Page 260 - Cardiac Nursing

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236 P A R T III / Assessment of Heart Disease
muscle rupture because of the development of sudden and pro-
found heart failure.
S S
A 1 2 B S 1 S 2 In the setting of acute aortic dissection, coronary artery bypass
grafting with a friable aorta, or aortic valve replacement, new-onset
aortic insufficiency indicates retrograde dissection of the aorta, or
S S
C 1 2 D S 1 S 2 valve dehiscence. The murmur of aortic insufficiency is an early
diastolic, decrescendo murmur, heard at the second right or third
left ICS that radiates toward the apex. In acute aortic insuffi-
E S 1 S 2
ciency, the intensity of S 1 is frequently diminished because of the
■ Figure 10-27 Configuration of murmurs. (A) Crescendo. (B) increase in ventricular volume, and P 2 may be accentuated be-
33
Decrescendo. (C) Crescendo-decrescendo (diamond). (D) Plateau cause of the rapid rise in pulmonary vascular pressure. Acute left
(even). (E) Variable (uneven). (From Perloff, J. K. [1990]. Physical ex- ventricular failure may result from volume overload alone or, in
amination of the heart and circulation [p. 208]. Philadelphia: WB the case of continued retrograde dissection, from myocardial in-
Saunders.)
farction secondary to dissection of the coronary arteries.
Pericardial Friction Rubs. Pericardial friction rubs are char-
acteristic of pericarditis, which occurs in more than 15% of pa-
insufficiency (regurgitant or holosystolic murmurs), and ventricu- tients with acute myocardial infarction. A pericardial friction rub
lar septal defect (early systolic murmurs) secondary to myocardial develops in approximately 7% of patients with myocardial infarc-
infarction. In older adults, the murmur of aortic sclerosis (thick- tion, commonly by the fourth day after myocardial infarction.
ening of aortic valve leaflets) is common. The most common di- Rubs may be transient, lasting only several hours. The rub occurs
astolic murmurs are produced by the reverse set of circumstances: with heart movement; each movement creates its own short,
insufficiency of semilunar valves (early regurgitant murmurs) and scratchy sound (Fig. 10-28). Pericardial friction rubs are classified
stenosis of the atrioventricular valves (mid- to late-diastolic rum-
bles). The loudness of the murmur may not correlate with the
severity of the valvular lesion (e.g., a patient with a grade 5 to 6
murmur in whom cardiogenic shock develops actually may have
reduced intensity of the murmur because of diminished cardiac
blood flow). Refer to Chapter 29 for descriptions of the murmurs
of aortic and mitral stenosis and regurgitation.
Recognizing an innocent murmur is an important and difficult
skill. The innocent murmur can often be diagnosed by its clinical
features and the absence of other clinical abnormalities. Clinical
features of innocent murmurs include the following: always sys-
tolic, soft, short, modified by change in posture, normal S 2 , and
3
most common at left sternal border. Echocardiography may be
needed to confirm its innocence, and follow-up is essential. The
precordial “whoop” or “honk” may be an innocent finding in pa-
tients without organic heart disease or may represent an exagger- Ventricular Ventricular Atrial
ated phase of an organic murmur. 3,33 systole diastole systole
In the cardiac care unit, nurses are most often concerned with
changes in murmurs rather than in their diagnosis. However, it is
important to diagnose accurately the onset of murmurs of papil-
lary muscle dysfunction and aortic insufficiency. S 1 S 2 S 1
Normally, papillary muscle contraction allows for complete
closure of the atrioventricular valves. However, when the papillary
muscles are ischemic (most often in the left ventricle), they are un- Timing May have three short components, each associated
with cardiac movement: (1) atrial systole,
able to contract properly, preventing the chordae tendineae from (2) ventricular systole, and (3) ventricular diastole.
being held tautly and, in turn, from holding the mitral valve Usually the first two components are present; all
leaflets closed during left ventricular contraction. Blood is, there- three make diagnosis easy; only one (usually the
fore, allowed to flow backward through the mitral valve (mitral re- systolic) invites confusion with a murmur.
gurgitation) during systole. The murmur of mitral regurgitation Location Variable, but usually heard best in the 3rd left ICS
secondary to papillary muscle dysfunction is systolic (occurring in
early- to mid-systole) and usually soft, high pitched, and Radiation Little
crescendo–decrescendo in configuration. In the presence of heart Intensity Variable. May increase when the patient leans
failure or angina, the murmur may become holosystolic. forward, exhales, and holds breath (in contrast to
A new murmur of papillary muscle dysfunction in the patient pleural rub)
with acute myocardial infarction must be recognized immediately Quality Scratchy, scraping
because interventions must be instituted to relieve the papillary Pitch High (heard better with a diaphragm)
muscle ischemia and prevent progression to papillary muscle
infarction. Should the papillary muscles infarct, they also may
rupture; there is a high mortality rate associated with papillary ■ Figure 10-28 Pericardial friction rub.