Computer generated transcript

Warning!
The following transcript was generated automatically from the content and has not been checked or corrected manually.

Cardiology: The Cardiac Cycle, ECG and common conditions 31/03/2025 Tutor: Molly KellyLearning outcomes ▶ Describe the mechanical and electrical events that occur during the cardiac cycle ▶ Describe the pressure and volume changes that occur in each chamber of the heart ▶ Understand the basics of ECG interpretation ▶ Has basic knowledge of common ECG abnormalitiesThe Cardiac Cycle 1. Atrial Systole 2. Ventricular Systole 3. DiastoleThe Cardiac Cycle S1 = Lub = Mitral & Tricuspid valves closing S2 = Dub = Aortic & Pulmonary valves closeCardiac Output, Heart Rate and Stroke Volume ▶ Cardiac Output = Volume of blood pumped per minute ▶ Heart Rate = Number of heart contractions per minute ▶ Stroke Volume = Volume of blood pumped by each ventricle beat Cardiac Output (CO) = Heart Rate (HR) x Stroke Volume (SV) KEY POINT = Chambers do not empty completely ▶ Ejection Fraction = % Volume of blood pumped outFrank Starling Stroke volume determined by: 1. The force of contraction 2. The volume of blood in the ventricle at the end of diastole Therefore: Stroke Volume ∝ Diastolic Filling ▶ Afterload = resistance to blood flow away from the heartAnatomy of Conducting System ▶ SAN ▶ Atria ▶ AVN ▶ Bundle of His ▶ Purkinje Fibres KEY POINT: ▶ Cardiac muscle is myogenic - generates its own action potentials at SAN ▶ Skeletal muscle is neurogenicCardiac Action Potential ▶ Na+ & Ca2+ entry causing depolarisation ▶ K+ exit causing repolarisation KEY DIFFERENCES: ▶ Longer depolarisation ▶ Controls duration ▶ Influx/Efflux of CalciumDisruption to the Conducting System ▶ Noradrenaline = increases Na+ and Ca2+ ▶ Acetylchloine = increases K+, reduces Ca2+Normal ECG ▶ 12 lead ECG ▶ Used to record heart rate and rhythmThe Cardiac Cycle Depolarisation = Systole Repolarisation = DiastoleECG interpretation ▶ 1 large box (5mm) = 0.2s ▶ HR = 300/large squaresArrhythmias ▶ Tachyarrhythmia - any abnormality of cardiac rhythm resulting in a fast heart rate ▶ Supraventricular Tachycardia ▶ Atrial Fibrillation ▶ Atrial Flutter ▶ Ventricular Tachycardia ▶ Bradyarrhythmia - any abnormality of cardiac rhythm resulting in a slow heart rate ▶ Heart block (1st, 2nd and 3rd degree)Atrial FibrillationMCQsQ1 During the cardiac cycle, atrioventricular valves shut: 1. Directly after atrial filling 2. Before atrial systole 3. After atrial systole and before ventricular systole 4. After ventricular systole and before atrial fillingQ1 During the cardiac cycle, atrioventricular valves shut: 1. Directly after atrial filling 2. Before atrial systole 3. After atrial systole and before ventricular systole 4. After ventricular systole and before atrial fillingQ2 What does the P wave on an ECG represent? 1. Ventricular systole 2. Diastole 3. Atrial systole 4. Opening of AV valves 5. Blood flow into the aortaQ2 What does the P wave on an ECG represent? 1. Ventricular systole 2. Diastole 3. Atrial systole 4. Opening of AV valves 5. Blood flow into the aortaQ3 What is venous return? 1. The volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction 2. Amount of blood leaving the heart through the aortic valve 3. Amount of blood entering ventricle in systole 4. Amount of blood entering ventricle in diastole 5. Amount of blood leaving the heart through the pulmonic valveQ3 What is venous return? 1. The volume of blood pumped out of the left ventricle of the heart during each systolic cardiac contraction 2. Amount of blood leaving the heart through the aortic valve 3. Amount of blood entering ventricle in systole 4. Amount of blood entering ventricle in diastole 5. Amount of blood leaving the heart through the pulmonic valve Q4 What is the main electrochemical cellular movements during phase 2? 1. Na+ entry, Ca2+ exit 2. No electrochemical movement 3. Ca2+ entry, K+ exit 4. K+ entry, Ca2+ exit 5. Na+ and K+ entryQ4 What is the main electrochemical cellular movements during phase 2? 1. Na+ entry, Ca2+ exit 2. No electrochemical movement 3. Ca2+ entry, K+ exit 4. K+ entry, Ca2+ exit 5. Na+ and K+ entryQ5 When listening with a stethoscope over the apex what is the cause of the first heart sound? 1. Aortic valve opening 2. Mitral valve opening 3. Ventricular filling 4. Mitral valve closing 5. Aortic valve closingQ5 When listening with a stethoscope over the apex what is the cause of the first heart sound? 1. Aortic valve opening 2. Mitral valve opening 3. Ventricular filling 4. Mitral valve closing 5. Aortic valve closingFeedback Please take a minute now before you leave to fill in a quick feedback form! https://app.medall.org/feedback/feedback-flow?keyword=7cddf5 d8468c4c6284cdd14b&organisation=accessibility-in-medicine Thank you for coming! ▶ If you have any more questions, feel free to email me at s2151748@ed.ac.uk or email accessibilityinmedicine@gmail.com ▶ Give our Facebook page a like for updates and opportunities, just search @AIMEdinburghSign up to the mailing list ▶ Sign up to the AIM mailing list to be the first to hear about tutorials, discounts, and opportunities! ▶ https://forms.gle/qJ NyeoFzA9B5urND7Thank you to our sponsors