Cardiomegaly
John Coe and Ron Sand
Cardiomegaly is a common, nonspecific finding that can be detected by physical examination, electrocardiogram (ECG), chest radiograph, or echocardiogram. With rare exceptions, it is a sign of organic heart disease. The absence of cardiomegaly does not rule out significant cardiac pathology. Cardiomegaly, especially in the elderly and those with coronary artery disease, is associated with a poor prognosis (1).
Approach
Cardiomegaly can be caused by chamber dilation, wall hypertrophy, or both. The underlying causes can be grouped into three categories: volume overload, pressure overload, or cardiomyopathy. The false impression of cardiomegaly can be seen with pericardial effusion or thickening, mediastinal mass, thoracic deformities, or faulty radiographic technique.
History
A. Presenting symptoms. As congestive heart failure (CHF) and cardiomegaly represent the final common path for many patients with these common conditions, the typical symptoms are exertional dyspnea, syncope, fatigue, and angina. Many patients are asymptomatic at the time of diagnosis and sudden death can be the presenting event (2) (Chapter 7.5).
B. Etiology. The most common conditions that result in cardiomegaly include hypertension, coronary artery disease, rheumatic and degenerative valvular heart disease, anemia, alcoholism, endocrinopathies, and infectious and inflammatory conditions.
C. Family history. Premature atherosclerosis and ischemic cardiomyopathy can be caused by familial dyslipidemia. A family history of early CHF may indicate familial dilated cardiomyopathy and premature sudden death may indicate familial hypertrophic obstructive cardiomyopathy.
Physical examination
The typical signs of CHF are usually noted on examination. A decreased arterial pulse with narrowed pulse pressure is common. Cyanosis is rare. Significant cardiac enlargement should be evident on physical examination. Examples of these finding include the following:
A. Lung sounds. Rales or pleural effusion with dullness to percussion and decreased breath sounds may be indicative of left ventricular failure.
B. Heart sounds. Gallops, soft heart sounds, and regurgitant heart murmurs are nonspecific findings of advanced CHF. Alterations in S1 or S2, specific murmurs, (e.g., a Valsalva-enhanced systolic murmur in hypertrophic obstructive cardiomyopathy), and muffled sounds with pericardial effusion, all indicate specific underlying pathology.
C. Cardiac pulsations or point of maximal impulse (PMI). Visible pulsations seen lateral to the midclavicular line signify cardiac enlargement unless is found a thoracic deformity or congenital absence of the pericardium.
D. Apical beat or PMI. The apical beat, or PMI, which is typically palpable in only 40% of cases, is highly dependent on body habitus. Use the flat of the hand to palpate the PMI. Time the pulsations using the carotid pulse or auscultated heart sounds. The left lateral decubitus position increases the palpability of both normal and pathologic apical beats.
A PMI within or superior to the fifth intercostal space is normal. Left ventricular enlargement displaces the PMI laterally and downward. A PMI lateral to the midclavicular line or more than 10 cm lateral to the midsternal line is a sensitive but nonspecific indicator of left ventricular enlargement. An apical impulse of more than 3 cm diameter is an accurate sign of left ventricular enlargement.
With moderate or severe left ventricular hypertrophy, the outward systolic thrust persists throughout ejection, often lasting up to the second heart sound. In patients with volume overload or sympathetic stimulation, the left ventricular impulse is brisker and larger than normal but is hypokinetic in patients with reduced stroke volume (e.g., acute myocardial infarction or dilated cardiomyopathy). Large left ventricular aneurysms are palpable above and medial to the apex beat. Thoracic deformities—particularly scoliosis and pectus excavatum—can laterally displace a normal heart.
E. Percussion. In the absence of an apical beat, as in patients with pericardial effusion or with dilated cardiomyopathy and a markedly displaced, hypokinetic apical beat, the left border of the heart can be outlined by means of percussion. Percussed dullness in the left fifth intercostal space more than 10.5 cm from the midsternal line is sensitive and specific for cardiomegaly (3).
Testing
A. Radiographs. The cardiothoracic ratio is quick to measure and relatively reliable as an indicator of cardiomegaly on an adequate, upright, posterior–anterior chest film. Watch for rotation and adequate inspiration: the diaphragm should be lowered to at least the posterior portion of the ninth rib. Calculate the ratio by first measuring the transverse cardiac diameter horizontally through the widest part of the cardiac silhouette. Divide this by the chest diameter measured at the widest part between the inner surface of the ribs. A ratio of 0.5 to 0.55 or less can be considered within the limits of normal for an adult. Ratios of up to 0.6 are normal in children and infants. Fluid accumulation in the pericardium causes distention, enlarging the cardiac silhouette and overlapping and obscuring the hilar vessels. In CHF, the vessels become congested and appear more prominent than normal. Also, the epicardial fat line (radiolucent stripe) on the lateral chest film between the anterior surface of the heart and the retrosternal mediastinal fat should be no more than 1 to 2 mm. Widening beyond this is a reliable indicator of pericardial effusion.
B. Sonography. An echocardiogram is generally considered the standard in assessing cardiac dimensions. With evidence of cardiomegaly on physical examination, an echocardiogram is appropriate if clinically useful in the patient’s care.
C. ECG. The ECG is almost invariably abnormal in true cardiomegaly. Common findings are premature ventricular contractions, atrial fibrillation, atrioventricular and intraventricular conduction abnormalities, and nonspecific ST segment and T-wave changes. Left ventricular hypertrophy and atrial enlargement can be diagnosed by morphology and voltage, but the ECG is rarely diagnostic of a specific underlying cause. Pericarditis causes ST elevation with flat or concave ST segments. Pseudoinfarction patterns are seen in hypertrophic obstructive cardiomyopathy (4).
Diagnostic assessment
The significance of cardiomegaly is determined by the underlying pathology. The most common presenting conditions to consider are listed in Table 7.1.
References
1. Frishman WH. Cardiomegaly on chest x-ray: prognostic implications from a ten-year cohort study of elderly subjects: a report from the Bronx Longitudinal Aging Study. Am Heart J 1992;124:1026–1030.
2. Craddock LD. Cardiac enlargement and the cardiomyopathies. In: Friedman HH, ed. Problem oriented medical diagnosis, 5th ed. Boston: Little, Brown and Company, 1991:67–71.
3. Heckerling PS. Accuracy of precordial percussion in detecting cardiomegaly. Am J Med 1991;91:328–334.
4. Kamiyama N. Electrocardiographic features differentiating dilated cardiomyopathy from hypertrophic cardiomyopathy. J Cardiol 1997;30:301–306.
Pictures
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.
Other Book Chapters Related to Heart symptoms
Read excerpts from these other book chapters related to Heart symptoms:
Medical Books Excerpts
- Cardiomegaly
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.
More About Causes of Heart symptoms
» Next page: Congestive Heart Failure (The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
