What is Temporary Cardiac Pacing?
Temporary Cardiac Pacing is the temporary delivery of electrical impulses, delivered by electrodes contacting the heart muscles, to regulate and automate the beating of the heart. The primary purpose of temporary cardiac pacing is to maintain an adequate heart rate, either because the heart’s native(intrinsic) pacemaker is not fast enough, or there is a block in the heart’s electrical conduction system.
In Intensive Care Temporary Cardiac Pacing is instigated by a pacing box that is attached to small electrodes(pacing wires) that are connected to the Patient’s heart muscle. Those small electrodes(pacing wires) are usually implanted during cardiac surgery(Coronary Artery Bypass Graft (CABG) or they have been inserted through a vein, either a Central Line(Central Venous Lines) or a Swan-Ganz Cather(Pulmonary Artery Catheters). In either case pacing has been instigated as a temporary measure and once your loved one is stable and the heart is back in their own normal rhythm, pacing is superseded. In some cases temporary pacing may lead to permanent pacing and if the case it would lead to a pacemaker or defibrillator implant.
- How does a normal heartbeat occur?
- What can go wrong with the Heart Rhythm?
- Why is it done?
- What are the Risks?
How does a normal heartbeat occur?
Normally the adult heart beats 60-100 beats per minute. This is also known as the pulse rate. This normal heart rate in a healthy person, ensures adequate blood pressure through adequate contracting of the heart muscle. This is an essential function to deliver enough oxygen and nutrients to the body’s organs and tissues.
The heart has an intrinsic/internal electrical conduction system that is a transmitter of electrical activity(current) that is transmitted from the Atrial Node all the way through the heart down to the Atrioventricular node. The intrinsic/internal electrical conduction system is made up of specialised tissue called nodes and fibres. Each heartbeat follows the electrical current from the Atrial Node all the way through the heart down to the Atrioventricular node(top to bottom). The electrical current or electrical impulse causes the heart muscle to contract and pushes blood from the atrium to the ventricle and also pushes blood from the ventricles into the body.
What can go wrong with the Heart Rhythm?
As explained above, if the conduction system fails to work in order(top to bottom) this can lead to different types of irregular heart rhythms(arrhythmia’s).
The most common types of arrhythmias that may lead to pacing are
- Atrial Fibrillation(AF)
- Atrial Flutter
- Junctional rhythm
- Heart blocks
- Sinus Bradycardia
- Ventricular Tachycardia(VT)
- Ventricular Fibrillation(VF)
If the conduction system fails to work in order, it means that the electrical current can fire from anywhere in the conduction system, leading to an uncoordinated and therefore irregular heartbeat. This can lead to low blood pressure and hypoxia(lack of oxygen) as less blood reaches the tissues, organs and cells.
A failed and uncoordinated conduction system can also lead to the atrium and the ventricle beating non- synchronous or independently. That can lead to differences in the heart rate in the atrium and the ventricle, leading to a heart block.
A battery powered pacing box (see figure above) is attached by cables to the pacing wires. An electrical pathway is set up between the pacing box and the heart.
Why is it done?
Temporary cardiac pacing is used to maintain a normal heart rate in Patients whose own heart rate is not pumping enough blood around the body. This may be in slow heart rhythms (bradycardia or heart blocks), fast rhythms (atrial fibrillation or ventricular tachycardia or when the heart fails to beat (sick sinus syndrome). Temporary cardiac pacing may be used when:
- Following a heart attack (acute myocardial infarction);
- Following cardiac surgery;
- Awaiting insertion of a permanent pacemaker;
- When the heart stops beating(cardiac arrest).
- It can also be used to make the heartbeat faster in order to over ride an undesirable rhythm.
What are the risks?
In Patients where temporary cardiac pacing has been established by placing a catheter into the heart via a large blood vessel or after surgery, complications may include:
- Bleeding at the insertion site
- malfunction of the pacemaker through empty batteries(normally the pacemaker and the batteries need to be checked 2-3 times a day)
- Infection (more likely if the wire is left in place for several days), normally the wire should be removed within 3-4 days after insertion
- Internal bleeding at the entry site of the wire to the heart(very rare)
- Pneumothorax through puncturing of the lung(rare)
- Hiccup, if the diaphragm gets electrical impulses from the pacemaker and starts. This can usually be resolved by replacing the electrodes
Of course, if you have any questions or concerns, please discuss them with the ICU nurses and doctors.
All Intensive Care interventions and procedures carry a degree of potential risk even when performed by skilled and experienced staff. Please discuss these issues with the medical and nursing staff who are caring for your loved one.
The information contained on this page is general in nature and therefore cannot reflect individual Patient variation. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. INTENSIVE CARE HOTLINE attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual Patient. Please refer to the full disclaimer.