1. Cardiovascular physiology. Dr James Ker

2. 2 scenario`s in cardiology: Systemic diseases affecting the cardiovascular system. Systemic diseases affecting the cardiovascular system. Primary cardiovascular diseases. Primary cardiovascular diseases.

3. How can these diseases affect the cadiovascular system ? Components of the cardiovascular system: Myocardium: myocarditis, cardiac failure etc Myocardium: myocarditis, cardiac failure etc Valves: Stenosis, incompetence etc Valves: Stenosis, incompetence etc Electrical system: Dysrhythmias. Electrical system: Dysrhythmias. Vessels: Arteries, veins, lymphatic vessels. Vessels: Arteries, veins, lymphatic vessels.

4. Physiological disturbances: Disturbances in the following may occur: Disturbances in the following may occur: Blood pressure Blood pressure Cardiac rhythm Cardiac rhythm Valvular function Valvular function Cardiac systole and diastole Cardiac systole and diastole Blood flow Blood flow

5. Blood pressure: BP = Cardiac output (CO) x peripheral vascular resistance (PVR) BP = Cardiac output (CO) x peripheral vascular resistance (PVR) 3 components of blood pressure: 3 components of blood pressure: Systolic component Systolic component Diastolic component Diastolic component Mean arterial pressure Mean arterial pressure

6. BP = 120/80 mmHg BP = 120/80 mmHg Mean arterial pressure = (S + 2D)/3 or Mean arterial pressure = (S + 2D)/3 or D + 1/3 PP D + 1/3 PP Pulse pressure=S – D (120-80=40 mmHg) Pulse pressure=S – D (120-80=40 mmHg)

7. Cardiac output: CO = Stroke volume x heart rate CO = Stroke volume x heart rate Thus: Thus: 2 ways to increase CO: SV vs CO Determines systolic BP Systolic vs diastolic HT Normal CO: 5L/min Cardiac index=CO corrected for body surface area

8. Causes of increased CO: Fever Fever Anaemia Anaemia Hyperthyroidism Hyperthyroidism Pregnancy Pregnancy Exercise Exercise Etc.. Etc..

9. Presents as: Systolic HT with: Systolic HT with: ↑ pulse pressure ↑ pulse pressure Stroke volume: Volume of blood pumped by ventricle during systole (70 ml at rest) Stroke volume: Volume of blood pumped by ventricle during systole (70 ml at rest)

10. Physiological control of CO: Preload: Venous filling Preload: Venous filling Afterload: BP against which LV must expel stroke volume Afterload: BP against which LV must expel stroke volume Inotropy: Strength of myocardial contraction. Starling`s law, catecholamines Inotropy: Strength of myocardial contraction. Starling`s law, catecholamines

11. Physiological control of heart rate: Intrinsic: SA node Intrinsic: SA node Extrinsic: Extrinsic: Hormonal: thyroid, catecholamines Neurological: Autonomic nervous system Fever, electrolytes

12. Peripheral vascular resistance: Determined by diameter of peripheral arteries. Determined by diameter of peripheral arteries. Determines diastolic blood pressure Determines diastolic blood pressure

13. Control of PVR: Hormonal: AT II, endothelins, NO, bradykinin, catecholamine etc Hormonal: AT II, endothelins, NO, bradykinin, catecholamine etc Neurological: Autonomic nervous system Neurological: Autonomic nervous system Myogenic/Local. Myogenic/Local.

14. The ECG: Einthoven`s trangle Einthoven`s trangle Einthoven`s law Einthoven`s law

15. Einthoven`s triangle: I II III +-+- ---- +

16. Einthoven`s law: Lead II = Lead I + Lead III Lead II = Lead I + Lead III Standard limb leads: I, II, III Standard limb leads: I, II, III Lead I: connects 2 arms Lead I: connects 2 arms Lead II: connects right arm with left leg Lead II: connects right arm with left leg Lead III: connects left arm with left leg Lead III: connects left arm with left leg

17. aV leads: Limb leads are bipolar Limb leads are bipolar Unipolar limb leads=aV leads: aVR, aVL and aVF Unipolar limb leads=aV leads: aVR, aVL and aVF

18. Precordial (V) leads: V1: Just to the right of the sternum in the 4`th intercostal space. V1: Just to the right of the sternum in the 4`th intercostal space. V2: Just to the left of the sternum in the 4`th intercostal space. V2: Just to the left of the sternum in the 4`th intercostal space. V3: Halfway between V2 and V4 V3: Halfway between V2 and V4

19. V4: Left midclavicular line in the 5`th intercostal space V4: Left midclavicular line in the 5`th intercostal space V5, 6: 5`th intercostal space in anterior and midaxillary line respectively V5, 6: 5`th intercostal space in anterior and midaxillary line respectively

20. Physiological use of the ECG: Rhythm: Sinus vs other Rhythm: Sinus vs other Chamber thickening: Atrial and ventricular hypertrophy Chamber thickening: Atrial and ventricular hypertrophy Damage: Endocardial, myocardial, pericardial Damage: Endocardial, myocardial, pericardial Info on systemic conditions: Hypothermia, electrolyte disturbances, pH disturbances Info on systemic conditions: Hypothermia, electrolyte disturbances, pH disturbances

21. Rate, complexes, intervals: P-wave: Atrial depolarization P-wave: Atrial depolarization QRS-complex: Ventricular depolarization QRS-complex: Ventricular depolarization T-wave: Ventricular repolariation T-wave: Ventricular repolariation