Blood supply of heart

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Learning objectives

Coronary Arteries – Origin, Course & Branches

Coronary dominance

Coronary anastomosis

Variations

Applied anatomy

Venous return

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Introduction: Coronary arteries -

VASAVASORUM arising from aortic sinuses of Valsalva of Ascending aorta

Rt CA - from Rt aortic sinus (ant)

Lt CA from Lt aortic sinus(left post)

Post Aortic sinus - non coronary

Max filling of sinuses - in diastole

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Basic considerations

• A-V groove

• I-V groove

• Crux of Heart

• SA node & its location

• A-V node & its location4

Rt Atrioventricular Groove, Ant Interventricular groove

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Atrioventricular groove (CS) &Post Interventricular groove

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Crux

Posteroinferior view

Meeting point of

•IA groove

• Post AV groove

•Post IV groove

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SA Node & AV Node location

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Rt Coronary Artery

Passes to rt & forwards b/w infundibulum of rt ven & rt auricle

Runs downwards in ant AV groove

Reaches inf margin of heart; winds around it to the diaph surface; runs in post AV groove

Ends by anastomosing with circumflex br of LCA -60%

Conus brs

Ventricular brs

AV nodal br

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Branches of Rt coronary Artery Rt conus artery-

Annulus of Vieussens SA Nodal br – 60% Ant atrial branches Ant ventr branches Rt Marginal artery:

(Largest br) Post ventr branches Post IV br arises near

CRUX – 70% br of RCA Post atrial branches AV Nodal artery – 80%

Conus brs

Ventricular brs

AV nodal br

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Conus brs

Ventricular brs

AV nodal br

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Lt Coronary Artery Origin: Lt Aortic

sinus

Passes behind infundibulum of Rt ventricle

Length: 0 to 10mm

Bifurcates into Ant IV branch (LAD) & Circumflex artery

Conus brs

Ventricular brs

AV nodal br

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LAD (Ant IV) artery Continuation of

LCA Extends beyond the

apex, ends by anastamosing with post IV artery (br of RCA)

Branches: Ant ventr brs:i. Diagonal arteriesii. Lt Conus artery Septal branches

Conus brs

Ventricular brs

AV nodal br

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Circumflex artery Runs in Ant AV groove and post AV groove Terminates by anastamosing with RCA near crux

Branches:

i. Atrial brsii. Ventr branchesiii. SA nodal (40% cases)iv. Lt Marginal v. Post IV br (only 10% cases)vi. Kugel’s arteryvii.AV nodal br (10-20%)

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Branches of Coronary arteries

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Coronary dominance CA that gives post IV branch is supposed to be

dominant

Misleading term as LCA supplies greater part of myocardium, but in 70% cases post IV is a br of RCA (Rt coronary dominance)

3 types – Rt (70%), Lt (20%) & Balanced (10%)

Clinical importance: In Lt dominance a block in LCA affect entire Lt ventricle and IVseptum, while in Rt or balanced dominance a block in RCA atleast spares part (2/3) of septum and lt ventricle

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Summary:

RCA:• Rt atrium• Lt atrium (ant part)• Rt ventr except a small strip along the Ant IV groove• Diaphragmatic surface of Rt ventricle• Post 1/3 of IV septum• SA Node and AV Node in majority• Most conducting system of heart except Lt branch of

Bundle of His

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LCA:

• Post part of Lt Atrium

• Ant and Lat walls of Lt ventricle

• Ant 2/3 of IV septum

• Lt br of Bundle of His

• SA & AV Nodes in 30% cases

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Coronary Anastomosis

-Anatomically CA are not end arteries but functionally they behave like end arteries.

-Anastomosis occur at: • superficial • subepicardial • Myocardial• subendocardial levels

Important sites:

i) b/w terminations of RCA & LCA near crux of heart ii) b/w their IV brs (in septum)iii) b/w conus As iv) apex Prognosis better in slow occlusion

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VariationsCongenital anomalies

- LCA arising from Pul trunk; cyanosis occurs

- LCA arises from right aortic sinus; may get compressed b/w Pul trunk & aorta in strenuous exercise; may cause sudden cardiac death

- Post IV A arising from Cx A (left dominance)

- SA nodal A in 40% from Cx A; AV nodal A in 20% from Cx A

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Post IV A arising from Circumflex br of LCA

Post IV Artery

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Venous Drainage

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Coronary Sinus

Heart is drained by CS - empties into Rt Atrium.

Two set of veins empty directly into Rt Atrium Venae cordis minimi Ant cardiac vein, s/t Rt marginal vein also

CS - dilatation of Great Cardiac Vein located in post part of AV groove

Opens into Rt atrium b/w IVC and Tricuspid opening guarded by incomplete semicircular “Thebasian valve”

Tributaries- all have valves except oblique V of lt atrium25

Tributaries of Coronary sinus:

1. Great Cardiac vein• Begins near apex of

heart; acc. Ant IV A & more proximally cx artery

• Terminates at lt end of coronary sinus

2. Middle cardiac vein• Accompanies Post IV

artery and opens at termination of coronary sinus

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3. Small Cardiac vein• Accompanies rt marginal artery• Runs in AV groove to end into rt end of CS• May open directly into rt atrium

4. Oblique Vein of Lt Atrium (of Marshall)• Runs in the post surface of Lt Atrium and drains into Lt end of Coronary sinus

5. Post Vein of Lt Ventricle• Runs on diaphragmatic surface of Lt ventricle and ends in middle of coronary

sinus

6. Rt Marginal vein• Accompanies Rt Marginal artery and drains into Small Cardiac vein or directly into

the Rt Atrium

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Oblique Vein of Lt Atrium (of Marshall)

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Veins directly emptying into Rt Atrium

1. Ant Cardiac Veins:

• 3-4 in no .drains the infundibulum of Rt ventricle• opens into Rt Atrium through its Ant wall

2. Venae Cordis Minimi/ Thebasian veins• Numerous small veins opening into the Post wall of

Rt Atrium

3. Small cardiac vein – may open directly into Rt atrium

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Applied Anatomy:

• Coronary Artery Disease (CAD)

• Coronary Angiography

• PTCA (Percutaneus Transluminal Coronary Angioplasty)

• CABG ( Coronary Artery Bypass Graft)

• Cardiac catheterisation30

Coronary Artery Disease (CAD) & Ischaemic Heart

Diseases (IHD) – due to atherosclerosis

- Angina Pectoris – transient myocardial ischemia- Myocardial Infarction – occlusive thrombus

Investigations for CAD & IHD

a) ECG b) Coronary Angiography

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Treatment of CAD

1. Medical T/t for angina

2. Stents- simple or drug-eluting (vasodilators)

3. Coronary Angioplasty (PTCA) - single vessel disease

4. Coronary Artery Bypass Graft (CABG) – triple vessel disease-median sternotomy-thymus incised-pericardium incised-SVC & IVC cannulated, venous blood goes to bypass machine-graft used: reversed Gr Saph V or Int Th A

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M. I.

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STENTING

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CABG

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CABG

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CORONARY CATHETRISATION

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Thank you

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