BODY INSIDE CATCH THE RHYTHM

WRITER: ADRIAN FINOL, M.D.

The idea seems counterintuitive. Our bodies are made of flesh and blood, organs, tissues, and cells. Our bodies regenerate, degenerate, and respond to light, water, and temperature. It is all so very natural — organic, if you will. Yet, this natural, organic system is regulated by an elaborate electrical system.

Take heart rhythm, for example. In order for our bodies, organs, and brains to work properly, we need our heart to beat at a certain interval. When that interval is too fast or too slow, we have problems, and these days, a computer is often the cure — we call it a pacemaker.

The medical procedure of inserting a pacemaker into the body has become a fairly safe, effective, and common medical procedure. But what is a pacemaker, and how does it work? This is where patients start wondering about these “unnatural machines” being placed in their bodies. If the entire concept seems like science fiction to you, know you are not alone. I frequently have discussions like the one below as I do my best to explain how pacemakers fit into the big physiological picture.

Patient: Doctor, I have been very dizzy and lightheaded. Doctor: It is possible you have an electrical problem.

Patient: An electrical problem?

Doctor: The heart works because there is an electrical system that keeps it beating at the right pace. Sometimes this system fails and your heart does not beat as fast as it should. This means the heart can’t pump as much blood as the body needs, and when this happens you can have symptoms such as lightheadedness, fatigue, dizziness, shortness of breath or fainting spells.

Every heart beat starts with an electrical signal. The signals are sent and received by special electrical cells within the heart called nodes (the sinoatrial (SA) node or atrioventricular (AV) node). As the signals move through the heart they tell the chambers that pump blood to contract. When you are active, the signals speed up to pump blood faster; when you are resting, the signals return to normal pace.

Patient: Do I need batteries to make my heart beat correctly?

Doctor: Sometimes. If you do, the device is called a pacemaker. There are different reasons your heart fails to beat at the pace you need it to beat, but most common is when there are problems with the nodes in your heart. In some cases, the heartbeat is slow once in a while; in other cases, the heartbeat is slow all of the time. Sometimes the heartbeat fails to rise during activity. The cause of these problems could be changes in your heart due to aging, heart disease, previous heart surgery, medications, or even an undetected heart defect.

The most common reasons to get a pacemaker are sick sinus syndrome or heart block. Sick sinus syndrome occurs when the SA node: is too slow (sinus bradycardia); skips a beat (sinus pauses); or alternates between very fast and too slow (tachy-brady syndrome). Heart block occurs when the electrical signals don’t pass from one chamber to the other.

Doctor: Okay, so I have the results of your electrocardiogram (EKG), and you have a heart block. I think we should place a pacemaker.

Patient: What is that? How does it work? I have seen some of my friends with it, and it looks like a “lump in the chest.”

Doctor: A pacemaker is a small, lightweight electronic device. It has a tiny computer that senses the beats of your heart and it sends an electrical signal to the heart to start the beat if it becomes too slow. Also, the sensors in the pacemaker keep track of your activity level and can adjust the signals as needed. The pacemaker consists of a generator with a computer and wires (leads) that connect the generator to the heart.

Patient: How is it placed? Is it dangerous?

Doctor: The placement or implantation of the pacemaker is done in the hospital. It could be placed in different places but most commonly is in the left chest. Also taken into account is whether you are right-handed or left-handed, as well as the types of activities you participate in, like hunting or shooting a rifle.

It is usually performed in the operating room under sedation and local anesthetic. An incision is done beneath your collarbone, and a “pocket” is created under the skin to fit the generator. To place the leads to your heart, the doctor will access a vein that leads to it. The leads are guided inside your heart with the help of X-rays. The leads are then attached to your heart with small anchors at the end or with a very small screw and then to the generator before being placed in the pocket beneath the skin. Next, the incision is closed. The pacemaker is “interrogated” to make sure there is good communication with the leads and good reading of the electrical conduction of the heart. Once this is done, you are transferred to the recovery area and then to your hospital room where you usually stay for twenty-four hours for antibiotics and another “interrogation” the following day.

The placement of a pacemaker is usually a safe procedure with low risk of complications. However, like any other surgical procedure, complications could happen — such as bleeding, infection, bruising, puncture of the lung or heart muscle, damage to vein or artery, or dislodgment of the leads and need for reposition.

Patient: What happens after? How I do take care of it?

Doctor: Usually you will need a little pain medication. Once home, you could be discharged with an arm sling or told not to raise the arm on the side of the pacemaker above shoulder level.

The reason is to avoid movement or dislodgment of the leads. It is normal to have some bruising, and normal activities are encouraged after discharge. Each doctor has his or her own routine for incision care, but usually after forty-eight hours, it is okay to shower and let the incisions get wet and “patted” dry. No bathing or swimming is allowed until instructed by your doctor. At any sign of infection, you should call your doctor right away.

Once the incision is completely healed (around six weeks), your doctor will place you in a “pacemaker clinic.” Depending on the individual, this could be every six months. At this time, the pacemaker will be interrogated and settings may be changed as needed. Also, some devices can be constantly checked at home, and results are sent to your doctor.

Contrary to common misconceptions, most machines will not interfere with your pacemaker. Microwaves, ovens, computers, radios, television, hair dryers, electric blankets, and power tools should not have an effect on your pacemaker. However, some equipment could cause momentary changes of settings like cellphones or strong magnets. In addition, most pacemakers are not MRI compatible, and you will want to keep your pacemaker ID with you at all times.

Patient: Does it last forever?

The life of the generator lasts five to ten years, depending on the use. The replacement is usually a simple outpatient procedure.