Anatomy: Heart And Pericardium

Anatomy of the Pericardium & Heart Karlos Noel R. Aleta, M.D. Dept of Surgery San Beda College of Medicine 1

Outline • •

Pericardium Heart • Surface anatomy • Internal anatomy • Valves • Chambers • Skeleton • Conduction pathway • Nerve • Blood supply • Arterial • Coronary artery disease • Venous

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PERICARDIUM • •

fibroserous sac w/c surrounds heart & root of great vessels Invaginate the serous sac from behind during devt

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Components of the pericardium 1. FIBROUS Pericardium •

outer layer of pericardial sac ~ cone shaped bag

Boarders: • superior: pretracheal fascia • posterior: trachea & 1° bronchi • anterior: sternum • Inferior: fused w/ diaphragm Structures w/c pass thru: • 4 pulmonary veins • IVC [R side] 4

Components of the pericardium 2. SEROUS Pericardium a. PARIETAL • lines inner surface of fibrous pericardium b. VISCERAL • ‘epicardium’ • lines outer surface of ♥ • completely invests heart EXCEPT POSTERIORLY b/w entrance of 2 vena cavae & 4 pulmonary veins

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Pericardial Cavity • • • • •

space b/w parietal & visceral percardium (+) small amt of pericardial fluid ~ prevents friction, “lubrication” normal capacity ~ 50 ml max capacity ~ 300 ml Pericardial effusion ~ accumulation of fluid w/in sac 6

Pericardial tamponade • •

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“cardiac tamponade” Limits diastole (PRELOAD) ~restricted expansion of relaxed heart ~compromise ability to fill w/ blood properly ~inadequate amount propelled to systemic circ 60 ~ 100 ml acute accumulation of blood/clots/fluid can produce tamponade 7

Cardiac tamponade Clinical picture • Beck’s triad (hypotension, distended neck veins, muffled heart sounds) • Pulsus paradoxus (exaggerated fall in systolic BP during inspiration • Drain fluid 8

Constrictive Pericarditis • • • • •

Inflammation~affects both parietal & visceral Thickening ~ adherence to underlying myocardium May initially present w/ pericardial effusion Chronic constriction In PI, TB #1 etiology

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Pericardiectomy/pericardial stripping •

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Pericardiectomy ~ allow chamber to expand Thickened pericardium Anterior, posterior CP bypass machine

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Constrictive Pericarditis

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Constrictive Pericarditis

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Constrictive Pericardiectomy

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Sinuses 1. Transverse • Breakdown of embryonic dorsal mesocardium • passage fr L --> R • behind pulmonary trunk & ascending aorta • sign ific anc e: ligate pulmonary trunk & asc. aorta during cardiac transplant 14

Transverse Sinus

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Sinuses 2. Oblique • behind LV & LA • LA & 4PV enter LA in base/posterior • Serous p reflects onto inner surface of fibrous p as parietal p • Reflection of serous p forms blind ending sac 16

Oblique Sinus

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Nerve supply •

Fibrous / Parietal - Somatic N [ fr phrenic N]

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Visceral - Autonomic N [ fr coronary plexus] • insensitive to pain

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Blood supply of Pericardium •

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Fibrous & parietal → branches from: – internal thoracic [mammary] a – bronchial a – pericardiacophrenic a – aorta – arteries to diaphragm Visceral → coronary a [ share w/ myocardium ] 19

Pericardial pain •

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felt diffusely posterior to the sternum ~ substernal pain • May radiate to other areas Acute inflammation of pericardial sac ~ pericarditis ~ Pain, +/- effusion • Auscultation ~ pericardial friction rub 20

Heart • •

central organ of circulatory system wall : EPICARDIUM - external surface MYOCARDIUM - middle, muscular, thickest ENDOCARDIUM - internal surface

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Heart • •

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short CONE base: faces posteriorly • formed b y LA & part of RA apex: points downward, to Left & forward formed by LV Apex beat is Point of Maximal Impulse located at 5th ICS, L midclavicular line

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Surfaces 1. Diaphragmatic or inferior • LV & part of RV • rests on diaphragm 2. Left surface • LV 3. Right surface • RA 4. Sternocostal • faces anteriorly • RV , partly by RA & LV • RV = m ost c ommon ly injur ed in penetrating trauma 23

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Penetrating cardiac injury • •

Pathophysiology Injury pattern • Right ventricle • Left ventricle • Right atrium • Left atrium • Complex • Coronary arteries

most common (>40 %) 2nd most common (40%) 24% 3% 8% 5% 25

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Cardiac Box - Penetrating cardiac injury - In stable patients ~ r/o (+/─) pericardial effusion ~ prove if blood - In unstable patients ~ open/surgery to locate & repair external cardiac injury 27

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Traumatic cardiac tamponade

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Traumatic Cardiac Injury

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D. Internal Anatomy 1. Chambers : R atrium L atrium

R ventricle L ventricle

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Internal Anatomy 2. Openings/ Valves Function of valves: prevent backward flow of blood a. Tricuspid = R atrioventricular, valve w/ 3 cusps b. Mitral = L atrioventricular, valve w/ 2 cusps c. Aortic = bet LV & aorta d. Pulmonic = bet. RV & pulmonary trunk e. Aortic sinuses - dilated pockets bet cusps & aortic wall - origin of coronary arteries 32

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Rheumatic Heart Disease • • • • •

vegetations calcifications affects mainly mitral valve cause stenosis or insufficiency severity may affect other valves

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Valvular surgery • • •

Closed Valve repair Open Valve repair Open Valve replacement

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PROSTHETIC VALVES •

Types of valves • Mechanical • Tissue • Xenografts • autografts/human homografts

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MECHANICAL VALVES

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TISSUE VALVES

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VALVE REPLACEMENT

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CHAMBERS of the HEART

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1. R ATRIUM • quadrangular shaped • receives blood fr SVC, IVC & coronary sinus • communicates w/ RV thru R AV opening

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R ATRIUM • crista terminalis = smooth muscular ridge w/c divides into 2 parts: • 1. sinus venarum = smooth,thin, posterior part where vena cava open, coronary sinus • 2. musculi pectinati = rough, thick, anterior part 45

R ATRIUM •

fossa o va lis ~ depression above orifice of IVC

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marks location of former foramen ovale [opening thru w/c blood flows fr RA → LA before birth]

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Congenital Heart Disease Atrial septal defect = incomplete closure of foramen ovale (most common) ~ “patent foramen ovale” (PFO) = blood flows fr LA → RA 47

ATRIAL SEPTAL DEFECT

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Hole in interatrial septum (IAS) of variable sizes Left-to-right shunting → atrial level Association with other cardiac anomalies

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TYPES OF ASD 1.

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Sinus venosus • 5-10% • PAPVR Ostium primum • Partial AV canal defects • 10-15% Ostium secundum • 80% • Patent foramen ovale (PFO)

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ASD REPAIR

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2. R VENTRICLE •

C -shaped cavity ~ capacity of 85 ml

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leads to Pulmonary trunk

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trabeculae carnae = fleshy ridges on ventricular wall

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interventricular septum = partition b/w RV & LV 51

R VENTRICLE •

2 parts: 1] membranous = thin 2] muscular = thick

Ventricular septal defect = affects membranous part

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R VENTRICLE • se ptoma rgin al tra becu la = elevated band w/c bridges interventricular septum & anterior wall near apex = transmits right branch of conducting system • papilla ry mu scl es = column-like projections fr trabeculae 3 sets: anterior - most constant & largest posterior septal 53

R VENTRICLE •

chordae tendinae = fibrous cords attached to apices of papillary muscles fr cusps of valves

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function of papillary muscle & chordae: * prevent eversion of cusps of valves into atrium

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VENTRICULAR SEPTAL DEFECT

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Congenital or acquired Hole/s in interventricular septum (IVS) May be part of other major cardiac anomalies 55

VENTRICULAR SEPTAL DEFECT

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VSD PATCH CLOSURE

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3. L ATRIUM •

sm al ler but t hicke r wall (v s. R A)

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base of heart

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mo st co mm on si te of b enign ca rdiac tumo rs ca lled my xo ma

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L ATRIUM 2 par ts : 1. Princ ip al c avity = contains openings of 4 pulmonary veins =AV opening [mitral valve] is smaller than R = smooth surface

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L ATRIUM 2. A ur icle = longer & narrower (vs RA) = interior marked by ridges of musculi pectinati

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4. L VENTRICLE

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more wor k than RV ~pump into systemic circulation long er , m ore conical, thic ker walls than RV

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L VENTRICLE •

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trabeculae carnae are more nume rou s & dense ly packe d papillary mu scl es are l arg er Interventricular septum • > oblique position

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SKELETON OF THE HEART • • • •

formed by merging of fibrous rings attachment for myocardium attachment for cusps of valves keep valves patent & from overdistension

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SKELETON OF THE HEART • • •

“Wringing” of blood in Allows myocardium to contract against a rigid base Provides connective tissue skeleton for controlled contraction of the heart

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SKELETON OF THE HEART co mp onents : 1. 4 fib ro us rings = each encircles a valve 2. 2 f ibrous trigones = bet aortic ring and AV ring 3. te ndon of co nus

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CONDUCTING SYSTEM • •

modified cardiac muscles w/ power of spontaneous rhythmicity & conduction more highly developed than rest of the heart

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CONDUCTING SYSTEM Parts: 1. SINO ATRIAL (S A) No de - in crista terminalis at junction of SVC-RA - not visible grossly - initiates contraction of heart internal PA CEM AKER 2. Atriov entricular (A V) node - near orifice of coronary sinus in septal wall of RA 67

CONDUCTING SYSTEM 3. Atri ov en tricu lar bundle (B undle of H is) • begins at AV node & follows along membranous septum towards the L AV opening for a distance of 1-2 cm a. Right branch → RV b. Left branch → LV 4. Purki nje f ibers • terminal conducting fibers • ramify on individual fibers throughout ventricle

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Conduction pathway:

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SA node ---> AV node ---> AV bundle ----> bundle branch ----> Purkinje fibers

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Cardiac Plexus • • • •

Controls impulse conduction for the ♥ Enables ♥ to respond to Δ-ing physiological needs located at base of ♥ extends fr trachea to aortic arch, pulmonary trunk & ligamentum arteriosum

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Cardiac Plexus 1. Parasympathetic – fr Vagus n - ↓ in heart rate - ↓ force of heartbeat - constricts CAs 2. Sympathetic - fr cervical & thoracic ganglia - ↑ in heart rate - ↑ force of heartbeat - dilates CAs 71

Sy mpa the tic Subdivisions: 1. Superficial cardiac plexus -lies in arch of aorta 2. Deep cardiac plexus -deep to arch of aorta

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Angina Pectoris & Myocardial Infarction • •

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Cardiac referred pain Commonly present as: • Substernal • L pectoral • L arm medial Less common → R shoulder & arm • w/ or w/o concommitant L side pain 74

Cardiac referred pain • • •

Heart insensitive to touch, cutting, cold & heat Ischemia + accumulated metabolic products ~ stimulate pain endings in myocardium Sympathetic trunk

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Blood Supply Coronary arteries - fr aortic sinus of ascending aorta 1) Right 2) Left

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Right coronary artery (RCA) branches: 1. posterior interventricular branch = supplies diaphragmatic surface of both ventricles, lo ng est 2. marginal 3. br to SA node 4. br to AV node 5. br to conus

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Left coronary artery (LCA)

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bifurcates into:

1. anterior interventricular = both ventricles, interventricular septum, conus 2. circumflex Branches : -Posterior L ventricular art -Marginal -Intermediate -branch to SA node & AV node

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Coronary Angiogram

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Coronary Angiogram

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Coronary Angiogram

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Venous system 1.

coronary sinus ~ main venous drainage (except 2.) ~ opens into RA

2. small veins ~ drain directly into chambers - venae cordis minimae - anterior cardiac v 82

Venous Drainage Coronary sinus tributaries: 1. Great cardiac 2. Middle cardiac 3. Small cardiac 4. Left posterior ventricular 5. Left oblique atrial

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Myocardial ischemia - insufficient blood supply to heart - necrosis of an area of myocardium - Myocardial Infarct or MI

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Common sites of coronary occlusion: “ Triple vessel disease” 1. Anterior interventricular branch of Left coronary art (LCA) 2. Circumflex branch of LCA 3. Posterior interventricular branch of RCA

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Most common cause of coronary occlusion : Atherosclerosis

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Heart-Lung Bypass Machine

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Heart-Lung Bypass Machine

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Heart-Lung Bypass Machine

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Internal Mammary Artery Grafts

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CORONARY ARTERY BYPASS GRAFTING (CABG)

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THANK YOU

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