion
Pacemaker generator with new battery ▪ extra batteries ▪ connecting cable ▪ atrial epicardial wires ▪ ventricular epicardial wires ▪ sterile rubber finger cot, glove, or plastic cap ▪ sterile dressing materials (if the wires won’t be connected to a pulse generator) ▪ antiseptic solution such as a chlorhexidine-based solution ▪ gloves ▪ tape ▪ electrocardiogram (ECG) monitoring equipment. (See “Cardiac monitoring,” page 108.)
For Removal
Gloves ▪ gown ▪ goggles or a face shield with a mask ▪ sterile gauze pads ▪ antiseptic solution such as a chlorhexidine-based solution ▪ tape ▪ suture removal kit ▪ cardiac monitor ▪ emergency cart, including temporary transcutaneous or transvenous pacing equipment and IV catheter.
Preparation of Equipment
For Insertion
Insert a new battery into the pulse generator and make sure it’s functioning properly.
For Removal
Check that the emergency cart with temporary transcutaneous or transvenous pacing equipment is readily available.
Implementation
For Insertion and Care
Confirm that a written informed consent has been obtained and that the consent is in the patient’s medical record.1,2,3
Confirm the patient’s identity using at least two patient identifiers according to your facility’s policy. 7
Perform a preprocedure verification to make sure that all relevant documentation, related information, and equipment is available and correctly identified to the patient’s identifiers.8
The surgical team will conduct a time-out immediately before starting the procedure to perform a final assessment that the correct patient, site, positioning, and procedure are identified and all relevant information and necessary equipment are available.9
The doctor will hook epicardial wires into the epicardium just before the end of surgery. Depending on the patient’s condition, the doctor may insert atrial wires, ventricular wires, or both.
After insertion, attach the patient to the bedside cardiac monitor to monitor the patient’s heart rhythm and evaluate pacemaker function.
If indicated, attach the connecting cable to the pulse generator by connecting the positive pole on the cable to the positive pole on the pulse generator and the negative pole on the cable to the negative pole on the pulse generator.10
Expose the epicardial pacing wires and identify the atrial and ventricular wires if both are present. Epicardial wires that exit the chest to the right of the sternum originate in the atrium; wires that exit to the left of the sternum originate in the ventricle.10
Using the connecting cable, connect the epicardial wires to the pulse generator. Connect the positive electrode to the positive terminal on the pulse generator through the connecting cable; connect the negative electrode to the negative terminal.10
Set the pacing mode, rate, and energy level (output or milliamperes) according to the doctor’s order, or as determined by sensitivity (how sensitive the pacemaker is to intrinsic cardiac depolarization) and stimulation threshold testing (the minimum amount of voltage necessary to capture the heart consistently).10 (See Sensitivity and stimulation threshold testing.)
After adjustment of pacemaker settings, place the protective plastic cover over the pacemaker controls or lock the controls.
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