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Cardiac Cycle

(Learning Activities)

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Background Info

The cardiac cycle is the sequence of events that occurs during a single heartbeat. During a cardiac cycle, both the atria and ventricles undergo periods of contraction (systole) and relaxation (diastole), which are coordinated by the heart’s pacemaker cells.

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Phases of the Cardiac Cycle
(Slider)

Cardiac cycle phase 1
Cardiac cycle phase 2
Cardiac cycle phase 3
Cardiac cycle phase 4
Cardiac cycle phase 5
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Phases of the Cardiac Cycle
(Interactive Narrative)

Wigger’s Diagram and the Cardiac Cycle
(Interactive Narrative)

Sample Assessment and Evaluation
(Click to See Answers)

1. Atrial systole begins during which portion of ECG.

Midway through the P wave.