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Advanced Cardiac Anatomy

Advanced Cardiac Anatomy

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 (AV) 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 


                            ii. 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 (Bachmann’s bundle) 

   3. Middle internodal tract (Wenckebach’s tract) 

   4. Posterior internodal tract (Thorel’s tract) 

7. Anatomical tracts that bypass the atrioventricular node 


                   i. considered possible conduction routes that account for anomalous atrioventricular conduction (Wolff-Parkinson- White syndrome, 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 70-80 cycles/minute average 

   3. Events that occur in 1 cardiac cycle: 


     a. Atrial systole

1. AV valves open and SL valves closed 

2. ventricles relaxed 

3. preceded by P wave on ECG 


      b. Isovolumetric contraction

1. between start of ventricular systole and opening of SL 
valves 

2. ventricular volume remains constant 

3. onset coincides with R wave on ECG 

4. first heart sound heart (S1)

a)  caused by ventricles contracting and closure of cuspid valves 


b)  “lubb” sound 


1. c. Ejection -- Initial, shorter, rapid ejection followed by longer phase 
of reduced ejection
   1. Residual volume of blood remains in ventricles following 
ejection phase 

   2. Residual volume increases in states of heart failure 

2. d. Isovolumetric relaxation
   1. period between closure of SL valves and opening of AV 
valves 

   2. ventricles are relaxing 

   3. second heart sound heard during this phase (S2)

a)  caused by closure of SL valves 


b)  “dubb” sound 


1. e. Rapid ventricular filling 
f. Reduced ventricular filling (diastasis) 


1. Cardiac output 


                   1. Heart rate X stroke volume

• Starling’s law 

• Contractility 


 

Content Creator: Bridget Kammerzelt

CAPCE Course Number: 16-EMTP-F3-7201

Total CE Hours: 1

Level: Advanced

EMT-CE uses the NEMSES guidelines as the foundation for every course outline.