Cardiovascular Structure & Function Cardiovascular Structure & Function.

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Cardiovascular Structure & Function
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Transcript of Cardiovascular Structure & Function Cardiovascular Structure & Function.

  • Cardiovascular system:The heartArteriesVeinsCapillariesLymphatic vessels

  • Weighting of the heart ceremony: Ancient Egyptians

  • William Harvey and Blood Flow April 1, 1578 June 3, 1657

  • IntroductionThe most basic functions of the cardiovascular system are:

    To deliver oxygen and nutrients to body tissuesTo remove wasteTo regulate temperature

  • Circulatory system

  • Circulatory system1. Left ventricle2. Aorta3. Arterial system4. Vena cava5. Right atrium6. Right ventricle7. Pulmonary artery8. Lungs9. Pulmonary veins10. Left atrium1. Left ventricle

  • Heart valves PulmonaryAorticMitralTricuspid

  • Systolic and Diastolic phases Diastolic phase =Ventricular fillingSystolic phase =Ventricular ejection

  • Cardiac cycle SystoleDiastoleAnimation: http://library.med.utah.edu/kw/pharm/hyper_heart1.html

  • Aortic and Ventricular Pressures

  • Left Atrium2-11Left ventricle90-140 / 5-12Aorta90-140 / 60-90

    Right Atrium0-8Right ventricle15-30 / 0-8Pulmonary artery15-30 / 4-12Normal pressuresUnit = mmHg [1 mmHg = 133 Pa]

  • Intra-cardiac and arterial pressures

  • HypertensionHypertension is defined as an abnormal increase in arterial pressureHypertension results in an increase in ventricular work and ventricular hypertrophy

  • Pressure and Flow

  • Systolic pressure = maximal pressureDiastolic pressure = minimal pressure

    CATEGORY SYSTOLIC (mmHg) DIASTOLIC (mmHg)Normal< 130< 85 Normal ++130-13985-89Hypertension STAGE 1 (Mild)140-15990-99 STAGE 2 (Moderate)160-179100-109 STAGE 3 (Severe)180-209110-119 STAGE 4 (Very Severe)>209 >119 A very low pressure should also by examined by a Doctor. Classification of arterial pressure (> 18 years)

  • Ventricular pressure-volume curves 608010012014016002040608010012000.20.40.60.805010000.20.40.60.880100120140160Time (s)Pressure (mmHg)Ventricular Volume (mL)Ventricular pressure (mmHg)Ventricular volume (mL)Isovolumetric contraction2. Ventricular ejectionIsovolumetric relaxation Ventricular fillingStroke volumeStrokevolume

  • P : Ventricular pressureV : Ventricular volumeVentricular work 1 J

  • Effect of systemic hypertension

  • Ventricular work as a f(preload,afterload)

  • Factors influencing flow and pressure

  • Mean pressure (MAP) and pulsed pressure (PP)MAP 2/3 DP + 1/3 SPPP = SP DP

  • Normal conditions (120/80 mmHg) :R = 1.1 mmHg.s/mLC = 2.0 mL/mmHg

    Severe hypertension (190/115 mmHg) :R = 1.7 mmHg.s/mLC = 0.8 mL/mmHgResistance and compliance Resistance : R MAP / COMAP : mean arterial pressureCO : cardiac output

    Compliance : C SV / PPSV : stroke volume PP : pulse pressure

  • Normal flow rate : SV = 70 mL, CO = 5L/min

    Resistance : R MAP / COR increases MAP increases

    Compliance : C SV / PPC decreases PP increases00.511.5050100mmHgMAPPPResistance and compliance

  • Hypertension and aortic pressure 00.511.5010020000.511.50100200Normal (120 / 80)Severe hypertension (190 / 115)MAPPPR = 1.1 mmHg.s / mLC = 2.0 mL / mmHg

    MAP = 95 mmHgPP = 40 mmHg

    R = 1.7 mmHg.s / mLC = 0.8 mL / mmHg

    MAP = 140 mmHgPP = 75 mmHg

    MAPPP14095

  • Arterial Pressure Flow, resistance and compliance of the arterial system are significant determinants of arterial pressure

    Another parameter that can determine arterial pressure is wave reflection in the arterial system.

  • Arterial pressure and wave reflectionaortaFemoral aarterydorsalispedis

  • Incident waveReflected waveArterial pressure and wave reflection

  • Heart Sounds

  • Two heart sounds can be distinguished: S1 and S2.

    S1 is synchronized with early systolic phase.

    S2 is synchronized with the end of systolic phase.

    The frequencies are between 10 and 500 Hz with low intensityHeart Sounds

  • 1st stethoscope1816 Laennec was examining a young female patient

    He was embarrassed to place his ear to her chest

    Rolled up 24 sheets of paper, placed one end to his ear and the other end to the womans chest

    Discovered that the sounds were also louder and clearer

  • Examples of stethoscopesIn 1819, the French doctor Ren Lannec invented the stethoscope.

  • En 1851, Dr. Marsh developed the 1st commercial model.Examples of stethoscopes

  • Pathological heart sounds Several pathologies induce turbulence in the flow in the cardiovascular system.

    High frequencies in the turbulent flow generate audible sounds.

  • Aortic stenosis Animation: http://www.healthcentral.com/heart-disease/valves/

  • Aortic valveNormal vs Stenosed

  • Aortic stenosis : different origins

  • Aortic stenosisValvular surgeries in Canada (1996-1997)The most common valvulopathy in industrial countries. Prevalence 1 to 2 % in people > 65 years old.

  • Carabello et al. NEJM, 1997Aortic stenosis

  • Symptoms Angina pectoris Syncope Intolerance to exercise

  • Investigation of the severity of aortic stenoses Gorlin Equation Energy loss coefficient

  • Valve replacement

  • Bioprosthetic valves Pericardial valves Porcine valves

  • Mechanical valves

  • Surgery

  • Surgeryhttp://heart-surgeon.comAnimation: http://www.healthcentral.com/heart-disease/valves/