Left ventricular diverticulum: A case report and differential diagnosis in an asymptomatic woman

Abstract

Left ventricular diverticulum is a rare congenital cardiac anomaly characterized by a myocardial outpouching that typically contracts synchronously with the left ventricle. It is usually incidentally detected and may mimic other ventricular outpouchings with distinct clinical and prognostic implications. We report the case of a 68-year-old woman referred for evaluation of systemic hypertension without prior cardiovascular disease. Transthoracic echocardiography raised suspicion of an interventricular communication due to an apparent septal discontinuity and hypertrophic moderator band. Cardiac magnetic resonance (CMR) performed on a 1.5-T system using cine balanced steady-state free precession, T2-weighted fat-suppressed sequences, and late gadolinium enhancement imaging excluded an interventricular defect. CMR instead demonstrated a left ventricular outpouching with a narrow neck, preserved myocardial wall thickness, and synchronous systolic contraction. No late gadolinium enhancement was present. An incidental thin membranous structure in the right atrium was consistent with partial cor triatriatum dexter. Given preserved biventricular function and absence of symptoms, a conservative strategy with clinical and imaging follow-up was adopted. The patient remained stable during follow-up. CMR is the reference modality for characterization of left ventricular diverticulum and reliable differentiation from other ventricular outpouchings, including aneurysm, pseudoaneurysm, myocardial cleft, and double-chambered left ventricle.

Introduction

The most relevant ventricular wall defects include aneurysms, pseudoaneurysms, and diverticula, each of them presenting distinct etiologies, prognoses, and therapeutic implications. Among these, left ventricular diverticula (LVD) are the rarest, with an estimated prevalence of 0.4% [1]. LVD is defined as an outpouching of the ventricular wall and its dimensions and the diameter of its connection to the left ventricular chamber are variable. The most typical feature is its synchronous contraction with the other cardiac walls [2]. Although LVD can occur anywhere on the left ventricular wall, the apex is where it is most frequently localized. Apical diverticula are often associated with other midline thoracoabdominal defects and cardiac malformations, whereas diverticula in other locations tend to be isolated and not linked to additional cardiac anomalies. LVD is typically asymptomatic, and its detection is often incidental, discovered during imaging studies performed for unrelated clinical indications [2,3]. Definitive diagnosis of LVD required imaging techniques such as echocardiography, cardiac CT and cardiac magnetic resonance (CMR).

Learning objective: This case report emphasizes the importance of cardiac magnetic resonance (CMR) in differentiating left ventricular diverticulum from other ventricular outpouchings. Understanding this rare anomaly aids in accurate diagnosis, avoiding misclassification with more severe conditions like pseudoaneurysms or aneurysms. Clinicians should recognize the implications of incidental LVD findings and tailor management strategies accordingly, balancing conservative follow-up with surgical intervention in selected cases.

Case report

A 68-year-old patient was referred to our department for hypertension. She had no significant previously medical history, except for hypothyroidism (well-controlled), and no significant cardiovascular risk factors or family history of sudden cardiac death. Physical examination revealed elevated blood pressure (measuring 150/100 mmHg). Electrocardiography showed moderate signs of left ventricular hypertrophy, consistent with hypertensive heart disease. For a better evaluation, she underwent an echocardiographic examination that showed a normo-volumetric left ventricle with mild septal thickening and a focal defect exhibiting a cribriform appearance. Left ventricular systolic function was normal, but there was evidence of a first grade diastolic dysfunction. The right ventricle was normal in volume and function, with a hypertrophic moderator band measuring 9 mm (Fig. 1). Echocardiography raised suspicion of a potential interventricular communication; however, aneurysm and pseudoaneurysm were considered and subsequently excluded.

Fig. 1.

(A) Apical four-chamber transthoracic echocardiography showing a hypertrophic moderator band in the right ventricle and an apparent discontinuity of the interventricular septum. (B) Color Doppler demonstrating aliasing consistent with flow across the septal region, initially raising suspicion of an interventricular communication. These findings prompted further evaluation with cardiac magnetic resonance imaging. (C) Continuous-wave Doppler tracing obtained across the suspected septal defect region, showing turbulent high-velocity flow within the right ventricular cavity. (D) Four-chamber cardiac magnetic resonance image demonstrating an intact interventricular septum and confirming the absence of a true ventricular septal defect, with the apparent discontinuity related to the prominent hypertrophic moderator band.

Differential diagnosis

Differential diagnosis included ventricular aneurysm, pseudoaneurysm, myocardial cleft, and double-chambered left ventricle (DCLV). Based on echocardiographic findings, an interventricular defect was initially suspected; however, this was considered less likely due to preserved ventricular function and absence of definite septal discontinuity.

Cardiac magnetic resonance (CMR) was subsequently performed on a 1.5-T system using a standardized protocol including cine balanced steady-state free precession sequences, T2-weighted fat-suppressed imaging, and late gadolinium enhancement (LGE) acquisitions obtained 10-15 minutes after intravenous administration of gadolinium-based contrast agent (0.1 mmol/kg).

CMR demonstrated normal biventricular volumes and function, with no evidence of myocardial fibrosis or scar. Cine SSFP sequences excluded an interventricular defect and confirmed a normal appearance of the right ventricular moderator band. In the left ventricle, a focal outpouching with preserved wall thickness (∼ 9 mm) was identified, associated with a hypertrophic posterior papillary muscle. The lesion showed synchronous systolic contraction with the adjacent myocardium, and all sequences demonstrated signal characteristics consistent with normal myocardium, supporting the diagnosis of left ventricular diverticulum (LVD).

Additionally, CMR revealed a thin membranous structure within the right atrium, consistent with partial cor triatriatum dexter (Fig. 2).

Fig. 2.

(A–B) Balanced steady-state free precession (bSSFP) cine images demonstrating a left ventricular outpouching with a narrow neck and preserved myocardial wall thickness. (C–D) Late gadolinium enhancement (LGE) images showing absence of abnormal myocardial enhancement. (E–F) Diastolic cine images demonstrating expansion of the diverticulum. (G–H) Systolic cine images demonstrating synchronous contraction with near-complete reduction in diverticular size. (I–L) CMR images demonstrating a thin membranous structure within the right atrium (yellow arrow), consistent with partial cor triatriatum dexter.

Given the absence of symptoms and preserved ventricular function, a conservative management strategy was adopted. The patient was referred for clinical follow-up with periodic imaging surveillance. At the time of manuscript preparation, no adverse events or progression of the diverticulum were reported.

Discussion

LVD is a rare, nonhereditary cardiac anomaly characterized by an outpouching of the cardiac wall, forming a sac connected to the left ventricle via a narrow neck. LVD can be congenital or acquired, with the congenital form being more common and typically diagnosed in pediatric population [4,5]. According to the histological composition, ventricular diverticula are classified as either fibrous or muscular. Fibrous diverticula are usually sub-annular and not commonly associated to other cardiac anomalies. Muscular diverticula are usually located at the apex and are frequently associated with other cardiac malformations. A notable association is the “Cantrell’s syndrome,” a complex condition characterized by a pentalogy of defects: 1) a midline abdominal wall defect;2) a caudal sterna defect; 3) an anterior diaphragmatic defect; 4) a pericardial defect; 5) a heart defect such as LVD and occasionally right ventricular diverticulum [3,6]. The etiology of LVD is not well known, but its development is thought to be the result of a partial disruption of ventricle embryogenesis, with a defect in mesoderm formation between days 14 and 18 of pregnancy [1,7]. An important feature, common to all types of cardiac diverticula and particularly useful for diagnosis, is their systolic contraction. Diverticula exhibit synchronous contraction with the rest of the cardiac walls, as observed in echocardiography or CMR. Smaller diverticula may even close completely during systole. These diverticula usually have a narrow neck, with sizes ranging from 1 cm to 9 cm in length (with possible extension beyond anatomic cardiac boundary) and a depth of less than 1 cm. Moreover, CMR shows normal myocardial signal without enhancement on LGE sequences [4,8]. Although LVD is associated with relatively few complications, some of the most reported include cerebral events (2.9%), arrhythmias (9.9%), heart failure (6.8%), and rupture (4.2%) [8]. Due to its rarity, there is a lack of established treatment guidelines, and management typically depends on symptomatology. Clinical follow-up is generally sufficient for stable diverticula that do not increase in size. Surgery is recommended in case of symptomatic patients, large diverticula with high risk of rupture, or when other symptomatic anomalies are associated [[1], [2],[5], [6], [7]]. It is crucial to differentiate LVD from other forms of ventricular outpouching, such as pseudoaneurysm, aneurysm, cleft and dual chambered left ventricle (DCLV). Advancement in imaging modalities had led to an increase in frequency of diagnosis for all these anomalies; in particular, even if echocardiography remains the first diagnostic approach, CMR is gaining prominence due to its superior capability for anatomical assessment (with minimal limitations) and its ability to provide detailed tissue characterization (Table 1, Table 2).

Table 1.

Imaging features and differential diagnosis of left ventricular outpouchings.

Condition	Neck morphology	Wall composition	Contractility	LGE pattern	Key CMR features
Left ventricular diverticulum	Narrow neck	Full myocardial layers	Synchronous contraction	No enhancement	Preserved wall thickness, normal signal intensity
True aneurysm	Wide neck	Thinned myocardium	Akinetic/dyskinetic	Subendocardial or transmural scar	Post-infarction remodeling, fibrotic wall
Pseudoaneurysm	Narrow neck	Pericardial wall only	Paradoxical motion	Pericardial and infarct enhancement	High rupture risk, abrupt transition
Myocardial cleft	No true neck	Normal myocardium	Systolic obliteration	No enhancement	Linear invagination, no true outpouching
Double-chambered LV	Wide communication	Muscular septum	Contractile accessory chamber	Normal myocardium	Accessory chamber within LV cavity

Table 2.

Clinical timeline of diagnostic work-up and management.

Time point	Clinical event	Findings/Action
Initial presentation	Routine evaluation for hypertension	ECG: LV hypertrophy
Day 0	Transthoracic echocardiography	Suspected interventricular defect
Day +X	Cardiac MRI	Diagnosis of left ventricular diverticulum confirmed
Same study	Incidental finding	Cor triatriatum dexter
Post-imaging	Clinical decision	Conservative management
Follow-up	Outpatient surveillance	No progression reported

Left ventricular clefts are anatomical fissures located on the inferior or septal walls of the left ventricle, running perpendicular to endocardial border. These clefts usually exhibit contractility, becoming obliterated during systole, making difficult their differentiation from small diverticula. They result from the disarray of myocardial fibers. Isolated clefts usually occur in normal heart, while multiple clefts are commonly associated with hypertensive cardiomyopathy or hypertrophic cardiomyopathy (HCM). In particular, recent studies have suggested clefts as potential biomarker in individuals with gene mutations linked to HCM [5,9]. Left ventricular aneurysm and pseudoaneurysm are abnormal outpouching, most commonly resulting from myocardial infarction, though other etiologies such as trauma, iatrogenic injury and Chagas disease are also recognized. The aneurysmal sac consists of endocardium, myocardium and epicardium, similarly to the structure of a diverticular sac. However, the myocardial layer within an aneurysm is typically thinned and exhibits akinetic or dyskinetic behavior. Aneurysm generally presents with a wide neck, demonstrating a gradual transition from the normal cardiac wall to the aneurysmal wall. CMR provides insight into both kinetic abnormalities and the presence of fibrotic scar tissue, thanks to LGE technique. CMR can also detect thrombus formation in chronic aneurysms. In contrast, pseudo-aneurysmal sac is only composed by pericardial layer. Pseudoaneurysms are usually secondary to myocardial infarction, that caused left ventricle rupture, buffered by pericardium. CMR can show a narrow neck connected to a large sac, and a thin wall with paradoxical contractility, without gradual transition to normal cardiac wall. LGE reveals subendocardial enhancement indicative of infarction, as well as pericardial enhancement, due to inflammation. While aneurysms are generally stable and managed conservatively, pseudoaneurysms carry a significant risk of rupture and require urgent surgical intervention [[1], [2], [3],5]. Another condition to distinguish from LVD is the DCLV, an extremely rare congenital anomaly of heart, also known as “cor triventriculare sinistrum.” Only a few cases are described in literature, reporting an estimated prevalence of 0.04%-0.42%. The main feature is the presence of a septate left ventricular chamber, usually divided into right-left by an accessory septum, composed of muscle or fibromuscular tissue. Most patients are asymptomatic, and this condition is often detected incidentally. CMR can differentiate an accessory chamber similar to a diverticulum, with all 3 layers of cardiac tissue, a systolic contraction and the same signal intensity of myocardium on LGE sequences. DCLV can be distinguished only for the wide connection to the main left ventricular chamber [10].

Conclusion

Left ventricle diverticulum represents an infrequent incidental finding, usually asymptomatic, rarely associated with arrhythmia, heart failure and embolisms. Imaging techniques such as echocardiography and, more specifically, CMR with its tissue characterization capabilities, are crucial for differentiating LVD from other left ventricular outpouchings. Management is dependent on clinical presentation, the size of the diverticulum, and any concomitant cardiac abnormalities. Treatment options range from conservative management, including clinical and imaging follow-up, to surgical intervention when indicated. This case highlights the importance of multimodality imaging and structured differential diagnosis in the evaluation of ventricular outpouchings.

Patient consent

Complete written informed consent was obtained from the patient for the publication of this study and accompanying images.