Fourth heart sound
| Fourth heart sound | |
|---|---|
| Other names | Atrial gallop, presystolic gallop |
.svg) | |
| Diagram of the heart. | |
| Specialty | Cardiology |
The fourth heart sound or S4 is an extra
This produces a rhythm classically compared to the cadence of the word "Tennessee."[1][full citation needed][2] One can also use the phrase "A-stiff-wall" to help with the cadence (a S4, stiff S1, wall S2), as well as the pathology of the S4 sound.[3]
Physiology
The normal heart sounds, S1 and S2, are produced during the closing of the atrioventricular valves and semilunar valves, respectively. The closing of these valves produces a brief period of turbulent flow, which produces sound.[4]
The S4 sound occurs, by definition, immediately before S1, while the atria of the heart are vigorously contracting.[5] It is manifest as a vibration of 20 to 30 Hz within the ventricle.[5] While the mechanism is not absolutely certain, it is generally accepted that S4 is caused by stiffening of the walls of the ventricles (usually the left), which produces abnormally turbulent flow as the atria contract to force blood into the ventricle.[5][4] This for example occurs in conditions that decrease ventricular compliance like left ventricular hypertrophy.[4]
S4 is sometimes audible in the elderly due to a more rigid ventricle. When loud, it is a sign of a pathologic state,
S4 has also been termed an atrial gallop or a presystolic gallop because of its occurrence late in the heart cycle. It is a type of gallop rhythm by virtue of having an extra sound; the other gallop rhythm is called S3. The two are quite different, but they may sometimes occur together forming a quadruple gallop. If the heart rate is also very fast (tachycardia), it can become difficult to distinguish between S3 and S4 thus producing a single sound called a summation gallop.
Treatment
The S4 heart sound itself does not require treatment; rather plans should be laid to stop the progression of whatever causes the underlying ventricular dysfunction. The S4 heart sound is a secondary manifestation of a primary disease process and treatment should be focused on treating the underlying, primary disease.
References
- ^ clinical examination A systemic guide to physical diagnosis
- ^ "Techniques - Heart Sounds & Murmurs Exam - Physical Diagnosis Skills - University of Washington School of Medicine". depts.washington.edu.
- ^ "The Fourth Heart Sound". The Auscultation Assistant - Rubs and Gallops.
- ^ PMID 31082054, retrieved 2023-10-26
- ^ PMID 21250185– via www.ncbi.nlm.nih.gov.
- ^ "THE PHONOCARDIOGRAPHY". Retrieved 2009-03-06.
- PMID 8914783.
External links
- KUO PT, SCHNABEL TG, BLAKEMORE WS, WHEREAT AF (1957). "Diastolic gallop sounds, the mechanism of production". J. Clin. Invest. 36 (7): 1035–42. PMID 13449156.