Page 110 - Critical Care Nursing Demystified

Chapter 3 CARE OF THE PATIENT WITH CRITICAL CARDIAC AND VASCULAR NEEDS 95

The fourth heart sound has a hollow, low-frequency, snappy sound. It is an
atrial gallop produced by atrial contractions forcing blood into a noncompliant
ventricle that is resistant to filling. The sound increases in intensity during inspi-
ration. It is heard late in diastole prior to the onset of S1 of the next cardiac
cycle, and has the rhythm of the word “Tennessee,” or “le-lub-dub.” An S4 can
be normal in an elderly person. It can also been heard in a myocardial infarction
(MI) when atria contract forcefully against a distended blood-filled ventricle.

Other Heart Sounds
Murmurs Heart murmurs are prolonged extra sounds that occur during systole
or diastole. They are heard loudest over the valve that is affected. They are
vibrations caused by turbulent blood flow through the cardiac chambers. Mur-
murs are not always caused by cardiac valvular disease. Other causes include
fever, anemia, exercise, or structural defects such as a patent foramen ovale. The
intensity of a murmur is measured on a scale of 1 to 6. The higher the number,
the louder the murmur. A grade 1 can barely be heard even with turning the
patient to his or her left side. A grade 4 can usually be felt through the chest
wall, and a grade 6 can be heard at the bedside without a stethoscope. Murmurs
are also characterized by systolic or diastolic timing, high or low pitch, location, Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
radiation, and quality, for example, “blowing,” “harsh,” or “grating.”

NURSING ALERT

New, extremely loud, harsh murmurs radiating in all directions from the apex of the
heart suggest an emergency situation requiring immediate intervention. Call the
responsible health care provider stat.

Pericardial Friction Rubs This abnormal heart sound is described as a high-pitched
back-and-forth scratching or grating sound that is equivalent to cardiac motion
within the pericardial sac. It is accompanied by chest pain secondary to pericar-
dial inflammation or effusion that can occur 1 week post cardiac surgery or post
myocardial infarction. The pericardial friction rub can be auscultated at Erb’s
point, which is the 3rd intercostal space to the left of the sternum. When a
pericardial friction rub is heard, report it to the health care provider immedi-
ately as anticoagulant therapy may need to be stopped. A pericardial friction
rub can indicate bleeding in the pericardial sac that would worsen with the use
of anticoagulants.