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Cardiovascular SystemCardiovascular System
John P. McDonough,John P. McDonough, CRNA, Ed.D., ARNPCRNA, Ed.D., ARNP
VesselsVessels
ArteriesArteries– carry blood away from the heartcarry blood away from the heart
» oxygenated (except PA)oxygenated (except PA)
VeinsVeins– carry blood to the heartcarry blood to the heart
» desaturated (except PV)desaturated (except PV)
CapillariesCapillaries– local circulationlocal circulation– connects arteries to veinsconnects arteries to veins
““Great” VesselsGreat” Vessels
Vena cavaVena cava– superior & inferiorsuperior & inferior
Pulmonary arteryPulmonary artery Pulmonary veinPulmonary vein AortaAorta
Blood Flow Through the HeartBlood Flow Through the Heart
Rt AtriumRt Atrium Tricuspid valveTricuspid valve Rt ventricleRt ventricle Pulmonic valvePulmonic valve Lt atriumLt atrium Mitral valveMitral valve Lt ventricleLt ventricle Aortic valveAortic valve
Structure of the HeartStructure of the Heart
PericardiumPericardium– visceralvisceral– parietalparietal– pericardial fluidpericardial fluid
MyocardiumMyocardium– contractile heart musclecontractile heart muscle
EndocardiumEndocardium– cavity lining cavity lining
Circulation to the Heart ItselfCirculation to the Heart Itself
Lt main coronary arteryLt main coronary artery– Lt anterior descending Lt anterior descending – Lt circumflexLt circumflex
Rt coronary arteryRt coronary artery Coronary perfusionCoronary perfusion
– occurs during diastole occurs during diastole – rate changes effect rate changes effect diastolediastole onlyonly
Cardiac Conduction SystemCardiac Conduction System(electrical (electrical mechanical function) mechanical function)
Sinoatrial (AS) nodeSinoatrial (AS) node– ““pacemaker of the heart”pacemaker of the heart”
Intra-atrial conduction pathwaysIntra-atrial conduction pathways Atrioventricular (AV) nodeAtrioventricular (AV) node Bundle of HisBundle of His Rt bundle branchRt bundle branch Lt bundle branchLt bundle branch
– Lt anterior & posterior faciclesLt anterior & posterior facicles
Circulatory SystemCirculatory System 2 separate circuits, serially connected2 separate circuits, serially connected Output of one Output of one the input of the other the input of the other
– pulmonary, systemicpulmonary, systemic Heart is functions as 2 pumpsHeart is functions as 2 pumps
– Rt = pulmonary, Lt = systemicRt = pulmonary, Lt = systemic ArteriesArteries VeinsVeins CapillariesCapillaries
Adrenergic Control of Heart RateAdrenergic Control of Heart Rate
-adrenergic receptors (generally dilates -adrenergic receptors (generally dilates & excites)& excites) 11 found mostly in the heart (conduction found mostly in the heart (conduction
system)system) 22 found mostly in the lungs (bronchi), but also found mostly in the lungs (bronchi), but also
in the coronary arteriolesin the coronary arterioles
Adrenergic Control of Heart RateAdrenergic Control of Heart Rate
-adrenergic stimulation will -adrenergic stimulation will heart rate & heart rate & dilate bronchidilate bronchi
-adrenergic blockade will -adrenergic blockade will heart rate & heart rate & constrict bronchiconstrict bronchi
Norepinephrine binds with Norepinephrine binds with 1 1 receptorsreceptors
Epinephrine binds with Epinephrine binds with 22 receptors receptors
Adrenergic Control of Heart RateAdrenergic Control of Heart Rate
-adrenergic receptors -adrenergic receptors – some in the heart, but mostly in vesselssome in the heart, but mostly in vessels
Stimulation causes constrictionStimulation causes constriction
Autonomic Control of Heart Autonomic Control of Heart RateRate
SympatheticSympathetic– thoracic chain ganglia thoracic chain ganglia – neurotransmitter = norepinephrine (NE) neurotransmitter = norepinephrine (NE)
parasympatheticparasympathetic– vagus nerve (CN-X)vagus nerve (CN-X)– neurotransmitter = acetylcholine (Ach)neurotransmitter = acetylcholine (Ach)
Other Controls of Heart RateOther Controls of Heart Rate
Volume controlVolume control– Barinbridge reflexBarinbridge reflex
Pressure controlPressure control– baroreceptorsbaroreceptors
Factors Effecting Cardiac OutputFactors Effecting Cardiac Output
PreloadPreload AfterloadAfterload Heart RateHeart Rate ContractilityContractility
1, 300, 000 Myocardial 1, 300, 000 Myocardial Infarctions yearly in the Infarctions yearly in the
United StatesUnited States
50% are fatal50% are fatal
Risk Factors for CV DiseaseRisk Factors for CV Disease
SmokingSmoking Diabetes mellitusDiabetes mellitus HypertensionHypertension HyperlipidemiaHyperlipidemia
Risk Factors for CV Disease Risk Factors for CV Disease (con’t)(con’t)
Genetic predisposition Genetic predisposition ObesityObesity Sedentary life-styleSedentary life-style Type A personality Type A personality
HypertensionHypertension
50 million Americans have it50 million Americans have it Diagnosed if >2 B/P measurements show:Diagnosed if >2 B/P measurements show:
– diastolic readings >90diastolic readings >90– average of 2 systolic >140average of 2 systolic >140
Mortality rates:Mortality rates:– white women white women 4.7%4.7%– white menwhite men 6.3%6.3%– black womenblack women 29.3%29.3%– black menblack men 22.5%22.5%
Determinants of Hypertension Determinants of Hypertension
Essential hypertensionEssential hypertension– stressstress– dietdiet– genetic factorsgenetic factors
Secondary hypertensionSecondary hypertension– pheochromocytomapheochromocytoma– renal vascular diseaserenal vascular disease– Cushing’s syndromeCushing’s syndrome– thyrotoxicosisthyrotoxicosis
Effect of Vessel DiameterEffect of Vessel Diameter
With the same 100mg/Hg pressure driving:With the same 100mg/Hg pressure driving:– d=1 d=1 1 ml/min 1 ml/min– d=2 d=2 16 ml/min 16 ml/min– d=3 d=3 256 ml/min 256 ml/min
Complications of HypertensionComplications of Hypertension
Myocardial ischemiaMyocardial ischemia Ventricular failureVentricular failure Pulmonary edemaPulmonary edema Aortic dissectionAortic dissection Intracerebral hemorrhageIntracerebral hemorrhage
Common AntihypertensivesCommon Antihypertensives
Beta BlockersPropanolol, esmolol,metoprolol, atenolol
Blocks effect ofcate. at receptors.Decreases HR &CO
Orthostatichypotension
ACE InhibitorsCaptopril, enalapril,
Dec conversion ofAT-1 To AT-2
Bronchospasm,bradycardia,hypotension
CalciumantagonistsNifedipine, diltiazem
Inhibits Ca++uptake, decperipheralresistance
Reflex tach,hypotension
Cardiomyopathies Cardiomyopathies
Primary disorders of the muscle itself Primary disorders of the muscle itself – not related to CAD, HTN or valve disordersnot related to CAD, HTN or valve disorders
Dilated cardiomyopathyDilated cardiomyopathy– toxins, ETOH, infection, nutrition,toxins, ETOH, infection, nutrition,
Hypertrophic cardiomyopathy Hypertrophic cardiomyopathy – usually congenital usually congenital
Restrictive cardiomyopathyRestrictive cardiomyopathy– usually infiltrative disease processusually infiltrative disease process
Congestive Heart FailureCongestive Heart Failure(a (a symptom symptom complex)complex)
Each side of the heart can fail separately Each side of the heart can fail separately Left HF is a frequent cause of right HFLeft HF is a frequent cause of right HF
– frequent, but the not the onlyfrequent, but the not the only S/S Left heart failureS/S Left heart failure
– dyspneadyspnea– pulmonary congestionpulmonary congestion
S/S Right heart failureS/S Right heart failure– peripheral edemaperipheral edema– vein distentionvein distention
Treatment of CHFTreatment of CHF
Rate controlRate control Digitalis glycosides (lanoxin)Digitalis glycosides (lanoxin) DiureticsDiuretics Phosphodiesterase (PDE) inhibitorsPhosphodiesterase (PDE) inhibitors
Cardiac muscle extracts the largest amount of Cardiac muscle extracts the largest amount of oxygen because of the extensive work the heart oxygen because of the extensive work the heart
does (manifested as contractility) even during rest.does (manifested as contractility) even during rest.At rest: 8-10 ml OAt rest: 8-10 ml O22/min/100g of myocardium./min/100g of myocardium.
During exercise this can increase by a factor of 10.During exercise this can increase by a factor of 10.
But what drives the contraction But what drives the contraction process in myocytes?process in myocytes?
Answer: ATPAnswer: ATP
As demand goes up, inotropic response of the As demand goes up, inotropic response of the heart increases and the coronary vasculature heart increases and the coronary vasculature adapts by vasodilating to provide an adequate adapts by vasodilating to provide an adequate oxygen supply.oxygen supply.
If, due to atherosclerotic disease, the coronary If, due to atherosclerotic disease, the coronary arteries are unable to sustain the myocardium, arteries are unable to sustain the myocardium, ischemia ensues and the flow is predicted by:ischemia ensues and the flow is predicted by:
Q = Q = P rP r44/ 8 n L/ 8 n Lwhere r is radius of vessel, n is viscosity and L is vessel length.where r is radius of vessel, n is viscosity and L is vessel length.
Factors in Supply & DemandFactors in Supply & Demand
Decreased supplyDecreased supply– reduced contentreduced content
– reduced coronary flowreduced coronary flow
– increased LV pressureincreased LV pressure
– fixed vascular fixed vascular obstructionobstruction
Increased demandIncreased demand– positive chronotropismpositive chronotropism
– positive inotropismpositive inotropism
– increased LV volumeincreased LV volume
– increased wall tensionincreased wall tension
– increased afterloadincreased afterload
Visualization of intracellular oxygenation:Microspectrophotometry
Reference: Takahashi, E. and K. Doi. Visualization of oxygen level inside a single cardiac myocyte. Am. J. Physiol. 268: H2561-H2568, 1995.
Aerobic environmentHappy myocytes
Anoxic environmentMyocytes not happy
HistoryHistory PainPain DyspneaDyspnea PalpitationPalpitation EdemaEdema SyncopeSyncope Fatigue & Fatigue &
WeaknessWeakness CyanosisCyanosis
Hemodynamic to Formulae Hemodynamic to Formulae
BP = CO x SVRBP = CO x SVR CO = SV x HRCO = SV x HR SV = LVEDV - LVESVSV = LVEDV - LVESV SVR = MAP - CVP x 80 / COSVR = MAP - CVP x 80 / CO
– normal = 800-1200 dyne/sec/cmnormal = 800-1200 dyne/sec/cm-5-5
Congestive Heart Failure Congestive Heart Failure (diagnostic problems)(diagnostic problems)
Volume overloadVolume overload BronchospasmBronchospasm PneumoniaPneumonia Pulmonary embolismPulmonary embolism Ischemically mediated pulmonary edemaIschemically mediated pulmonary edema
Characteristics of Chest PainCharacteristics of Chest Pain
ANGINAANGINA– retrosternal, diffuseretrosternal, diffuse
– Lt arm, jaw, backLt arm, jaw, back
– aching, dull, pressing, aching, dull, pressing, squeezing,squeezing,
– minutesminutes
– effort, emotion, eating effort, emotion, eating coldcold
– rest, NTGrest, NTG
PROBABLY NOTPROBABLY NOT– Lt inframam, localizedLt inframam, localized
– Rt armRt arm
– sharp, cutting, sharp, cutting, shooting, shooting,
– seconds, hours, daysseconds, hours, days
– respiration, posture, respiration, posture, motionmotion
– nonspecificnonspecific
Cardiac Causes of Chest PainCardiac Causes of Chest Pain
CADCAD aortic valve diseaseaortic valve disease pulmonary pulmonary
hypertensionhypertension
mitral valve prolapsemitral valve prolapse pericarditispericarditis IHSSIHSS
Pulmonary Causes of Chest PainPulmonary Causes of Chest Pain
pulmonary embolismpulmonary embolism pneumoniapneumonia pleuritispleuritis pneumothoraxpneumothorax
Musculoskeletal Causes of Chest Musculoskeletal Causes of Chest PainPain
costochondritiscostochondritis arthritisarthritis muscular spasmmuscular spasm bone tumorbone tumor
GI Causes of Chest PainGI Causes of Chest Pain
ulcer diseaseulcer disease bowel diseasebowel disease hiatal herniahiatal hernia pancreatitispancreatitis cholecystitischolecystitis
Other Causes of Chest PainOther Causes of Chest Pain
VascularVascular– aortic dissectionaortic dissection
EmotionalEmotional– anxietyanxiety– despressiondespression
Common Causes of PalpitationsCommon Causes of Palpitations
extrasystolesextrasystoles tachyarrthymiastachyarrthymias bradyarrthymiasbradyarrthymias drugsdrugs
smokingsmoking caffeinecaffeine thyrotoxicosisthyrotoxicosis
Common Causes of DyspneaCommon Causes of Dyspnea
CardiacCardiac– Lt failureLt failure
– mitral stenosismitral stenosis
PulmonaryPulmonary– obstructive diseaseobstructive disease
– asthmaasthma
– restrictive diseaserestrictive disease
– pulmonary HTNpulmonary HTN
EmotionalEmotional High altitude exposureHigh altitude exposure AnemiaAnemia
Physical Exam of the HeartPhysical Exam of the Heart
inspectioninspection blood pressure blood pressure assess arterial pulseassess arterial pulse assess JV pulseassess JV pulse
percussion percussion palpationpalpation auscultationauscultation evaluation of edemaevaluation of edema
Murmur DescriptionMurmur Description
timing in cycletiming in cycle locationlocation radiationradiation durationduration intensityintensity
pitchpitch qualityquality relationship to relationship to
positionposition relationship to relationship to
respirationrespiration
Grading of Murmurs (I-V/VI)Grading of Murmurs (I-V/VI)
I lowest intensityI lowest intensity II low intensityII low intensity III medium intensity (without thrill)III medium intensity (without thrill) IV medium intensity (with thrill)IV medium intensity (with thrill) V loudest murmur with scope on chestV loudest murmur with scope on chest VI loudest, heard with scope off chestVI loudest, heard with scope off chest
Location of Murmurs within Cardiac Cycle
“Shape” of Murmurs
Three Most Three Most Important Survival Important Survival
FactorsFactors MYOCARDIAL PRESERVATIONMYOCARDIAL PRESERVATION MYOCARDIAL PRESERVATIONMYOCARDIAL PRESERVATION MYOCARDIAL PRESERVATIONMYOCARDIAL PRESERVATION
““Dead meat don’t beat!”Dead meat don’t beat!”