26/08/2022
Here is your Guideline for CVS. As it is divided into two parts, the guidance related to heart is here, relating to circulation will be uploaded soon.
CVS is the most important topic in 1st year physiology, you should study this topic from Guyton. For the physiology of heart you need to go through chapter 9, 10, 11, 13
Chapter 12 is optional, if you have sufficient time you can give it a go.
🔴🔴🔴Chapter 9:
▪️Cardiac muscles as a syncytium
📌Action potentials in cardiac muscle:
▪️ Mechanism of development of plateu in cardiac muscle action potential and the channels involved
▪️The reason for rapid conduction of excitatory signal in Purkinje fibers as compared to atrial and ventricular muscle fibers
▪️Refractory period of cardiac muscles(this concept will be used in the chapters ahead), graph for early and later premature contraction. (9-4)
📌Excitation-contraction coupling:
▪️Role of T-tubules in providing surplus Ca++
▪️Mechanism of Excitation contraction coupling and relaxation.(Very important)
▪️Cardiac Cycle
▪️Effect of heart rate on duration of cardiac cycle and why the time proportion of diastole is decreased at higher heart rates
📌📌📌(Fig-9-6) this graph is very important in relating the pressure and volume changes during different phases of cardiac cycle. You must be able to relate ECG and Phonocardiogram along with P and V changes. Closure and opening of valves during a specific event must be at your finger tips.
▪️a, c, v wave development in atrial pressure curve(important for mcqs)
▪️What is meant by isovolumic contraction and isovolumic relaxation.
▪️Values of end diastolic and end systolic volume( try to visualize the graph on hearing these terms)
▪️Difference between the AV and semilunar valves.
▪️Incisure development
▪️Graphical analysis of ventricular pumping keeping in view the left ventricle and measurement of stroke volume as well as cardiac work output from it.
▪️Preload and after load(concept)
📌📌Frank-Starling Law( can relate ventricular function curves for understanding but these curves as such are not important)
▪️Effect of sympathetic and parasympathetic stimulation of heart and its effect on cardiac output and heart rate
▪️Effect of Potassium and Calcium ions on heart function,(relate membrane physiology here)
🔴🔴🔴Chapter 10:
▪️SA node, its location, characteristics of SA nodal fibers.
📌 Self Excitation of SA node, mechanism of self excitation, ion-channels involved and comparison with the ventricular muscle fiber.
▪️Why depolarization and repolarization each separately is maintained forever in SA nodal fibers.
▪️Role of inter nodal pathways.
▪️AV node, its location, two parts, and the reason for the slow condiction of excitatory signal in it.
▪️Reason for rapid consuction in AV bundle.
📌📌 (Fig 10-4) when the wave of excitation arrives at a particular point in conducting system and how much delay occurs at a particular point, total delay adds upto 0.22 sec.
▪️Why SA node is pacemaker not the AV node.
📌Concept of ectopic pacemaker and Stokes-Adams syndrome.
📌📌📌 Effect of Sympathetic and parasympathetic stimulation on the conduction system of heart, neuro transmitters which are released, ion-channels involved and membrane potential (whether there is hyperpolarization or depolarization), and how ventricular escape occurs.
🔴🔴🔴 Chapter 11:
▪️This chapter is essential for concept
building. Simply go through it.
▪️The difference between depolarization and repolarization waves.
▪️Relation of monophasic action potential of ventricular muscles with ECG
▪️You need to learn which wave occurs prior or due to which specific cardiac event.
▪️Why the repolarization wave for atria is missing
📌📌📌Voltage and time calibration of ECG(learn whole heartedly)
📌📌📌Voltage and time interval of a particular wave on ECG.
▪️Flow of current in chest around heart and their direction.
📌📌📌ECG leads:
Should know what is Einthovens triangle amd law.
Waveform(positive or negative) for aVR, aVL, aVF and V1 to V6, amplitude of lead I, II, III.
🔴🔴🔴 Chapter 13:
This chapter by far is the most important chapter as you have to apply your previous knowledge here.
P wave, The QRS complex, S wave, T wave, U wave, P-R interval, Q-T interval, R-R interval, S-T interval.
Have a look on development of respective waves and what the changes in these waves and intervals on ECG represent.
(for each condition see ECG provided)
▪️Tachycardia, causes.
▪️Bradycardia, causes.
📌📌 Bradycardia in athletes.
▪️Respiratory sinus arrythmia and effects on RR interval during inspiration and expiration.
Inspiration: Heart rate⬆️, RR interval ⬇️
Expiration: Heart rate⬇️, RR interval ⬆️
▪️Sinoatrial Block, effects, and changes on ECG
📌📌📌▪️Atrioventricular Block, causes, 1st, 2nd(Mobitz Type 1 and Mobitz type 2block) and 3rd degree AV block, and how to determine type of block from beat to dropped beats ratio, changes on ECG.
Mobitz Type I is also called Wenckebach Phenomenon
Mobitz Type II is also called John Hay/Hay phenomenon.
▪️Incomplete Intra ventricular block(special electrical alternans pattern)
📌▪️Premature atrial contraction and pulse deficit due to it.
▪️AV nodal and AV bundle premature contractions, premature ventricular contractions.
▪️LQTS, causes, (torsades de pointes, special feature on ECG), some people with LQT syndrome may get startled by a sudden noise.
⬆️risk factors for developing ventricular fibrillation,
treatment
▪️Atrial, AV nodal, ventricular paraoxysmal tachycardias(not so important
📌📌📌📌Ventricular fibrillation, causes, mechanism, ECG features, treatment
▪️Defibrillator
▪️CPR
📌📌Atrial Fibrillation and Atrial Flutter.
Try to digest this chapter slowly, you should have a strong grip on it.
Remember Team Cafeteria in your prayers ✨
