How Can a Cardioverter-Defibrillator Treat Congestive Heart Failure?

Congestive heart failure is a common condition affecting the muscles of the heart and peripheries of the body. It leads to inefficient pumping action from the heart, which in turn results in a lesser amount of blood reaching the various parts of the body. Being highly prevalent in people aged over 60, the condition causes symptomatic fatigue, shortness of breath, and swelling in the lower limbs.

 

The treatment of congestive heart failure is extremely variable and includes medications, heart transplant, lifestyle changes, managing the potential reversible factors, and various mechanical therapies.

 

What is a Cardioverter-Defibrillator/ICD?

This lifesaving device is very useful in prevention of sudden deaths related to heart abnormalities. An implantable or automated cardioverter-defibrillator is implanted inside the body, and it is capable of performing restoration of the normal heart rhythm and controlling abnormally fast heart rate. The modern generation ICDs perform dual function and act as pacemakers, too. A pacemaker is a device which stimulates the heart to beat faster if it detects an abnormally slow heart rate.

 

How does a Cardioverter-Defibrillator Treat Congestive Heart Failure?

An ICD is battery powered to keep track of the heart rate and is placed under the skin. Wires from the device are connected to the heart and capable of detecting abnormal heart rhythm, also known as arrhythmia. When it senses arrhythmia, it sends electrical shocks to the heart. This will help the heart correct arrhythmia and restore the heart rate to normal. ICD is programmed depending on the problem with the heartbeat and the therapy required, including:

1. Cardioversion: This involves a higher range of electric shock. This therapy is considered for a severe problem with abnormal fluctuations in the heart rhythm. During the shock, the patient feels as though he is being thumped in the chest region.
2. Defibrillation: The process of delivering the strongest therapeutic electric shock to the heart for restoring the normal heart rate is called defibrillation. During this therapy, it feels like being kicked in the chest region. In few cases, the high grade electric shock might even knock the patients off their feet.
3. Low energy pacing: This is considered for patients with mild disruptions in the heart. During the therapy, the patient either feels nothing or a painless fluttering sensation in the chest region.

 

Indications

An ICD is placed in people who are at a high risk of cardiac death. Cardiac death is a medical emergency where the heart stops beating. It needs to be treated within a few minutes, otherwise the affected person can die. Basically, ICD is used when the doctors have ruled out the normal correctable conditions of arrhythmia, like inadequate blood flow to the heart, drug toxicity, electrolyte imbalance etc. An ICD is implanted under certain conditions, such as:

1. Pulse of more than 100 beats per minute with irregular heartbeats in between
2. Rapid, irregular, and unsynchronized contractions of muscle fibers
3. Abnormal rapid heart rhythms
4. Relapsing heart attack
5. Rare congenital conditions of the heart
6. A sudden cardiac arrest
7. Genetic disease like Brugada Syndrome or arrhythmogenic right ventricular dysplasia

 

The following are at a high risk of cardiac death. Sudden cardiac death is the leading cause of death in the world. The risk factors are broadly divided into modifiable and non-modifiable factors.

• Life-threatening periods of arrhythmia, such as ventricular tachycardia (VT) or ventricular fibrillation (VF). The heart is divided into 4 chambers and the ventricles are the lower two chambers of your heart.
• A birth defect
• Hereditary susceptibility to cardiac death
• Weak heart which does not pump the blood well. This could be contributed to by heart attacks and heart failures
• Drug or alcohol abuse
• Age factors, as incidence increases with age
• Personal history of hypertension, diabetes, high blood cholesterol, chronic kidney diseases, abnormal cardiac findings related to heart failure
• A sedentary lifestyle

 

Description of a Cardioverter-Defibrillator

A cardioverter-defribrillator has three main parts, including:

• Pulse generator: A pulse generator is almost the size of a large pocket watch. It reads the electrical activity of your heart with the help of a battery and electrical circuits.
• Electrodes: The electrodes are also called leads. They are wires that go to your heart through your veins. Your ICD may have one, two, or three electrodes.
• Pacemaker: ICDs have a built-in pacemaker. Your heart might need pacing if it’s beating too slow or too fast, or if you had a shock from the ICD.

Preparation

• Inform your doctor about all the medicines that you are taking.
• Before the day of your surgery, inform your doctor about any infection that you have, including a cold, the flu, etc.
• You will be asked to wash your body well with a special soap.
• You will be given an antibiotic to prevent infections.
• You will have to undergo absolute fasting from midnight the previous night until your surgery.
• You cannot have water during fasting. If you feel your mouth is dry, you can rinse your mouth but shouldn’t sip water. You will have to take your medicines with minimal water.

 

How is a Cardioverter-Defibrillator/ICD implanted?

• The area below your collarbone is anesthetized. In some procedures, a general anesthesia is given wherein you will not be awake. However, here you will be awake, as it’s only a local anesthesia being used.
• An ICD is mostly inserted close to your left shoulder.
• It is inserted between your skin and muscle.
• With the help of special X-rays, electrodes are inserted into your veins and then into your heart.
• These electrodes are attached to the pulse generator and pacemaker.
• This procedure usually takes 2 to 3 hours.

 

After the surgery

Most probably, you will be able to go home within a day of surgery. You can resume your normal routine soon. Full recovery may take 4 to 6 weeks.

• Remember to check with your doctor on how much you can move the arm where the ICD was placed.
• Don’t lift more than 10 to 15 pounds.
• Don’t stretch/pull/twist your arm for 2 to 3 weeks.

Risks involved with ICD

These are uncommon, but there are chances of the following in case of ICD implantation.

• Infection, swelling, bleeding at the implant site
• Collapsing of lungs
• Allergic reaction to medications used during or after the procedure
• Damage to veins or valve where ICD leads are placed
• Life-threatening bleeding around the heart

Final Thoughts

Your doctor, probably a cardiologist, will decide whether or not an ICD is right for your situation. In some cases, an ICD is not necessary, as the condition can be managed with other forms of therapy.