Pacemakers

• Pacemakers may be incompatible with MRI scans, TENS machines used for pain management, and diathermy used during surgical procedures
• Some smartphones may interact with pacemakers if held too close
• Pacemakers

  • Consist of a pulse generator (the pacemaker box) and pacing leads, which carry electrical impulses to the relevant part of the heart
  • Implanted under the skin, most commonly in the left anterior chest wall
  • Wires are fed into the left subclavian vein and through the venous system to the relevant chambers of the heart
  • Patients with a pacemaker are followed up regularly to download information from the pacemaker, check everything is working ok, and decide when the battery needs replacing
  • Patients are given an identity card and bracelet
• Single-chamber pacemakers


  • Have leads in a single chamber, either the right atrium or the right ventricle
  • Placed in the right atrium if the issue is with
• Pacemakers must be removed before cremation in deceased patients
• Pacemakers

  Deliver controlled electrical impulses to specific areas of the heart to improve heart function
• Pacemakers do not interact with most day-to-day electrical activities
• Devices with strong magnets can affect the pacemaker function
• Many modern pacemakers are MRI-compatible
• Indications for a pacemaker include symptomatic bradycardias, Mobitz type 2 heart block, third-degree heart block, atrioventricular node ablation for atrial fibrillation, severe heart failure (biventricular pacemakers)
• Dual-chamber pacemakers placement

  Have leads in both the right atrium and right ventricle. The pacemaker coordinates the contraction of the atria and ventricles
• Implantable Cardioverter Defibrillators (ICDs)

  Continually monitor the heart and apply a defibrillator shock if they identify ventricular tachycardia or ventricular fibrillation. Used in patients at risk of ventricular tachycardia or fibrillation
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• It is worth ensuring you can identify the type of pacemaker on an ECG, as this is common in exams
• ECG Changes: The pacemaker intervention can be seen as a sharp vertical line on all leads on the ECG trace. A line before each P wave indicates a lead in the atria. A line before each QRS complex indicates a lead in the ventricles. Therefore: A line before either the P wave or QRS complex but not the other indicates a single-chamber pacemaker. A line before both the P wave and QRS complex indicates a dual-chamber pacemaker
• Biventricular (Triple-Chamber) Pacemaker placement

  Have leads in the right atrium, right ventricle, and left ventricle. Usually in patients with severe heart failure. Coordinate the contraction of these chambers to optimise heart function. Referred to as cardiac resynchronisation therapy (CRT)
• Single-chamber pacemakers placement

  Placed in the right atrium if the issue is with the sinoatrial node and conduction through the atrioventricular node is normal. Stimulate depolarisation in the right atrium, and this electrical activity passes to the left atrium and ventricles. Placed in the right ventricle if conduction through the atrioventricular node is abnormal. Stimulate the ventricles directly
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• Zero To Finals 725K subscribers Understanding Pacemakers Zero To Finals Search Watch later Share Copy link Info Shopping Tap to unmute If playback doesn't begin shortly, try restarting your device. More videos More videos Share Include playlist An error occurred while retrieving sharing information. Please try again later. Watch on 0:00 0:00 / 6:34 • Live • An error occurred. Try watching this video on www.youtube.com, or enable JavaScript if it is disabled in your browser. The Zero to Finals Medical Revision Podcast Pacemakers (2nd edition) Audio Player 00:00 00:00 | 07:02 Rewind 10 seconds Speed Forward 30 seconds Info The Zero to Finals Medical Revision Podcast Pacemakers (2nd edition) Apr 05, 2023 Season 48 Episode 15 Thomas Watchman This episode covers pacemakers. Written notes can be found at https://zerotofinals.com/medicine/cardiology/pacemakers/ or in the cardiology section of the 2nd edition of the Zero to Finals medicine book. The audio in the episode was expertly edited by Harry Watchman. Share Subscribe Apple Podcasts Spotify More Apple Podcasts Spotify Google Podcasts Overcast Stitcher iHeartRadio TuneIn + Alexa Castro Castbox Pocket Casts Podfriend Goodpods RSS Feed Buzzsprout
• This episode covers pacemakers. Written notes can be found at https://zerotofinals.com/medicine/cardiology/pacemakers/ or in the cardiology section of the 2nd edition of the Zero to Finals medicine book. The audio in the episode was expertly edited by Harry Watchman