Pacemakers Flashcards
What is a pacemaker and how does it work?
A pacemaker delivers controlled electrical impulses to specific areas of the heart to improve heart function. It consists of a pulse generator (pacemaker box) and pacing leads that carry electrical impulses to the heart.
Where is the pacemaker pulse generator typically implanted?
The pacemaker pulse generator is typically implanted under the skin, most commonly in the left anterior chest wall.
How are pacemaker leads positioned in the heart?
Pacemaker leads are fed through the left subclavian vein into the venous system and then into the relevant chambers of the heart.
How often should patients with a pacemaker follow up?
Patients with a pacemaker should have regular follow-ups to download information, check the device’s function, and monitor when the battery needs replacing.
What are some devices or activities that may be incompatible with pacemakers?
Pacemakers may be incompatible with:
* MRI scans (due to powerful magnets)
* TENS machines (used for pain management)
* Diathermy (used during surgery)
* Devices with strong magnets (e.g., handheld security scanners at airports)
What is a critical tip for handling pacemakers during cremation?
Pacemakers must be removed before cremation. Cremation forms should confirm whether a pacemaker is present and if it has been removed due to the risk of it exploding.
What are the common indications for a pacemaker?
Common indications for a pacemaker include:
* Symptomatic bradycardias (e.g., due to sick sinus syndrome)
* Mobitz type 2 heart block
* Third-degree heart block
* Atrioventricular node ablation for atrial fibrillation
* Severe heart failure (requiring biventricular pacemakers)
What is a single-chamber pacemaker and where are its leads placed?
A single-chamber pacemaker has leads in either the right atrium or right ventricle. The right atrium is used if the issue is with the sinoatrial node, and the right ventricle is used if conduction through the atrioventricular node is abnormal.
What is a dual-chamber pacemaker?
A dual-chamber pacemaker has leads in both the right atrium and right ventricle. It coordinates the contraction of both the atria and ventricles.
What is a biventricular (triple-chamber) pacemaker and when is it used?
A biventricular pacemaker has leads in the right atrium, right ventricle, and left ventricle. It is used in patients with severe heart failure to optimize heart function through cardiac resynchronisation therapy (CRT).
What is an implantable cardioverter defibrillator (ICD)?
An ICD continually monitors the heart and delivers a defibrillator shock if it detects ventricular tachycardia or ventricular fibrillation. It is used in patients at risk of these conditions, such as those with a previous cardiac arrest.
What ECG changes can indicate pacemaker intervention?
On an ECG, a pacemaker’s intervention appears as a sharp vertical line before:
* The P wave (indicating an atrial lead)
* The QRS complex (indicating a ventricular lead)
How can you distinguish between different types of pacemakers on an ECG?
Distinguishing types of pacemakers on an ECG:
* Single-chamber pacemaker: A line before either the P wave or QRS complex, but not both.
* Dual-chamber pacemaker: A line before both the P wave and QRS complex.
