Anatomical Drawing of Human Heart The Cardiac Cycle

Origin and features of heart sounds

Heart Sounds
Mechanism
Clinical Features
Hear a Normal Sound
First (S1)
M-T valve closure*
Single
Second (S2)
A2-P2 valve closure**
Split***
Third (S3)
Early diastole
May be normal
Fourth (S4)
Late diastole
Pathologic
 
*Mitral and tricuspid
**Aortic and pulmonic
***A2-P2 interval widens with inspiration.

Drawing of Normal Cardiac Cycle

Back to Physical Exam

Hear Heart Murmurs

Objectives | History | Physical Exam | Cardiac Cycle | Murmurs |
Criteria for Referral | Compare Sounds | Case Studies | Samples of Murmurs