What is Pacemaker
Pacemaker is an artificial device used to electrically stimulate the heart.
It is composed of two parts:
• Battery-powered generator.
• Wire electrode—which is attached to the heart chamber to be stimulated (atrium or ventricle
or both).
Pacemaker may be single chamber or dual chamber. Two types of pacemaker—temporary and permanent.
Indications of Temporary Pacemaker
• Acute inferior myocardial infarction with second or third degree AV block or severe bradycardia with haemodynamic change.
• Acute extensive anterior MI with second or third degree AV block or new bifascicular block
(LBBB or RBBB with left anterior hemiblock, RBBB with left posterior hemiblock).
• Patient awaiting for permanent pacing.
• Some tachycardia, such as AV re-entry tachycardia and ventricular tachycardia can be terminated by overdrive pacing.
• After open-heart surgery.
• Some cases of cardiac arrest.
• Severe digitalis toxicity.
Indications of Permanent Pacemaker
• Most common—complete heart block with syncope or Stokes–Adams syndrome and sick
sinus syndrome.
Others
• Symptomatic or asymptomatic Mobitz type 2 second degree AV block.
• Symptomatic Mobitz type 1 second degree AV block.
• Bifascicular or trifascicular block with syncope.
• Carotid sinus syndrome with bradycardia.
• Repeated vasovagal syndrome with bradycardia.
• In some cases of permanent atrial fibrillation (when other treatment fails, radiofrequency ablation followed by permanent pacemaker).
ECG Findings (Atrial Pacing)
• There is a spike followed by P wave.
• QRS—normal.
ECG Findings (Ventricular Pacing)
• There is a spike followed by QRS.
• QRS -wide (looks like LBBB).
Complications of Pacemaker
1. Early—
–– Pneumothorax.
–– Infection.
–– Lead displacement.
–– Cardiac tamponade.
–– Pocket haematoma.
2. Late—
–– Infection.
–– Erosion of generator or lead.
–– Chronic pain at implant site.
–– Lead fracture.
–– Malfunction.
–– Perforation of ventricular wall.
–– Ventricular arrhythmia (PVC).
–– Electromagnetic interference.
–– Pacemaker failure.
–– Pacemaker mediated tachycardia (by dual-chamber pacing).
–– Pacemaker syndrome (by single-chamber pacing).