An AICD is a battery-powered device placed under the skin (below your collarbone). It monitors your heart’s electrical activity to detect arrhythmias (irregular heartbeats).
Arrhythmias can be caused by a variety of conditions that block or disrupt the heart’s electrical signals. Most arrhythmias are harmless, but some can be serious.
During an arrhythmia, the heartbeat can be too fast, too slow, or irregular. A heartbeat that’s too fast (over 100 beats per minute) is called tachycardia. A heartbeat that’s too slow (under 60 beats per minute) is called bradycardia. An irregular heartbeat is called dysrhythmia.
For the heart to work correctly, the atria (upper chambers) and ventricles (lower chambers) must beat in a coordinated pattern at a resting heart rate between 60 and 100 beats per minute.
Ventricular arrhythmias are especially dangerous. When they occur, the heart can’t pump blood well. If a normal heartbeat is not restored, you could pass out within seconds and die within minutes. Using a process called defibrillation, an ICD can help control life-threatening arrhythmias, especially those that can cause sudden cardiac arrest (SCA).
Thin wires called “leads” connect the ICD to one or more chambers in your heart. The leads allow the ICD to continuously read the electrical activity in your heart. If the device detects an irregular rhythm in your ventricles, it will use low-energy electrical pulses to restore a normal rhythm.
If the low-energy pulses don’t restore a normal rhythm, the ICD will switch to high-energy pulses for defibrillation. The device also will switch to high-energy pulses if your ventricles start to quiver (fibrillate) rather than contract. These high-energy pulses last only a fraction of a second, but they can be painful.
Some people say it feels like being hit in the back with a baseball bat. Others says it feels like being kicked by a horse. It differs with everyone and only lasts for a second. Most people feel it more in the back than in the front.
Implantable Cardioverter Defibrillator with Biventricular Pacemaker Implantation
A biventricular pacemaker, also called cardiac synchronization therapy, is used to synchronize the contractions of the left and right ventricles to improve the heart’s ejection fraction in patients with severe and moderately severe symptoms of heart failure.
A patient with heart failure has a low ejection fraction rate, which limits the heart’s ability to pump blood to various parts of the body. Ejection fraction is a measure of the blood pumped by the left ventricle of the heart. A normal ejection fraction is between 50% and 70%. Symptoms of heart failure include shortness of breath, dry cough, swelling of the ankles and legs, weight gain, increased urination, fatigue, and rapid or irregular heartbeat.
Biventricular implantation is considered in heart failure patients when they:
Have severe or moderately severe heart failure symptoms.
Have delayed electrical activation of the heart.
Have a risk or history of cardiac arrest.
Take long-term medications for heart failure
A biventricular pacemaker can be implanted in two ways:
An endocardial (transvenous) approach, in which the pacemaker is placed in the upper chest
An epicardial approach, in which the pacemaker is placed beneath the skin in the lower abdomen
A biventricular pacemaker usually has three leads: one is guided to the right ventricle, one to the left ventricle and the third (which is not always present) is guided to the right atrium.
When the heart rate drops below a predetermined rate, the biventricular pacemaker transmits triggers the left and right ventricles to contract simultaneously, improving the ejection fraction. If a lead is placed in the right atrium, it helps the heart function in a more balanced way.
Biventricular pacemaker implantation is only a part of a comprehensive heart failure management program. Medications, life style changes, and regular follow up with a cardiac specialist are all crucial for managing the symptoms and improving the quality of life in heart failure patients.
Noninvasive Program Stimulation
When a patient has an automatic implantable cardioverter defibrillator (AICD), a change in their health or new medications may interfere with how the AICD works. If your doctor needs to evaluate to your AICD to ensure that it is functioning properly, he may schedule you for a noninvasive program stimulation (NIPS) test.
Similar to a cardioversion, NIPS is a brief procedure. The doctor will send electric pulses through the catheters to make your heart beat at different speeds. This will signal tour ICD to deliver a shock or rapid pacing sequence to restore a normal rhythm. Your doctor can then adjust the device’s programming, if needed. You will be anesthetized during the test so you won’t feel anything; you should be able to go home a few hours later.