Lipomatous Hypertrophy of the Atrial Septum

Introduction

Lipomatous hypertrophy of the interatrial septum is a rare cardiac condition defined by the benign infiltration of fat into the interatrial septum. This finding is frequently observed in older and obese patients as an incidental discovery without any symptoms.

What Is Lipomatous Hypertrophy of the Interatrial Septum (LHIS)?

Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare heart condition defined by the benign accumulation of fatty tissue in the interatrial septum, typically without affecting the fossa ovalis. LHIS is microscopically identified by the presence of fat infiltrating the myocardial fibers within the atrial septum. Despite being histologically benign, LHIS has been linked to negative clinical outcomes such as supraventricular arrhythmias, syncope, and sudden death. LHIS can also generate a bulge resembling neoplasms containing fat, which can occur in the atrial septum. These neoplasms include rhabdomyomas, myxomas, rhabdomyosarcomas, and liposarcomas.

What Are the Pathological Features of the Condition?

Lipomatous hypertrophy of the atrial septum refers to the abnormal buildup of excessive fatty tissue in this part of the heart, resulting in a rounded thickening.

• This accumulation of fatty tissue typically protrudes into the right atrial cavity of the artery.

• Among many patients diagnosed with lipomatous hypertrophy of the atrial septum, the septum exhibited varying degrees of maximal thickness.

• The rhythm disorders are prevalent among the elderly population, and several patients were explicitly referred due to the presence of arrhythmias.

• A sample of patients hinders the accurate understanding of the relationship between lipomatous hypertrophy of the atrial septum and supraventricular arrhythmias.

• It is for conduction between nodes to pass through regions where significant fat buildup occurs.

• The occurrence of supraventricular arrhythmias in these individuals.

What Are the Diagnostic Methods?

For diagnostic purposes, Transthoracic Echocardiography (TTE), Transesophageal Examination (TEE), CT (preferred multislice CT or MSCT), and MRI are utilized.

• Transthoracic Echocardiography: An ultrasound exam that creates images of the heart using sound waves is called a transthoracic echocardiogram, or TTE. It is the most typical kind of echocardiography. Although transthoracic echocardiography is commonly conducted initially, its imaging capabilities are limited, providing poor diagnostic accuracy for cardiac structures.

• Transesophageal Examination: A test called transesophageal echocardiography (TEE) uses sound waves to produce images of the heart. Unlike conventional echocardiograms or ultrasounds, a transesophageal echocardiogram (TEE) uses internal imaging, not external imaging. Transesophageal examination (TEE) is considerably more precise and effectively reveals the pathological mass.

• Computed Tomography Scan: CT imaging permits the observation of adipose or fat tissue. Additionally, lipomatous alterations exhibit negligible contrast enhancement, enabling the exclusion of alternative pathologies that may be present. Analyzing the density of CT changes and the typical localization, shape, and image makes it possible to distinguish LHAS from cardiac tumors and establish a diagnosis without needing prior confirmation.

• Histopathological Examination: Histopathology diagnoses and investigates tissue diseases through microscopic examination of tissues and/or cells. In addition to confirming the diagnosis, histopathologists assist clinicians in managing patient care by making tissue diagnoses.

• Echocardiography: An echocardiogram generates images of the heart using sound pulses. This prevalent examination may demonstrate blood circulation across the myocardium and cardiac valves. The clinical significance of using echocardiography to observe lipomatous hypertrophy of the atrial septum remains uncertain.

What Are the Risk Factors for Lipomatous Hypertrophy of the Atrial Septum?

Risks for LHAS would include the following:

• Emphysema: Emphysema is a condition of the lungs characterized by shortness of breath with steroid treatment, more likely to have fat deposits in the mediastinum and heart

• Cerebrotendinous Xanthomatosis: A rare condition, cerebrotendinous xanthomatosis (CTX) impairs the body's capacity to metabolize cholesterols, which are lipid molecules. CTX renders patients incapable of degrading various types of cholesterol, which accumulate in specific organs and tissues.

• Mediastino-Abdominal Lipomatosis: A benign disease marked by symmetrical fat buildup inside the mediastinum that is not encased

• Long-Term Parenteral Nutrition: A medical technique that involves administering a specialized nutritional substance intravenously through a vein. The treatment's objective is to rectify or avert malnutrition.

• Arrhythmia: An irregularity in the rhythm or rate of the pulse, which is rarely linked to LHAS. However, the formation process is related to the infiltration of adipocytes into the atrial myocytes, disrupting their structure.

The major types of arrhythmia include the following:

1. Atrioventricular Fibrillation: Atrial fibrillation (AFib) is a cardiac arrhythmia with irregular and frequently accelerated heart rate.

2. Atrial Premature Complexes: A prevalent form of cardiac arrhythmia, atrial premature complexes (APCs) are distinguished by initiating premature heartbeats from the atria.

3. Supraventricular Arrhythmias: Supraventricular arrhythmias is an elevated heart rate that originates above the heart's two lower chambers.

4. Ectopic Rhythm: An ectopic rhythm is characterized by an irregular premature heartbeat.

5. Junctional Rhythm: In a junctional rhythm, the heartbeat comes from the AV node in the muscle where the atria and ventricle meet.

6. Atrial Flutter: Atrial flutter is a cardiac arrhythmia that arises from heart electrical circuitry abnormalities. The patient with symptomatic LHAS has these symptoms.

What Are the Treatment Procedures?

In numerous individuals, it is benign and frequently requires no treatment. However, in cases where there is severe obstruction of the superior vena cava or persistent rhythm disturbance that cannot be resolved, surgical removal with rebuilding of the interatrial septum may be explored.

A complex cardiac operation was executed successfully for LHAS, and asymptomatic patients do not necessitate cardiac surgery. Surgical intervention for LHAS should be restricted to patients presenting with marginal obstruction of the right atrium or the pulmonary artery, which necessitates both lesion resection and concurrent interatrial septum plasty.

• The executed procedure can potentially be a beneficial therapeutic option for arrhythmia patients. The investigation of the surgery's long-term benefits and the potential for recurrence still needs to be completed.

• The symptoms went away after the lesion was completely removed.

• The exact way that removing LHAS led to the return of the sinus rhythm is not clear; the area of arrhythmogenic foci (direct AF triggers or atrial premature beats that can be repeated on their own with coupling intervals of less than 350 ms or shots that happen over and over again.) included the right atrial wall.

• The uneven route connecting the right atrium and the superior vena cava (SVC) was severed during the surgical excision.

Conclusion

The lipomatous hypertrophy of the interatrial septum (LHAS) in a patient is being evaluated during a scheduled coronary artery bypass surgery. In such instances, surgical intervention is warranted to prevent subsequent blockages in the outflow. It is necessary to perform a histological investigation of these cardiac lesions to rule out additional fatty masses in the heart, specifically liposarcomas (a type of cancer that develops in the body's soft tissues, specifically in the fat cells).