Advanced Cardiac Physiology
Information Covered:
II. Physiology
1. Cardiac cycle
- Consists of systole and diastole of atria and ventricles
- Cycle occurs in about 0.8 seconds and 70-80 cycles/minute average
- Events that occur in 1 cardiac cycle:
a. Atrial systole
- AV valves open and SL valves closed
- ventricles relaxed
- preceded by P wave on ECG
b. Isovolumetric contraction
- between start of ventricular systole and opening of SL valves
- ventricular volume remains constant
- onset coincides with R wave on ECG
- first heart sound heart (S1)
a) caused by ventricles contracting and closure of cuspid valves
b) “lubb” sound
- c. Ejection -- Initial, shorter, rapid ejection followed by longer phase
of reduced ejection
- Residual volume of blood remains in ventricles following ejection phase
- Residual volume increases in states of heart failure
- d. Isovolumetric relaxation
- period between closure of SL valves and opening of AV valves
- ventricles are relaxing
- second heart sound heard during this phase (S2)
a) caused by closure of SL valves
b) “dubb” sound
- e. Rapid ventricular filling f. Reduced ventricular filling (diastasis)
- 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.