Heart Murmur, Systolic

Dale Bishop

Systolic murmurs can herald significant clinical deterioration and sudden death, or they can represent stable or clinically insignificant conditions. Although technologic advances in cardiac diagnostic testing continue, auscultation remains the mainstay of diagnosis and is the key to the cost-effective use of technology.

Approach

 Systolic murmurs can develop in all age groups. Close attention should be given to the history [looking for associated symptoms (e.g., dyspnea)] and to the physical examination (looking for specific murmur characteristics described below).

History

A. General issues in the history. The history can provide important clues as to whether the murmur is clinically significant. Any history of rheumatic fever, previously known valvular disease, congenital heart disease, or intravenous drug abuse would be important to ascertain.

Murmurs of early adulthood suggest congenital or rheumatic disease, whereas murmurs with onset later in life are consistent with degenerative valvular changes.

 B. Patient symptoms. Patients should be asked about shortness of breath, dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea. Patients with these symptoms warrant an expedited evaluation because these symptoms suggest cardiac decompensation. Advanced aortic stenosis specifically is associated with chest pain, syncope, and heart failure, although a gradient across the valve can exist for years prior to symptom onset. Chest discomfort is often present in advanced disease, but sudden death occurs in 15% of patients with no previous symptoms (1).

 C. Association of a murmur with a specific disease. Recent myocardial infarction endocarditis could cause papillary muscle dysfunction resulting in mitral or tricuspid regurgitation. Mitral regurgitation can be seen in connective tissue disease, coronary artery disease, and congenital disease, but is commonly associated with conditions leading to left ventricular dilatation such as congestive heart failure (CHF) (Chapter 7.5). Endocarditis, myocardial infarction, trauma, prolapse, or congenital heart disease usually precede tricuspid regurgitation. Mitral valve prolapse, which is clinically characterized by palpitations, fatigue, and chest pain, is often associated with anxiety. Hypertrophic cardiomyopathy can be seen in patients with a family history and usually presents between the ages of 20 and 40 years. Presenting symptoms include dyspnea on exertion, chest pain, palpitations, or syncope. It is an important cause of sudden death in athletes. A history of anemia, thyroid disease, or fever should also be elicited from patients being evaluated for
a systolic murmur as each of these conditions can cause a murmur from increased flow.

Physical examination

A. Technique. Auscultate the heart with the bell to best detect lower frequencies and the heart sounds (S₁-S₄). The quality of the murmur is best heard with the diaphragm. Inspiration increases the audibility of right ventricular sounds.

 B. Murmur characteristics. Table 7.4 presents a summary of the characteristics of different causes of systolic murmurs (2,3). Etchell et al. (3) have prepared a comprehensive review on the usefulness of specific physical examination findings in the diagnosis of systolic murmurs.

Testing

Testing of an undiagnosed cardiac murmur can include an electrocardiogram (ECG), a chest x-ray study (CXR), and an echocardiogram. Echocardiograms, although useful for quantification of stenotic valvular disease, can overestimate the degree of regurgitation.

A. Aortic stenosis. Specific ECG findings in aortic stenosis can include left ventricular hypertrophy (LVH), left axis deviation, conduction disturbances, and atrial hypertrophy. On CXR, cardiac size remains normal until stenosis is severe, then signs of CHF may be present. The echocardiogram may reveal thickened or calcified aortic leaflets, bicuspid valve, and LVH. The size of
the valve can be estimated and the pressure gradient across the valve can
be assessed. Cardiac catheterization can also be used to assess the size of the valve and the gradient. Even though echocardiography is accurate in measuring valve area and gradient, catheterization is usually indicated because 50% of patients above age 40 years have coronary artery disease.

 B. Mitral regurgitation. In mitral regurgitation, the ECG may reveal LVH with left atrial enlargement and later in the course, atrial fibrillation. In severe disease, CXR usually reveals cardiomegaly without pulmonary venous congestion. The echocardiogram reveals valvular anatomy, but can overestimate the severity of the regurgitation. Exercise testing can be used to determine clinical deterioration in mitral regurgitation. Catheterization is used to assess the contractile state of the ventricle as well as the regurgitant and forward stroke volume.

 C. Other disease processes. The ECG with tricuspid insufficiency often reveals atrial fibrillation. The CXR may show right atrial hypertrophy, and the echocardiogram shows valvular anatomy. Pulmonic stenosis will lead to ECG findings consistent with right ventricular hypertrophy. Hypertrophic cardiomyopathy is best diagnosed by echocardiography. ECG may reveal LVH and occasionally a shortened PR interval is seen. Cardiac catheterization can be used to quantify the gradient caused by the hypertrophic lesion.

Diagnostic assessment

 The history and physical examination with special emphasis on auscultation are the keys to the diagnosis of systolic murmurs. Those with symptomatic murmurs or in whom valvular disease is suspected should have an ECG, CXR, and echocardiogram. Murmurs of unknown duration or new murmurs should be worked up promptly with consideration of acute infarction in mind. If aortic stenosis is suspected, the workup should be expedited because sudden death can be the first clinical presentation. Valvular disease must always be considered with new onset congestive heart failure. Table 7.5 lists some of the online resources available to assist in the evaluation of heart murmurs.

References

1. Rackley C. Valvular heart disease. In: Bennett JC, Plum F, eds. Cecil textbook of medicine, 20th ed. Philadelphia: WB Saunders, 1996.

2. O’Connor D. The art of auscultation. Patient Care 1998;38:56–60.

3. Etchells E, Bell C, Robb K. Does this patient have an abnormal systolic murmur? JAMA 1997;277:564–571.

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Book Source Details

• Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
• Author(s): Robert B. Taylor (editor)
• Year of Publication: 2000
• Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.

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Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter Authors: Robert B. Taylor (editor) Publisher: Lippincott Williams & Wilkins Copyright: 2000 ISBN: 0-78172-094-X

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