Delayed Gadolinium Enhancement in the Atrial Wall

Abstract

Carditis is a well-recognized finding in rheumatic heart disease and is one of the major criteria in the diagnosis of rheumatic fever. Cardiovascular magnetic resonance with gadolinium enhancement has been used in the evaluation of several disease entities, most commonly in the imaging of myocardial infarctions. We retrospectively evaluated cardiovascular magnetic resonance studies within our institution to identify patients with rheumatic heart disease. Herein, we report the cases of 3 patients who had clinical and imaging findings of rheumatic heart disease, and in whom cardiovascular magnetic resonance revealed delayed gadolinium enhancement in the walls of 1 or both atria. In 1 patient, the delayed enhancement was also evident in both atrioventricular valves.

To our knowledge, this is the 1st report of atrial-wall or atrioventricular-valve delayed gadolinium enhancement in the presence of rheumatic heart disease. Further studies may clarify whether atrial delayed gadolinium enhancement is seen in rheumatic heart disease more often than in other diseases that cause atrial fibrillation, and the diagnostic and prognostic significance of such a finding.

Rheumatic fever is a sequela of group A streptococcus throat infection.¹ One manifestation of rheumatic fever is carditis, which can lead to chronic rheumatic heart disease. Valvular involvement is the most common late sequela of rheumatic heart disease.² Although the diagnosis of rheumatic heart disease chiefly relies upon the results of physical examination,³ echocardiography is typically used in the screening of patients for associated valvular disease.⁴ Echocardiography reveals morphologic changes within valvular tissue (including thickening and calcification) and the consequences of abnormal valvular function (including stenosis and regurgitation). Cardiovascular magnetic resonance (CMR), which yields more information than does echocardiography, is increasingly used in the evaluation of valvular disease.^5,6

Myocardial fibrosis is another sequela of rheumatic heart disease. However, fibrosis cannot be detected with use of conventional echocardiography. Delayed gadolinium (Gd) enhancement on CMR has been used to diagnose myocardial scarring in patients with ischemic injury and acute or chronic infarction.^7,8 Scarring and fibrosis have also been reported in patients with rheumatic heart disease.^9,10 However, to our knowledge, neither atrial-valve nor atrioventricular-valve delayed Gd enhancement on CMR has been reported in the presence of rheumatic heart disease.

Herein, we discuss our retrospective evaluation of 3 patients who had clinical diagnoses of rheumatic heart disease and who underwent CMR with delayed Gd enhancement.

Case Reports

We received Institutional Review Board approval to evaluate CMR studies in our institution retrospectively and to create a searchable database of CMR reports, from which we identified patients with histories of rheumatic heart disease.

From September 2004 through July 2008, CMR was performed with a 1.5T scanner (Horizon EchoSpeed EXCITE® system with Advanced Cardiac Package acquisition software; GE Healthcare, a division of General Electric Company; Fairfield, Conn). A dedicated cardiac phased-array coil (IGC-Medical Advances, Inc.; Milwaukee, Wisc) was used. Each patient received an intravenous injection of 30 cc of gadobenate dimeglumine (MultiHance®, Bracco Diagnostics Inc.; Princeton, NJ), and imaging began 10 minutes after the injection. Delayed-enhancement sequences were typically performed with a matrix size of 256 × 256 pixels and a 40-cm field of view. Of the 413 patients whose study reports we reviewed, we identified 3 cases for discussion herein.

Patient 1

A 36-year-old Central American woman presented with a 3-month history of increasing chest pain, palpitations, and dyspnea on exertion. A review of systems revealed polyarthritis. She had chronic atrial fibrillation and had received a bioprosthetic mitral valve 10 years before. As a child, she had probable streptococcal pharyngitis. The diagnosis of rheumatic heart disease was originally made at the time of the patient's bioprosthetic valve replacement on the basis of history and imaging findings.

On physical examination, her breathing was labored. Cardiac auscultation revealed an irregular rhythm that was consistent with atrial fibrillation. A loud S₂ with a grade 3/6 holosystolic murmur that was best heard over the right lower sternal border was attributed to mitral regurgitation. A transthoracic echocardiogram (TTE) showed critical mitral stenosis, severe tricuspid regurgitation, biatrial enlargement, and the prosthetic mitral valve.

Cardiovascular magnetic resonance showed severe tricuspid regurgitation and severe right ventricular enlargement with globally diminished right ventricular function. The mitral regurgitation and stenosis were difficult to grade because of the prosthetic mitral valve. Gadolinium enhancement sequencing at an inversion time of 200 ms, a repetition time of 8.5 ms, and an echo time of 3.5 ms showed patchy and extensive delayed Gd enhancement in the walls of the left and right atria (Fig. 1).

Fig. 1 Patient 1. A ) Cardiovascular magnetic resonance (4-chamber view) shows delayed gadolinium enhancement in the left atrial wall (arrowheads). B ) Two-chamber view of the right atrium and ventricle shows patchy delayed gadolinium enhancement in the right atrial wall (arrows).

Patient 2

A 68-year-old black man presented with chronic rheumatic heart disease and a progressive decrease in exercise tolerance. A grade 3/6 holosystolic murmur, heard over the apex, was attributed to mitral regurgitation. A review of systems revealed symptoms of recurrent migratory polyarthritis, which was thought to be due to rheumatic fever. A TTE showed severely reduced left ventricular systolic function, thickened mitral leaflets with calcifications in the mitral valve and annulus, moderate mitral stenosis, and moderate mitral regurgitation.

Cine steady-state free-precession CMR sequences at a repetition time of 3.6 ms, an echo time of 1.6 ms, and a flip angle of 45° showed thickening of the mitral valve and the subvalvular apparatus (Fig. 2). Gadolinium enhancement sequences at an inversion time of 200 ms, a repetition time of 7 ms, and an echo time of 1.5 ms showed delayed enhancement in the atrial walls and abnormally prominent delayed enhancement in the atrioventricular valves (Fig. 3). The mitral stenosis and regurgitation were confirmed, and tricuspid regurgitation was noted.

Fig. 2 Patient 2. Cardiovascular magnetic resonance steady-state, free-precession, pre-contrast images. A ) Two-chamber and B ) short-axis views show thickening of the posterior leaflet of the mitral valve (white arrows) and of the subvalvular apparatus (black arrow).

Fig. 3 Patient 2. Cardiovascular magnetic resonance (4-chamber view) shows delayed gadolinium enhancement in the atrial wall (arrows) and atrioventricular valves (arrowheads).

Patient 3

An 82-year-old Hispanic man presented at the emergency room with a 3-day history of increasing shortness of breath. His medical history included atrial fibrillation and chronic rheumatic heart disease. A review of systems revealed chronic, painless, firm, subcutaneous nodules along tendons and musculature, specifically at the backs of the elbows and to a lesser extent in the forearms. A grade 3/6 holosystolic murmur was best heard over the apical and right lower parasternal areas. An electrocardiogram revealed atrial fibrillation. A TTE showed pulmonary hypertension, biatrial enlargement, and severe mitral and tricuspid regurgitation.

Upon the patient's hospital admission, a chest radiograph showed a widened mediastinum and an enlarged cardiac silhouette. On magnetic resonance imaging, the aorta was normal in size but markedly tortuous; CMR showed distinct biatrial enlargement with mild ventricular enlargement, severe mitral and tricuspid regurgitation, and mild mitral stenosis. Patchy and extensive delayed Gd enhancement was seen in the walls of both atria (Fig. 4).

Fig. 4 Patient 3. A ) Cardiovascular magnetic resonance (4-chamber view) shows delayed gadolinium enhancement in the left atrial wall (arrowheads). The atria are markedly enlarged relative to the ventricles. B ) Two-chamber view through the right heart shows delayed gadolinium enhancement in the posterior right atrial wall (arrows).

Discussion

Rheumatic fever is a rare disease, with an incidence in the United States of 0.1 to 2 persons in 100,000.^11,12 In developing countries, tropical regions, and isolated communities, the incidence is much higher—up to 20 persons in 100,000.¹³ In the late 1980s and early 1990s, an increased incidence of rheumatic fever was noted,¹⁴ as was an increase in the severity of cardiac complications from rheumatic heart disease.¹⁵ Whereas the major and minor clinical and auscultatory criteria for the diagnosis of rheumatic fever have been delineated,¹ no imaging guidelines have been formally established.¹²

Cardiovascular magnetic resonance with delayed Gd enhancement sequencing yields detailed information about myocardial infarctions and other causes of fibrosis.¹⁶ Although such sequencing is chiefly used to reveal the details of myocardial infarctions,¹⁷ delayed enhancement occurs in other disease processes, including sarcoidosis, amyloidosis, viral myocarditis, and hypertrophic cardiomyopathy.¹⁸

We found only 1 previous report of delayed Gd enhancement in the presence of rheumatic heart disease.¹⁹ In that instance, patchy subepicardial delayed enhancement was seen in the left ventricle. To our knowledge, no other reports have described delayed Gd enhancement in the atrial wall or the atrioventricular valves, in the presence of rheumatic heart disease.

Delayed Gd enhancement has been reported in the atrial walls of patients who have undergone radiofrequency ablation for atrial fibrillation^20,21 and in 1 patient with cardiac amyloidosis.²² Given the extensive nature of the delayed Gd enhancement in our 3 patients, we did not attribute the enhancement to the prior surgical procedure in patient 1.

Atrial fibrosis has been seen in atrial fibrillation, congestive heart failure, and aging.^23–28 Atrial delayed Gd enhancement was reported in 3 patients who had atrial fibrillation but not rheumatic heart disease.²⁹ However, those patients may have had a novel or undescribed atrial myopathy, because the atrial Gd enhancement (which was dramatic) is not typically observed in atrial fibrillation. Atrial-wall fibrosis has various causes, so the enhancement seen in the 3 patients reported could indicate either atrial fibrosis from atrial fibrillation or myocardial inflammation from rheumatic carditis.

On the basis of our evaluation, we believe that the atrial delayed Gd enhancement in our 3 patients was related to carditis and valvulitis from rheumatic heart disease. Further studies may clarify whether atrial delayed Gd enhancement is seen in rheumatic heart disease more often than in other diseases that cause atrial fibrillation, and may clarify the diagnostic and prognostic significance of such a finding.