* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download General Principles Cardiac Cycle
Survey
Document related concepts
Cardiac contractility modulation wikipedia , lookup
Heart failure wikipedia , lookup
Coronary artery disease wikipedia , lookup
Lutembacher's syndrome wikipedia , lookup
Myocardial infarction wikipedia , lookup
Electrocardiography wikipedia , lookup
Aortic stenosis wikipedia , lookup
Hypertrophic cardiomyopathy wikipedia , lookup
Mitral insufficiency wikipedia , lookup
Atrial fibrillation wikipedia , lookup
Dextro-Transposition of the great arteries wikipedia , lookup
Arrhythmogenic right ventricular dysplasia wikipedia , lookup
Transcript
12/13/2010 Cardiovascular Physiology At end of this lecture you should be able to know: General principles of cardiac cycle Different events of cardiac cycle Mechanical events’ phases of cardiac cycle Correlation with ECG & heart sounds Volume changes in cardiac cycle Dr. Abeer A. AlMasri Pressure changes in cardiac cycle Complete picture correlating cardiac cycle events MBBS, MSc, PhD Assistant Professor Consultant Cardiovascular Physiologist College of Medicine, KSU 2 General Principles Cardiac Cycle Describing sequence of events (electrical & mechanical) that take place in the heart in each beat Blood flows from an area of high pressure to an area of low pressure Events on Rt & Lt sides of the heart are the Cardiac cycle duration = 0.8 sec … same, but pressures are lower on Rt side ■ When HR 75/min ■ Shortened when HR 4 3 Definitions Definitions … (Cont.) Systole = Phase of contraction Diastole = Phase of relaxation End-diastolic volume (EDV): Volume of blood in ventricle at end of diastole 110-120 ml o o Stroke volume (SV): Ventricular systole = 0.3 sec Ventricular diastole = 0.5 sec o Amt of blood ejected from each ventricle during systole 70 ml/beat o Atrial systole = 0.1 sec Atrial diastole = 0.7 sec Importance of ventricular diastole: 1. Coronary blood flow 2. Ventricular filling 6 1 Normally diastole is longer > systole 5 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Intra-cardiac Pressures Right Side Definitions … (Cont.) Left Side Right ventricle: End-systolic volume (ESV): Amt of blood left in each ventricle at end of systole 40-50 ml Left ventricular: 25-30/2-8 mmHg 100-120/3-12 mmHg Pulmonary artery: Aorta: 15-30/4-12 mmHg Ejection fraction (EF): 120/80 mmHg (mean press 9-18 mmHg) Right atrium: Fraction of end-diastolic volume that is ejected 60 % Left atrium: 2-10 mmHg 2-8 mmHg (pulmonary wedge press) 8 7 To study cardiac cycle: Mechanical Events: I: II: Ventricular Ventricular in diastole repeated systole next beat Volume changes III: Pressure changes IV: Heart sounds V: 10 Mechanical events Electrical events (ECG) 9 Mechanical Events: Phases of the cardiac cycle Cardiac cycle consists of 8 phases ■ Early ventricular diastole: 1. Protodiastole 2. Isometric relaxation phase 3. Rapid filling phase ■ Mid ventricular diastole: 4. Reduced filling phase ■ Late ventricular diastole: 5. Atrial systole Ventricular diastole ■ Ventricular systole: 1. Isometric contraction phase Ventricular systole 2. Rapid ejection phase 3. Reduced ejection phase 12 2 11 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Phases of cardiac cycle: 1. Atrial systole: At end of ventricular diastole AV-vs open, (semilunarvs closed) Tops off last 27-30% of ventricular filling Blood arriving heart can’t enter atrium, it flows back up jugular vein 14 13 Atrial Pressure Curve - Atrial Systole - ECG - Atrial Systole - "a" wave occurs, due to ↑ atrial press during atrial contraction P wave occurs, due to atrial depolarization In jugular venous pulse, " first wave" occurs due to back regurgitation of blood to jugular vein 16 15 Pressure & Volume Curve - Atrial Systole - Heart Sounds - Atrial Systole Associated with fourth heart sound (S4) S4 is abnormal ? Normal in elderly 18 3 17 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Phases of cardiac cycle: Atrial Pressure Curve - Isometric Contraction Phase - 2. Isometric contraction phase: At beginning of systole Period b/w closure of AV-vs & opening of semilunar- vs Lasts 0.04 sec Ventricle is a closed chamber, contract w/out change in volume Volume in ventricle is EDV Ascending limb (+ve) of“c" wave occurs: o ↑ atrial press as a result of RV contraction o Pushes TV into atrium (bulging of cusps) Ventricular press < aortic press Aortic v opens at end of this phase (when LV = 80mmHg) 20 Heart Sounds - Isometric Contraction Phase - 19 ECG - Isometric Contraction Phase - QRS complex occurs, due to ventricular First heart sound (S1, "lub") occurs, due to depolarization closure of AV vs & associated blood turbulence 22 Phases of cardiac cycle: 3. Maximum (rapid) ejection phase: 21 Pressure & Volume Curve - Isovolumetric Contraction Phase - Contraction of ventricle causes ventricular press to > aortic press Semilunar-vs open at beginning of this phase Volume of blood ejected = SV Ventricular volume rapidly 24 4 23 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Atrial Pressure Curve - Maximum (rapid) Ejection Phase - ECG - Maximum (rapid) Ejection Phase - Descending limb (–ve) of "c" wave occurs: o due to atrial press as a result of pulling down of AV No Deflections cusps by fibrous AV ring & ventricular contraction N.B. Atrial press gradually due to continuous VR 26 Pressure & Volume Curve - Maximum (rapid) Ejection Phase - 25 Heart Sounds - Maximum (rapid) Ejection Phase - None 28 27 Phases of cardiac cycle: ECG - Reduced Ejection Phase - 4. Reduced ejection phase: At end of systole Ventricular volume more slowly semilunar v close at end of this phase T wave occurs, due to ventricular Ventricular press < repolarization aortic press 30 5 29 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Pressure & Volume Curve - Reduced Ejection Phase - Heart Sounds - Reduced Ejection Phase - None 32 Phases of cardiac cycle: 31 Phases of cardiac cycle: 6. Isometric relaxation phase: 5. Protodiastolic phase: At beginning of diastole Period b/w end of ventricular cont action & aortic v closure Lasts 0.04 sec ventricular press < aortic press Aortic v closes by end of this phase as a result of back press (when LV press 110 mmHg) Atrial press still , due to continuous VR Period b/w closure of semilunar- vs & opening of AV-vs Lasts 0.04 sec LV is a closed chamber, i.e. relax w/out change in volume Volume of bl in ventricle = ESV LV relaxes w press AV-vs open at end of this phase 34 33 Atrial Pressure Curve - Isometric Relaxation Phase - ECG - Isometric Relaxation Phase - "v" wave occurs, due to back flow of blood hitting closed AV v No Deflections Ventricular press continues Atrial press gradually due to continuous VR on top of closed AV v 36 6 35 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Pressure & Volume Curve - Isometric Relaxation Phase - Heart Sounds - Isometric Relaxation Phase - Second heart sound (S2, "dup") occurs when semilunar (aortic & pulmonary) vs close S2 normally splits, as aortic v closes slightly earlier than pulmonary v 38 37 Phases of cardiac cycle: ECG - Rapid Filling Phase - 7. Rapid filling phase: Atrial press > ventricular press AV-vs open 60-70% of blood passes passively to ventricles along press gradient No Deflections Ventricular volume rapidly 40 39 Pressure & Volume Curve - Rapid Filling Phase - Heart Sounds - Rapid Filling Phase - Third heart sound (S3) occur, due to rapid passive ventricular filling S3 is usually abnormal ? Normal in children 42 7 41 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology ECG - Reduced Filling Phase - Phases of cardiac cycle: 8. Reduced filling phase (Diastasis): Remaining atrial blood flows slowly into ventricles AV-vs still open LV volume > slowly No Deflections 44 43 Pressure & Volume Curve - Reduced Filling Phase - Heart Sounds - Reduced Filling Phase - None Aortic closes Aortic opens Mitral opens Mitral Closes S4 S1 S2 45 Atrial Systole Reduced Ventricular Filling Isovolumic Relax. Rapid Ventricular Filling Reduced Ejection Rapid Ejection Atrial Systole Isovolumic contract. 46 The Complete Picture Correlation of events in cardiac cycle S3 48 8 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Correlation of events in cardiac cycle 50 Phase Ventricular volume 1. 2. 3. 4. Atrial systole Isometric contraction phase Rapid ejection phase Reduced ejection phase 5. 6. 7. 8. Protodiastole Isometric relaxation phase Rapid filling phase Reduced filling phase Constant rapidly slowly Constant Constant rapidly slowly 49 Cardiac Cycle 52 Aortic pressure Arterial pressure waves Pulmonary artery pressure Atrial pressure Jugular venous pulse wave Cardiac Cycle 54 9 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Pressure changes: 1. Aortic pressure changes … 120/80 a. Ascending or anacrotic limb: = diastolic P + 1/3 (systolic P - diastolic P) with max ejection phase Aortic press up to 120 mmHg b. Descending or catacrotic limb: with reduced ejection phase Passes in 4 stages Pressure changes: 1. Aortic pressure changes … 120/80 Pulse pressure = Systolic P – Diastolic P 56 Clinical significant of aortic pressure changes: 55 Descending or catacrotic limb: Passes through 4 stages ♥ Aortic Stenosis 1. Aortic press: ■ Amt of blood enters aorta < leaves ♥ Shock or dehydration 2. Dicrotic notch (incisura): = Sudden drop in aortic press ♥ Aortic Regurgitation ♥ Hypertension ♥ Pregnancy ■ Due to sudden closure of aortic v ■ At end of protodiastole phase 3. Dicrotic wave: = Slight in aortic press ■ Due to elastic recoil of aorta 4. Slow aortic press: up to 80 mmHg ■ Due to continued flow of blood from aorta systemic circulation 58 Pressure changes: 3. Pulmonary artery pressure changes … 21-25/5-10 57 Pressure changes: 2. Arterial pressure changes … 110-130/70-90 Similar to aortic press changes but with difference in magnitude Similar to aortic press waves but sharper Reflects a systolic peak press of 110-130 mmHg & a diastolic press of 70-90 mmHg 60 10 59 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Pressure changes: 4. Atrial pressure changes: Causes of atrial pressure waves: ‘a’ wave: Atraial systole x ‘c’ wave: Ventricular sytole o +ve bulging of TV into RA during isovolumetric contraction phase o -ve pulling of atrial ms during ventricular contraction y Results in: 3 upward deflection a, c, & v o 2 components in each wave: +ve ( press), -ve ‘v’ wave: Atrial diastole or VR … RA press due to filling of atrium w blood ( press) 2 downward deflection x & y The 3 wave (a, c, & v) are equal to ONE cardiac cycle = 0.8 sec 62 61 Pressure changes: 5. Jugular venous pulse changes: x Causes of atrial pressure waves … (Cont.) ‘x’ descent: Downward displacement of TV during rapid ejection phase y ‘y’ descent: Rapid blood flow from RA to RV ‘a-c’ interval: ■ Measured from the start of ‘a’ wave to start of ‘c’ wave Also results in: ■ Indicates time of conduction of excitation waves ■ 3 upward waves: a, c, & v ■ 2 downward waves: x & y through AV node & bundle ■ Corresponds to P-R interval of ECG 64 63 Detected over anterior chest wall by: ■ Stethoscope, (auscultation) Cardiac Cycle ■ Phonocardiography, (sound recording device) 66 11 Dr. Abeer AlMasri, Faculty of Medicine, KSU 12/13/2010 Cardiovascular Physiology Different Heart Sounds Cause C-cycle Duration Frequency S1 S2 S3 S4 Sudden closure of AV-vs Sudden closure of semilunar vs Rush of bl during rapid vent filling vibration of vent ms. Vibration produced by cont of atrial ms (attributed to vent filling) Marks beginning of vent systole (Isovolumetric cont) 0.15 sec (Longer) 0.11-0.125 sec (Shorter) 25-35 Hz 50 Hz Low pitch (LUB) Character Best heard Marks beginning of vent diastole (When vent press fall below arterial press) (Louder) M& T Max vent filling phase of diastole 0.05 sec ‘4’ heart sounds: Atrial systole (just before 1st HS) 0.04 sec Important for diagnosis of valvular heart diseases (murmurs) High pitch (DUB) (Softer, sharper) Split into 2 sounds during inspiration = Physiological splitting (due to delay closure of pulm v). A & P Usually not audible Usually not audible (Rarely heard) M M 68 Thank You 12 ■ 1st & 2nd ht sounds … (usually heard) ■ 3rd & 4th ht sounds … (sometimes detected) 67 69 Dr. Abeer AlMasri, Faculty of Medicine, KSU