Public Safety Training Facility
Monroe Community College
Rochester, New York
The Forth Heart Sound
Examine the illustration and play the WAV file multiple times. It is more important to learn the cadence (pattern / timing) than the quality of the sounds at this point.
Remember and review the cardiac events as you listen. S4 is a low intensity, low pitch sound that is best heart with the bell of your stethoscope pressed lightly on the apex area of the heart. The sound of S4 occurs only in the presystolic time period. S4 is created when the atrial contraction rapidly distends the ventricle. When the stiff, non-complient ventricular wall reaches its physical limits, it suddenly tenses, and the S4 sound is created. Therefore, only patients with atrial contraction can have an S4 (atrial fibrillation and junctional rhythms should not have and S4). An S4 is always abnormal and can indicate Hypertension, AMI, or coronary artery disease. Most patients will have faster heart rates but this is a rate of 50 bpm to facilitate learning. Learning the cadence is your first task. Once you are very comfortable with the cadence, turn the volume down to a point where you can just hear the S4. This will be a more realistic representation of the S4 gallop. We will soon be providing examples of these heart sounds at different rates.
Once you have the S4 mastered, go on to the next case.
Return to Heart Sounds
Updated: September 23, 1997