Blood supply of heart (1)

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  • 1. Blood supply of the Heart & Conduction System
  • 2. Arterial supply of Heart   Right coronary artery Left coronary artery
  • 3. Right Coronary Artery   Arises from anterior aortic sinus of the  Ascending Aorta. It descends in the right atrioventricular  groove. Near inferior border continuous  posteriorly along the atrioventricular  groove.  Anastomose with left coronary artery in  the posterior interventricular groove.
  • 4. Right Coronary Artery
  • 5.   Branches of Right Coronary Artery 1.Right conus artery:        Supplies rt ventricular outflow tract.  2.Rt marginal branch: Supply free wall of rt ventricle. 
  • 6.   3. Branches of Right Coronary Artery Rt posterolateral branch: goes back of lt ventricle         supply inferior aspect of interventricular         septum 4. Atrial branches: Supply anterior and lateral surface of the  right atrium. One branch supply posterior  surface of both right and left atria.  Artery of Sinuatrial Node (60%)
  • 7.   Branches of Right Coronary Artery 5. Posterior interventricular (descending)  artery  Runs towards apex in the posterior  interventricular groove.  Supply right & left ventricles, including  its inferior wall.  Supply posterior part of the ventricular  septum (Excluding Apex).     Large septal branch Supply  Atrioventricular Node. 
  • 8. Clinical division of the RCA    Proximal - Ostium to 1st main RV branch Mid - 1st RV branch to acute marginal branch Distal - acute margin to the crux
  • 9. Area of distribution RCA      Rt atrium Greater part of rt ventricle except area adjoining ant interventricular groove Small part of lt ventricle adjoining post interventricular groove Whole of conducting system of heart except part of lt branch of AV bundle SA Node –supplied by LCA (40%)
  • 10. Left Coronary Artery   Larger then Right coronary artery. Arises from posterior aortic sinus of the  Ascending Aorta. Passes between pulmonary trunk and left  auricle. It enters in the atrioventricular groove and  divides into an anterior interventricular branch  and a circumflex branch. Supply greater part of the left Atrium, left  ventricle and ventricular septum.
  • 11.   Branches of Left Coronary Artery 1. Anterior interventricular (descending) artery:    Runs in the anterior interventricular groove to           the Apex.  Passes around the Apex to enter the posterior               interventricular groove & anastomoses  with the   terminal branches of Right coronary  artery.     Supply right and left ventricles & anterior  part of ventricular septum.    Left diagonal branch       wrap over anterolateral free wall of lt ventricle
  • 12. Left Coronary Artery
  • 13.   2.  Branches of Left Coronary Artery Circumflex artery: Winds around the left margin of the heart  in the atrioventricular groove.  obtuse marginal branch:       supply lateral free wall of lt ventricle       does not reach crux in pt with rt dominant          circulation   Atrial branches: Supply left atrium.     Artery of Sinuatrial Node (40%)
  • 14. Clinical division of the LAD    Proximal - Ostium to 1st major septal perforator Mid - 1st perforator to D2 (90 degree angle) Distal - D2 to end
  • 15. Clinical division of the LCX    Proximal - Ostium to 1st major obtuse marginal branch Mid - OM1 to OM2 Distal - OM2 to end
  • 16. Area of distribution of LCA      Lt atrium Greater Prt of lt ventricle except post interventricular groove Small part of rt ventricle adjoining ant interventricular groove Ant part of interventricular septum Lt branch of AV bundle
  • 17. Conducting system of Heart    S-A Node: Right coronary artery (60%)                        Left coronary artery (40%)    A-V Node and A-V Bundle: Right coronary artery  Right Bundle branch: Left coronary artery   Left Bundle branch:  Right & Left coronary      arteries 
  • 18. Coronary segment classification system   CASS investigators – 27 segments BARI – 29 segments ( ramus intermedius and 3rd diagonal branch) - Obstructive CAD : > 50% stenosis
  • 19. Cardiac dominance 85%-rt dominant coronary artery  8% lt dominant-post descending,posterolateral lt ventricular and AVnodal artery all supplied by terminal portion of lt circumflex coronary artery.rt coronary artery small and supply only rt atrium and rt ventricle  7%-codominant  RCA-PDA and terminates,circumflex artery-all post Lt ventricular branches 
  • 20. Congenital anomaly of coronary circulation   Anomalous pulmary origin of coronary artery(APOCA) Most common-origin of LCA from pulmonary artery Aortography-large RCA with absence of lt coronary ostium in lt aortic sinus
  • 21. Anomalous coronary artery from opposite sinus  Origin of LCA from rt aortic sinus causes sudden cardiac death after exercise in young person
  • 22. Coronary artery fistula  Abnormal communication between coronary artery and major vessels such as venacava,pulmonary artery or vein
  • 23. Myocardial bridging  All 3 major coronary artery generally course along epicardial surface of heart sometime short coronary artery segment descend into myocardium for variable distance occurs in 5-12% of pt and confined to LAD
  • 24. Coronary artery spasm Dynamic and reversible occlusion of epicardial coronary artery caused by focal constriction of smooth muscle cell within arterial wall occurs in prinzmetal angina aggrevated by cigaratte smoking,cocaine alcohal,GA Not aggrevated by emotion,cold 
  • 25. Most common-separate ostium for LAD and lcx,simillarly in RCA-conus branch may have Separate ostium Origin of circumflex from rt coronary artery RCA-originate high in aortic root 
  • 26. “ Dominance ”   A misnomer giving rise to PDA, at least 1 PLV & AV nodal A (BARI classification) - 85% right dominant - 8% left dominant - 7% co-dominant (70%/ 10%/ 20% – Hurst’s THE HEART)  Left dominance is 25-30% in Bi-AoV Gensini GG. Coronary Arteriography. Mount Kisco,NY: Futura Publishing Co; 1975:260–274.
  • 27. Venous Drainage of Heart    Coronary Sinus:  Runs in the coronary sulcus (posterior  atrioventricular groove). Largest vein of heart About 3 cm long Ends by opening into post wall of rt  atrium Tributaries:  Great cardiac vein  Middle cardiac vein
  • 28.  Small cardiac vein Post vein of lt ventricle  Oblique vein of lt atrium  Rt marginal vein All drains into coronary sinus which opens into rt atrium 
  • 29. 1. 2. 3. 4. Great cardiac vein-accompany ant interventricular artery and then LCA Middle cardiac vein –accompany post interventricular artery and joins middle part of coronary sinus Small cardiac vein-accompany rt coronary artery Post vein of lt ventricle-runs on diaphragmatic
  • 30. Surrface of lt ventricle and ends in middle of coronary sinus 5 oblique vein of lt atrium-small vein running on post surface of lt atrium 6 rt marginal vein-accompany marginal branch of rt coronary artery
  • 31. Contents of Heart grooves 1.   Right atrioventricular groove:          Right coronary artery        Small cardiac vein 2.    Left anterior atrioventricular groove:        Left coronary artery        3.    Left posterior atrioventricular groove:        Coronary sinus 4.    Anterior interventricular groove:        Anterior interventricular artery         Great cardiac vein 5.    Posterior interventricular groove:        Posterior interventricular artery         Middle cardiac vein
  • 32. Venous drainage Ant cardiac vein and venae cordis minimi opens directly into rt atrium Ant cardiac vein 3-4 small vein running parrelel to one another on ant wall of rt ventricle venae cordis minimi-Thebesian vein or smallest cardiac vein Small vein present in all chambers of heart 
  • 33. Cardiac Veins (Sternocostal Surface) Anterior cardiac veins
  • 34. Cardiac Veins (Diaphragmatic Surface)
  • 35. Conducting System    Network of specialized tissue that stimulates contraction Modified cardiac myocytes The heart can contract without any innervation
  • 36. The  Cardiac  Conduction  System   The impulse conduction system of the heart consists  of four structures: 1.  The sinoatrial node (SA node) 2.  The atrioventricular node (AV node) 3.  The atrioventricular bundle (AV bundle) 4.  The Purkinje fibers The cardiac muscle fibers that compose these  structures are specialized for impulse  conduction,rather than the normal specialization of  muscle fibers for contraction.
  • 37. The sinoatrial node ”. SA node-located at junction of sup vena cava     and rt atrium   SA node-discharge mostrapidly,depolarisation Spread from it to other region before they  discharge spontaneously Its rate of dischage determine rate at which  heart beat This is also why the SA node is said to be the  “pacemaker” of the heart
  • 38. Spread of cardiac exitation      Atrial activation Septal activation Activation of anteroseptal region Activation of major portion of ventricular myocardium Activation of posterobasal portion of lt ventricle
  • 39. Impulses from the SA node are then conducted across the atria from right to left. The impulse does not however pass directly to the ventricles. When both the right and left atria are completely depolarized, they contract simultaneously.
  • 40. As the atria depolarize, the impulse is picked up by another group of specialized muscle fibers called the atrioventricular node. The AV node is located in the floor of the right atrium next to the interatrial septum. This group of fibers is the only conduction pathway between the atria and ventricles. As the impulse is conducted through the AV node, its speed is reduced. This is due to the extremely small diameter of the conducting fibers.
  • 41. This is an extremely important phenomenon because the delay in the transmission from atria to ventricles allows time for the atria to completely depolarize and contract, thus emptying their contents into the still fully relaxed ventricles.
  • 42. From the AV node, the impulse travels down the atrioventricular bundle. The AV bundle divides into two lines of transmission just below the AV node and these conduct the impulse down the length of the interventricular septum. An important fact about the fibers that make up the AV bundle is that they are large in diameter and therefore the impulse speed increases so it is conducted very rapidly down them.
  • 43. About halfway down the interventricular septum the “bundle branches” themselves begin to branch off into enlarged conduction fibers called Purkinje fibers. These fibers extend out to all areas of the two ventricles and since they are further enlarged, the speed of the impulse conduction is also additionally increased. Upon completion of impulse transmission through the Purkinje fibers, the ventricles will fully depolarize and then contract simultaneously.
  • 44. What causes what ?  Conduction problem in AV NODE & HIS BUNDLE1st, 2nd & 3rd degree heart blocks  Conduction problems in left & right bundle branches- RBBB LBBB LAHB LPHB Bi & Tri –
  • 45. Ventricular Conduction Disorders. Left Bundle Branch Block. Right Bundle Branch Block. Other related blocks.
  • 46. Left Bundle Branch Block.     Block of the left bundle or both fasicles of the left bundle. Electrical potential must travel down RBB. De-polarisation from right to left via cell transmission. Cell transmission longer due to LV mass.
  • 47. Left Bundle Branch Block (LBBB).
  • 48. ECG Criteria for LBBB.    QRS Duration >0.12secs. Broad, mono-morphic R wave leads I and V6. Broad mono-morphic S waves in V1 (can also have small 'r' wave).
  • 49. LBBB consequence.  Mostly abnormal ECG finding - indicates heart disease.        Coronary artery disease (indication for thrombolysis - if associated with chest pain and raised Troponin). Valvular heart disease. Hypertension. Cardiomegaly. Heart failure. Impacts on prognosis - QRS duration. Use of Bi-Ventricular Pacemakers.
  • 50. Right Bundle Branch Block.     Impulse transmitted normally by left bundle. Blocked right bundle results in cell depolarisation to spread impulse (slower). Impulse to IV septum and RV delayed. Results in an additional vector.
  • 51. Right Bundle Branch Block (RBBB).
  • 52. Additional Info RBBB.       Can be normal. Sometimes related to asthma or other airway conditions. Possibly due to RVH in young individuals. Usually due to CAD in older persons. Often related to congenital heart disease (particularly ASD). Often apparent following cardiac surgery.
  • 53. Left Anterior Hemi-block Appearance.
  • 54. ECG Features of Left Anterior Hemi-block.      Abnormal left axis deviation (between -30 and -900). Either a qR complex or an R wave in lead I. rS complex in lead III (possibly also II and aVF). Extremely common and un-diagnosed ECG feature. NOT ALWAYS ASSOCIATED WITH BBB.
  • 55. ECG Features Left Posterior Hemiblock.     Axis of 90 - 180o - (right axis). An s wave in lead I and a q wave in lead III. Exclusion of RAE or RVH. REMEMBER - most common cause of right axis is RVH so this must be excluded before you diagnose LPH.
  • 56. Left Posterior Hemi-block.
  • 57. INTRODUCTION TO HEART BLOCKS    OCCUR WHEN THERE IS A PARTIAL OR COMPLETE INTERRUPTION IN THE CARDIAC ELECTRICAL CONDUCTION SYSTEM. CAN OCCUR ANYWHERE IN THE ATRIA BETWEEN THE SA NODE AND THE AV JUNCTION. IN THE VENTRICLES BETWEEN THE AV JUNCTION AND PURKINJE FIBERS. For more medical presentations www.pmcosa.com
  • 58. FIRST-DEGREE HEART BLOCK    DELAY OF IMPULSE BETWEEN THE ATRIA AND BUNDLE OF HIS. OCCURS WHEN THERE IS A PARTIAL INTERRUPTION ANYWHERE IN THE ATRIAL OR AV JUNCTIONAL CONDUCTION SYSTEM. THE IMPULSE IS EVENTUALLY CONDUCTED BUT IS DELAYED. For more medical presentations www.pmcosa.com
  • 59. degree heart block Just prolongation of PR interval.  Normal PR 1 st = .2 Sec  Here it is .28 Sec 
  • 60. MOBITZ I HEART BLOCK     MOBITZ I ( WENCKEBACH OR SECONDDEGREE HEART BLOCK, TYPE I). PROGRESSIVE BLOCK. IMPULSE FROM THE ATRIA IS INTERRUPTED AT THE AV JUNCTION. THE INTERRUPTION BECOMES LONGER WITH EACH IMPULSE DELAYING DEPOLARIZATION OF THE VENTRICLES UNTIL A COMPLETE INTERRUPTION BLOCKS THEFor more medical presentations IMPULSE. www.pmcosa.com
  • 61. For more medical presentations www.pmcosa.com
  • 62. MOBITZ II HEART BLOCK    OCCURS DUE TO AN INTERMITTENT INTERRUPTION NEAR OR BELOW THE AV JUNCTION. INTERRUPTION IS NOT PROGRESSIVE, BUT OCCURS SUDDENLY AND WITHOUT WARNING!! P WAVES BEFORE EVERY QRS COMPLEX AND ALL ARE THE SAME SIZE AND SHAPE. presentations For more medical www.pmcosa.com
  • 63. For more medical presentations www.pmcosa.com
  • 64. THIRD-DEGREE HEART BLOCK    COMPLETE HEART BLOCK OR COMPLETE AV DISSOCIATION. IMPULSE IS COMPLETELY BLOCKED BETWEEN THE ATRIA AND THE VENTRICLES. USUALLY TAKES PLACE BETWEEN THE AV JUNCTION AND BUNDLE OF HIS. For more medical presentations www.pmcosa.com
  • 65. Third degree heart block For more medical presentations www.pmcosa.com