ECG Atlas- Section 5

Pacemakers




Cardiac pacing is an important modality for treating patients with bradyarrhythmias due to chronic or intermittent AV conduction abnormalities, sinus node dysfunction, or neurocardiogenic syndromes.

Common indications for pacemaker insertion:

  • Symptomatic sinus node dysfunction
  • Symptomatic AV block
  • Bifasicular block with syncope
  • Alternating LBBB and RBBB
  • Tachyarrhythmias resistent to medical treatment
  • Hypertensive carotid sinus syndrome and neurocardiogenic syndrome

    Pacemaker Nomenclature:

  • Pacemakers are coded by specific abbreviation according to the type of pacemaker and mode of pacing.
  • The first letter refers to the chamber(s) being paced and the second to the chamber(s) being sensed.
  • The letters A and V indicate atrial or ventricular pacing and/or sensing.
  • If dual chambers are paced/sensed, the letter D is used.
  • The third letter refers to the response to a sensed event. Which can be inhibits I or triggers T. If a pacemaker can inhibit and trigger then D is designated.
  • A fourth letter denotes programmability.

    The following table summarises different type of pacemaker:

    Example: DDD pacemaker - Paces both the atrium and ventricle, senses both atrium and ventricle, is inhibited by atrial output and triggered by a ventricular paced complex after a sensed atrial complex.

    Atrial Pacing

    Case 1





    Ventricular Pacing

    Case 1





    Dual Chamber Pacing

    Case 1





    Problems with Pacing

    Case 1





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