Left ventricular apical aneurysm in chronic Chagas cardiomyopathy—A case report

Abstract

A 56-year-old female, who immigrated to the USA from Honduras, presented with worsening shortness of breath, orthopnea, paroxysmal nocturnal dyspnea, and decreased exercise tolerance over the previous 2 months. She was diagnosed 1 year previously with non-ischemic dilated cardiomyopathy and non-sustained monomorphic ventricular tachycardia. An implantable cardioverter defibrillator was placed. Cause for her dilated cardiomyopathy was unknown at that time. On admission, her electrocardiogram showed low voltage complexes, with frequent premature ventricular contractions. Transthoracic two-dimensional echocardiogram (2D ECHO) showed severely reduced ejection fraction of 20%, severe mitral regurgitation with left ventricular (LV) hypokinesis, and inferolateral and inferior wall akinesis. On review of her records, a contrast 2D ECHO from the previous year revealed an aneurysm of the LV apical region. Live three-dimensional (3D) ECHO on her present admission showed persistent LV apical aneurysm. Computed tomography angiogram showed no atherosclerotic lesions. Multiple episodes of non-sustained ventricular tachycardia were recorded on telemetry. Based on these findings, the diagnosis of Chagas cardiomyopathy was entertained. Serological tests for Trypanosoma cruzi antibodies were done and returned positive. We report a case of chronic Chagas cardiomyopathy that was initially missed but ultimately diagnosed based on the finding of LV apical aneurysm.

<Learning objective: Chagas cardiomyopathy is becoming increasingly prevalent in non-endemic countries. One hallmark finding associated with Chagas cardiomyopathy is left ventricle apical aneurysm. We were able to identify this finding with transthoracic contrast 2D ECHO and live 3D ECHO.>

Introduction

Chagas disease, caused by the parasite Trypanosoma cruzi, affects approximately 8–10 million people worldwide, with the majority of cases occurring in Latin America [1]. With the migration of people out of Latin America, there has been a change in the epidemiology of the disease with increasing reports of cases with Chagas disease in non-endemic regions. We report the first case of symptomatic Chagas cardiomyopathy diagnosed at our institution. Our clue to diagnosing this case was based on the detection of a left ventricular (LV) apical aneurysm with transthoracic contrast two-dimensional echocardiography (2D ECHO) and live three-dimensional echocardiography (3D ECHO).

Case report

A 56-year-old Hispanic female, who immigrated from Honduras 20 years previously to the USA, presented with progressively worsening shortness of breath, two pillow orthopnea, paroxysmal nocturnal dyspnea, and decreased exercise tolerance over the previous 2 months [New York Heart Association (NYHA) Class III].

Approximately 1 year previously, she was diagnosed with non-ischemic dilated cardiomyopathy with an ejection fraction of 20%, findings of ventricular mural thrombi, and non-sustained monomorphic ventricular tachycardia (VT). The cause of her cardiomyopathy was unknown at that time. She was treated with furosemide 20 mg oral daily, digoxin 0.125 mg oral daily, losartan 25 mg oral daily, and carvedilol 6.25 mg oral every 12 hours. An implantable cardioverter defibrillator (ICD) was placed. Her medical history was significant for pulmonary emboli, bilateral lower extremity deep venous thrombosis, and renal infarct, for which she was placed on warfarin 3 mg oral on alternating days. A thorough workup for her hypercoagulopathy showed protein C deficiency and positive lupus anticoagulant.

On physical examination, her blood pressure was 106/75 mmHg with no postural decrease. Pulse was regular, 78 bpm. She was afebrile and breathing comfortably. Cardiovascular examination showed no overt signs of right- or left-sided heart failure: absent jugular venous distention, pedal edema, hepatomegaly, and crackles. There was a 3/6 holosystolic murmur heard throughout the precordium, loudest over the mitral area, and radiating to the left axilla.

Investigations showed hemoglobin 12.7 g/dL, white blood cells 8000/μL, and platelets 288,000/μL. Peripheral blood film was normochromic and normocytic. Blood glucose was 82 mg/dL, urea 18 mg/dL, creatinine 0.72 g/dL, albumin 3.9 g/dL, aspartate transaminase 131 U/L, alanine transaminase 119 U/L, alkaline phosphatase 124 U/L, serum calcium 9.3 mmol/L, serum sodium 146 mequiv./L, serum potassium 4.8 mequiv./L, and three sets of serial troponins were negative.

Chest X-ray showed an enlarged cardiac silhouette and a small right-sided pleural effusion.

Electrocardiogram (Fig. 1) showed low voltage complexes, with frequent premature ventricular contractions. A transthoracic 2D ECHO was done which showed severely reduced ejection fraction of 20%, severe mitral regurgitation with LV hypokinesis, and inferolateral and inferior wall akinesis.

Fig. 1.

Twelve-lead electrocardiogram showing low voltage QRS complexes and premature ventricular contractions.

Off-axis scanning with contrast 2D ECHO from the previous year showed an aneurysm of the LV apical region (Fig. 2). Live 3D ECHO (Fig. 3) showed persistent LV apical aneurysm (see video clip). Due to the dilated LV, the apical aneurysm depicted on these modalities was partially lacking, but still evident.

Fig. 2.

Apical two view (off axis) with contrast demonstrating aneurysm of the left ventricle apex.

Fig. 3.

Image from live 3D ECHO depicting left ventricular apical aneurysm.

Supplementary Video 1 related to this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jccase.2014.04.010.

Computed tomography angiogram, which was done to assess the coronary arteries, showed no significant atherosclerotic lesions. The persistent finding of the LV apical aneurysm was suspicious for Chagas disease and this prompted serological testing for T. cruzi antibodies, which was done at the Centers for Disease Control and Prevention Laboratory in Atlanta, GA, USA.

The patient was placed on telemetry. The dose of furosemide was increased to 40 mg oral daily and she was continued on the same dosages of losartan, digoxin, and carvedilol with strict monitoring of daily intake and output. Telemetry showed multiple episodes of non-sustained monomorphic VT at 170 bpm. The ICD was interrogated and showed multiple episodes of non-sustained VT without shock delivery (VT zone set to 172 bpm). Electrophysiology was consulted and recommended no intervention at that time.

T. cruzi serology tests returned positive. The indirect immunofluorescence assay (IFA) titer was greater than 1:512 and enzyme immunoassay (EIA) was 2.084. A diagnosis of chronic Chagas cardiomyopathy was made on the basis of her clinical picture, electrocardiogram, ECHO, telemetry findings, and two positive T. cruzi serological tests for antibodies.

The patient's symptoms improved and she was discharged in a stable condition with follow-up in the cardiology clinic 2 weeks later.

Discussion

This is an interesting report of a patient who migrated to the USA 20 years previously and was diagnosed with symptomatic chronic Chagas cardiomyopathy. She migrated from Honduras where the prevalence of Chagas disease is 3.1%. There are about 300,000 reported cases of Chagas disease in the USA [1]. About 75% of patients with chronic Chagas cardiomyopathy remain asymptomatic [2].

Predictors of mortality in patients with chronic Chagas disease are impaired LV function, non-sustained VT, cardiomegaly, and NYHA Class III/IV symptoms [3].

Chagas cardiomyopathy has many similarities to idiopathic dilated cardiomyopathy on presentation as well as imaging; however, one of the distinguishing hallmarks of Chagas disease is LV apical aneurysm [4]. This is seen in about 45% of Chagas patients who have LV systolic dysfunction and heart failure [5]. In our case, we were unable to visualize the aneurysm on 2D ECHO. Instead we identified the aneurysm using contrast 2D ECHO and live 3D ECHO. The LV apical aneurysm was initially overlooked on contrast ECHO 1 year previously. On close revision of all of her ECHO images, we were able to visualize the LV apical aneurysm at her present admission.

Contrast ECHO has the advantage of enhancing endocardial border delineation as well as improving image alignment, allowing better depiction of the aneurysm [6].

Three-dimensional imaging displays complex ventricular geometry which 2D ECHO may not be able to show. With live 3D imaging we were able to crop away the anterior wall of the LV and reveal the apical aneurysm. The anatomy of the aneurysm, including the thinning of the walls as well as the wall motion abnormality, was demonstrated with this technique.

Contrast enhanced 2D ECHO and 3D ECHO, however, do have limitations. 2D ECHO has a limited sector angle, while 3D ECHO has a limited top angle [7]. When applied to a heart with dilated ventricles or aneurysm, this can lead to partial cutoff of the dilated LV [7].

Off-axis scanning with contrast enhanced 2D ECHO is sometimes done to circumvent this. In some cases it is unsuccessful [8]; however, we were able to partially capture the LV apical aneurysm with this technique.

A pyramidal angle of 60° × 60° was used for acquiring 3D ECHO images of the LV. In patients with dilated chambers, this angle can limit the ability to completely image the entire ventricle [9]. At the same time, increasing data sets up to 90° × 90° provide larger pyramidal scans at the expense of lower resolutions [10]. Hence, we found that with an angle of 60° × 60°, we were able to capture the LV apical aneurysm without compromising the resolution of the image.

Having established the LV apical aneurysm using contrast 2D ECHO and live 3D ECHO, computed tomography coronary angiogram was done to rule out an ischemic cause for the LV apical aneurysm. There were no significant coronary artery lesions seen. The LV apical aneurysm was not visualized on computed tomography angiogram as the images obtained were taken in mid-diastole when cardiac motion is limited. This allowed for better visualization of the coronary arteries by minimizing motion artifacts [11].

Combining the LV apical aneurysm along with other features such as systolic dysfunction, severe mitral regurgitation, low voltage QRS complexes, episodes of non-sustained VT, a negative computed tomography angiogram of the coronaries and history of previous residence in a country where Chagas disease is endemic, we were able to suspect T. cruzi as the cause of her cardiomyopathy and confirm it using two serological tests.

It is important for us to keep this diagnosis in mind when we encounter a patient with findings of dilated cardiomyopathy, especially in regions where there are significant Latin American immigrant population. Patients with Chagas cardiomyopathy are at risk for ventricular arrhythmias that can lead to sudden cardiac death. An ICD is invariably required to prevent sudden death. Ultimately heart transplantation is the definitive treatment in those patients with advanced heart failure.

Conflict of interest

The authors declare no conflict of interest.