Cardiovascular System Pacemaker

The heart is responsible for pumping blood to the whole body. This is necessary for all bodies and tissues to be supplied with the oxygen they need to function. In order to be pumped, the heart depends on electrical impulses, which are coursed from the atria to the ventricles. The stimulus is originated in the sinusal node, in the high portion of the right atrium, arrives at the junction between atria and ventricles (AV node), and then goes to the ventricles. A normal heart contracts with good rate and proper synchronization by these small stimuli (Figure 1).

Figure 1. Electrical impulses in the heart

When there is a defect in such electrical system, a portion or even the whole heart can have a rate lower than the normal one. This is called as bradycardia. With slow beats, the patient might feel dizziness, fainting, weakness, shortness of breath, and tiredness. There is a reduction in the circulation in the whole body, and the brain is the most sensitive organ. Many patients with this problem do not feel anything and the finding occurs casually. There can be also an acceleration (tachycardia) of the heartbeats in some diseases.

As the problem is located in the “electrical wiring”, it can be solved by placing a cardiac pacemaker (Figure 2). The pacemaker is a stimulation system that comprises a generator of electrical pulses and one or two electrodes. The generator, which is the system brain, is a miniaturized electronic circuit in a compacted battery. The electrodes are thin wires which aim is conducting electrical stimuli emitted by the generator to the heart.

Figure 2. Cardiac pacemaker

The modern pacemakers only begin to work when needed, when they feel that the heart has activity, staying in support, ready to go into action. Some have also sensors that identify times when there is need for a higher rate (for example, exercise) and enable a heart acceleration, similar to the normal heart.

Pacemaker Implantation

The technological evolution was fantastic in the last decades. Nowadays, the pacemaker implantation is a fast and safe procedure. The procedure lasts one hour in average. Local anesthesia, below the right or left clavicle is used in most cases. Sedation is used in some cases, together with local anesthesia. The electrodes are carefully introduced through a vein until the heart. An X-ray monitor is used to control the correct position of the electrodes inside the right atrium and ventricle. Several electrical tests are conducted in such time to confirm the ideal place of the electrodes. The pacemaker is implanted under the skin, on the chest, near the clavicle, where it is connected to the electrodes. Finally, the small incision is closed with a few stitches, which are not needed to be removed. The mean hospitalization time is from 2 to 3 days.

Figure 3. Implantable cardiac pacemaker

Multisite pacemaker or cardiac resynchronization

The multisite pacemaker is a special type of pacemaker, which aims to improve the contraction dynamics in the heart in some cases of severe heart failure. In these cases, the heart becomes large and weak, with alterations in the electrical system, impairing the blood pumping.

The patients that can be benefitted from such treatment are:

– patients with heart failure symptoms in spite of the medication (shortness of breath, tiredness, weakness, leg and belly swelling, appetite loss, and depression)
– weak and increases cardiac muscle
– delay in the electric system conduction from the atria to the ventricles.

Some candidates to this procedure also has a higher risk of sudden death and need the incorporation of an implantable defibrillator in the same device. Such equipment enables the identification and treatment of severe arrhythmias, which are precursory of sudden death. It also detects tachycardia and ventricular fibrillation (a type of cardiac arrest) and applies an electrical shock to revert them.

Postoperatory Care

Soon after the procedure, it is recommended that the patient does not raise the arm in the implant side a lot. This can be considered in the first two weeks, in order to prevent a possible electrode dislocation. After such period, there is the electrode cicatrization in the heart, with the electrode being fixated and not being under dislocation risk anymore. Walking is good and advisable since the hospital.

After the hospital discharge, a medical visit must be performed within 2 weeks. The pacemaker reviews must be performed every 6 months.

Every reprograming will be performed by an external programmer, a device placed over the skin, without need for more surgical interventions. Such programmer enables us to obtain information on the heart activity and the pacemaker function, which remains stored in the generator’s memory. Any event (arrhythmia) is also recorded. With such evaluations, we can alter the pacemaker programming aiming to prolong the battery duration and adjust its resources to each patient. The analyzer/programmer also informs us the battery charge and previously indicates when we have to change it.

The presence of the pacemaker is not felt and the electrical stimuli are very weak and imperceptible by the patient.

And the proper function of the battery of your pacemaker will be tested in each appointment.

As a general rule, you will be able to live a fully normal life after the implantation.

Besides these reviews, you must remain being followed by your cardiologist physician.

Care referring to the pacemaker:

After the pacemaker implantation, the patients will have a normal life, considering certain specific individual limitations. The physical exercise is released after two to three weeks.

Cell phones:

Try to use the cell phone on the ear opposed to the side where the pacemaker was placed. Avoid storing the device in a shirt or coat pocket next to the pacemaker.

Electrical devices and microwave ovens:

These can be used with no problem, provided they are working properly. Avoid electrical shocks, as any person should do.

Metal detector in banks and airports:

The modern devices come equipped with an excellent safety system against external interferences. However, a prolonged exposure to places with metal detectors with safety electronic system must be avoided. The ideal situation is to show the pacemaker card and then bypass the detector, as it will emit a sound when the pacemaker will be detected.

Avoid:

Violent sports with a lot of physical contact and magnetic resonance imaging (exam that involves a potent magnetic field to generate body images and can damage the device). If the exam is requested, inform the physician about the fact that you have a pacemaker.

Support notes

Heart failure: Heart difficulty in properly pumping blood to the body, when the heart usually increases in size. Click here to go to the page of Heart Failure and to know more about this subject.

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