KEY POINTS

1. Each heartbeat consists of ventricular systole and ventricular diastole.

2. Cardiac output equals heart rate multiplied by stroke volume.

3. Up to a point, increases in end-diastolic ventricular volume cause increases in stroke volume.

4. End-diastolic ventricular volume is determined by ventricular preload, ventricular compliance, and diastolic filling time.

5. Increases in ventricular contractility cause decreases in ventricular end-systolic volume.

6. Increasing the heart rate does not increase cardiac output substantially unless stroke volume is maintained.

7. Murmurs are abnormal heart sounds caused by turbulent flow through cardiac defects.

8. Some cardiac defects increase the heart's workload, which causes cardiac hypertrophy.

9. The pathological consequences of cardiac defects are direct results of the abnormal pressures, volumes, and workloads created in the cardiac chambers.