Here, you will learn about Pacemakers and Automated implantable cardioverter defibrillators

Table Of Contents

Pacemakers

Types of Pacemakers

• Single-Chamber Pacemaker

  • Uses one pacing lead implanted in either the right atrium (RA) or right ventricle (RV).

• Dual-Chamber Pacemaker

  • Utilizes two pacing leads—one in the RV and one in the RA—to coordinate pacing between the atria and ventricles.

  <aside> 🚨

  Right ventricular lead can damage the Tricuspid valve and precipitate Tricuspid regurgitation

  </aside>

Biventricular Pacing (Cardiac Resynchronization Therapy [CRT])

• Involves one or two leads in the ventricles and an additional lead in the coronary sinus;
  • To improve synchronization of ventricular contractions
  • Primarily used in heart failure patients with left ventricular dysfunction**.**

<aside> 💡

Indication

• LVEF ≤ 35% and QRS duration > 120 milliseconds, with symptomatic heart failure despite optimal medical therapy. </aside>

Permanent Pacemaker

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Indications for Permanent Pacemaker Implantation

1. Irreversible Mobitz Type II Heart Block or Complete Heart Block.
2. Persistent Symptomatic Bradycardia.
3. Heart Rate < 40 bpm and Asymptomatic. </aside>

Permanent pacemakers (PPMs)

Automated implantable cardioverter defibrillators (AICD)

Description

• An AICD consists of a pulse generator and leads that can sense VF and VT and deliver a shock to restore sinus rhythm.

Indications for AICDs

The primary goal of AICDs is to prevent sudden cardiac death from ventricular tachyarrhythmias.

• Primary prevention
  • Cardiac Channelopathies (e.g., congenital long QT syndrome, Brugada syndrome)
  • Severe congestive heart failure (EF < 35%) in NYHA Class II/III HF
  • Hypertrophic obstructive cardiomyopathy
  • Arrhythmogenic right ventricular cardiomyopathy
• Secondary prevention (In case the patient has a history of the following)
  • Sudden cardiac arrest (e.g., due to Vfib or Unstable VT)
  • Stable sustained VT

Cardiac Event Monitors

Types of Cardiac Event Monitors

1. Holter Monitor
   • Records continuous ECG over 1-2 days to assess for intermittent arrhythmias.
2. Loop Event Monitor
   • Patient-activated monitor worn for weeks to capture symptoms like palpitations.
3. Implantable Loop Recorder
   • Subcutaneous device implanted for long-term monitoring (months) of arrhythmias.

<aside> 💡 Indications for Cardiac Event Monitors:

1. Unexplained syncope or near-syncope.
2. Recurrent unexplained palpitations.
3. Monitoring for atrial fibrillation.
4. Screening for ventricular arrhythmias in patients with structural heart disease. </aside>

Comparison of PPMs, AICDs, and CRTs Indications

 🔸 Cardiac Channelopathies (e.g., congenital long QT syndrome, Brugada syndrome)
 🔸 Severe congestive heart failure (EF < 35%)  in NYHA Class II/III HF
 🔸 Hypertrophic obstructive cardiomyopathy
 🔸 Arrhythmogenic right ventricular cardiomyopathy

🔷 Secondary prevention (In case the patient has a history of the following)

 🔸 Sudden cardiac arrest (e.g., due to Vfib or Unstable VT)
 🔸 Stable sustained VT

| | CRTs | 🔷 Patients with CHF with LVEF ≤ 35% & a wide QRS |