PBL CARDIOVASCULLAR
- 1. Problem Based Learning Presented by : Group “C” Facilitator: Major Dr. Shavana Rana Nepalese Army Institute of Health Sciences College of Medicine 1
- 2. OBJECTIVES • Describe the gross anatomy of heart under following: external features, surface markings and areas of auscultation. • List the components of examination of Cardiovascular System. • Define cardiac cycle and its phases. • Define venous return, stroke volume, cardiac output, preload, afterload and ejection fraction with their normal range.
- 3. Heart • Conical hollow muscular organ • Situated in the middle mediastinum • Within the pericardium.
- 4. External Features •Dimensions – 12 X 9 cm. •Weight – M=300 gm, F=250 gm Apex •Left ventricle •Left 5th intercostal space, medial to midclavicular line 9 cm lateral to midsternal line. Base(Posterior surface) Consists left atrium(mainly), small part of right atrium Location • Supine – T5-T8 vertebra • Standing – descends by 1vertebra
- 6. 4 CHAMBERS • 2 Atria –Right and Left • 2 Ventricles – Right and Left GROOVES 1. Atrioventricular (Coronary sulcus) 2. Interatrial groove 3. Interventricular groove.
- 7. SURFACES 1. Anterior (Sternocostal) 2. Inferior (Diaphragmatic) 3. Left pulmonary surface 4. Right pulmonary surface BORDERS 1. Superior 2. Inferior 3. Right 4. Left
- 8. SURFACES 1. Anterior (Sternocostal) 2. Inferior (Diaphragmatic) 3. Left pulmonary surface 4. Right pulmonary surface BORDERS 1. Superior 2. Inferior 3. Right 4. Left
- 11. Components of Cardiovascular Examination INSPECTION Shape of the precordium Pulsations in the precordium Pulsations outside the precordium Look for distended veins in neck and thorax. PALPATION Apex beat Cardiac thrill Parasternal heave Palpable P2 Determination of JVP
- 13. PERCUSSION Gives information regarding cardiac borders. Dullness in the precordium. AUSCULTATION Function of heart valves. State of myocardium and pericardium. Four areas of auscultation.
- 14. Cardiac Cycle • Cardiac events that occur from the beginning of one heart beat to the beginning of the next. • Cardiac cycle consists of a period of relaxation called diastole, during which the heart fills with blood, followed by a period of contraction called systole. Phases of cardiac cycle 1. Atrial Systole 2. Atrial Diastole
- 15. 3. Ventricular Systole a. Phase of Isovolumetric Contraction b. Phase of ventricular Ejection i. Phase of rapid ejection (lesser duration) ii. Phase of reduced ejection (longer duration) 4. Ventricular Diastole a. Phase of Isovolumetric Relaxation b. Phase of ventricular filling i. Rapid filling phase ii. Reduced filling phase
- 16. Cardiac Cycle • Cardiac events that occur from the beginning of one heart beat to the beginning of the next. • Cardiac cycle consists of a period of relaxation called diastole, during which the heart fills with blood, followed by a period of contraction called systole. Phases of cardiac cycle 1. Atrial Systole 2. Atrial Diastole
- 17. 3. Ventricular Systole a. Phase of Isovolumetric Contraction b. Phase of ventricular Ejection i. Phase of rapid ejection (lesser duration) ii. Phase of reduced ejection (longer duration) 4. Ventricular Diastole a. Phase of Isovolumetric Relaxation b. Phase of ventricular filling i. Rapid filling phase ii. Reduced filling phase
- 19. Venous Return Venous return is the amount of blood that returns to the right atrium from systemic venous circulation each minute. Normal value is: 5 L/min Stroke Volume Stroke volume(SV) is defined as the volume of blood ejected by each ventricle with each beat. Normal Stroke volume is about 70 ml.
- 20. Cardiac Output Cardiac output is the quantity of blood pumped into the aorta each minute by the heart. This is also the quantity of blood that flows through the circulation. Cardiac Output = Stroke volume × heart rate Normal value: For young healthy men: 5.6 L/min For women: 4.9 L/min Preload The degree of tension on the muscle when it begins to contract. For cardiac contraction it is usually considered to be the end diastolic pressure when the ventricle has become filled.
- 21. Afterload It is the load against which the muscle exerts its contractile force. Afterload of the ventricle is the pressure in the aorta leading from the ventricle. Cardiac output is inversely proportional to the afterload. Ejection Fraction The percentage of end-diastolic volume ejected with each beat is the ejection fraction. It is the percentage ratio of stroke volume to end diastolic volume, i.e. EF = SV/ EDV × 100 Normal value: Normally EF is about 65%
- 22. References • Textbook of Medical Physiology, Guyton and Hall, 13th edition, 2016. • Textbook of Medical Physiology, GK Pal, 2nd edition, 2014. • Gray’s Anatomy for Students, 3rd edition, 2013. • BD Chaurasia’s Human Anatomy, volume 1, 7th edition, 2015. • Macleod’s Clinical Examination, 13th edition,2013.