Abnormal Color Flow Signal Traversing the Myocardial Wall: Not Everything is What it Appears to Be.

A case of a patient presenting with an acute myocardial infarction is presented. A transthoracic echocardiographic examination revealed an abnormal color flow signal that traversed the myocardial wall from a large inferior aneurysm and initially considered to be a ventricular septal defect. However, further echocardiographic manipulation utilizing modified views along with sequential injections of both agitated saline and Definity® proved very useful to identify a pseudoaneurysm. There was no further need for any other diagnostic test, and the patient was treated surgically, undergoing successful repair of the pseudoaneurysm as well as coronary artery bypass grafting of the left coronary artery.

INTRODUCTION

Identification of a myocardial pseudoaneurysm has a high morbidity and mortality and this case how special manipulation of the echocardiographic transducer not only identified the presence of an abnormal color Doppler signal, but also prompted the use of agitated saline and contrast injections to confirm the presence of a pseudoaneurysm. This intervention was sufficient to identify the diagnosis and ultimately direct definitive therapy.

CASE REPORT

We report a case of a 61-year-old Caucasian female who presents to a community hospital with chest pain, shortness of breath, and electrocardiographic changes suggestive of an acute inferior myocardial infarction. Upon arrival to our institution, cardiac catheterization was emergently performed in view of the persistent ST-segment elevations in the inferior leads II, III, and aVF with elevation in serum troponin levels and showed extensive disease of a dominant right coronary artery (RCA) with an 80–90% lesion in the midsegment followed by a long 60–70% more distal stenosis as well as a proximal 70% lesion of the left anterior descending artery. Right heart hemodynamics showed evidence of right ventricular infarction and multiple Taxus stents were used to treat the lesions within the RCA.

A transthoracic echocardiogram was then performed in the Intensive Care Unit for evaluation of left ventricular function showing an inferior wall aneurysm with overall preserved systolic function. Three days later, another transthoracic echocardiogram was performed for a new murmur, which showed an abnormal color flow signal suggestive of a ventricular septal defect in the short axis view as seen in Figure 1. From the apical 4-chamber view, a cystic structure was seen lateral to the right ventricular wall [Figure 2]. Inferior angulation of the transducer from the 4-chamber view, as seen in Figure 3, shows a long neck of the pseudoaneurysm connecting the inferior aneurysm to the cystic structure with color Doppler confirming blood flow within this structure.

Figure 1

A parasternal short axis view at the chordal level shows an abnormal color flow signal traversing the myocardium from the left ventricle, suggestive of a ventricular septal defect located in the posterior aspect of the inferior septum at the junction with the right ventricle. LV: Left ventricle, RV: Right ventricle

Figure 2

Four-chamber apical window view showing a cystic structure lateral to the right ventricular wall which appears to be within the ventricle shown by the white arrow. LV: Left ventricle, RV: Right ventricle

Figure 3

(a) Inferior angulation of the transducer from the 4 chamber view showed a long neck of a pseudoaneurysm connecting the inferior aneurysm to the cystic structure with (b) color Doppler confirming blood flow within this structure. LV: Left ventricle, RV: Right ventricle, Pseudo: Pseudoaneurysm

Injection of agitated saline failed to opacify the cystic structure [Figure 4]. However, opacification of this cystic structure occurred after the intravenous administration of Definity® [Figure 5]. Furthermore, a better definition of the contained rupture that compressed the basal right ventricular free wall was obtained with this maneuver [Figure 6]. Otherwise, left ventricular size and systolic function remained as previously described.

Figure 4

Injection of agitated saline was done and ruled out the presence of a ventricular septal defect or any other intracardiac shunt as the agitated bubbles stayed within the right ventricular chambers and this cystic structure was never opacified during this maneuver. RV: Right ventricle, LV: Left ventricle, LA: Left atria, Pseudo: Pseudoaneurysm

Figure 5

Opacification of this cystic structure occurs after the left ventricle was opacified with the intravenous administration of Definity®. LV: Left ventricle, RV: Right ventricle, LA: Left atria, Pseudo: Pseudoaneurysm

Figure 6

Furthermore, a better definition of the contained rupture or pseudoaneurysm that compressed the basal right ventricular free wall was obtained with this maneuver. LV: Left ventricle, RV: Right ventricle, RA: Right atria, Pseudo: Pseudoaneurysm

DISCUSSION

A pseudoaneurysm, or false aneurysm, develops after an acute myocardial infarction, which is complicated by a ventricular free wall rupture that is contained by localized pericardial adhesions.[1] The diagnosis needs to be established early since these aneurysms are prone to rupture.[2]

In the most extensive review of the literature, Frances et al. reported that 253 patients with a pseudoaneurysm in whom the cause was reported, 55% were related to an inferior wall myocardial infarction, as reported in our case.[3] In this review, the authors also reported that the second most common cause of pseudoaneurysm formation was surgery, which was responsible for 33% of cases followed by trauma that accounted for 7% of cases.

The site of pseudoaneurysm varies with etiology and in a review of 52 patients seen at the Mayo Clinic pseudoaneurysms were primarily seen in the inferior or posterolateral wall after a myocardial infarction, in the right ventricular outflow tract after congenital heart surgery, in the posterior subannular region of the mitral valve after mitral valve replacement, and in the subaortic region after aortic valve replacement.[4]

The most frequent symptoms associated with left ventricular pseudoaneurysm were chest pain and dyspnea.[3] Sudden cardiac death was the presenting manifestation in about 3%, whereas 12% of patients were asymptomatic.

The most reliable method for diagnosis of a pseudoaneurysm has been angiography, which demonstrates a narrow orifice leading to a saccular aneurysm and lack of surrounding coronary arteries.[5] Left ventricular angiography has resulted in a definitive diagnosis in over 85% of patients.[3] Transthoracic echocardiography has been considered a reasonable first step, but definitive diagnosis of pseudoaneurysm has only been reported in up 26% of patients.[6]

This case report presents this very unusual case showing how an abnormal color flow signal that traverses a myocardial wall is not always a ventricular septal defect. As described above, further echocardiographic manipulation utilizing modified views along with sequential injections of both agitated saline and Definity® proved very useful to identify the correct pathologic process and by itself was sufficient to provide definitive therapy. There was no further need for any other diagnostic test, and the patient was treated surgically, undergoing successful repair of the pseudoaneurysm as well as coronary artery bypass grafting of the left coronary artery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.