Cardiac Rhythm Management & Monitoring
Arrhythmias — irregular, slow, or rapid heart rhythms — range from harmless to life threatening. Cardiac rhythm management (CRM) is part of Electrophysiology and monitoring involves implanting a small, battery-powered device into the upper chest to follow and control the heart’s rhythm. There are two categories of CRM devices: pacemakers and defibrillators.
Pacemakers
A pacemaker is small device that is surgically implanted in the chest to regulate a slow or irregular heartbeat. Most pacemakers have three main components that work together to regulate the heartbeat.
1. The Pulse Generator
The pulse generator is a small, battery-operated metal case with a tiny computer that receives and responds to signals from the heart and regulates irregular rhythms.
2. Leads
Leads are wires connecting the pulse generator to the heart. These are usually placed through a large vein in the chest. A pacemaker may have one to three leads depending on the arrhythmia it is designed to regulate.
3. Electrodes
Electrodes are located on each lead to monitor the natural heartbeat. When the heartbeat is too slow, the electrodes send impulses to the heart to make it beat normally.
There Are Several Different Types of Pacemakers
A Single-Chamber Pacemaker
A single-chamber pacemaker has a single lead that connects the pulse generator to one chamber of your heart, usually the right ventricle.
A Dual-Chamber Pacemaker
A dual-chamber pacemaker has two leads, connecting to the right atrium and the right ventricle. The pacemaker regulates the contractions of both chambers, allowing blood to flow smoothly from the right atrium into the right ventricle.
A Biventricular Pacemaker
A biventricular pacemaker is mostly used for people with advanced heart failure but can also be beneficial for certain other conditions. The device consists of three wire leads and a pulse generator.
Leadless Pacemakers
Leadless pacemakers are an exciting breakthrough in the treatment of arrhythmia. Roughly the size of an AA battery, these remarkable devices don’t need a separate battery or leads — they are implanted directly in the heart’s right ventricle. As of this writing, leadless pacemakers are only available for people with certain conditions and those with bradycardia (slow heart rate) who only need pacing in one heart chamber.
Like any device, pacemakers can wear out or need new batteries. That’s why it’s recommended to “interrogate” your pacemaker every six months. This procedure can be performed in your cardiologist’s office. It involves placing a wand over the pacemaker and using a programmer to check effectiveness, battery life, and wire function, and ensure the device’s electric signals are traveling to and from the heart properly.
Implantable Defibrillators (ICD)
An implantable cardioverter-defibrillator (ICD) is a small battery-powered device that continuously monitors your heartrate. If it detects an abnormal rhythm, the device delivers an electric shock to restore a normal heartbeat. ICD continuously checks the heartbeat. It delivers electric shocks, when needed, to restore a regular heart rhythm.
You might need an ICD if you have a dangerously fast heartbeat called ventricular tachycardia or ventricular fibrillation. Traditional ICDs are implanted in the chest and have leads that attach to the heart.