Advanced Cardiac Anatomy

Course overview

Objectives Describe the anatomy and physiology of the heart Describe blood flow and supply both to and through the heart Explain the cardiac conduction cycle Content Information Covered Anatomy of the Cardiovascular System A Location 1 Layers 1 Myocardium 2 Endocardium 3 Pericardium 1 Visceral epicardium 2 Parietal 3 Pericardial fluid 2 Chambers 1 Atria 2 Ventricles 3 Valves 1 Atrioventricular valves 1 Tricuspid right 2 Mitral left 2 Semilunar valves 1 Pulmonic right 2 Aortic left 4 Papillary muscles 5 Chordae tendineae 6 Myocardial blood supply 1 Arteries 1 Left coronary artery a Anterior descending artery LAD i Distribution to the conduction system ii Distribution to the left and right ventricles b Circumflex artery i Distribution to the conduction system ii Distribution to the left ventricle iii Distribution to the left atrium 2 Right coronary artery a Posterior descending artery i Distribution to the conduction system ii Distribution to left and right ventricles b Marginal artery i Distribution to the conduction system ii Distribution to the right ventricle iii Distribution to the right atrium b Veins 1 Coronary sinus 2 Great cardiac vein 7 Conduction system 1 Sinoatrial node 2 Atrioventricular node 3 Atrioventricular bundle Bundle of His 4 Bundle branches 1 Left anterior fascicle 2 Left posterior fascicle 3 Right 5 Purkinje network 6 Internodal and interatrial pathways 1 Atrioventricular node 2 Left atrium Bachmanns bundle 3 Middle internodal tract Wenckebachs tract 4 Posterior internodal tract Thorels tract 7 Anatomical tracts that bypass the atrioventricular node Considered possible conduction routes that account for anomalous atrioventricular conduction including Wolff Parkinson White syndrome and Lown Ganong Levine syndrome a James fibers b Mahaim fibers c Accessory bundle of Kent 8 Vascular system 1 Aorta 1 Ascending 2 Thoracic 3 Abdominal 2 Arteries 3 Arterioles 4 Capillaries 5 Venules 6 Veins 7 Vena cava 1 Superior 2 Inferior II Physiology 1 Cardiac cycle 1 Consists of systole and diastole of atria and ventricles 2 Cycle occurs in about 0.8 seconds and 70 to 80 cycles per minute on average 3 Events that occur in one cardiac cycle a Atrial systole AV valves open and semilunar valves closed Ventricles relaxed Preceded by P wave on ECG b Isovolumetric contraction 1 Occurs between start of ventricular systole and opening of semilunar valves 2 Ventricular volume remains constant 3 Onset coincides with R wave on ECG 4 First heart sound S1 a Caused by ventricular contraction and closure of cuspid valves b Lubb sound c Ejection phase Initial short rapid ejection followed by a longer phase of reduced ejection Residual volume of blood remains in ventricles following ejection Residual volume increases in states of heart failure d Isovolumetric relaxation 1 Period between closure of semilunar valves and opening of atrioventricular valves 2 Ventricles are relaxing 3 Second heart sound S2 a Caused by closure of semilunar valves b Dubb sound e Rapid ventricular filling f Reduced ventricular filling diastasis 2 Cardiac output 1 Heart rate times stroke volume Starling law Contractility