Advanced Cardiac Physiology

Information Covered:

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 

  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 

    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: is 20-EMTP-F3-7202
Total CE Hours: 1.5
Level: Advanced
EMT-CE uses the NEMSES guidelines as the foundation for every course outline.