Importance of Multimodality Cardiac Imaging in the Diagnosis of Lipomatous Hypertrophy of the Interatrial Septum-A View beyond Standard Situations

Lipomatous hypertrophy of the interatrial septum (LHIAS) represents a benign proliferation of lipoid cells at the level of the interatrial septum (IAS) inducing an important thickening of this structure. It respects the fossa ovalis (FO) region, having a typical "hourglass" echocardiographic appearance. There are certain cases though, with unusual appearances and/or with associated pathologies that may induce similar lesions in the heart, in which the differential diagnosis cannot be guaranteed using only the standard methods. The final diagnosis has important implications in these patients' treatment plan. In this paper, we present an unusual case of a female patient undergoing chemotherapy for lung carcinoma, suspected of right atrial thrombosis/metastasis. As the diagnosis was unclear after transthoracic echocardiography (TTE), inducing the suspicion of an IAS mass with atrial wall infiltration, bi- and tridimensional transesophageal echocardiography (TOE) was performed, revealing a severely and homogenously hypertrophied IAS respecting the FO, but lacking a clear visualization of the atrial wall. The diagnosis of LHIAS was established by cardiac magnetic resonance (CMR) that certified the adipose nature of the structure, excluding the need for invasive investigations and/or treatment options. Multimodality imaging is very important for the clinician in adopting the best management plan for each individual patient.

Inter-atrial septal balloon dilation to facilitate intracardiac echocardiography guided left atrial appendage occlusion

INTRODUCTION

Percutaneous left atrial appendage occlusion (LAAO) is traditionally performed under general anesthesia with trans-esophageal echocardiography guidance. Intracardiac echo (ICE)-guided LAAO closure is increasing in clinical use. The ICE catheter is crossed into LA via interatrial septum (IAS) after the septum is dilated with LAAO delivery sheath. This step can be time-consuming and requires significant ICE catheter manipulation, which increases the risk of cardiac perforation. Pre-emptive septal balloon dilation can potentially help with ICE advancement in the LA. We sought to evaluate the effect of pre-dilation of the IAS with an 8 mm balloon on the ease of crossing the ICE catheter, fluoroscopy time for crossing, and overall procedure time.

METHODS

The Piedmont LAAO registry was used to identify consecutive patients who underwent LAAO. The initial 25 patients in whom balloon dilation of the IAS was performed served as the experimental cohort, and the 25 consecutive patients before that in whom balloon dilation was not performed served as controls. In the experimental group, after a trans-septal puncture, the sheath was retracted to the right atrium with a guidewire still in the LA. An 8 × 40 mm Evercoss™ over the wire balloon was inflated across the IAS. The ICE catheter was then crossed into the LA using the fluoroscopic landmark of the guide wire and the ICE imaging. The sheath was then advanced along the ICE catheter via the transseptal puncture (TSP) and the procedure continued. Follow-up compputed tomography imaging was obtained at 4-8 weeks.

RESULTS

Each group consisted of 25 patients. There were no significant differences in baseline characteristics. All procedures were performed successfully under conscious sedation and ICE guidance. There was a significant reduction in the overall procedure time, fluoroscopy time, and time for transseptal puncture to ICE in LA. There was no difference in the size of the acute residual interatrial shunt, as measured via ICE, or the size and presence of iatrogenic ASD at follow-up.

CONCLUSION

Balloon dilation of TSP is safe and is associated with increased efficiency in ICE-guided LAAO procedures.

The efficiency and safety of multidetector computed tomography-guided transseptal puncture during atrial fibrillation catheter ablation

Background

Transseptal puncture (TSP) is a crucial technique for catheter ablation of atrial fibrillation (AF). Although intracardiac echo (ICE) facilitates a safe and accurate TSP, it is not widely used in developing countries because of the expense. This study evaluated the efficiency and safety of a novel cardiac multidetector computed tomography (MDCT)-guided TSP during AF catheter ablation.

Methods

The study consisted of two cohorts. In the index cohort, TSP procedure was performed under the guidance of ICE, and we recorded the angulation of right anterior oblique of X-ray projection. In the validation cohort, we compared the efficiency and safety of TSP guided by MDCT-calculated angulation with propensity-score-matched patients who underwent TSP guided by ICE.

Results

We included 50 patients in the index cohort, and the mean angles of interatrial septum (IAS) measured from MDCT and ICE were 34.8 ± 6.3 and 35.1 ± 6.5, respectively. In the validation cohort, 376 patients were enrolled in the MDCT-guided group and ICE-guided group. Both groups had 1 case of cardiac tamponade. The mean axial plane angle was 35.46 ± 6.17 degrees, which was not influenced by age, gender, BMI, and LA size, while a moderate positive linear correlation between EF and the axial plane angle (R 2 = 0.14, p = .006).

Conclusion

Cardiac MDCT can provide a clear vision of IAS orientation, and provide the appropriate RAO angle and height for TSP. The efficiency and safety of our MDCT-guided TSP were comparable to ICE-guided TSP, which may serve as an alternative method for TSP with ICE unavailable.

Unexpected TEE Findings During Rheumatic Triple-Valve Surgery: Incidental, Yet Impactful

This E-Challenge highlights an incidental prebypass transesophageal echocardiographic (TEE) finding of a right atrial membrane that impacted cardiac surgical management during triple-valve surgery. Two-dimensional and advanced 3-dimensional (3D) TEE were used in real-time to assist intraoperative decision-making. The findings, clinical course, discussion of the differential diagnosis, final diagnosis, and patient management are detailed here.

The 2022 FASEB Virtual Catalyst Conference on the Cardiac Interatrial Septum and Stroke Risk, December 7, 2022

There is emerging evidence that the cardiac interatrial septum has an important role as a thromboembolic source for ischemic strokes. There is little consensus on treatment of patients with different cardiac interatrial morphologies or pathologies who have had stroke. In this paper, we summarize the important background, diagnostic, and treatment considerations for this patient population as presented during the Federation of American Societies for Experimental Biology (FASEB) Virtual Catalytic Conference on the Cardiac Interatrial Septum and Stroke Risk, held on December 7, 2022. During this conference, many aspects of the cardiac interatrial septum were discussed. Among these were the embryogenesis of the interatrial septum and development of anatomic variants such as patent foramen ovale and left atrial septal pouch. Also addressed were various mechanisms of injury such as shunting physiologies and the consequences that can result from anatomic variants, as well as imaging considerations in echocardiography, computed tomography, and magnetic resonance imaging. Treatment options including anticoagulation and closure were addressed, as well as an in-depth discussion on whether the left atrial septal pouch is a stroke risk factor. These issues were discussed and debated by multiple experts from neurology, cardiology, and radiology.

Uncommon Incidental Diagnosis of Lipomatous Hypertrophy of the Interatrial Septum

Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign non-neoplastic cardiac lesion that previously has not been readily described, but with the increasing usage of computed tomography and echocardiography, this is now becoming a more well-characterized incidental finding. This case highlights an incidental finding of LHIS while a patient was undergoing treatment for a routine gastrointestinal bleed.

Inferior Vena Cava Draining Into the Left Atrial Cavity Due to Atrial Septal Defect: Two Atypical Presentations

The inferior vena cava draining to the left atrium is a rare congenital anomaly. Patients usually present with hypoxia and dyspnoea. This condition is usually diagnosed by echocardiography and sometimes by CT scan. Here we report two cases that presented with normal saturation and their surgical management.

Facilitation techniques to cross the interatrial septum with intracardiac echocardiography during left atrial appendage closure

OBJECTIVES

This study aimed to assess the rate of difficult interatrial septum (IAS) crossing with the intracardiac echocardiography (ICE) probe during percutaneous left atrial appendage (LAA) closure and to identify techniques that facilitate IAS crossing with the ICE probe.

BACKGROUND

Percutaneous LAA closure is increasingly performed by ICE guidance. Although such an approach omits the need for general anesthesia, crossing of the IAS with the ICE probe may sometimes be challenging.

METHODS

All consecutive patients that underwent ICE-guided percutaneous LAA closure with an Amplatzer Amulet (Abbott) or WatchmanFLX (Boston Scientific) at our center in the period 2018-2021 were included. Cases in which IAS crossing with ICE was difficult were identified and techniques used to facilitate IAS crossing were identified and listed.

RESULTS

In 17 (5%) out of 354 cases, IAS crossing with the ICE probe was difficult and required use of additional techniques. Ultimately, IAS crossing was also successful in these 17 cases by using one of three possible facilitation techniques: the probing technique (12 cases), the double-wire technique (3 cases), and the snaring technique (2 cases). In one case, the double-wire technique was converted to the snaring technique, as crossing of the ICE probe remained challenging despite the use of two stiff guidewires.

CONCLUSION

Crossing of the IAS with the ICE probe can be challenging in 5% of ICE-guided percutaneous LAA closure procedures. Operators should be aware of possible facilitation techniques in challenging cases, as these show to be safe and effective.

Left atrial septal pouch in a six-year-old child: echocardiographic and magnetic resonance view

In a 6-year-old child patient, transthoracic echocardiography revealed a large saccular structure (with anechogenic content) in the left atrium, near the fossa ovalis, and diagnosis of the left atrial septal pouch was made. The left atrial septal pouch is a kangaroo pouch-like structure on the left side of the interatrial septum, opened into the left atrial cavity without a connection between the left and right atria. It occurs when the foramen ovale is absent but the septum primum and septum secundum are only partially fused. The left atrial septal pouch is believed to be present in 47% of population. In many cases, the pocket on the atrial septum is small and it could not be detected by transthoracic echocardiography. Our description is uncommon because we diagnosed a very large septal pouch. Based on our knowledge, this is the youngest reported case of the left atrial septal pouch and the longest follow-up described in this type of congenital heart malformation.

Comparing the safety and effectiveness of dedicated radiofrequency transseptal wires to electrified metal guidewires

Background

Application of electrocautery to a metal guidewire is used by some operators to perform transseptal puncture (TSP). Commercially available dedicated radiofrequency (RF) guidewires may represent a better alternative. This study compares the safety and effectiveness of electrified guidewires to a dedicated RF wire.

Methods

TSP was performed on freshly excised porcine hearts using an electrified 0.014″ or 0.032″ guidewire under various power settings and was compared to TSP using a dedicated RF wire with 5 W power (0.035″ VersaCross RF System, Baylis Medical). The primary endpoint was the number of attempts required to achieve TSP. Secondary endpoints included the rate of TSP failure, TSP consistency, the effect of the distance between the tip of the guidewire and the tip of the dilator, and effect of RF power output level. Qualitative secondary endpoints included tissue puncture defect appearance, thermal damage to the TSP guidewire or dilator, and tissue temperature using thermal imaging.

Results

The RF wire required on average 1.10 ± 0.47 attempts to cross the septum. The 0.014″ electrified guidewire required an overall mean of 2.17 ± 2.36 attempts (2.0 times as many as the RF wire; p < .01), and the 0.032″ electrified guidewire required an overall mean of 3.90 ± 2.93 attempts (3.5 times as many as the RF wire; p < .01). Electrified guidewires had a higher rate of TSP failure, and caused larger defects and more tissue charring than the RF wire. Thermal analysis showed higher temperatures and a larger area of tissue heating with electrified guidewires than the RF wire.

Conclusion

Fewer RF applications were required to achieve TSP using a dedicated RF wire compared to an electrified guidewire. Smaller defects and lower tissue temperatures were also observed using the RF wire. Electrified guidewires required greater energy delivery and were associated with equipment damage and tissue charring, which may present a risk of thrombus, thermal injury, or scarring.

Morphological Study of Fossa Ovalis in Formalin-Fixed Human Hearts and Its Clinical Importance

Background and Objectives: Our study aimed to investigate the gross anatomy aspects of the fossa ovalis (FO) and the presence of some anatomical variation resulting from the incomplete fusion of septum primum and septum secundum, such as an atrial septal pouch (SP) and left atrial septal ridge. Materials and Methods: Thirty-one adult human hearts removed from formalin-fixed specimens were examined to provide information about the morphology of the FO. The organs were free of any gross anatomically visible pathological conditions. Results: The most common variants were the FO located in the inferior part of the interatrial septum (64.51%), circular (61.3%), with a net-like structure (51.62%), prominent limbus (93.55%), and patent foramen ovale (PFO) (25.8%). The right SP was observed in 9.67% of specimens, the left SP was observed in 29.03% of cases, and in 51.61% of cases, a double SP was observed. One sample presented a right SP and a double left SP, and one case showed a triple left SP, which was not reported previously to our knowledge. Conclusions: Knowledge of the interatrial septal anatomy becomes important for interventional cardiologists and should be documented before transeptal puncture.

A histological and immunohistochemical study on the parabronchial epithelium of the domestic fowl's (Gallus gallus domesticus) lung with special reference to its scanning and transmission electron microscopic characteristics

The current study was designed to give complete histo-and immunohistochemical features of the parabronchial epithelium of domestic fowl's (Gallus gallus domesticus) lung with special reference to Scanning electron microscope (SEM) and mean transmission electron microscope (TEM) features. The lung exhibited variable-sized atrial openings encircled by exchange tissue zones. The parabronchial atrial chambers appeared as ovoid and polygonal-shaped that separated by the well-developed interatrial septum. The deep atrial lumens had blood vessels pierced by openings that represent the infundibula. The parabronchial blood capillaries meshwork was branched and exhibited ovoid-shaped air capillaries with numerous extravasated blood vessels. By TEM, there were several air capillaries and groups of squamous and endothelial respiratory cells and the squamous cells had oval nucleus with evenly distributed chromatin. The endothelial respiratory cells had few microvilli on their free surfaces. The parabronchial tubes opened into a group of widened atria that had smooth muscle bundles at the interatrial septa. The atrial chambers led to narrow infundibula. Moreover, the lining epithelium of parabronchi, atria, infundibula, and air capillaries was formed by simple squamous epithelium. Air capillary walls were lined by two types of respiratory cells (Types-I and II). Collagen fibers were concentrated within the tunica externa layers of the parabronchial blood vessels as well as, they were observed in CT interparabronchial septa. Immunohistochemically, the elastin immunoreactivity was detected around the parabronchial blood vessels, at the base of each parabronchial atria, and in the area encircling the alveolar-capillary walls. Our work concluded that there are a relation between the fowl's lifestyle and the surrounding environmental conditions.

Patient with sick sinus syndrome and implanted dual-chamber pacemaker with reduced P-wave duration following low interatrial septal pacing: Case report

INTRODUCTION

A dual-chamber pacemaker (DDD/R) for a sinus node disease is sometimes referred to as a physiological pacemaker as it maintains atrioventricular synchrony, however several clinical trials have proved its inferiority to a nonphysiological single-chamber ventricular back-up pacing.

PATIENT CONCERNS

A subject of the study is a 74-year-old woman with a sick sinus syndrome (SSS) and a previously implanted physiological DDD/R pacemaker. The SSS was diagnosed because of patient's very slow sinus rhythm of about 36 bpm, and due to several episodes of dizziness. After the DDD/R implantation the percentage of atrial pacing approached 100%, with almost none ventricular pacing.

DIAGNOSES

Sick sinus syndrome, complete Bachmann's bundle block, atrial fibrillation, atrial flutter.

INTERVENTIONS

The patient was previously implanted with a physiological DDD/R pacemaker. Several years after the implantation, the atrial fibrillation was diagnosed and the pulmonary vein isolation was then performed by cryoablation. During the follow-up after pulmonary vein isolation, the improvement of mitral filling parameters was assessed using echocardiography. Shortly thereafter the patient developed the persistent paroxysm of a typical atrial flutter which was successfully terminated using a radiofrequency ablation. No recurrence thereof has been observed ever since (24 months).

OUTCOMES

The atrial electrode of the pacing system was implanted within the low interatrial septal region that resulted in a reduced P-wave duration compared to native sinus rhythm P-waves. The said morphology was deformed because of the complete Bachmann bundle block. That approach, despite a nonphysiological direction of an atrial activation, yielded relatively short P-waves (paced P-wave: 179 ms vs intrinsic sinus P-wave: 237 ms). It also contributed to a significantly shorter PR interval (paced PR: 204 ms vs sinus rhythm PR: 254 ms).

CONCLUSIONS

The authors took into consideration different aspects of alternative right atrial pacing sites. This report has shown that in some patients with a sinus node disease, low interatrial septal pacing can reduce the P-wave duration but does not prevent from the development of atrial arrhythmias.

Use of a cerebral protection device to facilitate pulmonary vein isolation in a patient with left atrial mass arising from the interatrial septum

Sentinel cerebral embolic protection devices (CPDs) may limit periprocedural cerebrovascular events by preventing micro and macro-embolization to the brain, and has been used in many cardiology and radiology procedures. We hereby report the use of a Sentinel CPD to facilitate safe and effective atrial fibrillation ablation in a patient with a left atrial mass arising from the interatrial septum.

Lipomatous Hypertrophy of the Interatrial Septum Manifesting as Third Degree Atrioventricular Block

A 55-year-old patient was found to have complete heart block during preoperative assessment. Cardiac magnetic resonance imaging revealed an interatrial mass suggestive of primary cardiac tumor. Extensive evaluation including intracardiac biopsy and finally open resection revealed lipomatous hypertrophy masquerading as tumor. (Level of Difficulty: Intermediate.).

Presence of the annular ridge and location of the coronary sinus ostium as morphological features ofthe right atrium and interatrial septum in healthy common marmosets (Callithrix jacchus)

To effectively use a common marmoset (Callithrix jacchus) as an experimental animal species, it is critical to establish a normal characteristics and morphology of the organs of the common marmoset. Although gross morphology of the common marmoset heart is reportedly the same as that of humans, little information is available regarding detailed morphology of the right atrium and the interatrial septum. Heart specimens were collected from three male and 10 female marmosets aged 9 to 65 months to determine the morphological features of the right atrium and the interatrial septum. Ten specimens were evaluated morphologically with a stereoscopic microscope in accordance with preparation and investigation methods designed to facilitate evaluation. Three specimens were histologically evaluated after being stained with hematoxylin-eosin, Elastica van Gieson and periodic acid Schiff. An annular ridge that is not present in the human heart was present in the right atrium and the interatrial septum of the common marmoset hearts. Tissue structure of the annular ridge was similar to atrial myocardial fibers. Furthermore, location of the coronary sinus ostium was different to that in humans. Present findings were used to create a schematic view of the annular ridge in the common marmoset heart. In the common marmoset heart, the annular ridge may function as a valve of the superior vena cava ostium, inferior vena cava ostium, and coronary sinus ostium. Present study provides morphological evidence that common marmosets have a valve-like structure in the right atrium.

Topographic characteristics of the left atrial medial isthmus

BACKGROUND

The purpose of this study was to provide detailed topography of the left atrial medial isthmus (situated between the right inferior pulmonary vein ostium and the medial part of the mitral annulus).

METHODS

Two hundred human hearts (Caucasian, 22.5% females, 48.7 ± 4.9 years old) were investigated.

RESULTS

The mean length of the medial isthmus was 42.4 ± 8.6 mm. Additionally, the medial isthmus line was divided by the oval fossa into three sections with equal mean lengths (upper: 14.2 ± 7.2 vs middle: 14.1 ± 6.1 vs lower: 14.9 ± 4.6 mm; P > .05). The left upper section of the atrial wall was thinner than the lower section (2.5 ± 1.1 vs 3.4 ± 1.6 mm; P < .0001). This study noted three separate spatial arrangements of the isthmus line. Type I (54.5%) had an oval fossa located outside the isthmus line; type II (32.5%) had an oval fossa crossed by the isthmus line, and type III (13.0%) had an oval fossa rim located tangentially to the isthmus line. In 68.5% of the examined specimens, the isthmus area had a smooth surface. Conversely, the remaining 31.5% had additional structures within its borders such as diverticula, recesses, and tissue bridges.

CONCLUSION

This study is the first to describe the morphometric and topographical features of the left atrial medial isthmus. Interventions within the medial isthmus line should be performed cautiously, especially when they are transected by the oval fossa (32.5%). Careful navigation of the area is also recommended due to the possibility of existent additional structures. The latter could lead to catheter entrapment during ablation procedures.

Incidental Finding of Lipomatous Hypertrophy of the Interatrial Septum during 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography for Cervical Cancer

Lipomatous hypertrophy of the interatrial septum is a benign but less recognized pathology of the heart caused by benign fatty infiltration of the interatrial septum which most often spares the fossa ovalis. We share images of the incidentally detected fluorodeoxyglucose (FDG) uptake in the interatrial septum during the restaging of 18F-FDG positron emission tomography/computed tomography scan of cervical cancer.

Dissecting Aneurysm of the Interatrial and Interventricular Septum with Concomitant Ventricular Septal Defect-Multimodality Cardiac Imaging and Surgical Repair

We report an exceedingly rare case of spontaneous dissecting aneurysm involving the interatrial and interventricular septum, concomitant ventricular septal defect in an 8-year-old girl, echocardiographic and multislice computed tomographic imaging, and successful surgical repair.

Lipomatous hypertrophy of the interatrial septum in a child with atrial tachycardia

A 13-year-old girl who had been on home parenteral nutrition for 6 months has been presented with multifocal atrial tachycardia and atrial fibrillation. Echocardiography and multislice computed tomography showed fat accumulation on the interatrial septum. Lipomatous hypertrophy of the interatrial septum has never been reported in children.

Role of echocardiography in patients with intravascular hemolysis due to suspected continuous-flow LVAD thrombosis

OBJECTIVES

This study sought to characterize the echocardiographic findings of patients presenting with intravascular hemolysis (IVH) due to suspected continuous-flow left ventricular assist device (LVAD) pump thrombosis.

BACKGROUND

LVAD patients who develop pump thrombosis often present with IVH. Echocardiography may be able to detect device dysfunction in this setting.

METHODS

Continuous-flow LVAD patients presenting with IVH due to suspected pump thrombosis were identified. Patients underwent echocardiography with cannula Doppler flow velocity interrogation. Findings were compared with baseline and follow-up studies, and with 49 stable LVAD control patients.

RESULTS

Of 145 patients, 14 (10%) had IVH due to suspected pump thrombosis. The mean age was 55 ± 15 years, 93% were men, and 50% received LVAD as destination therapy. Mean duration between implantation and IVH was 231 ± 218 days. Eleven (79%) patients presented with hemoglobinuria, 9 (64%) with jaundice, and 5 (36%) with acute heart failure. Reduced cannula diastolic flow velocity and increased systolic/diastolic (S/D) flow velocity ratio were the only echocardiographic parameters significantly different from controls (outflow cannula 0.3 ± 0.2 m/s vs. 0.8 ± 0.3 m/s, p = 0.03, and 5.9 ± 2.8 vs. 1.7 ± 0.7, p < 0.01, respectively), and were worse for IVH patients with acute heart failure compared with those without (outflow cannula 0.2 ± 0.1 m/s vs. 0.5 ± 0.2 m/s, p = 0.04, and 7.2 ± 3.3 vs. 5.3 ± 2.0, p = 0.02, respectively). Outflow cannula diastolic flow velocity and S/D flow velocity ratio changed significantly from baseline (p = 0.01 and p < 0.01, respectively) in IVH patients, whereas systolic flow velocity did not change (p = 0.59). Odds ratios for outflow cannula diastolic flow velocity and S/D flow velocity ratio for predicting IVH were 0.60 (95% confidence interval [CI]: 0.51 to 0.73), p = 0.02, and 2.45 (95% CI: 2.37 to 2.52) p < 0.01, respectively. Corresponding inflow cannula values were similarly significant. Pump thrombosis was confirmed in 7 (50%) patients after LVAD retrieval.

CONCLUSIONS

Reduced cannula diastolic flow velocity and increased S/D flow velocity ratio identified continuous-flow LVAD dysfunction in patients with IVH due to suspected pump thrombosis better than other echocardiographic parameters.

A prominent Eustachian valve dividing the right atrium imaged by three-dimensional transesophageal echocardiography

A 63-year-old man underwent transesophageal echocardiography (TEE) to rule out left atrial thrombi prior to cardioversion. Initial two-dimensional TEE with color flow Doppler imaging was suggestive of an atrial septal defect. However, three-dimensional TEE imaging revealed that the unusually large elongated Eustachian valve extended toward the superior vena cava and mimicked the interatrial septum, while the true septum was located more posteriorly than the Eustachian valve. Three-dimensional TEE imaging was crucial to understanding the anatomical relationship between the Eustachian valve and the interatrial septum and hence proved helpful in characterizing this unusual anatomical variant.

Massive lipomatous hypertrophy of the right atria

A case of a 70-year-old female with a history of hypertension, atrial fibrillation, pacer implantation for symptomatic bradycardia, and a prior cerebrovascular accident, and had developed persistent methicillin-sensitive Staphylococcus aureus bacteremia is reported here. As part of her evaluation, a transesophageal echocardiogram was performed, and even though no vegetations were seen on either pacer wires or cardiac valves, a massive homogeneous thickening of the superior portion of the interatrial septum extending to the posterior and roof portions of the right atrial wall as well as to the superior vena cava causing proximal compression of this vessel was noted. Computed tomographic examination of the chest helped to determine that this mass density was not a tumor but in fact intrapericardial fat. Imaging findings and existing literature on this topic are reviewed.