How Do Pacemakers Work?

9 de febrero de 2024

3 min de lectura

Pacemakers are small electronic devices implanted in the chest or abdomen, usually by surgery, to stabilize abnormal heart rhythms or arrhythmias.

The cardiac pacing devices use low-energy electrical impulses to control the rhythm and rate of the heartbeat.

Types of pacemakers

Pacemakers are of two primary types.

Traditional transvenous pacemakers

Traditional pacemakers send electric pulses through wires, also called leads. The matchbox-sized device is placed outside the heart, in the chest or abdomen. It is connected through wires to electrodes inside one to three heart chambers.

Traditional pacemakers can be classified as:

Single chamber pacemaker: The type sends electrical pulses to the lower right heart chamber.
Double chamber pacemaker: The type sends electric pulses to both the upper and lower chambers of the heart.
Biventricular pacemaker: Also known as a cardiac resynchronization pacemaker (CRT device), this type sends electric pulses to the ventricles and an atrium. The device coordinates signaling between the two ventricles while strengthening the heart muscles.

Wireless pacemakers

Wireless pacemakers are smaller than traditional pacemakers. They have the electrodes and pulse generator in one device, about the size of a large pill capsule.

The wireless pacemakers are placed inside the heart chamber through a small tube inserted in one of the veins. They are recommended for people with a slow heartbeat or electrical block, which occurs when there is a delay in the flow of electricity between the upper and lower heart chambers.

The device senses the right atrium (chamber) and allows it to match the signal it sends to the ventricle, helping the two heart chambers beat in sync.

Other pacemakers types

Other types of pacemakers include CRT devices with Implantable Cardioverter Defibrillators (ICD). ICDs deliver electric shocks to kickstart the heart in people with life-threatening heart rhythm disturbances like ventricular fibrillation or ventricular tachycardia.

Parts of a pacemaker

Pacemakers are small electrical devices with the following parts.

Leads: Leads are flexible, thin, electrically insulated wires that are implanted on the right side of the heart chambers.
Electrodes: Located at the tip of each lead, electrodes are contact points between the heart and the pacemaker. Electrodes deliver electrical pulses from the pacemaker to the heart, receive information about the heart-signaling action, and carry it back to the pacemaker.
Pacemaker box: The leads are attached to a small pacemaker box containing a battery-operated computer that records heart rhythm abnormalities.
Battery: The pacemaker runs on a battery that lasts for 6-7 years.
Barbs or screws: The leads are attached to the heart muscle with tiny barbs or screws.

How do pacemakers work?

The sinus node located in the upper right heat chamber (atrium) is the heart’s natural pacemaker. It sends electrical pulses to regulate your heartbeat. Pacemakers are used when the sinus node fails to work correctly.

You may need a pacemaker if you have:

A history of chronic, irregular heartbeat
Have heart failure

A pacemaker works when the heart beats irregularly. When the heartbeat slows, the pacemaker sends electrical impulses to correct the malfunction.

Pacemaker risks

Some risks associated with pacemakers include:

Malfunction of pacemakers or their leads: Sometimes, the pacemaker may get jostled out of the position or break free.
Malfunctions of pacemakers caused by outside sources: Pacemakers can have operating problems caused by outside electrical interference.
Blood clots: Blood thinning medications are recommended to reduce the risks of blood clots.
Allergic reactions: You may be allergic to the medications given or the materials used in the pacemaker.
Unexpected heart rhythm problems: You may develop unexpected heart rhythm problems from pacemakers.

The signs of a malfunctioning pacemaker include:

Heart palpitations
Breathing troubles or shortness of breath
Chest pain or discomfort
Muscle twitching in the abdomen
Fainting
Feeling dizzy or lightheaded
Hiccups

Pacemaker precautions

People with pacemakers must avoid:

Electrical interferences from devices that give off electromagnetic waves, like magnets and electric fences.
Medical procedures, like MRI and CT scans, that can interfere with the pacemaker.

Sources

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Types of pacemakers