echo class 2_05262015

External Heart: Arteries that Supplythe Heart

• Coronary circulation is the functional blood supply to the heart muscle itself (i.e. the fuel

for the heart)• Collateral routes ensure blood delivery to

heart• even if major vessels are occluded/clogged

Different parts of the heart are supplied bydifferent coronary artery segments

Heart chambers in geometricmodels are subdivided intoperfusion zones usinganatomic knowledge in theFMA ontology

CORONARY ARTERIES SUPPLYING THE HEART WITH OXYGEN-RICH BLOOD

Right Coronary Artery (RCA)

Left Main Coronary Artery (LMCA)

Left Anterior Descending Artery (LAD)

Posterior Descending Artery (PDA)

Left Circumflex Coronary Artery (LCx)

Arterial Coronary Circulation

External Heart: Arteries that Supply the Heart

• Right coronary artery (in atrioventriculargroove)– Supplies the right atrium and nearly all the

right ventricle– marginal –supply the myocardium of the– lateral right side of the heart– posterior interventricular artery – supply the– interventricular septum and adjacent portions

of the ventricular walls

External Heart: Arteries that Supplythe Heart

• Left coronary artery:– Circumflex supplies the left atrium and theposterior wall of the left ventricle– Anterior interventricular artery supplies theanterior wall of both ventricles

CERTAIN HEART WALL SEGMENTS ARE FED BY CERTAIN CORONARY ARTERIES AS SPECIFIED BELOW:

BASE

MID

APEX

A4C

A2C

PARASTERNALLONG-AXIS

Key:Red = LADYellow = LCxGreen = RCA

LAD = Left Anterior Descending Coronary Artery, LCx = Left Circumflex Coronary Artery, RCA = Right Coronary Artery

DIVIDING THE LEFT VENTRICLE INTO KEY SEGMENTS

Apical Third Mid

ThirdBasal Third

FURTHER DIVIDING THE LEFT VENTRICULAR WALLS INTO 17 SPECIFIC SEGMENTS DEFINED AS:

Anterior

Anterolateral

InferolateralInferior

Inferoseptal

AnteroseptalApex

AnteriorAnteroseptal

Inferoseptal

Anterolateral


Anterior

SeptalLateral

Inferior

Apex

Basal

Mid-Cavity

Apical

1. Basal Anterior2. Basal Anteroseptal3. Basal Inferoseptal4. Basal Inferior5. Basal Inferolateral6. Basal Anterolateral7. Mid Anterior8. Mid Anteroseptal9. Mid Inferoseptal10. Mid Inferior11. Mid Inferolateral12. Mid Anterolateral13. Apical Anterior14. Apical Septal15. Apical Inferior16. Apical Lateral17. Apex

PUTTING IT TOGETHER: HEART WALL SEGMENTS AND CORRESPONDING CORONARY ARTERIES

Coronary Artery: Segments:

LAD 1, 2, 7, 8, 13, 14, 17

RCA 3, 4, 9, 10, 15

LCX 5, 6, 11, 12, 16

LAD = Left Anterior Descending Artery

RCA = Right Coronary Artery

LCX = Left Circumflex Artery

Anterior

Anterolateral


Inferoseptal

AnteroseptalApex

AnteriorAnteroseptal

Inferoseptal

Anterolateral


Anterior

SeptalLateral

Inferior

Apex

ANOTHER PERSPECTIVE – 17 SEGMENT MODEL OF LEFT VENTRICLE

1. Basal Anterior2. Basal Anteroseptal3. Basal Inferoseptal4. Basal Inferior5. Basal Inferolateral6. Basal Anterolateral7. Mid Anterior8. Mid Anteroseptal9. Mid Inferoseptal10. Mid Inferior11. Mid Inferolateral12. Mid Anterolateral13. Apical Anterior14. Apical Septal15. Apical Inferior16. Apical Lateral17. Apex

SAMPLE – SEGMENTAL SCORING

Ortiz-Perez, J. T. et al. J Am Coll Cardiol Img 2008;1:282-293

Representative Segmentation and Pattern of Contrast HE Over 17-Segments of the LAD, RCA, and LCX

Arteries

Ortiz-Perez, J. T. et al. J Am Coll Cardiol Img 2008;1:282-293

HEART ANATOMY – COVERINGS OF THE HEART

• Coverings of the Heart: Anatomy• Pericardium – a double-walled sac around the• heart composed of:• A superficial fibrous pericardium• A deep two-layer serous pericardium• The parietal layer lines the internal surface• of the fibrous pericardium• The visceral layer or epicardium lines the• surface of the heart• They are separated by the fluid-filled• pericardial cavity• Coverings of the Heart: Physiology• The pericardium:• Protects the heart

COVERINGS OF THE HEART: PHYSIOLOGY

• The pericardium:– Protects and anchors the heart– Prevents overfilling of the heart with blood– Allows for the heart to work in a relatively– friction-free environment

PERICARDIUM OF THE HEART

• Pericardium (3 layers)• 1) Outer-fibrous pericardium

– Serous pericardium• 2) parietal • 3) visceral (epicardium)

• Pericardial Cavity– between layers of serous pericardium– serous fluid– lubricate heart while beating

Pericardial Layers of the Heart

Heart Wall – Layers of the Heart

• Epicardium – visceral layer of the serous• pericardium• Myocardium – cardiac muscle layer forming• the bulk of the heart• Fibrous skeleton of the heart – crisscrossing,• interlacing layer of connective tissue• Endocardium – endothelial layer of the inner• myocardial surface• Cardiac Muscle Bundles• External

Cardiac Muscle 1000X

intercalated disc

striations nucleus

Purkinje fibers 40X

EXTERNAL FEATURES OF THE HEART

• Interventricular sulcus• Coronal/Coronary sulcus• Auricles of atria• Apex• Base• Coronary vessels• Ligamentum Arteriosum

External Heart: Major Vessels ofthe Heart (Anterior View)

• External Heart: Major Vessels ofthe Heart (Anterior View)• Vessels returning blood to the heart include:– Superior and inferior vena cava– Right and left pulmonary veins

• Vessels conveying blood away from the heart:– Pulmonary trunk, which splits into right and– left pulmonary arteries– Ascending aorta (three branches) –– brachiocephalic, left common carotid, and– subclavian arteries

External Heart: Veins that Drain theHeart

External Heart: Major Vessels ofthe Heart (Posterior View)

Vessels returning blood to the heart include: •Right and left pulmonary veins• Superior and inferior vena cava• Vessels conveying blood away from the heartinclude:• Aorta• Right and left pulmonary arteries

FLOW OF BLOOD• O2-poor blood (S+I VC, Coronary Sinus) enters Rt Atrium• Travels through Tricuspid Valve into Rt Ventricle• Pumped out through Pulmonary Semilunar Valve into Pulmonary trunk (branches into Pulmonary Arteries) and to lungs•After circulating through lungs, O2-rich blood returns to the heart through 4 Pulmonary veins• The O2-rich blood enters the Left Atrium• Travels through Bicuspid/Mitral Valve into Left Ventricle• Pumped out through Aortic Semilunar Valve into Aorta to be distributed to rest of body by descending aorta and branches of aortic arch

Pathway of Blood Through theHeart and Lungs

Right atrium > tricuspid valve > right ventricle >pulmonary semilunar valve > pulmonary arteries > Lungs > pulmonary veins > left atrium >Mitral valve > left ventricle > Left ventricle > aortic semilunar valve > aorta > systemic circulation

THE PATHWAY OF THE HEART

Cardiovascular Flow of Blood

• HeartArteries(conducting-distributing) ArteriolesCapillaries of tissues• At Capillaries O2 is delivered and CO2 picked up•CapillariesVenulesVeinsHeart

DETAILED IMAGES OF THE HEART’S ANATOMY – CHORDAE TENDONAE

THE CARDIAC CYCLE

Semilunar Valve Function

Cardiac Intrinsic Conduction

IMPORTANT - Various nodes and intrinsic Heart Rate Generated:

• SA Node – 60 – 100 Beats/min

• AV Node – 40 – 60 Beats/min

• Bundle of His – 40 – 60 Beats/min

•Purkinje Fibers – Last resort – 20 – 40 Beats/min

Heart Excitation Related to ECG

atrial excitation beginsImpulse delayedat AV nodeImpulse passes toheart apex; ventricularexcitation beginsVentricular excitationcompleteSA node AV node PurkinjefibersBundlebranches

Electrocardiography

Electrical activity is recorded byelectrocardiogram (ECG)• P wave corresponds to depolarization of SA•node•QRS complex corresponds to ventricular•depolarization•T wave corresponds to ventricular repolarization•Atrial repolarization record is masked by the•larger QRS complex

Electrocardiography

Electrocardiography

PR interval•Atrial depolarization and contraction•QT interval•Ventricular depolarization, contraction andrepolarization•PR segment•Atrial contraction•ST segment•Ventricular contraction•ECG Tracings•Heart

ECG TracingsHeart

Cardiac Cycle

Cardiac cycle refers to all events associatedwith blood flow through the heart•Systole – contraction of heart muscle•Diastole – relaxation of heart muscle

Phases of the Cardiac CyclePhases of the Cardiac Cycle• Isovolumetric relaxation – early diastole• Ventricles relax• Backflow of blood in aorta and pulmonary trunk closes semilunar valves• Dicrotic notch – brief rise in aortic pressure caused by backflow of blood. This

backflow• causes the valve to close and creates a slight pressure rebound

Phases of the Cardiac Cycle

THE CARDIAC CYCLE

Cardiodynamics

Cardiac output (CO) : the amount of bloodpumped by each ventricle in one minute

•Cardiac output equals heart rate times strokevolume

Cardiac output (ml/min) =

Heart Rate (HR) (beats/min) X

Stroke Volume (SV) (ml/beat)

Cardiodynamics

Heart rate (HR) : number of heart beats in a minute

•Stroke volume (SV) – amount of blood ejected from the ventricles with each beat

•SV = EDV - ESV

Cardiac Output: Example

CO (ml/min) = HR (75 beats/min) x

SV (70 ml/beat)

•CO = 5250 ml/min (5.25 L/min)

Cardiodynamics

Ventricular pressure increases forcing bloodthrough the semilunar valves: ventricularEjection

•End-systolic volume (ESV)

•Amount of blood that remains in theventricles after the contraction and closing ofthe semilunar valves

Factors Affecting stroke volume(EDV-ESV)

EDV (end diastolic volume) is affected by

•Venous return - amount of blood returning to the heart or blood flow during filling time

•High venous return= high EDV

•Slow heartbeat and exercise increase venousreturn to the heart, increasing SV


Filling time -duration of ventricular diastole

•Depends on the heart rate

•Blood loss and extremely rapid heartbeatdecrease SV

•The longer the filling time the higher theEDV will be


Preload• Stretchiness of the ventricles during Diastole

• Directly proportional to the EDV

• Frank-Starling principle (“more in = more out”) or increased EDV=increased SV


ESV (end systolic volume). It is influenced by: •Contractility

• Force produced during a contraction

• Positive inotropic (increase Calcium entry)

• Increased sympathetic stimuli

• Certain hormones, some drugs

• Increase SV by decreasing ESV


Afterload

•The pressure that must be overcome for theventricles to eject blood (back pressureexerted by blood in the large arteries leavingthe heart)

• Increased afterload will increase ESV anddecrease SV

• Increased by factors that restricts arterial bloodflow

PRELOAD AND AFTERLOAD DEPICTED

STRESS PERFUSION IMAGES

Stress-Perfusion

Rest-Perfusion

Baseline LV contrastuptake

RV contrastuptake

Myocardialcontrast uptake

Viability andcoronaryangiography

Walls of the ventricles:Left wall is thicker!

Find:1. Walls of the ventricles2. Auricles3. Inner walls of the atria4. Fossa ovalis5. Trabeculae carnae6. Atrioventricular valve(a) "Bicuspid valve"(b) "Tricuspid valve"7. Chordae tendonae8. Papillary muscles9. Aortic & pulmonary valves

Coronary arteries are the FIRST branches of the aorta!

1. Coronary arteries(a) Left coronary artery(b) Right coronary artery(c) Interventricular branches(d) Right marginal branch

2. Cardiac veins

Heart in VENTRAL view.

(You see mostly right ventricle!)

Heart in DORSAL view.

(You see mostly left ventricle.)

Intrinsic regulation of heart beat

1. Sinoatrial node is PACEMAKER OF HEART, and beginning of process. Geenrates periodic impulses that initiate contraction of right atrium.

2. Signal then runs to Atrioventricular node. Message is passed along a track of Purkinje fibers called the...

3. Atrioventricular bundle. Atrioventricular bundle then splits into right and left limbs/branches that pass to individual inner ventricular walls on right and left.

Maximum Heartrate Calculation(Suggested) MAXIMUM HEARTRATE can be calculated by the formula:

208 - (0.7)(your age) = normal maximum heartrate.

Heartrate

Resting heartrate average is variable depending on ages, sex, weight, etc.

MAXIMUM HEARTRATE used to be calculated by the formula:

220 - your age = normal maximum heartrate.(This is now known to be oversimplified and incorrect.)

echo class 2_05262015

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