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Home , Fourth heart sound, Gallop rhythm, Pulse

sociated with an effective atrial contraction. The atrial gallop is occasionally heard in patients with no evidence of disease, particularly during times of high such as occur with thyrotoxicosis or pregnancy. This presystolic Information sound is also heard in patients with first degree atrioventricular block (prolonged P-R interval on electrocardiogram). However, an audible usually indicates heart disease and its presence is usually dependent on three fac- tors: (1) effective atrial contraction, (2) unim- peded ventricular filling, and (3) diminished ROBERT A. O'RouRKE., M.D. ventricular distensibility (stiff ). The fourth heart sound is never present in Material Supplied by the American patients with and is an un- Heart Association common finding in patients with diminished left ventricular filling due to moderate or severe mitral stenosis. It is usually absent in patients THE TERM "GALLOP RHYTHM" was originated by with constrictive pericarditis. The atrial gallop Professor Bouillaud and propagated by his pu- generally signifies reduced ventricular distensi- pil Potain more than a century ago. However, bility and is frequently but not always associ- even today, the majority of gallop sounds are ated with an increase in ventricular unrecognized or misinterpreted. This is unfor- end-diastolic tunate because gallop rhythm is frequently the pressure. only positive physical finding in patients with The presystolic gallop may originate in the heart disease and its presence often has impor- right or left ventricle. Left-sided fourth heart tant diagnostic and therapeutic implications. sounds are commonly present in patients with Gallop rhythm is an auscultatory phenomenon diastolic , severe , in which a tripling or quadrupling of heart myocardiopathies and acute mitral regurgitation. sounds resembles the canter of a horse. Tachy- Most patients with an acute myocardial infarc- cardia need not be present. Gallop sounds are tion and sinus rhythm have a prominent fourth low frequency diastolic events related to two heart sound. A presystolic gallop is a frequent periods of ventricular filling: the rapid filling finding in patients with coronary disease phase (third heart sound, ventricular gallop) but may be only heard during an episode of and the presystolic filling associated with atrial . (fourth heart sound, atrial gallop). Both Left-sided fourth are frequently third and fourth heart sounds may be present in accompanied by visible palpable presystolic. dis- the same patient. During or ad- tension of the left ventricular apex. This is best vanced first degree A-v block, both gallop sounds observed with the patient on his left side. On may occur at almost the identical time, produc- , the low frequency vibrations ing a summation gallop. The summation gallop of the atrial gallop are coincident with the pre- may be confused with the diastolic rumble of systolic"a"% wave of the apexcardiogram. The mitral stenosis. However, decreasing the heart left-sided fourth heart sound is best heard by rate by transient carotid sinus pressure will sep- using light pressure with the bell of the stetho- arate the two gallops and distinguish them from scope and is maximal in intensity at the left a diastolic rumble. ventricular apex with the patient in the left lat- eral position. If patients are not turned to this Fourth Heart Sound position during , over 50 percent of atrial gallops will be undetected. The left-sided The fourth heart sound (presystolic gallop, presystolic gallop is usually most prominent dur- atrial gallop) is a low frequency sound produced ing the expiratory phase of respiration. in the as- ventricle during the ventricular filling The atrial gallop increases in intensity and Dr. O'Rourke is from the Department of , University of California, San Diego, School of Medicine. the fourth heart sound-first heart sound interval

CALIFORNIA MEDICINE 85 The Western Journal of Medicine lengthens as the result of an increase in ventric- quency sound is most prominent during expira- ular filling, a prolongation of atrioventricular tion. The right-sided ventricular gallop, fre- conduction or a decrease in ventricular distensi- quently present in patients with right heart bility. During bedside auscultation the left- failure or tricuspid regurgitation, is heard best sided atrial gallop is usually accentuated after at the lower left sternal border and increases coughing and during mild supine exercise. It with inspiration. It is often accompanied by a also becomes prominent during a sustained prominent late systolic "v"' wave in the jugular handgrip contraction. During these maneuvers venous , the systolic murmur of tricuspid the fourth heart sound-first heart interval fre- regurgitation, and a large liver which pulsates quently increases in contrast to splitting of the in late systole. The third heart sound occurs first heart sound which becomes less evident later in than the higher frequency A-V with the increase in . valve opening snap from which it must be dis- Right-sided fourth heart sounds are frequently tinguished. The ventricular gallop, unlike the present in patients with right ventricular hyper- opening snap, decreases or disappears when the trophy secondary to either pulmonary hyperten- patient assumes the upright position. sion or pulmonary stenosis. They are commonly accompanied by a prominent presystolic "a" wave in the jugular venous pulse and a para- sternal or subxiphoid right ventricular lift. These low frequency sounds are heard best at the third to fifth left intercostal spaces and often increase in intensity during inspiration. Both the right- and left-sided fourth heart sounds can often be distinguished from the two components of the first heart sound by applying increasing chest wall pressure with the bell piece Comprehensive Melanoma of the . As pressure is increased the bell functions as a diaphragm and low frequency Clinic sounds such as the fourth heart sound usually decrease in intensity or disappear. In contrast, THE COMPREHENSIVE MELANOMA CLINIC is a the high frequency components of the first heart new service available at the University of Cali- sound persist unchanged. fornia, San Francisco, medical center. Under the direction of Dr. M. Scott Blois, Professor in Residence of Dermatology, the clinic offers a Third Heart Sound complete program of diagnosis and treatment The third heart sound (ventricular gallop, for melanoma patients. proto diastolic gallop) is a low frequency sound The clinic was established in mid-1971 to pro- produced in the ventricle in early diastole dur- vide a central facility for the diagnosis and treat- ing passive rapid filling. This early diastolic ment of melanoma, a malignant lesion account- sound is a frequent finding in normal children ing for 1 to 2 percent of all cancers. The staff and young adults and also in patients with a includes consultants from several specialties - high cardiac output. However, the presence of oncology, surgery, radiology, immunology, der- a third heart sound in patients over the age of matology and pathology - whose services are 40 generally indicates ventricular decompensa- available to all clinic patients. tion or A-V valve regurgitation. The ventricular Diagnostic and therapeutic services not gen- gallop, like the fourth heart sound, can be pro- erally available are provided by the clinic. duced in either ventricle and is heard best with Among these are immunologic screening and the bell piece of the stethoscope. The left-sided biochemical studies which relate to disease stag- third heart sound, commonly present in patients ing and prognosis. with left or mitral regurgitation, is Referrals to the Comprehensive Melanoma heard best on the left ventricular apex with the Clinic should be made through the Dermatology patient in the left lateral position. This low fre- Outpatient Clinic, (415) 666-2053.

86 MAY 1972 * 16 * 5