Understanding Pacemakers

hi this is tom from zero finals comm in this video I'm going to be talking to you about pacemakers you can find written notes on this topic at zero da finals comm or in the cardiology section of the zero to finals Medicine book so let's jump straight in the purpose of pacemakers is to deliver controlled electrical impulses to specific areas of the heart to restore the normal electrical activity and improve the heart function they consist of what's called a post generator and that's the little pacemaker box and then they have pacing leads that carry the electrical signals from the pulse generator to the relevant part of the heart this little box or the pulse generator is implanted under the skin most commonly in the left anterior chest wall or the left axilla and the wires are implanted into the relevant chambers of the heart modern pacemakers have a computer that monitors the electrical activity and tailors the function of the pacemaker to the electrical activity that already exists in the heart so basically if the heart is already working perfectly no intervention is provided by the pacemakers the batteries in a pacemaker last about five years so quite a long time and they don't interact with day-to-day electrical activities like using a mobile phone but they might be a contraindication for MRI scans due to the powerful magnets in the MRI and electrical interventions like tens machines and diathermy that's used in surgery many of the modern pacemakers are MRI compatible but you need to check before requesting an MRI for somebody with a pacemaker whether their machine will be compatible it's worth noting that it's essential that pacemakers are removed prior to cremation in deceased patients so on the cremation form one of the most important tasks is to confirm and sign to say that you've checked the deceased patient doesn't have a pacemaker and if they do to check whether it's been removed you'll hear stories when you become a junior doctor about pacemakers that have been left in and when the patient has been cremated they blow up the entire Croma toriel while the indications for pacemaker symptomatic bradycardia 's mobitz type 2 AV block third-degree heart block part failure where they use by ventricular or triple chamber pacemakers and hypertrophic obstructive cardiomyopathy where they have implantable cardioverter defibrillators there's a few different configurations of how the leads are implanted into the heart you can have single chamber pacemakers dual-chamber pacemaker x' by ventricular or triple chamber pacemakers and implantable cardioverter defibrillators so we'll go through what those are now single chamber pacemakers have a lead in a single chamber and this is either in the right atrium or the right ventricle they're placed in the right atrium if the AV conduction in the heart is normal and the issue is with the sinoatrial node so by doing this they stimulate depolarization in the right atrium and then this electrical activity passes to the left atrium through the AV node to the ventricles and normal contraction of the heart is stimulated if the AV conduction in the patient is abnormal they place the single chamber pacemaker in the right ventricle and this bypasses the atrium and stimulates the ventricular contraction directly dual-chamber pacemaker x' have leads in both the right atrium and the right ventricle and this allows the pacemaker to synchronize the contractions of the atria and the ventricles by ventricular or triple chamber pacemakers have leads in the right atrium right ventricle and left ventricle and these are usually used in patients with severe heart failure and the objective is to synchronize the contractions of all the Chamber's to try and optimize the heart function they're also called cardiac resynchronization therapy or CRT pacemakers and they have quite good results for patients with severe heart failure implantable cardioverter defibrillators or AI CDs I CDs continually monitor the heart and apply a defibrillator shocked cardiovert the patient back into sinus rhythm if they identify the patient has developed a shockable arrhythmia so if the patient goes into VT these cardiac defibrillators will deliver a shock and try and put the patient directly back into sinus rhythm finally let's talk about ECG changes with pacemakers and this is quite a common thing to be asked to do in one of your auskey examinations they'll ask you to have a look at an ECG and identify the type of pacemaker that the patient has the pacemaker intervention on an ECG can be seen as a sharp vertical line on all the leads on the ECG as electricity is applied to the heart so a line before the P wave indicates that a leaders in the atria and the line before the QRS complex indicates that the lead is in the ventricles therefore if you have a line before the P or the QRS complex but not the other you know it's a single chamber pacemaker and you know the location of that lead and if you have a line before the P and the QRS complex you know it's a dual-chamber pacemaker so it's quite straightforward really so thanks for watching I hope you found this video helpful if you did don't forget there's plenty of other resources on the zero to finals website including loads and loads of notes on various different topics that you might cover in medical school with specially made illustrations there's also a whole test section where you can find loads of questions to test your knowledge and see where you're up to in preparation for your exams there's also a blog where I share a lot of my ideas about a career in medicine and tips on how to have success as a doctor and if you want to help me out on YouTube you can always leave me a thumbs up give me a comment or even subscribe to the channel so that you can find out when the next videos are coming out so I'll see you again soon

Channel: Zero To Finals

Views: 258,942

Keywords: medical, education, medicine, doctor, pacemakers, ecg, cardiology, heart block, bradycardia, mobitz, implantable cardioverter defibrillator, cardiac resyncronisation therapy

Id: 53_jyoA47Fk

Length: 6min 33sec (393 seconds)

Published: Mon Nov 26 2018