Types Of Pacemaker

Before discussing the types of cardiac pacemaker types, it would be helpful to briefly explain how the heart works.The heart is one of the most important organs in our body. It maintains blood circulation by rhythmically contracting and relaxing through regular electrical signals.

Under normal conditions, the sinus node (the heart’s natural cardiac pacemaker) located in the upper right part of the heart generates electrical impulses, regulating the heart rhythm and causing it to beat approximately 60–100 times per minute. However, lifestyle factors, various diseases, aging, damage caused by heart attacks, or congenital defects can affect this delicate electrical conduction system. This can lead to slowed or irregular heart rhythms or cause different parts of the heart to work out of sync.

In such cases, cardiac pacemakers are medical devices used to regulate the disrupted electrical system, ensuring the heart maintains a normal rhythm by sending electrical impulses when necessary. These devices, one of modern medicine’s most significant innovations, are categorized into two main types: temporary or permanent, depending on the patient’s needs and the urgency of their condition. With advances in technology, cardiac pacemakers have become smaller, smarter, and more specialized to address the unique needs of various patient groups.

Cardiac Pacemaker Types

Cardiac Pacemakers are designed in different types based on their usage duration and the patient’s needs. Each type is specifically tailored for certain patient groups, and the most suitable type is determined by the cardiologist based on the patient’s condition.

Temporary Cardiac Pacemakers

These devices are used in emergencies or during the transitional period before a permanent cardiac pacemaker is implanted. Their primary advantages are that they can be applied quickly and easily removed when needed.

Permanent Cardiac Pacemakers

Permanent cardiac pacemakers are designed for long-term or lifelong use and are implanted into the body through a surgical procedure. There are several types of permanent pacemakers:

Single-Chamber Pacemakers

Single-chamber pacemakers stimulate and monitor only one chamber of the heart. There are two variations:

• VVI Pacemakers: These monitor and stimulate the heart’s lower chambers (ventricles) when needed.
• AAI Pacemakers: These monitor and stimulate the upper chambers (atria) of the heart.

Dual-Chamber Pacemakers

Dual-chamber pacemakers (DDD) control both the atria and ventricles. They provide a working mechanism that closely resembles the natural heart rhythm by monitoring both chambers and ensuring synchronized operation. These devices are particularly preferred in patients with atrioventricular conduction issues. They can automatically adjust the heart rate during exercise, providing a more physiological heart rhythm. Dual-chamber pacemakers are often used in conditions such as complete heart block, sick sinus syndrome, and conduction system diseases.

Cardiac Resynchronization Therapy Devices (CRT)

Also known as biventricular pacemakers, CRT devices play a crucial role, particularly in the treatment of heart failure. One lead is placed in the right atrium, another in the right ventricle, and a third is positioned to stimulate the left ventricle by placing it in the vein branches located behind the left ventricle.

Unlike traditional pacemakers, CRT devices operate continuously to ensure the heart contracts more efficiently with each beat. This improves cardiac function, reduces heart failure symptoms, enhances quality of life, and lowers hospitalization rates. CRT is especially preferred for patients with advanced heart failure, left bundle branch block, weakened heart pumping ability, or persistent symptoms despite medical therapy.

Defibrillator Pacemakers (ICD, CRT-D)

Defibrillator pacemakers not only have the standard pacemaker features but also deliver shock therapy when needed. There are single-lead ICDs, dual-lead ICDs, and triple-lead CRT-D types.

• ICD (Implantable Cardioverter Defibrillator): This device detects dangerous arrhythmias and provides electrical shocks when necessary. It continuously monitors the heart rhythm and stores the data. ICDs are used in patients with a high risk of sudden cardiac death, those who have experienced life-threatening arrhythmias, or individuals at risk due to heart attack damage or certain genetic heart conditions.
• CRT-D: A more advanced device, CRT-D combines Cardiac Resynchronization Therapy (CRT) with defibrillator capabilities. This device synchronizes the heart muscle’s contractions for heart failure treatment and provides life-saving shock therapy when required. It helps maintain the coordinated functioning of the heart muscle while managing dangerous arrhythmias.

Leadless Pacemakers

Unlike traditional pacemakers, leadless pacemakers are small, wireless devices weighing 3–4 grams that are implanted directly inside the heart. They do not require leads or any external components. These devices attach to the heart using small hooks and activate only when necessary. Leadless pacemakers do not have shock therapy capabilities.

In this video, I explain topics such as the types of pacemakers and battery replacement.