Fourth Heart Sound Gallop
The patient's position should be supine.
In the recording, note that the fourth heart sound (S4) occurs in late diastole just before S1. The S1 intensity is decreased, while S2 intensity is increased. The fourth heart sound is low-pitched. Use the stethoscope bell, pressing lightly on the chest wall.
The fourth heart sound is generated by increased left ventricle stiffness due to scar tissue formation. This condition could be due to coronary heart disease.
Essential hypertension and aortic stenosis can also lead to fourth heart sounds. The anatomy animation video provides an example of S4.