The main normal heart sounds are the S1 and the S2 heart sound. The S3 can be normal ... this is affected by the duration of the PR interval on the ECG. Length of PR interval: Remember that ...

Remember: Systole occurs between the S1 and S2 heart sounds, while diastole occurs between S2 and S1. With the knowledge of the possible cardiovascular conditions that cause systolic or diastolic ...