Cardiac Cycle Notes (PDF)

Cardiac Cycle Med_students0 Objectives: By the end of this lecture, you should : ❑Describe events in cardiac cycle. ❑Describe atrial, ventricular and aortic pressure changes during cardiac cycle. ❑Describe the changes in ventricular volume & stroke volume during cardiac cycle....

Cardiac Cycle Med_students0 Objectives: By the end of this lecture, you should : ❑Describe events in cardiac cycle. ❑Describe atrial, ventricular and aortic pressure changes during cardiac cycle. ❑Describe the changes in ventricular volume & stroke volume during cardiac cycle. Med_students0 ❑Relate ECG changes to the phases of cardiac cycle. ❑Describe the functions of cardiac valves and relate their state to the production of heart sounds during cardiac cycle. References: Textbook of Medical Physiology by Guyton 12th ed. Pages: 104-107.  THE CARDIAC CYCLE Definition: ❑ It is the cardiac events that occur from the beginning of one heart beat to the beginning of the next beat. ❑ These events consists of periods of contraction called "systole" and a period of relaxation called "diastole". Duration: ❑ Assuming a heart rate of 75 beat/min. the average duration of each cycle is 0.8 (60 / 75) second. Phases of the cardiac cycle: I- Atrial systole. (during which the ventricle is relaxed) II- Ventricular systole, (during which the atrium is relaxed) III- Ventricular diostole, (during which the atrium is relaxed) (i.e., relaxation of the whole heart). Med_students0 Phases of the cardiac cycle: I- Atrial systole. (during which the ventricle is relaxed) II- Ventricular systole, (during which the atrium is relaxed) It occurs in 3 phases : a- Isometric (or isovolumetric) contraction phase. b- Maximum ejection phase. c- Reduced ejection phase. III- Ventricular diostole, (during which the atrium is relaxed) (i.e., relaxation of the whole heart). It occurs in 3 phases: a- Isometric (or isovolumetric) relaxation phase. b- Rapid filling phase. c- Reduced filling phase.  I- Atrial Systole Duration 0.1 second Increases temporarily from zero to 2 mmHg due to atrial contraction. By the end of this phase, the pressure returns back to zero due to relaxation of the atrium and evacuation of blood into the ventricles. Atrial pressure The constriction of the circular muscle sleeve present around the orifices (openings) of the superior and inferior venae cavae and pulmonary veins prevents blood regurgitation into these veins. A-V valve opened ↑slightly due to rush of blood from the atria, then Intraventricular pressure. decreases again as the ventricles are still relaxed (it dilates).  I- Atrial Systole Increases slightly due to entry of blood from Ventricular volume. the atria into the ventricles. Semilunar valves closed Decreases gradually due to continuous Aortic pressure flow of blood into the peripheral circulation. The 4th heart sound occurs in this phase. Heart sounds. This sound is normally inaudible, but can be recorded by the phonocardiogram. Electrocardiogram (ECG). The P wave starts 0.02 second before atrial systole.  II- Isometric contraction phase Duration 0.05 second Shows slight, but sharp increase due to sudden closure of AV valve and ballooning of its cusps Atrial pressure towards the cavity of the atrium by the sudden rise of intraventricular pressure. A-V valve Closes suddenly As ventricular systole starts, the Ventricular pressure very rapidly exceeds the atrial pressure, leading to sudden closure of the AV valves. Now, all the valves are closed and the ventricle Intraventricular pressure becomes as a closed chamber. So, the ventricle contract isometrically. i.e without change in the length of the muscle fibers. Intraventricular pressure↑ from zero to 80 mm Hg in the left ventricle.  II- Isometric contraction phase Ventricular volume. No change Semilunar valves Still closed Is still decreasing and the aortic valve is Aortic pressure still closed. Early part of the 1st heart sound is present which is mainly due to sudden closure of Heart sounds. AV valves. The Q wave starts 0.02 second before this Electrocardiogram (ECG). phase, and the remaining part of the Q R S complex occurs during it. Med_students0  III- Maximum Ejection Phase IV- Reduced Ejection Phase Duration 0.15 second 0.1 second Shows a sharp decrease followed by Shows gradual increase due to gradual increase. The decrease is due continuous accumulation of to shortening of ventricular muscle venous return. (by systole), pulling down the AV ring, increasing atrial capacity and so decreasing the atrial pressure. The Atrial pressure gradual increase of atrial pressure is due to: - Accumulation of venous blood in the atria. - Upward displacement of AV ring to its normal position. A-V valves Remain closed Remain closed ↓rapidly due to ejection of Still ↓ing. Ventricular most of ventricular blood into volume the aorta.  III- Maximum Ejection IV- Reduced Ejection Phase Phase Markedly ↑ as a result of Slightly ↓ due to reduced continuous contraction of force of pumping of blood Intraventricular ventricular muscle. The into aorta. pressure ventricular pressure is slightly higher than the aortic pressure. Semilunar opened Still opened valves Is increased due to ejection of Drops slightly because the blood blood from the left ventricle. leaving the aorta to the peripheral The amount of blood entering circulation is greater than the the aorta exceeds the amount blood pumped into the aorta from Aortic pressure leaving it to the peripheral the ventricle. circulation. So, the aortic pressure increases, but remains lower than the ventricular pressure.  III- Maximum Ejection IV- Reduced Ejection Phase Phase 1st Heart sound No sounds are produced continues, due to continuous flow of Heart sounds. blood from the ventricles to the aorta causing vibration of its walls The T wave starts in The top of T wave Electrocardiogram the late part of this (ECG) phase Med_students0  V- Isometric Relaxation Phase Duration 0.06 second Atrial pressure Still increasing due to continuous venous return A-V valve Remain closed ↓rapidly. The ventricle is now a completely closed chamber. So, it relaxes isometrically i.e Intraventricular without changing the length of its muscle pressure. fibers. Therefore, there is no change in volume but the pressure rapidly falls towards the zero line. Ventricular volume. No change  V- Isometric Relaxation Phase Aortic pressure Shows an initial sharp decrease due to sudden closure of the aortic valve, called the “diacrotic notch”. This is followed by secondary rise of pressure due to the elastic recoil of the aorta. It is called the “diacrotic wave”. semilunar valves Closes suddenly Heart sounds. The 2nd heart sound is present, due to sudden closure of the aortic valve. Electrocardiogram T wave ends during this phase. (ECG).  VII- Reduced Filling VI- Rapid Filling Phase Phase Duration 0.1 second 0.2 second At the beginning of this phase, Around zero or still increasing atrial pressure is more than the due to continuous venous ventricular pressure leading to return. opening of the AV valve and Atrial pressure rushing of blood by its weight into the relaxed ventricle. This leads to rapid ventricular filling and decrease in the atrial pressure. (A-V) valve opened Still opened Intraventricular Around zero Around zero line but pressure. below atrial pressure. Marked ↑ due to rapid gradual increase Ventricular volume ventricular filling with blood from the atria.  VII- Reduced Filling VI- Rapid Filling Phase Phase Aortic pressure Gradually decreases due to still decreasing. continuous escape of blood to the peripheral circulation. State of semilunar closed Still closed valves Heart sounds. The 3rd heart sound is No sound is present present Electrocardiogram U wave may be P wave, for the next (ECG). present cardiac cycle begins. N.B.: Systolic B.P. in the left ventricle = 130 mmHg Diastolic B.P in the left ventricle = zero Systolic B. P. in the right ventricle = 35 mm Hg Diastolic B. P. in the right ventricle = zero Systolic B. P. in the aorta = 120 mm Hg Diastolic B. P. in the aorta = 80 mm Hg Systolic B. P. in pulmonary artery = 30 mm Hg Diastolic B. P. in pulmonary artery = 10 mm Hg Med_students0 Cardiovascular system Protected by the pericardium Inner layer: epicardium Chambers 4 2: atrium 2: ventricles Blood´s path Superior vena cava Inferior vena cava The heart’s rhythm Contractions of the heart occur in a rhythm Regulated by impulses that begin at the sinoatrial node (SA) (pacemaker) Atrioventricular node (AV) Bundle of His Trough the Purkinge fibers(ventricular contaction)  Autonomic nervous system Parasympathetic division Acts on the SA and AV nodes Slows heart rate Reduces impulse conduction Dilates coronary arteries Sympathetic división Acts on the SA and AV nodes Increases heart rate and impulse conduction Constricts and dilates the coronary arteries Cardiac cycle ✓ The period from the beginning of one heart beat to the beginning of the next ✓ Provide adequate blood flow to all body parts ✓ Two phases: Systole: period when the ventricles contract Diastole: when the heart relaxes Vascular network… Veins Carry blood toward the heart Carry oxygen- depleted blood (*pulmonary vein)  Vital signs The physiologic condition of a patient Pulse and blood presure are directly related to the cardiovascular system Pulse: expansion and contraction of an artery in a regular, rhythmic pattern  Blood pressure ♡ Influenced by the volumen of blood, the lumen of the arteries and arterioles, and the force of the cardiac contraction ♡ 120/80 mmHg ♡ Systolic blood pressure: 120 ♡ Diastolic blood pressure: 80 Tools of the trade Sphygmomanometer Stethoscope  Physical examination  Inspection: cyanosis, pallor, diaphoresis  Palpation: edema  Auscultation: murmur, blowing, fluttering and bruit  Diagnostic tests  Blood tests: PTT (partial thromboplastin time), CK (creatine kinase), cardiac troponin.  Radiologic tests: cardiac catheterization, angiocardiography, agiography, radionuclide scan, thellium stress test  Electrophysiologic studies  Pericardiocentesis  Transesophageal echocardiography Noninvasive tests  Electrocardiogram  Echocardiography Disorders  Cardiac arrhythmias  Congenital heart defects  Degenerative disorders  Inflamatory heart disease  Vascular disorders  Valvular heart disease  Cardiac arrhythmias  Atrial flutter  Bradycardia  Fibrillation  Heart block  Paroxysmal atrial tachycardia  Premature atrial contraction  Premature ventricular contraction  Tachycardia  Ventricular tachycardia  Congenital heart defects  Atrial septal defect  Coarctacion of the aorta  Patent ductus arteriosus  Tetralogy of fallot  Ventricular septal defect  Degenerative heart conditions  Coronary artery disease  Dilated cardiomyopathy  Heart failure  Hypertension  Hypertrophic cardiomyopathy  Heart attack  Restrictive cardiomyopathy Inflamatory heart disease  Endocarditis  Myocarditis  Pericarditis  Rheumatic fever Vascular disorders  Arterial occlusive disease  Raynaud’s disease  Thrombophlebitis  Aneurysm (abdominal aorta, thoracic aorta, saccular, fusiform, dissecting and false) Valvular disorders  Stenosis (aortic, mitral, tricuspid)  Insufficiency (aorta, mitral, tricuspid and pulmonary valve)  Treatments Drug therapy:  Adrenergics  ACEI’s  Antianginal  Antiarrhythmics (vaughan william’s)  Antihypertensives  Beta-adrenergic blockers  Calcium channel blockers  Cardiac glycosides  Diuretics  Thombolytic therapy Surgery  Ablation  Cardiac conduction surgery  Coronary artery bypass graft  Heart transplantation  Other treatments  Advanced cardiac life support  Cardiopulmonary resuscitation  Defibrillation  Implantable cardioverter-defibrillator  Intra-aortic balloon counterpulsation  Laser-enhanced angioplasty  Pacemarkers  Percutaneous translimunal coronary angioplasty  Stent  Synchronized cardioversion  Valve replacement surgery  Ventricular assist device Basic EKG Cardiac Anatomy  Cardiac Cycle Step 1: Rapid filling of ventricles Ventricular pressure drops below atrial pressure AV valves are open, semilunar valves are closed Rapid ventricular filling occurs 70-90% of the ventricles fill with blood  Cardiac Cycle Step 2: Atrial systole P wave occurs Atrial contraction Pushed 10-30% more blood into ventricle  Cardiac Cycle Step 3: Isovolumetric contraction QRS just occurred Contraction of the ventricles causes ventricular pressure to rise above atrial pressure, AV valves close Ventricular pressure is still less than aortic pressure Semilunar valves are closed Volume of blood in the ventricle is EDV  Cardiac Cycle Step 4: Ejection Contraction of the ventricles causes ventricular pressure to rise above aortic pressure, Semilunar valves open Ventricular pressure is still greater than atrial pressure AV valves are still closed Volume of blood ejected by the ventricles: stroke volume (SV)  Cardiac Cycle Step 5: T-wave occurs Ventricular pressure drops below aortic pressure Back pressure causes semilunar valves to close  Cardiac Cycle Step 6: Isovolumetric relaxation AV valves are still closed Semilunar valves are still closed Volume of blood in ventricles: ESV  QRS P T The Limb Leads The Precordial Leads The Precordial Leads  Sequence of ECG Interpretation 1. Rate 2. Rhythm 3. Axis 4. Hypertrophy 5. Infarction 6. Injury 7. Ischemia  Interpretation Sequence Check the patient details - is the ECG correctly labelled? What is the rate? Is this sinus rhythm? If not, what is going on? What is the mean frontal plane QRS axis (You may wish at this stage to glance at the P and T wave axes too) Are the P waves normal (Good places to look are II and V1) What is the PR interval?  Interpretation Sequence Are the QRS complexes normal? Specifically, are there: – significant Q waves? – voltage criteria for LV hypertrophy? – predominant R waves in V1? – widened QRS complexes? Are the ST segments normal, depressed or elevated? Quantify abnormalities. Are the T waves normal? What is the QT interval? Are there abnormal U waves?  What is the Rate? Identify an R wave that falls on the marker of a `big block' Count the number of big blocks to the next R wave. 300 / # of big squares or 300, 150, 100, 75, 50 sequence 1500 / # of small squares What is the Rate? What is the Rate?  Step 2. What is the Rhythm? Sinus? Junctional? Ventricular? Pacemaker? AF? VF? Junctional or AV Nodal Rhythm Step 3. What is the QRS Axis?  Frontal QRS Axis Extreme RAD Left axis NW axis deviation Right axis Normal axis deviation Using leads I and aVF the axis can be calculated to within one of the four quadrants at a glance.  The QRS Axis Normal axis : both I and aVF (+) Right axis deviation : lead I (-) and aVF (+) Left axis deviation: lead I (+) and aVF (-) Northwest Territory : both I and aVF (-)  Causes of left axis deviation Left ventricular hypertophy Inferior myocardial infarction Artificial cardiac pacing Emphysema Hyperkalemia Wolff-Parkinson-White syndrome - right sided accessory pathway Tricuspid atresia Ostium primum ASD  Causes of right axis deviation Normal finding in children and tall thin adults Right ventricular hypertrophy Chronic lung disease even without pulmonary hypertension Anterolateral myocardial infarction Left posterior hemiblock Pulmonary embolism Wolff-Parkinson-White syndrome - left sided accessory pathway Atrial septal defect Ventricular septal defect  Causes of a Northwest axis Emphysema Hyperkalemia Lead transposition Artificial cardiac pacing Ventricular tachycardia Step 4. Check the P-R Interval for AV blocks  Second Degree AV Block Mobitz Type I (Wenckebach) Mobitz Type II  Causes of AV Blocks Autonomic Drug-related Carotid sinus Beta blockers hypersensitivity Adenosine Ca channel blockers Metabolic/endocrine Hyperkalemia Antiarrhythmics Hypothyroidism (class I & III) Hypermagnesemia Digitalis Adrenal insufficiency Lithium  Causes of AV Blocks Infectious Heritable/congenital Endocarditis Congenital heart disease Tuberculosis Maternal SLE Lyme disease Kearns-Sayre syndrome Diphtheria Emery-Dreifuss MD Chagas disease Myotonic dystrophy Toxoplasmosis Progressive familial heart Syphilis block  Causes of AV Blocks Inflammatory Neoplastic/traumatic SLE Lymphoma MCTD Radiation Rheumatoid arthritis Mesothelioma Scleroderma Catheter ablation Infiltrative Melanoma Amyloidosis Hemochromatosis Degenerative Sarcoidosis Lev disease Coronary artery disease Lenègre disease Acute MI  Step 5. Look for Ectopic beats Atrial? Ventricular? Step 6. Is there Chamber Enlargement?  Left atrial enlargement a. P wave duration equal or more than 0.12 sec. b. Notched, slurred P wave in lead I and II (P mitrale). c. Biphasic P wave in lead V1 with a wide deep and negative terminal component.  Right atrial enlargement a. P wave duration equal or less than 0.11 sec. b. Tall, peaked T wave equal or more than 2.5 mm in amplitude in lead II,III or aVF (P pulmonale). c. Mean P wave axis shifted to the right (more than +70 degrees). Ventricular Hypertrophy Left Ventricular Hypertrophy  Left ventricular enlargement a. "Voltage criteria": 1. R or S wave in limb lead equal or more than 20mm 2. S wave in V1,V2 or V3 equal or more than 30mm 3. R wave in V4,V5 or V6 equal or more than 30mm. b. Depressed ST segment with inverted T waves in lateral leads(strain pattern ;more reliable in the absence of digitalis therapy. c. Left axis of -30 degree or more. d. QRS duration equal or more than 0.09 sec. e. Time of onset of the intrinsicoid deflection ( time from the beginning of the QRS to the peak of the R wave ) equal or more than 0.05 sec in lead V5 or V6.  Right ventricular enlargement a. Tall R waves over the right precordium and deep S waves over the left precordium ( R:S ratio in lead V1 > 1.0) b. Normal QRS duration (if no bundle branch block) c. Right axis deviation. d. ST-T "strain" pattern over the right precordium. e. Late intrinsicoid deflection in lead V1 or V2. Step 7. Examine QRS Duration  Left bundle branch block a. QRS duration equal or more than 0.12 sec. b. Broad , notched or slurred R wave in lateral leads( I, aVL , V5,V6 ) c. QS or rS pattern in the anterior precordium. d. Secondary ST-T wave changes ( ST and T wave vectors are opposite to the terminal QRS vectors). e. Late intrinsicoid deflection in lead V5 and V6.  Right bundle branch block a. QRS duration equal or more than 0.12 sec. b. Large R' wave in lead V1( rsR' ). c. Deep terminal S wave in lead V6. d. Normal septal Q wave. e. Inverted T wave in lead V1 ( secondary T wave changes ). f. Late intinsicoid deflection in lead V1 and V2. Step 8. Look for ST Segment Abnormalities Localization of Infarction Localization of MI with the help of EKG Anterior wall V1 through V6 Anteroseptal V1 through V3 Inferior II, III, aVF Right ventricular V4R, V3R Posterior wall V7 through V9 V1 through V3 ( ST depression) Thank you for not sleeping! CARDIAC OUTPUT - I  OBJECTIVES ◼ Definition. ◼ Measurement of cardiac output. ◼ Variations in cardiac output. ◼ Regulation of cardiac output. ◼ Heart lung preparation. ◼ Cardiac & vascular function curves. Thursday, October 3, 2024 Some Facts……… ❖ Is about 4.8 inches tall and 3.35 inches wide ❖ Weighs about.68 lb. in men and.56 lb. in women ❖ Beats about 100,000 times per day ❖ Beats 2.5 billion time in an average 70 yr. lifetime ❖ Pumps about 2000 gallons of blood each day ❖ Circulates blood completely 1000 times each day ❖ Pumps blood through 62,000 miles of vessels ❖ Suffers 7.2 mil. CAD deaths worldwide each year Thursday, October 3, 2024  DEFINITION. ◼ Amount of blood ejected by each ventricle per minute. ◼ CO = SV * HR….. ◼ SV – Stroke Volume. ◼ HR – Heart rate. ◼ Cardiac output ◼ 80 * 70 = 5.6 L/min. Thursday, October 3, 2024  SIGNIFICANCE ◼ It’s the cardiac output that decides the rate of blood flow to the different parts of the body. ◼ Decrease in cardiac output ◼ Decrease in blood flow Thursday, October 3, 2024  RELATIONSHIP OF CARDIAC OUTPUT & VENOUS RETURN ◼ VENOUS RETURN ◼ It is the quantity of blood returned from all over the body through the veins into the right atrium each minute ◼ Venous return = cardiac output Thursday, October 3, 2024  Components……. ◼ Stroke volume ◼ Amount of blood pumped by each ventricle per beat or per contraction. ◼ 80 ml. ◼ Stroke volume depends on – ◼ End diastolic volume ◼ contractility Thursday, October 3, 2024 Components……. ◼ Heart rate ◼ Under normal circumstances 70 times/min. ◼ Increase in heart rate increases Cardiac output… but upto limit ◼ After it decreases due to decrease in Cardiac filling. Thursday, October 3, 2024  MINUTE VOLUME It is the amount of blood pumped out by each ventricle per minute. MINUTE VOLUME = Stroke volume x HR Normal value: 5litres/ventricle/minut e. Thursday, October 3, 2024  CARDIAC INDEX. ◼ Cardiac output is the amount of blood pumped out per ventricle per minute per square meter of body surface area. ◼ Expressed in relation to the body surface area. ◼ Normal value – 3.2L/min/m2 Thursday, October 3, 2024  CARDIAC RESERVE. ◼ Maximum increase in ◼ Normal values. the cardiac output ◼ Adults – 300-400% above the normal value. ◼ Old age – 200-250% ◼ Expressed in ◼ Athletes – 500-600% Percentage. ◼ Variations ◼ Maximum – Heavy exercise. ◼ Minimum – Cardiac diseases. Thursday, October 3, 2024  MEASUREMENT OF CARDIAC OUTPUT. ◼ Methods based on Fick’s principle ◼ Indicator or dye dilution method. ◼ Thermodilution ◼ Inhalation of inert gases. ◼ Physical methods ◼ Doppler echocardiography. ◼ Ballistocardiography. ◼ Cineradiographic technique. Thursday, October 3, 2024  METHODS BASED ON FICK’S PRINCIPLE ◼ Fick’s principle – ◼ Q = (A-V) F Amount of substance taken up by an organ ◼ F= Q per unit of time (Q) is equal to the arterial ------- level of the substance (A-V) (A) – venous level of ◼ 2 methods substance (V) × Blood ◼ Direct flow(F) ◼ Indirect Thursday, October 3, 2024  METHODS BASED ON FICK’S PRINCIPLE Thursday, October 3, 2024  DIRECT METHOD. ◼ Principle – pulmonary ◼ Amount of O2 taken blood flow = Rt determined by ventricular blood flow = Lt spirometer. ventricular blood flow. ◼ PVO2 – from any ◼ Pulmonary blood flow = peripheral artery amount of O2 taken by ◼ PAO2 – from lungs pulmonary artery. ------------------------------- PVO2-PAO2 Thursday, October 3, 2024  DIRECT METHOD. ◼ Pulmonary blood flow = ◼ Disadvantages. amount of O2 taken by ◼ Invasive, risk of lungs infection & ------------------------------- hemorrhage. PVO2-PAO2 ◼ Pt is conscious so CO is ◼ CO = 2000/ (200-160) × more than normal 100 ◼ Complications – ◼ CO = 5000ml/min ventricular fibrillations. Thursday, October 3, 2024  DIRECT METHOD. Thursday, October 3, 2024  INDIRECT METHOD. ◼ Same as direct ◼ CO = CO2 output/min method only ---------------------- ◼ CO2 excretion by lungs PACO2-PVCO2 is measured by spirometry. ◼ PACO2 from alveolar air. ◼ PVCO2 – Rebreathing into closed bag. Thursday, October 3, 2024  INDICATOR OR DYE DILUTION METHOD. ◼ Principle – Known ◼ F = blood flow in amount of dye injected L/min. into Rt atrium & mean ◼ Q= quantity of dye concentration of its injected. first passage through ◼ C = Mean Conc. of dye. an artery is determined. ◼ T = Time duration in sec of first passage of ◼ Blood flow (F)= Q/Ct dye. Thursday, October 3, 2024  IDEAL INDICATOR. ◼ Should be nontoxic. ◼ Mix evenly. ◼ Easy to measure. ◼ Not alter cardiac output or haemodynamic. ◼ Not be changed by body. ◼ E.g. Evan’s blue, radioactive isotopes. Thursday, October 3, 2024  PROCEDURE. ◼ 5 mg of Evan’s blue dye mixed with venous blood. ◼ Duration of first passage of dye(t) & mean conc of dye (C) in arterial blood estimated. ◼ CO= Q/ct × 60 = 5/1.5L ×40 × 60 = 5 L/min Thursday, October 3, 2024  THERMODILUTION ◼ PRINCIPLE – same as indicator dye dilution method except cold saline is used. ◼ Resultant change in blood temperature in pulmonary artery is determined. Thursday, October 3, 2024  INHALATION OF INERT GASES. ◼ NO, Acetylene – used. ◼ Pulmonary blood flow is determined from following values ◼ Quantity of gas absorbed in given time. ◼ Partial pressure of gas in alveolar air. ◼ The solubility of gas. Thursday, October 3, 2024  PHYSICAL METHODS ◼ Doppler echocardiography – ◼ Ultrasonic evaluations of cardiac functions. ◼ B-scan ultrasound at a frequency of 2.25 MHz using a transducer. ◼ Measure EDV, ESV,CO & Valvular defects. Thursday, October 3, 2024 Thursday, October 3, 2024  PHYSICAL METHODS ◼ Ballistocardiography ◼ Graphical record of the pulsations created due to ballistic recoil of the pumping heart. Thursday, October 3, 2024  PHYSICAL METHODS ◼ CINERADIOGRAPHIC TECHNIQUE. ◼ The making of a motion picture record of successive images appearing on a fluoroscopic screen. ◼ Radiography of an organ in motion, for example, the heart, the gastrointestinal tract. Thursday, October 3, 2024  VARIATIONS IN CARDIAC OUTPUT. ◼ Physiological causes. ◼ Anxiety excitement, ◼ Age – CI children > Eating, Exercise, adult. Pregnancy, High altitude – direct ◼ Sex – females > Males relation. ◼ Diurnal variations- ◼ Posture change – low in early morning. sitting or standing > ◼ Environmental lying down due to temperature – direct venous pooling. relation. Thursday, October 3, 2024  VARIATIONS IN CARDIAC OUTPUT. ◼ Pathological – its mainly due to low peripheral resistance ◼ Increase ◼ Fever ◼ Anemia. ◼ Hyperthyroidism. ◼ Beriberi ◼ Arteriovenous fistula Thursday, October 3, 2024  VARIATIONS IN CARDIAC OUTPUT. ◼ Decrease ◼ CCF ◼ Rapid arrhythmias ◼ Cardiac shock ◼ Incomplete heart block ◼ Hemorrhage ◼ Hypothyroidism. Thursday, October 3, 2024  Thank you. Thursday, October 3, 2024 LYMPHATIC SYSTEM WHAT IS LYMPHATIC SYSTEM?  The lymphatic system is part of the circulatory system and an important part of the immune system, comprising a network of lymphatic vessels that carry a clear fluid called lymph (fromLatin, lympha meaning"water”)directionally towards the heart. Functions of lymphatic system  Components of Lymphatic System 1. Lymph 2. lymph capillaries 3. Lymphatic vessels 4. Lymphoid organs a) Lymph nodes b) spleen c) Thymus 5. Epithelio- Lymphoid system 6. Bone marrow lymph  The tissue fluid that enters the lymph capillaries.  Lymph composition  The composition of lymph is similar to that of plasma but the constituents have some additional substances that are too large to pass through blood capillary walls. The lymph transport plasma protein that seeps out of capillary beds back to blood stream  It also carries away larger particles eg. bacteria cell debris which is then filterd out and destroyed by lymph nodes.  Thus the lymph contains:  Lymphocytes  Macromolecules of protein  Fat droplets  Particulate matter  Lymph Fluid Lymph is formed when high arterial pressure forces fluid out of the capillaries and into the tissue. *About 30lt of fluid passes from arterial end of capillaries into intercellular space every day. Out of this ,about 27lt of fluid consisting of micromolecules are absorbed back by venous end of the capillaries.the remaining 3lt of fluid consisting of macromolecules is absorbed by lymph capillaries. Lymph Capillaries  Microscopic blind-ended lymph vessels which begin in the intercellular spaces.  They form vast network in intercellular spaces of most of the tissues of the body.  The wall of lymph capillaries are made of single layer of endothelial cells.  The lymph capillaries are different from blood capillaries in following respect: 1. Begin blindly in intercellular spaces 2. Have bigger lumen which is less regular 3. Are permeable to bigger molecules.  The sites where lymph capillaries are absent 1. Epidermis 2. Hair 3. Nails 4. Cornea 5. Articular cartilage 6. Brain and spinal cord 7. splenic pulp LYMPH VESSELS  Lymph capillaries unite to form lymphatic vessels.  Thin walled vessels.  Beaded appearance.  Flow of lymph in lymphatic vessel is unidirectional.  The lymphatic vessels pass through a series of l.node before lymph is drained into venous system. Clinical correlation  Lymphangitis  Elephantiasis Lymphatic ducts Thoracic duct  What is duct? A duct is a circumscribed channel leading from an organ.  Length-45cm  Ascends through the diaphragm and passes upwards in the thoracic cavity. It drains Lymph from  Lower extremites  abdomen  Left Thoracic region  Left side ofHead & Neck  Left upper Limbs. THE RIGHT LYMPHATIC DUCT  IT LIES IN THE ROOT OF THE NECK AND OPEN INTO RIGHT SUBCLAVIAN VEIN.  IT DRAINS LYMPH FROM 1. RIGHT THORACIC REGION 2. RIGHT SIDE OF HEAD AND NECK 3. RIGHT UPPER LIMB Structure of lymphatic duct  Like wall of veins , the wall of lymphatic ducts have same three layers, ie tunica adventitia, tunica media and tunica intima.  Lumen of LD.contains valves which are numerous and closely packed than veins.  The lumen of vessel proximal to the valve is expanded into a sinus.  The valves are so closely paced that l.vessels when filled with lymph has a beaded appearance. Superficial and deep lymph vessels  According to location lymph vessels are divided into two types:- 1. Superficial lymph vessels 2. Deep lymph vessels Drainage of lymph  Contraction of smooth m/s in the wall of the lymph vessel  Pulsation of arteries near the lymph vessels.  Massaging action from contraction of surrounding muscles.  Respiratory movements  Negative pressure in brachiocephalic vein  Valves within lumen of lymph vessels. Lymphoid Organs  Lymphoid organs are made up of lymphatic tissues.  The lymphatic tissue is a specialized connective tissue and consist of: 1. Framework of reticular fibers and reticular cells 2. Lymphocytes and related plasma cells and macrophages.  The lymphoid organs are classified into following two types:  Primary L.O.- which are involved in the production of lymphocytes.  secondaryL.O.-which are involved in activation of lymphocytes and initiation of an immune response. LYMPH NODES  Lymph nodes are bean shaped organs along with course of lymph vessels  Up to 1 inch in size  Lymph passes through a number of lymph nodes before reaching the large lymphatic duct.  These nodes are considerably in size: some are as small as a pin head & the largest are about the size of an almond.  They are pink in living body and brownish in cadaver. Lymph node contd..  Structure l.Node are oval in shape They present a slight depression on side k/a HILUM. Each lymph node consists of fibrous capsule and gland substance  Below the capsule is sub capsular substance.  The gland sustance is divided into 1. The outer portion is called cortex. 2. The inner portion is called medulla. Lymph node contd.. Functions 1. Filtration of lymph 2. Evoke immunological response(the plasma cells of lymph node produce anti bodies in response to action) 3. Produce lymphocytes(the germinal center of lymphatic nodules within the node are site of lymphocyte production) 4. provide portal of entry of lymphocytes into lymphatic channels.  SPLEEN This is the largest lymphoid organ,posterior to the stomach SPLEEN STRUCTURE  (spleen is about the size of a fist).  a. Capsule  b. Trabeculae  c. Red pulp  d. White pulp WHITE PULP: (made of masses of lymphocytes) RED PULP: (made of sinuosoid capillaries) functions  Filters the blood from antigens and microorganism  Evokes immunological response against the antigens circulating in blood  Produces B and T lymphocytes.  Remove old and abnormal rbc’s  Removes bacteria by phagocytosis  Stores blood  Forms blood cell during fetal life Thymus  Lies in the upper part of the mediastinum behind the sternum &extends upwards into the root of the neck.  The thymus is devoid of lymph capillaries and lymphoid nodules.  Weighs about 10-15 g at birth and 20- 30 gms at puberty. Then it regress and converted into fibro fatty tissue. Function  The thymus is the site of production of t lymphocytes  It recieves immunologically incompetent stem cells from bone marrow.  In the thymus these cells divide and mature into T- lymphocytes.  T lymphocyes are important for both cellular and humoral immunological responses.  Thymus secrete hormone k/a thymosin which support the activity of T-lymphocytes throughout the body Epithelio-lymphoid system  Epithelio- lymphoid system comprises mucosa associated lymphoid tissue(MALT)  The large amount of unencapsulated lymphatic tissue exist in walls of alimentary, respiratory and genitourinary tracts. It is collectively termed as mucosa associated lymphoid tissue(MALT)  The MALT tissue is generally subdivided into the following two types: 1. bronchus associated lymphoid tissue(BALT) in respiratory system. 2. Gut assosiated lymphoid tissue(GALT)  The collections or aggregations of mucosa – associated lymphoid tissue are as follows: 1. Pharyngeal tonsil 2. Tubal tonsil 3. Palatine tonsil 4. Lingual tonsil 5. Peyer’s patches 6. Abdominal tonsil BONE MARROW  The Red Bone Marrow is a key element of the lymphatic system  Being one of the primary lymphoid organs that generate lymphocytes from immature hematopoietic progenitor cells  The bone marrow and Thymus constitute the primary lymphoid tissues involved in the production and early selection of lymphocytes Clinical anatomy  Lymphadenoma  Lymphangitis  Elephentasis  Spread of cancer  Lymphadenitis(acute infection of lymph nodes)  splenomegaly PULMONARY CIRCULATION  OBJECTIVES. ❖ FUNCTIONAL ANATOMY ❖ CHARACTERISTIC FEATURES ❖ FUNCTIONS ❖ REGULATION OF PULMONARY BLOOD FLOW.  FUNCTIONAL ANATOMY Lungs have 3 circulation. ◼ Pulmonary circulation ◼ Bronchial circulation ◼ Lymphatic circulation. Thursday, October 3, 2024  PULMONARY CIRCULATION ◼ Pulmonary trunk ◼ Right & left pulm artery ◼ Right & left lungs ◼ Capillaries lining of alveoli ◼ Get oxygenated & return back via pul veins to left atrium. Thursday, October 3, 2024  BRONCHIAL CIRCULATION ◼ Descending thoracic aorta give right & left bronchial arteries ◼ Supply oxygenated blood to lungs (connective tissue, septa & bronchi) & after joins pulm veins without (Bypass) oxygenation. ◼ So forms Physiological shunt. Thursday, October 3, 2024  OTHER EXAMPLE OF PHYSIOLOGICAL SHUNT ◼ Drainage of Coronary vessel in to left side of heart. ◼ Effects of shunts – ◼ Reduce oxygenation of arterial blood slightly. ◼ Increase left ventricular output by 1-2% than right. Thursday, October 3, 2024  LYMPHATIC CIRCULATION. ◼ Present in walls of terminal bronchioles & supportive tissues of lung. ◼ Removes particulate matter, plasma proteins – thus prevents pulmonary oedema Thursday, October 3, 2024  LYMPHATIC CIRCULATION. Drainage pathway ◼ Deep lymphatic ◼ Pulmonary nodes ◼ Bronchopulmonary nodes ◼ Tracheobronchial nodes ◼ Bronchomediastinal trunk. Thursday, October 3, 2024  PULMONARY CIRCULATION CHARACTERISTIC FEATURES. ◼ Pulmonary circulation is low pressure, low resistance & high capacitance system. ◼ Thickness of Right ventricle and pulmonary artery 1/3rd of left ventricle & aorta ◼ Pulmonary capillaries are larger in diameter than systemic capillaries. ◼ Each alveolus is enclosed in basket of capillaries. Thursday, October 3, 2024  PRESSURES IN PULMONARY SYSTEM. ◼ Right ventricular pressure. ◼ Pulmonary artery pressure. ◼ Left atrial pressure. ◼ Pulmonary capillary pressure. Thursday, October 3, 2024  RIGHT VENTRICULAR PRESSURE. ◼ During each cardiac cycle, ◼ During Systole – reaches peak 25 mm Hg.(120 mm Hg in Left ventricle) ◼ During Diastole – 0-1 mm Hg (5 mm Hg in left ventricle) Thursday, October 3, 2024  PULMONARY ARTERY PRESSURE. ◼ Systolic pressure 25 mm Hg (120 mm Hg in Aorta) ◼ Diastolic pressure 8 mm Hg (8 mm Hg in Aorta) ◼ Mean arterial pressure 15 mm Hg (100 mm Hg in Aorta) ◼ Pulse pressure 17 mm Hg (40 mm Hg in Aorta) Thursday, October 3, 2024  LEFT ATRIAL PRESSURE. ◼ Major pulmonary veins pressure avg 5 mm Hg ◼ So Pressure gradient in pulmonary system Mean pulmonary artery pressure – mean pulmonary vein pressure 15-5 = 10 mm Hg. Thursday, October 3, 2024  PULMONARY CAPILLARY PRESSURE. ◼ 10 mm Hg. ◼ Colloidal osmotic pressure is 25 mm Hg ◼ So net suction force of 15 mm Hg draw fluid from pulmonary interstitial fluid into pulmonary capillary ◼ So keeps Alveoli dry Thursday, October 3, 2024  SIGNIFICANCE OF LOW PULMONARY CAPILLARY PRESSURE ◼ So if pulmonary capillary pressure rises above 25 mm Hg ◼ Fluid escapes into interstitial spaces ◼ Lead to pulmonary oedema ◼ Conditions raising this pressue ◼ Exercise at high altitude ◼ Left heart failure ◼ Mitral stenosis ◼ Pulmonary fibrosis. Thursday, October 3, 2024  PULMONARY WEDGE PRESSURE ◼ Estimate left atrial pressure. ◼ Measured by passing a catheter through right ventricle, pulmonary artery up to smallest branch of pulmonary artery. ◼ Used to study left atrial pressure in patients of CCF Thursday, October 3, 2024  PULMONARY BLOOD VOLUME ◼ Pulmonary vessels contains – 600 ml; its capacitance vary from 200-900 ml ◼ Pulmonary blood volume decreases during standing & during haemorrhage to compensate , so acts as Reservoir. Thursday, October 3, 2024  PULMONARY BLOOD FLOW ◼ Pulmonary blood flow nearly equal to cardiac output. ◼ Blood flow through lung depend on – ◼ Relationship between pressures of Pulmonary artery, pulmonary vein & alveolar artery. Thursday, October 3, 2024  EFFECT OF GRAVITY ON REGIONAL PULMONARY BLOOD FLOW. ◼ In supine position mean arterial pressure is same all over lung so all regions equally perfused. ◼ In erect position gravity affects due to hydrostatic pressure effect. Thursday, October 3, 2024  EFFECT OF GRAVITY ON REGIONAL PULMONARY BLOOD FLOW. ◼ Zero reference plane is at level of right atrium. ◼ So pulmonary arterial pressure ◼ In middle of lung –is 15 mm Hg ◼ At apex – 4 mm Hg ◼ At the base 26 mm Hg. Thursday, October 3, 2024  EFFECT OF GRAVITY ON ALVEOLAR VENTILATION ◼ In Supine Position – alveolar ventilation evenly distributed ◼ In Upright Position – ◼ Alveolar pressure is zero throughout lung ◼ Intrapleural pressure – at apex -10 mmHg & at base -2 mm Hg. ◼ So transpulmonary pressure -10 & -2 at apex & base respectively. ◼ So linear reduction in regional alveolar ventilation from base to apex. Thursday, October 3, 2024  CLINICAL SIGNIFICANCE ◼ So arterial oxygenation in unilateral lung diseases is improved by keeping good lung in Dependent Position. ◼ Opposite is done in INFANT. Thursday, October 3, 2024  ALVEOLAR VENTILATION : PERFUSION RATIO ◼ Ratio of alveolar ventilation per minute to quantity of blood flow to alveoli per min. ◼ VA/Q = 4.2/5 = 0.84- 0.9 Thursday, October 3, 2024  EFFECT OF GRAVITY ◼ Linear Reduction of blood flow and alveolar ventilation from base to apex. ◼ But gravity affects perfusion more than ventilation. ◼ So as we go up from middle VA/Q goes on increasing , about 3 at apex. ◼ At the base it is over perfused than over ventilated so at the base is 0.6 Thursday, October 3, 2024  CAUSES OF ALTERATION. ◼ Causes of altered ◼ Causes of altered alveolar ventilation pulmonary perfusion. ◼ Anatomical shunts ◼ Bronchial asthma ◼ Pulmonary embolism ◼ Emphysema ◼ Decrease in pulmonary ◼ Pulmonary fibrosis vascular bed in ◼ Pneumothorax emphysema ◼ Congestive heart failure ◼ Increase pulmonary resistance in pulmonary fibrosis, Pneumothorax, CHF Thursday, October 3, 2024  EFFECTS OF ALTERATION IN VA/Q RATIO. ◼ Normal VA/Q ratio –both normal alveolar pO2 = 104 mmHg, pCO2 =40 mmHg. ◼ Increased VA/Q ratio. – alveolar dead space air, VA/Q = infinity, pO2 = 149 mmHg, pCO2 = 0 mmHg. ◼ Decreased VA/Q ratio, pO2 = 40 mmHg, pCO2 = 45 mmHg. Thursday, October 3, 2024  EFFECT OF EXERCISE ON REGIONAL PULMONARY BLOOD FLOW ◼ During exercise blood flow increases in all regions of blood. ◼ Near base increased by 2-3 time ◼ Near apex increased by 8 times. ◼ It occurs due to ◼ Recruitment of capillaries. ◼ Distension of capillaries. Thursday, October 3, 2024  PULMONARY CAPILLARY DYNAMICS ◼ Pulmonary transit time – mean transit time in pulmonary circulation from pulmonary valves to left atrium – 4 sec. ◼ Capillary transit time for RBC is 0.8 sec at rest and 0.3 sec during exercise. Thursday, October 3, 2024  MEAN FILTRATION PRESSURE AT PULMONARY CAPILLARY = 1 mm Hg. ◼ Starling’s forces at capillary membrane are ◼ Outward forces (29 mm Hg) ◼ Interstitial oncotic pressure – 14 mmHg ◼ Interstitial hydrostatic pressure - -8 mm Hg ◼ Capillary Hydrostatic pressure 7 mm Hg ◼ Inward forces (28 mm Hg) ◼ Plasma oncotic pressure 28 mm Hg. Thursday, October 3, 2024 Thursday, October 3, 2024  PULMONARY OEDEMA ◼ Occur due to increase capillary filtration from pulmonary capillary. ◼ Conditions – ◼ Increase capillary hydrostatic pressure from 7 mm Hg to 28 mm Hg (safety factor of 21 mm Hg) ◼ Capillary permeability increase – due to infection, irritant gases. ◼ Acute left heart failure – increase in capillary pressure to 50 mm Hg. Thursday, October 3, 2024  FUNCTIONS ◼ Respiratory gas exchange ◼ Other functions ◼ Reservoir for left ventricle ◼ Filter for removal of emboli & other particles from blood. ◼ Removal of fluid from alveoli. ◼ Role in absorption of drugs. ◼ Synthesis of Angiotensin converting enzyme. Thursday, October 3, 2024  REGULATION OF PULMONARY BLOOD FLOW. ◼ Neural control. ◼ Efferent sympathetic vasoconstrictor nerves ◼ Innervates pulmonary blood vessels. ◼ Participate in vasomotor reflexes. ◼ Baroreceptor stimulation – causes reflex dilatation of pulmonary vessels ◼ Chemoreceptor stimulation – causes pulmonary vasoconstriction. Thursday, October 3, 2024 Afferent control through vagus is mediated through receptors. ◼ Pulmonary baroreceptors ◼ pulmonary volume receptors ◼ J receptors. Thursday, October 3, 2024  CHEMICAL CONTROL ◼ Local Hypoxia – causes change in blood flow by vasoconstriction. ◼ Hypercapnia & acidosis – causes vasoconstriction.(Vasod ilatation in systemic circulation) Thursday, October 3, 2024  CHEMICAL CONTROL ◼ Chronic Hypoxia ◼ Occurs in high altitude dwellers associated with pulmonary hypertension followed by right ventricular hypertrophy, right heart heart failure & pulmonary oedema. Thursday, October 3, 2024 THANK YOU