A cardiac pacemaker is an electronic device that delivers direct stimulation to heart causing electrical depolarization and cardiac contraction. The pacemaker initiates and maintains the heart rate when the natural pacemakers of the heart are unable to do so.
CLINICAL MANIFESTATION:
1. Sympathetic bradyarhythmias
- Sinoatrial bradyarrhythmias
- Sinoatrial arrest
- Sick sinus syndrome
- Second degree heart block
- Complete heart block
- Following acute MI, arrhythmias and conduction defects.
- Before or following cardiac surgery
- During coronary arteriography
- Before permanent pacing
- Supraventricular
- Ventricular
1. Demand (synchronous, non-competitive) atrial ventricular.
- It triggers electrical firings only when the heart rate goes slow.
- It does not compete with the hearts basic rhythms.
- If the client's heart rate falls below a predetermined escape interval (programmed into pulse generator), an electrical stimulus is delivered to the heart.
- It delivers an electrical stimulus at a preset constant rate that is independent of the patient's own rhythm.
- Does not allow atrial contribution to the cardiac output. May be valuable in complete heart block
- A demand form of pacing which is able to increase heart rate to accompany the physiological demands of the body.
- An actual electrode senses the patient's atrial depolarization, waits for a preset interval (simulated PR interval) and triggers firing of ventricular pacer
- If rapid atrial rhythm occurs, the ventricular pacemaker stimulates the ventricle at a fixed rate independent of atrial activity.
Temporary pacing of the heart is usually done as an emergency procedure that allows observation of the effects of pacing on heart function before a permanent pacemaker is implanted.
- Transvenous approach to position the electrode in the apex of right ventricle is done
- The external pulse generator is attached to the patient.
Permanent pacing of the heart may be implanted through the following:
1. Transvenous (Endocardial)
- The electrode is threaded through cephalic or external jugular vein into the right ventricle. This is done under local anesthesia.
- The peripheral end of the electrode is connected to the pulse generator, which is implanted underneath the skin below the right or left pectoral region.
- Anterior chest is opened and electrodes are sutured to the surface of the right or left ventricle or atrium, then threaded subcutaneously to the abdominal wall either above or below the waist.
- Monitor ECG following implantation of pacemaker, including VS.
- Observe for indications of pacemaker malfunction as dizziness, faintness, lightheadedness, chest pain, shortness of breath.
- Make sure all equipment in the client's unit is grounded, to prevent ventricular fibrillation.
- Practice sterile technique for dressing changes to prevent wound infection.
- Provide psychosocial support: Explore concerns of the client, encourage utilizing coping mechanisms, Ensure client comfort, and maintain a positive body image.
- Provide client education, which includes the following.
- Avoid going near or using microwave oven
- Wear loose - fitting clothing around the area of the pacemaker.
- Observe for signs and symptoms of infection around generator and leads -fever, heat, pain, skin impairment at the implant site.
- Avoid contact sports for electrode may be displaced.
