Address correspondence to: Luís F. Gonçalves, MD, Dept. of Radiology, Vanderbilt University Medical Center, 21^st Avenue South, Nashville, TN, 37232-5316, Ph: 615-343-0595, Fax: 615-343-4890. Norton Hospital, Dept of Pathology

Synonyms: Confused with diverticulum of the heart, especially in the old literature.

Definition: Localized outpouching of a fibrous ventricular wall associated with akinesia or dyskinesia.

Prevalence: 0.05:10,000 births, M1:F1.

Etiology: Possibly fetal endocarditis, obstruction of the cardiac lymphatics, endocardial fibroelastosis, and, in some postnatal cases, myocardial infarctions resulting from an anomalous origin of the left coronary artery from the pulmonary artery. A familial occurrence has been reported.

Pathogenesis: Unknown in the majority of cases.

Differential diagnosis: Diverticulum of the heart.

Associated anomalies: Usually none, but atrial septal defect, mitral valve prolapse, and regurgitation have been reported¹.

Recurrence risk: Unknown.

Prognosis: Poor when associated with heart failure. Forty percent of the patients are asymptomatic during childhood or adulthood.

Management: Individualized, depending on the hemodynamic conditions of the fetus. In case of intrauterine heart failure, digitalization may be attempted.

Post­natally, asymptomatic patients are followed clinically, and symptomatic patients usually undergo surgery with good results.

MESH Heart-Aneurysm-congenital BDE 0988 CDC 746.880 ICD9 746.89

Introduction

An aneurysm of the left ventricle is a very rare anomaly whose prenatal diagnosis has been reported only twice^2,6. We report a third case, associated with heart failure, fetal hydrops and intrauterine death.

Case report

A 19-year-old G₁P₀ patient was referred for ultrasound examination because of a low-lying placenta at 29 weeks gestation. A previous ultrasound performed elsewhere at 15 weeks was unremarkable.

A survey of the cardiac anatomy demonstrated a massively enlarged left ventricle, measuring about 30 mm in diameter. The contractility of the free and diaphragmatic walls of this ventricle were minimal. The interventricular septum was displaced towards the right ventricle (fig. 1).

 Figure 1: Massively dilated left ventricle (LV). The ventricular septum is displaced towards the right ventricle (RV). In the right image, the arrow points at the regurgitant mitral valve, in the left atrium.

 Color Doppler revealed very little flow through the left ventricle but normal flow through both atria and right ventricle (fig. 2). The origin of the right coronary artery could be observed arising from the aorta and was unremarkable (fig. 3). The left coronary artery was not visualized. Left and right ventricular outflow tracts were seen arising from the appropriate ventricles (fig. 2). Signs of cardiac failure included ascites, hyperechogenic kidneys, pericardial effusion, and hydrocele (fig. 4-6).

Figure 2: Color Doppler demonstrates normal flow through the right ventricle and outflow tract, whereas no flow is observed through the left ventricle.

 Figure 3: Section just above the aortic valve anulus, showing the origin of the right coronary artery (arrow).

 Figure 4: Oblique scan through the fetal abdomen demonstrating hyperechogenic kidneys and ascites.

 Figure 5: View of the heart showing pericardial effusion.

 Figure 6: View through the fetal scrotum showing hydrocele.

 The patient was admitted and placed on digoxin 0.5 mg p.o./ day) for four days in an effort to improve cardiac function and revert the course of hydrops. Despite digitalization, hydrops progressed and the fetus died in utero at 31 weeks gestation.

The autopsy confirmed hydrops fetalis and cardiomegaly (fig. 7-8).

 Figure 7: Autopsy specimen. The massive cardiomegaly is visible.

Figure 8: Autopsy specimen. The enlarged left ventricle is opened. The thrombus at the apex of the left ventricle is post-mortem.

The heart weighed 31g (normal: 18g). Both ventricles were dilated. However, the left ventricle was massively dilated. The left ventricular wall near the apex had an outpouching with an associated thinning of the myocardium to 2 mm in thickness. The left ventricular endocardium was thickened, especially along the left ventricular free wall, giving the mitral valve papillary muscles a contracted, fibrotic appearance. Microscopic examination demonstrated an increase in fibroelastic tissue lying between the endocardium and the myocardial layers and also focal fibrosis throughout the myocardium. The diagnosis of endocardial fibroelastosis was made.

Discussion

A ventricular aneurysm is a localized outpouching of a fibrous ventricular wall with akinesia or dyskinesia¹. The neck of the defec is broad, and the wall of the aneurysm is composed of myocardium and fibrous tissue². It may be multilobulated. According to the location, it can be classified as¹:

Left ventricle

Annular subvalvular

·         subaortic

·         submitral

·         apical

Right ventricle

·         Outflow tract

·         Apical

Table 1: Previously reported cases of congenital left ventricular aneurysm.

Etiology

Aneurysms of the left ventricle can be congenital or acquired. The acquired aneurysm is more common and may be caused by abnormal origin of the left coronary artery from the pulmonary artery, chest trauma, myocardial infection, myocardial infarction, postoperative cardiac surgery and mucocutaneous lymph node syndrome^1,3. The etiology for the congenital form is unknown but probably includes endocardial fibroelastosis⁴, myocarditis and ischemic myocardial injury during the fetal period. A familial incidence has been recognized, pointing also to a hereditary cause⁵.

Prevalence

The disease is very rare and is estimated to occur in 0.05:10,000 births. The prevalence is the same among males and females. However, in the case of endocardial fibroelastosis, the incidence increases to 1.7:10,000 births and the male to female prevalence ratio changes to M0.6:F1⁵.

Pathogenesis

Aneurysm of the left ventricle is considered an acquired lesion, secondary to ischemia of the myocardium, and to be occasionally associated with diffuse endocardial sclerosis¹⁵. Likewise the pathogenesis of endocardial fibroelastosis has been attributed to anoxia, as well as to several other conditions including: endocarditis, oxygen excess, genetic factors and viral infections¹⁶. However, there is a primary—or idiopathic— form of endocardial fibroelastosis for which a definitive pathogenetic mechanism cannot be advanced. Regardless of the etiology, once the disease process becomes severe enough as to impair myocardial contraction, the natural consequence is cardiac failure with hydrops and a high risk of death.

In this case, the gross and microscopic findings were compatible with the diagnosis of endocardial fibroelastosis. If this was the primary form of endocardial fibroelastosis, then it is possible that it is the pathogenetic mechanism of the aneurysm. However, since both lesions can be acquired, it can only be speculated that this is the etiology of the aneurysm.

Diagnosis

Prenatal diagnosis

Fetal  echocardiography allows for the prenatal diagnosis of this rare condition. A review of the cases diagnosed prenatally is presented in Table 1^2,6.

Our case documents the first in utero heart failure due to ventricular aneurysm. The defective contratility of the free and diaphragmatic left ventricular wall associated with the aneurysm could be demonstrated (fig. 1). Color Doppler provided further information by confirming the low left ventricular output in comparison to normal flow in both atrium and right ventricle (fig. 2).

Postnatal diagnosis

Congenital ventricular aneurysms are asymptomatic in 40% of the cases during childhood⁷. In the remaining 60% of the patients, symptoms include chest discomfort, palpitation and convulsion^1,8. However, most of the patients are referred to the cardiologist because a nonspecific murmur or abnormal heart silhouette on chest x-ray. Echocardiography is the most useful diagnostic tool to demonstrate the akinetic or dyskinetic outpouched ventricular wall. The electrocardiogram may show signs of myocardial damage, including abnormal ST-T segments or Q waves, premature ventricular contractions, left axis deviation, left atrial overloading, and varying degrees of heart block¹. The chest x-ray may demonstrate cardiac enlargement or an abnormal silhouette^1,9.

Differential diagnosis

Diverticulum of the heart is a term that has been used in the past to describe ventricular aneurysms¹⁰. However, the diverticulum involves primarily the apex of the heart, has a narrow connection with the ventricular cavity¹ and contracts⁶. Associated anomalies are frequent and include other intracardiac defects as well as defects in the pericardium, diaphragm and midline body wall^1,3,6.

Recurrence risk

The recurrence risk is unknown. The empirical risk of recurrence for patients with a previous fetus affected with endocardial fibroelastosis is 3.8%⁵.

Associated anomalies

Most of the congenital ventricular aneurysms arise from the left ventricle and are usually isolated anomalies³. Occasionaly reported  anomalies include mitral valve prolapse, mitral regurgitation and atrial septal defect¹.

Prognosis

The natural history of the disease has not yet been clarified due to its rarity. However, it seems that the congenital ventricular aneurysm is progressive in nature with a consequent poor prognosis^11,12. The majority of the 60% symptomatic patients will eventually develop heart failure. Other complications are rare and include thrombosis, coronary insufficiency, cardiac rupture, arrhythmias, subacute bacterial endocarditis and angina^1,6.

Management

Due to the lack of knowledge regarding the natural history of this anomaly, decisions regarding expectant versus surgical management must be done in an individual basis. Usually, asymptomatic patients have been followed medically, whereas symptomatic patients have been candidates for surgical repair^2,13. In a recent series of 5 patients with malignant ventricular arrhythmias associated with congenital left ventricular aneurysms, two were treated with aneurysmectomy combined with subendocardial resection and cryotherapy, two were controlled with antiarrhythmic therapy and one received an implantable cardioverter defibrilator with successful control of the symptoms¹⁴.

When the disease is diagnosed prenatally, the route of delivery should be individualized and based on the degree of fetal compromise. In the case of heart failure, digitalization may be attempted in an effort to improve myocardial contractility and revert the hydrops. Affected fetuses should be delivered in a tertiary care facility. Immediate access to a pediatric cardiologist accelerates diagnostic procedures, the antibiotic prophylaxis for endocarditis, the antithrombotic prevention and the early treatment of  potential complications⁶.

References

1. Hamaoka K, Masamitsu O, Tanaka T, et al. Congenital ventricular aneurysm and diverticulum in children. Pediatr Cardiol 8:169-75, 1987.

2. Jacobson RL, Perez A, Meyer R, et al. Prenatal diagnosis of fetal left ventricular aneurysm: a case report and review. Obstet Gynecol 78:525, 1991.

3. Singh A, Katkov H, Zavoral JH, et al. Congenital aneurysms of the left ventricle. Am Heart J 99:25-32, 1980.

4. Gerlis LM, Partridge JB, Fiddler GI, et al. Two chambered left ventricle: three new varieties. Br Heart J 46:278, 1981.

5. Buyse ML. Birth Defects Encyclopedia. Blackwell Scientific Publications, Cambridge, Massachussets, 1990.

6. Gembruch U, Steil E, Redel DA, et al. Prenatal diagnosis of a left ventricular aneurysm. Prenat Diagn 10:203-9, 1990.

7. Schmaltz AA, Neumann J, Quintenz R, et al. Aneurysm of the heart: a correlative study of 102 proved cases. Medicine (Baltimore) 33:43-56, 1983.

8. Inoue D, Terashima S, Shirayama T, et al. A case of left ventricular aneurysm of uncertain etiology presenting as ventricular tachycardia. Int J Cardiol 21:135-41,1988.

9. Arora RR, Issenberg HJ, Spindola-Franco H, et al. Congenital aneurysm of the left ventricle: its recognition and significance. JAMA 259:3306-8, 1988.

10. Abbot ME. In: Osler W, McCrae T, eds. Modern Medicine. Lea & Febiger, Philadelphia, 2nd ed., 1915, p. 43.

11. Abraham DG, Bartoon CJ, Cockshott WP, et al. Annular subvalvular left ventricular aneurysms. Q J Med 31:345-60, 1962.

12. Folger GM Jr, Stanton PE. Annular subvalvular left ventricular aneurysm in a North American infant. Am Heart J 81:392-7, 1971.

13. Grossi EA, Colvin SB, Galloway AC, et al. Repair of posterior left ventricular aneurysm in a six year-old boy. Ann Thorac Surg 51:484-7, 1991.

14. Meyer BJ, Amann FW, Jenni R, et al. Malignant ventricular arrhythmias in congenital aneurysms of the left ventricle in adulthood. Helv Chir Acta 58:479-83, 1992

15. Arey JB: Cardiovascular pathology in infants and children. Philadelphia, WB Saunders Co. 196-7, 1984.

16. Garson A, Bricker TJ, McNamara DG (Eds.): The science and practice of pediatric cardiology. Vol III. Philadelphia, Lea and Febiger, 1624-6, 1990.