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376.e2 Gallops and Other Extra Heart Sounds

Gallops and Other Extra Heart Sounds
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• A gallop sound is likely to be associated
BASIC INFORMATION
with signs of heart failure such as dyspnea, DIAGNOSIS
Definition tachypnea, heart murmurs, and a rapid heart Diagnostic Overview
Extra heart sounds are classified as sounds or rate. A gallop sound is identified purely on ausculta-
vibrations other than the normally ausculted • In the fluid-overloaded cat, the gallop is most tion of the heart. Phonocardiography, although
first and second heart sounds. These alter prominent along the left parasternal thoracic confirmatory, is performed very infrequently.
the sound of a heartbeat but not the cardiac region. Clinical findings that suggest imminent or
rhythm. Gallop sounds and extra heart sounds existing heart failure are compatible.
are different from premature cardiac beats and Etiology and Pathophysiology
arrhythmias. • Normally, only the S 1 and S 2 sounds are Differential Diagnosis
heard when auscultating the heart of the Triple heart sounds occurring at a slow rate
Synonyms dog or cat. are not likely to be gallop sounds and must
Third heart sound, fourth heart sound, dia- • When the usually inaudible third or fourth be differentiated from arrhythmias (extra
stolic heart sound, protodiastolic heart sound, sounds are so loud that they can be heard beats, heart block), systolic clicks, split heart
presystolic heart sound, summation diastolic (a gallop), they are an indication of ven- sounds, and opening snaps. See characteristics
heart sound tricular systolic and/or diastolic dysfunc- for differentiation above.
tion and are usually an indication of heart
Epidemiology failure/dysfunction. By definition, they Initial Database
SPECIES, AGE, SEX occur during diastole and are generated by Cardiac evaluation in the form of auscultation,
Dogs and cats of any age and either sex, in the vibration of ventricular walls during thoracic radiography, laboratory analyses, and
the presence of heart disease/heart failure/ early or passive ventricular filling (S 3 ) or echocardiography usually is sufficient to identify
ventricular dysfunction (gallop sounds) active or late ventricular filling (due to atrial a specific abnormality.
contraction [S 4 ]) into a poorly compliant
RISK FACTORS ventricle. TREATMENT
• Gallop sounds: congestive heart failure, • Additional heart sounds:
systolic and diastolic ventricular dysfunc- ○ Splitting of the normal heart sounds: Treatment Overview
tion, iatrogenic fluid/intravascular volume split S 1 due to the asynchronous closure Extra heart sounds in and of themselves are
overload of atrioventricular (AV) valves or split S 2 not treated. Attention is directed to identifying
• Systolic clicks: early mitral valvular insuf- due to asynchronous closure of aortic the underlying cause and determining whether
ficiency or flail leaflet and pulmonic (semilunar) valves caused treatment is required for the primary cause.
• Split heart sounds: increased ventricular pres- by alterations in pressures in the heart
sure (causing splitting sounds due to delayed and great vessels causing early or delayed Acute and Chronic Treatment
aortic or pulmonic valve closure in specific valve closure. Split heart sounds are best Treatment of the underlying disease is
circumstances), delayed intraventricular heard with the diaphragm of the stetho- appropriate.
conduction scope. Normal large-breed dogs may
• Pericardial friction rubs (rare): pericarditis, have split first and/or second sounds on PROGNOSIS & OUTCOME
inflammation of the external pericardial auscultation.
lining ○ Extracardiac rubbing sounds Varies, depending on cause
○ Systolic clicks: cause unidentified, pos-
Clinical Presentation sibly due to the warping/snapping of a
HISTORY, CHIEF COMPLAINT diseased, prolapsed mitral valve. They PEARLS & CONSIDERATIONS
• Heart failure and its concomitant clinical are usually heard best on the point of Comments
signs of virtually any cause can be associated maximal intensity of the heartbeat on • The bell of the stethoscope is useful for
with gallop sounds. the thorax and with the diaphragm differentiating low-frequency sounds such
• Split heart sounds may be normal or an of the stethoscope, in contrast to the as gallop sounds (bell disproportionately
indication of delay in valvular closure due gallop sound, which is a lower-frequency enhances the third heart sound) from other
to increased pressure(s) in one or both sound heard better with the bell. The heart sounds of higher frequency, such as
sides of the heart or due to high pressure systolic click may be single or multiple. split heart sounds and systolic clicks (heard
delaying valvular opening as in pulmonary It also may be consistent, or it may come more clearly with the diaphragm of the
hypertension. and go between consecutive cardiac stethoscope).
• Systolic clicks are not usually associated with cycles. • Many newer stethoscopes have only one
clinical signs. ○ Opening snaps: heard in diastole and head. In this case, press gently for the
• Pericardial rubs are associated with peri- indicative of a calcified or hardened lower-frequency sounds and more firmly
cardial diseases and their associated clinical valve leaflet making a snapping sound for a greater range of the heart sounds.
signs. when the valve opens during that phase
of the cardiac cycle. These are rarely Technician Tips
PHYSICAL EXAM FINDINGS heard in dogs and cats, but they may be • Because gallop sounds and systolic clicks
• A triple heart sound sequence with accen- demonstrated by phonocardiography. They result in a triple cadence, they can sometimes
tuated low-frequency sounds mimicking a may be associated with mitral stenosis, a be confused on physical examination.
cantering horse best describes a gallop sound. congenital heart condition. • Systolic clicks are higher frequency and
This low-frequency sound is heard best with ○ Friction rubs: due to rubbing of a dis- most common in small-breed dogs (that
the bell of the stethoscope and usually over eased pericardium against portions of the are predisposed to developing myxomatous/
the mitral and/or tricuspid valve area. thorax degenerative valve disease), whereas gallop

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