As technology advances, so does the number of implanted cardiac devices. Today more patients than ever will come into the endoscopy lab with an implanted device. The use of cardiac devices has expanded from the original pacemaker and the implanted cardioverter-defibrillator (ICD) to new devices that can help the chambers of the heart beat together more effectively. These devices are specifically programmed and are monitored frequently by arrhythmia physicians and nurse practitioners.
However, it is possible for the device to malfunction or for its delicate programming to be damaged during an endoscopy procedure if electrocautery is used. This article discusses the most common types of implanted cardiac devices, and gives the most likely reasons for a patient to have an implanted cardiac device, as well as how to care for a patient with an implanted cardiac device. The ASGE guidelines are also included as a reference.
Implanted Cardiac Devices
A pacemaker is an implanted device that delivers an electrical impulse that stimulates the heart to pump at a rate that can be programmed and monitored by the patient’s physician. The primary purpose for a pacemaker is to maintain an adequate heart rate because the patient’s natural conduction system is beating too slowly and inefficiently, or it has failed. There are many types of conduction system abnormalities and the cardiologist will follow the guidelines developed by the American College of Cardiology, and the American Heart Association, when treating a conduction abnormality with an implanted pacemaker.
The single-chamber pacemaker has one lead that is placed in the right atrium or right ventricle. The placement of the lead depends on the type of blockage that the patient has experienced.
The dual chamber pacemaker has one lead placed in the right atrium and the other is placed in the right ventricle. This pacemaker delivers an impulse to both chambers of the heart. These impulses are set so that the atrium is stimulated before the ventricles.
Pacemakers are sensitive to the patient’s movement so they can increase or decrease the patient’s heart rate to adjust to the body’s demand.
ICDs
ICD is a device that can be used to deliver a pacing impulse and can also deliver an electrical shock to the ventricle if it detects a dangerous rhythm. The patient who has had an ICD placed has been identified as being at risk of sudden cardiac death due to venturcillar tachycardia (VT), or venturcillar fibrillation (VF).
Single-chamber ICD is a type of ICD that shocks a life-threatening rhythm. The lead is placed in the right ventricle.
Dual-chamber ICD is a type of ICD that has two leads. One lead is implanted in the right atrium and a second is implanted in the right ventricle. A dual-chamber ICD is most often implanted in patients when the atrium and the ventricles do not beat in a coordinated manor. This type of ICD helps the heart beat in synchronous rhythm with the atrium pumping before the ventricles.
A biventricular ICD has three leads. The leads are placed in the right atrium and both the right and left ventricles. It paces the atrium and both ventricles. This is called cardiac resynchronization therapy (CRT). This type of ICD is used when the ventricles are not contracting efficiently. This is most often caused by advanced heart failure or cardiomyopathy.
Electrocautery and Endoscopy
Eletrocautery is used in many endoscopic procedures to control bleeding and to ablate tissue. When the patient has an implanted cardiac device, the potential for pacemaker or ICD-dysfunction exists.
Electrocautery uses a radiofrequency electric current that passes from one or more electrodes to where the cauterization occurs with the patient’s body acting as a ground.
Tissue-coagulate electrocauteriztion is the process of destroying tissue using heat conduction from a metal probe heated by an electrical current. The procedure is used to stop bleeding from small vessels or for cutting through soft tissue.
Types of Electrocautery
Monopolar electrocautery uses high-frequency electric current passed from a single electrode. Monopolar electrocautery is used during argon plasma coagulation in the ablation of mucosal lesion.
Bipolar electrocautery uses current flow between two sides of the forceps. With a small amount of current, only the localized tissue is affected. The significant advantage of bipolar electrocautery is the reduction in the surrounding tissue damage. The electrons heat only the tissue interposed in the forceps.
Unipolar electrocautery is used for dissection and homoeostasis. The grounding plate must be attached to the patient. The current passes from the active electrode of the surgical device, then passes back to the generator. This type of cautery generates a much larger electric field than the other two types of electrocautery.
When using electrocautery on a patient with an implanted pacemaker or ICD, there is a possibility of damage to the pulse generator. Damage to the pulse generator of these devices can result in a loss of the sensing circuit, possibly leading to a life-threatening arrhythmia. And in the case of an ICD, inappropriate electrical shock can also happen to the patient.
When caring for the patient with an implanted device, it is important to determine the type of device, the indication for the device, and the degree to which the patient is dependent on the device.
Patients who have implanted devices have been instructed to carry a product information card with them at all times. These cards come from the device manufacturer and have important information related to the types of restrictions that the patient should abide by. The card also has a Web address and a patient service number if information is needed before the procedure.
Use of the Magnet With a Pacemaker
If the patient has a pacemaker, a magnet can be placed over the lower one-third of the device. This will result in asynchronous pacing at a constant rate determined by the manufacturer of the device. The most common rate is 70-100. The magnet can be taped or held in place and is for temporary use only. If the patient requires prolonged electrocautery, the doctor may want to have the device reprogrammed by a cardiologist.
The use of a magnet in a patient with an ICD is much more complex than that of a pacemaker. As we have discussed, there are several types of ICDs. It is very important to have an understanding of the type of ICDs that the patient has before the procedure starts. When you have assessed that the patient has an ICD, you may want to look up the device online to see where the magnet should be placed on the generator. In general, the guidelines for magnet placement are as follows:
Identify the type of device.
Place the patient on a cardiac monitor.
Place the magnet over the recommended area on the generator and monitor the patient’s heart rate.
The magnet should not interfere with any of the ICD’s pacing function. The magnet when placed as recommended will result in a temporary suspension of the VT/VF detection capability of the device, as well as its ability to shock these rhythms.
The magnet application will not affect the pace function of the ICD, so the use of it still has the potential to inhibit pacing, resulting in arrhythmias.
Equipment needed in the procedure area:
Cardiac monitor
External pacemaker and defibrillator
Resuscitation cart with emergency drugs
Pacemaker magnet
Emergency airway equipment
When using electrocautery in a patient with these types of devices, it is recommended that the grounding pad be placed as far from the generator as possible. Always use the lowest level of energy possible.
Monitor the patient in the procedure area in the recovery room for arrhythmias; it is possible to have damaged the pulse generator and not notice it until the patient has reached the recovery area.
If the patient has had his device reprogrammed for prolonged cautery, remember that it must be returned to its original settings before the patient is discharged.
There is a possibility of myocardial burns caused by voltage being shunted away from the generator and down the pacemaker electrode, which may result in scarring and a rise of the capture threshold, increasing the potential for arrhythmias.
ASGE –2007 Recommendations
Consult a heart-rhythm specialist for interrogation and reprogramming of an ICD both before and after the procedure. If the patient with an ICD is pacemaker dependant and the device cannot be reprogrammed to the asynchronous mode, strongly consider the use of bipolar cautery.
Pre-procedure safety determinations
Type of device
Indications for the device
Underlying cardiac rhythm
Degree of pacemaker dependence
Frequency of VT/VF
Need for reprogramming the device
Consult with a heart-rhythm specialist to determine the optimal solution for an ICD interrogation and reprogramming of the ICD before and after the procedure.
If the patient has an ICD and is pacemaker dependant and the ICD cannot be set to an asynchronous rate, then the use of bipolar electrocautrey is strongly recommended.
Intra-procedure safety recommendations:
Monitor cardiac rhythm continuously
Have available external defibrillator with transcutaneous pacing capability
Use short and repetitive bursts of energy rather than long sustained flows
Consider the use of bipolar electrocautery in patients with ICDs who are pacemaker dependant when working in the distal esophagus, proximal stomach or splenic colonic flexure.
Electrocautery is used every day during endoscopy procedures and pacemakers and ICDs are placed in patients more often than ever before. With knowledge shared between the two specialties, we will can deliver safe care to the patients who depend on us.
General Information
If you have a patient, family member or neighbor who has had an ICD placed and they are the type of person who likes to do their own yard work, it is not recommended that they use welding equipment or chainsaws due to the electric current interfering with the generator. There are many other types of tools and procedures that require special precautions for the patients. The most reliable source is the manufacturer’s Web site or patient services number.
Maria C. Espinosa, RN, BSN, moved from Puerto Rico 17 years ago and since that time, she has worked in several of the critical care areas at the Nashville, Tenn. VA Medical Center. She currently works in the cardiac cath lab.
Cynthia R. King, RN, BSN, CCRN, has also worked at the Nashville, Tenn. VA Hospital for the past 17 years, in various departments. She recently transferred to the cardiology department.
References
1. Invasive Cardiology A Manual for Cath Lab Personnel. 2nd edition. Sandy Watson RN, BN, NFESC and Kenneth A. Gorski RN, RCIS, FSICP. Pages 297-382
2. Endoscopy in patients with implanted electronic devices, volume 65, No 4: 2007. American Society of Gastrointestinal Endoscopy.org (ASGE). ASGE- Technology status evaluation
3. Electrocautery Use in patients with implanted Cardiac Devices, Volume 40, No 6 1994. ASGE- Technology assessment status evaluation @ ASGE.org4. ASGE –Recommendations for patients with implanted Cardiac devices @ ASGE.org
