Permanent Pacemakers (PPM)

1. Single-Chamber Pacemaker

• Lead Position: One lead is placed either in the right atrium or the right ventricle.
• Indication:
  • Right atrial lead: Used for conditions like sick sinus syndrome where the problem is primarily in the sinus node (the heart’s natural pacemaker). This setup stimulates the atria.
  • Right ventricular lead: Used when the patient has complete heart block (atrioventricular block) or other issues affecting ventricular conduction. This stimulates the ventricles to maintain a steady heart rate.

2. Dual-Chamber Pacemaker

• Lead Position: Two leads are used—one in the right atrium and one in the right ventricle.
• Indication: This setup mimics the heart's natural rhythm by coordinating atrial and ventricular contractions. It is used for conditions like atrioventricular block, sick sinus syndrome with atrioventricular dysfunction, and other cases where both atrial and ventricular pacing are required to optimize heart function.

3. Biventricular Pacemaker (Cardiac Resynchronization Therapy, CRT-P)

• Lead Position: Three leads are used:
  • Right atrium
  • Right ventricle
  • Coronary sinus or left ventricular epicardial vein (this lead stimulates the left ventricle via the coronary sinus to achieve biventricular pacing).
• Indication: Biventricular pacemakers are used in patients with heart failure and ventricular dyssynchrony (as in left bundle branch block) to synchronize the contractions of the left and right ventricles. This improves the efficiency of the heart’s pumping ability, reducing heart failure symptoms.

4. Leadless Pacemaker

• Lead Position: This pacemaker does not have leads. The pacemaker device itself is implanted directly into the right ventricle.
• Indication: Leadless pacemakers are used for patients with bradycardia who only require single-chamber pacing (usually in the right ventricle). This can be an option when lead placement is difficult or there is a high risk of infection.

5. Transvenous vs. Epicardial Leads

• Transvenous Leads: The leads are threaded through veins (usually the subclavian vein) into the heart chambers (right atrium, right ventricle, or coronary sinus).
• Epicardial Leads: The leads are placed on the surface of the heart (epicardium), often used in pediatric patients or in cases where transvenous lead placement is not possible (e.g., due to venous abnormalities or after heart surgery).

DDD pacer = Dual paced, Dual sensed, Dual response (triggered and inhibited)

VVI pacer is ventricle only and cannot be triggered by an atrial beat.  It can only be inhibited by an intrinsic ventricular beat.

Several residents misunderstood the concept of "failure to sense," believing it to be a cause of absence of pacing.