From the Guidelines
A pacemaker is required for a heart block when the block is associated with symptomatic bradycardia, ventricular arrhythmias, or periods of asystole greater than or equal to 3.0 seconds, as indicated by the most recent guidelines 1. The decision to implant a pacemaker is based on the severity of the heart block and the presence of symptoms such as dizziness, fainting, or shortness of breath.
- The type of heart block that requires a pacemaker includes third-degree and advanced second-degree AV block at any anatomic level, as stated in the guidelines 1.
- The pacemaker implantation procedure is a relatively straightforward process, performed under local anesthesia and mild sedation, and typically takes about 1-2 hours.
- The surgeon makes a small incision below the collarbone, creates a pocket under the skin for the pacemaker generator, and threads thin insulated wires (leads) through a vein into the heart chambers.
- These leads are connected to the generator, which is programmed to detect when the heart rate falls below a certain threshold and deliver small electrical impulses to maintain a normal rhythm, as described in the guidelines 1.
- After implantation, patients typically stay overnight in the hospital for monitoring and have activity restrictions for about a month to allow the leads to secure in place.
- The pacemaker battery lasts 7-15 years, requiring eventual replacement, and patients need regular follow-up appointments to ensure proper functioning, as recommended by the guidelines 1.
- It is essential to note that the decision to implant a pacemaker should be made on a case-by-case basis, taking into account the individual patient's symptoms, medical history, and the severity of the heart block, as emphasized in the guidelines 1.
From the Research
Heart Block and Pacemaker Requirement
A heart block, also known as atrioventricular (AV) block, is a condition where the electrical signals between the heart's chambers are partially or completely blocked. This can lead to abnormal heart rhythms, which can be life-threatening if left untreated.
- In patients with sick sinus syndrome, a condition where the heart's natural pacemaker is not functioning properly, a pacemaker may be required to regulate the heart's rhythm 2, 3, 4.
- The type of pacemaker used depends on the patient's specific condition and needs. For example, a dual-chamber pacemaker (DDD) may be used to maintain AV synchrony, while a single-chamber pacemaker (AAI) may be used in patients with normal AV conduction 3, 4.
- Studies have shown that AAI pacing can be a safe and effective option for patients with sick sinus syndrome and normal AV conduction, with a low incidence of high-degree AV block and no significant differences in survival rates or freedom from atrial fibrillation compared to DDD pacing 2, 4.
- However, in patients with a high risk of developing AV block, a dual-chamber pacemaker may be preferred to maintain AV synchrony and prevent complications 3, 5.
Pacemaker Selection
The selection of an appropriate pacemaker system is crucial in treating patients with heart block or sick sinus syndrome.
- Dual-chamber systems (DDD) provide physiological stimulation by maintaining AV synchrony and are preferred in patients with a high risk of developing AV block 3, 5.
- Single-chamber systems (AAI) may be used in patients with normal AV conduction and can achieve similar clinical outcomes to DDD pacing 2, 4.
- The choice of pacemaker system depends on the patient's specific condition, medical history, and needs, and should be determined by a healthcare professional 2, 3, 4, 5.