THE CARDIAC CYCLE

Dr. Mariano J. Rey

1. To fully grasp the concept of the heart as a pump Ð through a thorough knowledge of myocardial performance and ventricular function.

2. To be able to describe the cardiac cycle in detail.

3. To understand all the physiologic factors that determine each of the components of the cardiac cycle.

1. Historical Background
• A. Erasistratus - the heart as a pump - (270 B.C.)
• B. Adolph Fck - cardiac output determination (1870)
• B. Forsmann - self cardiac catheterization (1929)
• C. Cournand - clinical catheterizations (1936)
• D. Wiggins - cardiac cycle diagram (1943)
2. Myocardial performance
• A. Starling's law of the heart
• B. Starling curves
• C. Pressure - volume loops
3. The Ventricular Cycle
• A. Systole
• (1) Isovolumetric Contraction
• (2) Ejection
• a. rapid ejection
• b. reduced ejection
• B. Diastole
• (1) Isovolumetric Relaxation
• (2) Filling
• a. rapid filling
• b. slow filling
4. The Atrial Cycle
• A. Systole
• B. Diastole
• C. a, c, and v waves
5. Cardiac Valves
• A. Semilunar valves
• (1) Aortic and Pulmonic
• B. Atrial-Ventricular Valves
• (1) Mitral and Tricuspid
6. Heart Sounds
• (S1, S2, S3, S4)
7. Determination of cardiac output
• A. Methods
• B. Cardiac index
• C. Stroke volume
• D. Ejection fraction

For Review

Define or Explain
• dp/dt
• inotropy
• lusotropy
• dye dilution method
• thermodilution method
• oxygen uptake/consumption method
Case Studies

Read over Case 2, Heart Block, in Chapter 27 (page 51). The discussion (page 157) demonstrates effectively the heart rate, stroke volume, and cardiac output relationships.

Computer Module

The A.D.A.M. Cardiovascular Module in a clever interactive fashion goes over the relevant issues discussed in this lecture. Section 7 - The Cardiac Cycle and Section 8 - Cardiac Output are the pertinent sections.

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