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720 PA R T I V / Pathophysiology and Management of Heart Disease
Diagnostic Tests diminished cardiac output. It is desirable to treat patients with
acute aortic regurgitation secondary to infective endocarditis with
Echocardiography is helpful in identifying the cause of aortic re- a minimum of 48 hours of appropriate intravenous antibiotics
gurgitation. Echocardiography can indicate left ventricular vol- before implanting a prosthetic valve. In patients with active en-
ume overload by the increased internal diameter of the ventricu- docarditis who are hemodynamically unstable, use of cadaveric
lar chamber during systole and diastole. Doppler echocardiography human aortic homografts may minimize the risk of prosthetic
is the best noninvasive means to detect aortic regurgitation. TEE valve endocarditis. Patients who have aortic regurgitation caused
is especially useful in imaging the ascending and descending aorta by ascending aortic dissection or dilation require replacement of
in patients with suspected aortic dissection. the ascending aorta as well.
Cardiac catheterization should be performed to visualize and In chronic aortic regurgitation, the aortic valve must be re-
quantify the extent of regurgitation before surgery. However, placed before irreversible left ventricular dysfunction develops. In
physical findings and noninvasive tests are sufficient to establish asymptomatic patients, it is usually recommended that the aortic
the diagnosis of aortic insufficiency. In patients with known or valve be replaced when left ventricular function begins to deterio-
suspected CHD, coronary angiography should be performed. In rate. Aortic valve replacement is recommended for the sympto-
patients with aortic root dilation, aortic root angiography may be matic patient when left ventricular ejection fraction drops to 0.50
performed concurrently with coronary angiography. or less, left ventricular systolic dimension is 55 mm or more, and
Radionuclide imaging can be used to estimate ejection fraction left ventricular diastolic dimension is 75 mm or more. 10
and determine myocardial perfusion defects in patients with con-
comitant CHD.
Exercise testing may be used to establish exercise tolerance and R EFEREN C E S
to evaluate asymptomatic patients. 1.Raju, B. S., & Turi, Z. G. (2008). Rheumatic fever. In P. Libby, R. O. Bonow,
Electrocardiography may be normal in patients with acute aor- D. L. Mann, et al. (Eds.), Braunwald’s heart disease (8th ed., pp. 2079–2086).
tic regurgitation or in patients with mild-to-moderate chronic re- Philadelphia: Saunders Elsevier.
gurgitation. Patients with moderate-to-severe chronic regurgita- 2. Towns, M. L., & Reller, L. B. (2003). Diagnostic methods: Current best
practices and guidelines for isolation of bacteria and fungi in infective en-
tion may have left-axis deviation and a pattern of left ventricular docarditis. Cardiology Clinics, 21, 197–205.
strain (Q waves in leads I, aVL, and V 3 to V 6 , with small R wave 3. Cabell, C. H., Abrutyn, E., & Karchmer, A. W. (2003). Bacterial endocardi-
in V 1 ). Intraventricular conduction defects may occur with left tis: The disease, treatment, and prevention. Circulation, 107, e185–e187.
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ventricular dysfunction or annular abscess. 4. Sexton, D. J., & Spelman, D. (2003). Current best practices and guide-
Chest radiography may show CHF only in the patient with lines: Assessment and management of complications in infective endo-
carditis. Cardiology Clinics, 21, 273–282.
acute aortic regurgitation because compensatory left ventricular 5. Karchmer, A. W. (2008). Infective endocarditis. In P. Libby, R. O. Bonow, D.
dilation has not yet occurred. In chronic aortic regurgitation, L. Mann, et al. (Eds.), Braunwald’s heart disease (8th ed., pp. 1713–1737).
the left ventricle enlarges in a leftward and inferior direction Philadelphia: Saunders Elsevier.
that causes little or no increase the transverse diameter. 10 Dila- 6. Olaison, L., & Pettersson, G. (2003). Current best practices and guide-
lines: Indications for surgical intervention in infective endocarditis. Car-
tion of the ascending aorta and a widened mediastinum may be diology Clinics, 21, 235–251.
noted in patients with aortic dissection. In patients with a di- 7. Sachdev, M., Peterson, G. E., & Jollis, J. G. (2003). Imaging techniques
lated aortic root or dissection, computed tomography or mag- for diagnosis of infective endocarditis. Cardiology Clinics, 21, 185–195.
netic resonance imaging may be necessary to better delineate 8. Nishimura, R. A., Carabello, B. A., Faxon, D. P., et al. (2008). ACC/AHA
the ascending aorta, transverse arch, and proximal descending Guideline update on valvular heart disease: Focused update on infective
endocarditis. Circulation, 118, 887–896.
aorta. 9. Dalen, J. E., & Fenster, P. E. (2000). Mitral stenosis. In J. S. Alpert, J. E.
Dalen, & S. H. Rahimtoola (Eds.), Valvular heart disease (3rd ed., pp.
75–112). Philadelphia: Lippincott Williams & Wilkins.
Medical Management 10. Otto, C. M., & Bonow, R. O. (2008). Valvular heart disease. In P. Libby,
R. O. Bonow, D. L. Mann, et al. (Eds.), Braunwald’s heart disease (8th ed.,
Patients who have asymptomatic aortic regurgitation should have pp. 1625–1712). Philadelphia: Saunders Elsevier.
afterload reduction with vasodilators. Diltiazem and verapamil are 11. Warnes, C. A. (2008). Pregnancy and heart disease. In P. Libby, R. O.
contraindicated in aortic regurgitation because they have a more Bonow, D. L. Mann, et al. (Eds.), Braunwald’s heart disease (8th ed., pp.
1967–1981). Philadelphia: Saunders Elsevier.
potent negative inotropic effect and may produce bradycardia, 12. Brady, T. J., Grist, T. M., Westra, S. J., et al. (2003). Valvular. In T. J.
which may worsen heart failure. In addition to long-acting Brady, T. M. Grist, S. J. Westra, et al. (Eds.), Pocket radiologist: Cardiac top
nifedipine and felodipine, angiotensin-converting enzyme in- 100 diagnoses (pp. 53–75). Salt Lake, UT: Amirsys.
hibitors may be used to reduce afterload. Sodium nitroprusside re- 13. Palacios, I. F., Sanchez, P. L., Harrell, L. C., et al. (2002). Which patients
duces preload and afterload and can be used to stabilize patients benefit from percutaneous mitral balloon valvuloplasty? Circulation, 105,
1465–1471.
with acute aortic regurgitation before surgery. Intra-aortic balloon 14. Mayes, C. E., Cigarroa, J. E., Lange, R. A., et al. (1999). Percutaneous mi-
counterpulsation cannot be used because inflation of the balloon tral balloon valvuloplasty. Clinics in Cardiology, 22, 501–503.
during diastole would increase the regurgitant volume into the left 15. Mazur, W., Parilak, L. D., Kaluza, G., et al. (1999). Balloon valvuloplasty
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ventricle, which acutely worsens left ventricular dilation and heart for mitral stenosis. Current Opinion in Cardiology, 14, 95–103.
failure. 16. Song, H., Kang, D. H., Kim, J. H., et al. (2007). Percutaneous mitral
valvuloplasty versus surgical treatment of mitral stenosis with severe mitral
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regurgitation. Circulation, 116(Suppl. I), I-246–I-250.
Surgical Management 17. Ewy, G. A. (2000). Tricuspid valve disease. In J. S. Alpert, J. E. Dalen, &
S. H. Rahimtoola (Eds.), Valvular heart disease (3rd ed., pp. 377–392).
Philadelphia: Lippincott Williams & Wilkins.
Acute aortic regurgitation requires urgent aortic valve replacement. 18. Jamieson, W. R. E. (2003). Update on new tissue valves. In K. L. Franco
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aortic regurgitation triggers rapid onset of CHF, tachycardia, and Hamilton, Ontario, Canada: BC Decker.