His Bundle Pacing represents a contemporary advancement in cardiac rhythm management. This technique aims to restore the heart’s natural electrical activation sequence, offering a more physiological approach to maintaining a steady and synchronized heartbeat. It involves precisely delivering electrical impulses to a specific part of the heart’s conduction system, thereby promoting coordinated contractions of the heart chambers. This method seeks to optimize the heart’s pumping efficiency, which can have positive effects on overall cardiac function.
Understanding His Bundle Pacing
The heart’s natural electrical system dictates its rhythm, starting with the sinoatrial (SA) node, often called the heart’s natural pacemaker. Electrical signals from the SA node spread through the atria, causing them to contract, before reaching the atrioventricular (AV) node. The AV node briefly delays these signals, allowing the atria to fully empty blood into the ventricles.
Following this delay, the electrical impulse travels into the Bundle of His, a specialized cluster of conductive muscle cells located in the heart’s interventricular septum. The Bundle of His then branches into the left and right bundle branches, which further divide into a network of Purkinje fibers. These fibers rapidly distribute the electrical signal throughout the ventricles, ensuring they contract in a synchronized and efficient manner to pump blood to the body. His Bundle Pacing directly stimulates this natural pathway, replicating the heart’s physiological activation, unlike traditional methods that stimulate the heart muscle directly.
Why His Bundle Pacing is a Preferred Option
His Bundle Pacing (HBP) aims to precisely replicate the heart’s natural physiological conduction, leading to more synchronized ventricular contractions. By directly stimulating the His-Purkinje system, HBP ensures that electrical activation spreads through the ventricles in a coordinated fashion, similar to a healthy heart. This contrasts with conventional right ventricular pacing, which can cause asynchronous ventricular activation and potentially lead to adverse effects over time.
One benefit of HBP is its potential to reduce the risk of pacing-induced cardiomyopathy, a condition where prolonged traditional pacing can weaken the heart muscle. Right ventricular apical pacing, a common traditional method, has been linked to an increased risk of heart failure and atrial fibrillation. HBP’s ability to activate the ventricles physiologically helps avoid this dyssynchrony, potentially preventing or even reversing pacing-induced heart damage.
HBP is indicated for patients with various heart rhythm disorders, including:
High-degree atrioventricular (AV) block, especially when ventricular pacing is expected more than 20% of the time.
First-degree AV block with a prolonged PR interval, either alone or combined with other rhythm issues.
Bundle branch block, which can often normalize the ventricular activation pattern.
As an alternative to biventricular pacing for cardiac resynchronization therapy, particularly in patients with heart failure and left bundle branch block.
The Implantation Procedure
His Bundle Pacemaker implantation involves precise lead placement. Patients undergo preparation similar to other pacemaker procedures, including local anesthesia. The procedure is performed in a specialized lab with continuous monitoring of the heart’s electrical activity using an electrophysiology (EP) recording system.
A small incision is made near the collarbone, through which a specialized sheath and lead are introduced into a vein, often the cephalic or axillary vein. The lead is then guided through the vein and into the heart, with its movement monitored using fluoroscopy, a type of real-time X-ray imaging. Unlike traditional lead placements that rely heavily on fluoroscopy, His lead placement primarily uses electrical mapping to pinpoint the exact location of the His bundle.
The goal is to position the lead tip precisely on or near the His bundle, in the atrial portion against the septum. The lead used is an active fixation lead, meaning it has a small screw at its tip that allows it to be securely anchored into the heart tissue, directly stimulating the His bundle fibers. Once the lead is in place and satisfactory electrical parameters are confirmed, the lead is connected to the pacemaker generator, which is then placed in a small pocket created under the skin. The entire procedure takes between 30 to 90 minutes.
Living with a His Bundle Pacemaker
Following His Bundle Pacemaker implantation, patients can expect a recovery period involving some local pain or discomfort at the incision site, which can be managed with medication. It is recommended to limit certain arm movements on the side of the implant for a few weeks to allow the lead to secure firmly and reduce the risk of dislodgement. The surgical wound should be kept clean and dry to prevent infection.
Long-term management involves regular follow-up appointments with a cardiologist or electrophysiologist. These appointments include device checks to monitor the pacemaker’s function, assess battery life, and ensure the pacing parameters remain optimal. Modern pacemaker batteries last between 5 to 10 years, depending on how frequently the device is actively pacing.
Patients with a His Bundle Pacemaker can resume most daily activities, with the goal of improving their quality of life and heart function. While safe, potential complications, such as lead dislodgement or infection, are rare but can occur. Studies indicate a low risk of complications. The device provides physiological pacing, aiming for improved heart synchronization and overall well-being.