Archive for October 9th, 2012

What is a gallop rhythm? Is it tachycardia plus S3 and/or S4?

Firstly, what is a gallop?

Oxford Advanced Learner’s Dictionary, 8th edition
gal • lop verb, noun BrE / ˈɡæləp / NAmE / ˈɡæləp /
1 [ singular ] the fastest speed at which a horse can run, with a stage in which all four feet are off the ground together
He rode off at a gallop .
My horse suddenly broke into a gallop .

2 [ countable ] a ride on a horse at its fastest speed to go for a gallop
3 [ singular ] an unusually fast speed
She always lives life at a gallop.
© Oxford University Press, 2010

This animation beautifully illustrates the “state in which all four feet [of a horse] are off the ground together“.  Actually, the story behind this animation is very interesting. It was to answer “a popularly debated question of the day [in 1872] — whether all four feet of a horse were off the ground at the same time while trotting“. You can read more here:
Some people define gallop rhythm as:

Gallop rhythm = S1 & S2 + S3 or/and S4 + Tachycardia

Today,this topic was raised in front of me. When I commented that the definition doesn’t include tachycardia. My colleagues were either silent or against my notion. Finally, the doctor said: “I have never heard of a definition of gallop rhythm that doesn’t include tachycardia!”. Well, all the following sources have something else to say. They all agree that:

Gallop rhythm = S1 & S2 + S3 or/and S4 (The definition ends here! No tachycardia!)

In more details: Gallop rhythm = S1 & S2 + S3     OR     S1 & S2 + S4     OR     S1 & S 2 + S3 & S4

Third and fourth heart sounds: These are pathological.

– A third heart sound is due to rapid ventricular filling and is present in heart failure.

– A fourth heart sound occurs in late diastole and is associated with atrial contraction.
Either, singly or together, will produce a gallop rhythm.

Source: Kumar & Clark’s Clinical Medicine, 7th Edition, 2009, p. 692:

Gallops — An abnormal S3 and S4 tend to be louder and of higher pitch (sharper) and are frequently referred to as gallops. S3 is the ventricular gallop and S4 is the atrial gallop sound. S3 and S4 can be fused during tachycardia to produce a loud diastolic filling sound, termed a summation gallop.

Source: Uptodate website and the citation of the above paragraph is: Shah, PM, Jackson, D. Third heart sound and summation gallop. In: Physiologic Principles of Heart Sounds and Murmurs, monograph No. 46, Leon, DF, Shaver, JA (Eds), American Heart Association, New York 1975. p.79.

Gallop: A triple cadence to the heart sounds; due to an abnormal third or fourth heart sound being heard in addition to the first and second sounds, and usually indicative of serious disease. Syn: bruit de galop, Traube bruit, cantering rhythm, gallop rhythm.

Gallop sound: the abnormal third or fourth heart sound which, when added to the first and second sounds, produces the triple cadence of gallop rhythm. See Also: gallop.

Source: Stedman’s Electronic Medical Dictionary, 6th edition, 2004.


A pathologic S3 or ventricular gallop sounds just like a physiologic S3. An S3 in a person over age 40 (possibly a little older in women) is almost certainly pathologic, arising from altered left ventricular compliance at the end of the rapid filling phase of diastole.62 Causes include decreased myocardial contractility, congestive heart failure, and volume overloading of a ventricle, as in mitral or tricuspid regurgitation. A left-sided S3 is heard typically at the apex in the left lateral decubitus position. A right-sided S3 is usually heard along the lower left sternal border or below the xiphoid with the patient supine, and is louder on inspiration. The term gallop comes from the cadence of three heart sounds, especially at rapid heart rates, and sounds like “Kentucky.”

Source: Bate’s Guide to Physical Examination and History Taking, 10th edition, 2009, chapter 9.

Gallop rhythm is an auscultatory phenomenon in which a tripling or quadrupling of heart sounds resembles the canter of a horse. Tachycardia need not be present.

Source: Gallop rhythm, R A O’Rourke, Calif Med. 1972 May; 116(5): 85–86,

Even Merriam-Webster website does not mention tachycardia in the definition:

gallop rhythm noun

Definition of GALLOP RHYTHM

: an abnormal heart rhythm marked by the occurrence of three distinct sounds in each heartbeat like the sound of a galloping horse—called also gallop