Asymptomatic Left Ventricular Dissection.

Intramyocardial dissection is an uncommon complication of myocardial infarction, chest trauma, and percutaneous intervention. It is usually caused by a hemorrhagic dissection among the spiral myocardial fibers. Carries high mortality and there is still uncertainty regarding invasive or conservative management. We present a case of the left ventricular dissection discovered incidentally.

Introduction

Intramyocardial dissection is an uncommon complication of myocardial infarction, chest trauma, and percutaneous intervention. It is usually caused by a hemorrhagic dissection among the spiral myocardial fibers. Carries high mortality and there is still uncertainty regarding invasive or conservative management. We present a case of left ventricular (LV) dissection discovered incidentally.

Case Report

A 66-year-old female patient was referred to cardiology outpatient clinic following an incidental finding on abdominal computed tomography, performed for renal calculosis, suggesting pericardial cyst Figure 1, (Panel A). She was known to suffer from hypertension and hyperlipidemia treated by angiotensin converting enzyme inhibitor, beta-blocker, aspirin, and statin therapy. Ten years ago, she was told that she may have had a myocardial infarction following a bout of mild chest pain. Currently, the patient had no cardiac symptoms, and her physical examination and vital signs were normal. Routine laboratory examinations were unremarkable except for hemoglobin of 91 g/L and an elevated N-terminal pro-brain natriuretic peptide level of 1508 pg/ml (normal 0–125 pg/ml). Her electrocardiogram showed sinus rhythm, normal QRS duration with poor R wave progression across the anterior leads with deep T wave inversion in the anterior and lateral leads. Echocardiography showed mild LV dysfunction with LV ejection fraction 40%–45%. The entire anterior wall was akinetic. There was a rupture of the mid-anterior segment of the LV forming an aneurysm with a discrete neck and bidirectional flow through it. The ruptured inner layer of the aneurysm was thin, consisting of endocardium, and the outer layer thick formed by myocardium and thrombus Figure 1, (Panel B and Video). Cardiac magnetic resonance imaging revealed thinning and dyskinesia of the mid-anterior segment which appeared to be a contained LV rupture. A small defect was depicted consistent with intramural hematoma in the wall of the LV Figure 1, (Panel C). Coronary angiography revealed nonsignificant stenosis of the left anterior descending artery and the right coronary artery. In view of the incidental finding, absence of symptoms, unknown timing of the dissection, she was treated conservatively. Since discharge, she has been followed up regularly in the clinic and remained symptom-free with no enlargement of the cavity size.

Figure 1

(a) CT of the heart demonstrated a hypodense lesion suspicious of a large thrombus contained by a thin wall (arrows). (b) Echocardiography is showing the partial rupture of the mid anterior segment forming aneurysm due to dissection of myocardium and color flow through it. In the aneurysm the ruptured inner wall is thin (endocardium, yellow arrow) and the outer wall is thick (myocardium and thrombus, green arrow). (c) Cardiac MRI reveals ruptured myocardium with a big thrombus (arrows) contained by fibrotic, thickened pericardium. (Top image: SSFP, left: early gadolinium, right: late gadolinium.

Discussion

Intramyocardial dissection is an uncommon complication of myocardial infarction, chest trauma, and percutaneous intervention. It is usually caused by a hemorrhagic dissection among the spiral myocardial fibers after the rupture of intramyocardial vessels into the interstitial space.[1] It consists of a cavity filled with blood, the outer wall of which is the myocardium and pericardium and the inner wall, which faces the ventricular cavity, is part of the myocardium and endocardium. Differential diagnosis includes pseudoaneurysm following complete rupture of the myocardial wall which is sealed by the pericardium. Intramyocardial dissection is differentiated by confirming the integrity of epicardium and demonstrating partially ruptured myocardium which resulting in a cavity filled with blood. There is a certain preference for surgical repair of the defect. However, despite prompt diagnosis and treatment, mortality remains high.[2] Pliam and Sternlieb[1] reviewed 15 cases of intramyocardial dissecting hematoma. Out of 10 patients treated conservatively only one survived, while surgically treated patients all survived. Following this review, there are several case reports with good results and acceptable mid- to long-term survival of conservatively treated patients who were hemodynamically stable.[3] In our opinion, the therapy should be individualized for each patient depending on patient's hemodynamic condition and surgical experience.

Conclusion

This rare case highlights the importance of the echocardiography and cardiac magnetic resonance imaging in the diagnosis and differential diagnosis of intramyocardial dissection and clinical decision making.

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Conflicts of interest

There are no conflicts of interest.