Left ventricular diverticulum

True diverticula of the left ventricle refer to congenital anomalies affecting the left ventricle.

Epidemiology

The condition typically occurs in children and is thought to occur in around 0.4% of cases based on autopsy studies.

Clinical presentation

In isolated cases, they are often asymptomatic and typically discovered incidentally.

Pathology

A left ventricular diverticulum is a pouch or sac branching out from the ventricle. They have a variable size and can range from 5 mm to 80-90 mm. It is thought to arise as a developmental anomaly, from around the 4^th embryonic week. Their connection to the ventricle may be narrow or wide.

Subtypes

They can be classified into two types ¹:

• muscular type
  • often originates at the apex and comprises mainly muscular fibers that contract synchronously with the ventricle
  • often associated with other congenital defects
• fibrous diverticulum: composed of mostly fibrous tissue

Associations 

They can be associated with other anatomic defects that involve the thoracoabdominal midline, and have syndromic associations such as pentalogy of Cantrell. Apical diverticula have a higher association with other anomalies. Diverticula occur in isolation in around 30% of cases.

Location

They are commonly found in the apex and perivalvular area, although they have been reported in almost all locations of the ventricular wall with the exception of the interventricular septum ⁴.

Radiographic features

CT

Can have a variable appearance based on its size and position but in general, is seen as a tubular outpouching arising from the ventricle. Some authors suggest the diagnosis can be made after exclusion of coronary arterial disease, local or systemic inflammation or traumatic etiologies as well as cardiomyopathies ⁷.

They often show synchronous contractility and small diverticula can close during systole.

MRI

Cine MRI

Often show synchronous contractility ⁸.

Treatment and prognosis

Surgical resection is often the treatment of choice in symptomatic patients while management strategies in asymptomatic patients are often challenging. Other described treatment options include anticoagulation following after systemic embolization, radiofrequency ablation or implantation of an implantable cardioverter defibrillator combined with class I or III antiarrhythmic drugs (e.g. in cases of associated symptomatic ventricular tachycardia) ⁷.

Complications

Recognized complications include:

• cardiac arrhythmias
• sudden death
• endocarditis
• systemic emboli
• heart failure
• cardiac rupture
• intraventricular obstruction

Differential diagnosis

Possible imaging differential considerations include:

• left ventricular pseudoaneurysm
• left ventricular aneurysm
• myocardial crypts