Accessory Appendages Research Articles

A Study on Variations in Size and Shape of Left Atrial Appendage from Formalin-fixed Cadavers

Introduction: Atrial appendages were once considered vestigial structures with no significant role in atrial function. However, they are now recognized as significantly impacting various pathophysiological conditions, including cardiac thromboembolism and arrhythmias. The left atrial appendage (LAA), in particular, has been found to have significant variations in shape and size, and its relationship with nearby structures, such as the pulmonary veins (PVs), is crucial in planning interventional and surgical procedures in and around the LAA. Although most studies examining variations in the LAA are image-based, few have focused on anatomical studies. Materials and Methods: In this study, we examined heart specimens from 54 cadavers for anatomical dissection at a tertiary care teaching hospital. After removing the heart from the pericardial cavity, we opened the left atrium and examined its interior. Observations were made regarding the LAA orifice and PV orifices, and measurements were taken. Subsequently, we removed the LAA along with a portion of the left atrial wall, observed its shape and number of lobes, and took measurements. To classify the shape, we used a system proposed by Wang et al. based on resemblance to familiar objects. Categorical variables were expressed as percentages and continuous as mean and standard deviation. The institutional research committee and the institutional ethics committee approved the study. Results: The most common shape variant observed was the Chicken Wing type, followed closely by the Windsock type. Specimens with Cauliflower or Cactus morphology were rare, with the Cactus variant being the least common. The LAA orifice was round or oval shaped in most cases. In most cases, the LAA orifice was at the same or lower level as the left superior PV orifice, with a prominent ridge between the two orifices in most patients. We observed most of the appendages to be trilobed, with considerable variations in length and diameter. We found two specimens with unusual morphologies but no specimens with accessory appendages. Conclusions: Based on our study, there are significant differences in findings compared to some of the previous studies reporting the shape variations of LAA. However, our findings are matching with those of some other earlier studies. The variations in the shape and size of LAA orifices and their relationship to PV orifices are similar to those reported in earlier studies. The distribution of variations in the size of LAA was also similar to those reported in earlier studies. Conducting larger studies to explore these variations could aid in designing and developing therapeutic interventions in the LAA.

Cardiac CT evaluation of left atrial diverticulum and accessory appendage

BackgroundThe aim of this study was to evaluate the prevalence, location, size, and morphological features of the left atrial accessory appendage and diverticulum with cardiac computed tomography. Cardiac computed tomography obtained consecutively from 1415 patients with normal ECG findings during a 2-year period were analyzed. Left atrial appendage and diverticulum type, location, and size were recorded and analyzed according to age and gender.ResultsCardiac computed tomography of 1415 (796 males and 619 females) participants aged 44.1 + 12.2 years old were re-evaluated, and 238 atrial diverticulum were found in 234 (16.5%) patients, accessory appendage in 93 (6.5%), and atrial diverticula and accessory appendage together in eight (0.56%) patients. The atrial diverticulum was most frequently observed in the anterosuperior localization (n = 157, 49.2%). One hundred and twenty-three (52%) of the atrial diverticulum were cystic, and 107 (45%) were tubular form. Accessory appendage was observed most frequently in the anterior superior location (n = 65, 20.4%).ConclusionsThe frequency of left atrial diverticulum was found to be 16%, and the frequency of accessory appendage was 6%, consistent with the majority of the literature. Left atrial diverticulum and accessory appendage were detected more frequently in men than in women. Cystic form is more common in left atrial diverticulum.

Centrosome maturation - in tune with the cell cycle.

Centrosomes are the main microtubule-organizing centres, playing essential roles in the organization of the cytoskeleton during interphase, and in the mitotic spindle, which controls chromosome segregation, during cell division. Centrosomes also act as the basal body of cilia, regulating cilium length and affecting extracellular signal reception as well as the integration of intracellular signalling pathways. Centrosomes are self-replicative and duplicate once every cell cycle to generate two centrosomes. The core support structure of the centrosome consists of two molecularly distinct centrioles. The mother (mature) centriole exhibits accessory appendages and is surrounded by both pericentriolar material and centriolar satellites, structures that the daughter (immature) centriole lacks. In this Review, we discuss what is currently known about centrosome duplication, its dialogue with the cell cycle and the sequential acquisition of specific components during centriole maturation. We also describe our current understanding of the mature centriolar structures that are required to build a cilium. Altogether, the built-in centrosome asymmetries that stem from the two centrosomes inheriting molecularly different centrioles sets the foundation for cell division being an intrinsically asymmetric process.

Incidentally detected accessory left atrial appendage in a patient being planned for left atrial appendage closure

Left atrial appendage closure (LAAC) has been an accepted treatment strategy to anticoagulation in patients with nonvalvular atrial fibrillation (AF) who qualify for anticoagulation with a high bleeding risk.1 Left atrial accessory appendages (LAAA) are now being increasingly detected with use of cardiac computed tomography (CT). However, the clinical significance of LAAA remains unknown and there is no clear consensus in the management strategy in patients with LAAA being planned for LAAC. We report a case of an incidentally noted LAAA in a patient being planned for LAAC.

Influence of Cardiovascular Risk Factors on Prevalence of Left Atrial Accessory Appendages and Diverticula in Patients with Atrial Fibrillation

Influence of Cardiovascular Risk Factors on Prevalence of Left Atrial Accessory Appendages and Diverticula in Patients with Atrial Fibrillation

Influence of Cardiovascular Risk Factors on Prevalence of Left Atrial Accessory Appendages and Diverticula in Patients with Atrial Fibrillation

Influence of Cardiovascular Risk Factors on Prevalence of Left Atrial Accessory Appendages and Diverticula in Patients with Atrial Fibrillation

Left atrial diverticula: Innocent bystanders or wolves in sheep's clothing?

The finding of left atria diverticula (LAD) on cardiac computed tomographyimages obtained from patients with atrial fibrillation (AF) referred for pulmonary vein isolation is not uncommon. Prior studies reporting on LAD do not always provide definitions of LAD resulting in confusion with other anatomical structures such as left atrial accessory appendages (LAAA) and atrial aneurysms. The aim of this review is to identify an accurate definition of LAD and to describe distinctive properties between LAD and other left atrial structures, such as LAAA and aneurysms. Also, the relation between LAD and development of atrial tachyarrhythmias is discussed. PubMed was searched for studies reporting on atrial aneurysms, left atrial diverticula, left atrial accessory appendages and atrial congenital aneurysms, resulting in 36 papers. LAD can be distinguished from LAAA by taking into account embryologic origins of the left atrium and their locations, resulting in the following definitions: (a) LAAA are contractile, trabeculated structures with circumscriptive ostia and narrow necks, originating from the primitive atria, (b) LAD are contractile, sac like structures with either smooth or trabeculated inner surfaces, circumscriptive ostia, narrow necks, and variable morphologies, originating from the embryologic common pulmonary vein, that incorporates into the LA, and (c) atrial aneurysms are non-contractile structures with wide necks and sac like bodies. There are no differences in prevalences of LAD between patients with sinus rhythm and AF. The pathophysiology of LAD is not yet fully understood. It is unlikely, that LAD are related to the development of atrial tachycardia's and AF by either being a source of ectopic activity or being part of an arrhythmogenic substrate. No differences in LAD prevalences between patients with sinus rhythm and AF have been found. Thus, it is unlikely that LAD could potentially be wolves in sheep's clothing.

Hurry Up and Get Out of the Way! Exploring the Limits of Muscle-Based Latch Systems for Power Amplification.

Animals can amplify the mechanical power output of their muscles as they jump to escape predators or strike to capture prey. One mechanism for amplification involves muscle-tendon unit (MT) systems in which a spring element (series elastic element [SEE]) is pre-stretched while held in place by a "latch" that prevents immediate transmission of muscle (or contractile element, CE) power to the load. In principle, this storage phase is followed by a triggered release of the latch, and elastic energy released from the SEE enables power amplification (PRATIO=PLOAD/PCE,max >1.0), whereby the peak power delivered from MT to the load exceeds the maximum power limit of the CE in isolation. Latches enable power amplification by increasing the muscle work generated during storage and reducing the duration over which that stored energy is released to power a movement. Previously described biological "latches" include: skeletal levers, anatomical triggers, accessory appendages, and even antagonist muscles. In fact, many species that rely on high-powered movements also have a large number of muscles arranged in antagonist pairs. Here, we examine whether a decaying antagonist force (e.g., from a muscle) could be useful as an active latch to achieve controlled energy transmission and modulate peak output power. We developed a computer model of a frog hindlimb driven by a compliant MT. We simulated MT power generated against an inertial load in the presence of an antagonist force "latch" (AFL) with relaxation time varying from very fast (10ms) to very slow (1000ms) to mirror physiological ranges of antagonist muscle. The fastest AFL produced power amplification (PRATIO=5.0) while the slowest AFL produced power attenuation (PRATIO=0.43). Notably, AFLs with relaxation times shorter than ∼300ms also yielded greater power amplification (PRATIO>1.20) than the system driving the same inertial load using only an agonist MT without any AFL. Thus, animals that utilize a sufficiently fast relaxing AFL ought to be capable of achieving greater power output than systems confined to a single agonist MT tuned for maximum PRATIO against the same load.

Fgf- and Bmp-signaling regulate gill regeneration in Ambystoma mexicanum

Gill regeneration has not been well studied compared to regeneration of other appendages, such as limb and tail regeneration. Here, we focused on axolotl gill regeneration and found that Fgf- and Bmp-signaling are involved in their gill regeneration mechanism. Axolotls have three pairs of gill rami, and each gill ramus has multiple gill filaments. The gills consist of mesenchyme rich in extracellular matrix and epidermis. The gill nerves are supplied from the trigeminal ganglia located in the head. Denervation resulted in no gill regeneration responses. Nerves and gills express Bmp and Fgf genes, and treating animals with Fgf- and Bmp-signaling inhibitors results in phenotypes similar to those seen in denervated gills. Inducing an accessory appendage is a standard assay in amphibian regeneration research. In our study, an accessory gill could be induced by lateral wounding, suggesting that thin axon fibers and mesenchymal Fgfs and Bmps contributed to the induction of the accessory structure. Such accessory gill induction was inhibited by the denervation. Exogenous Fgf2+Fgf8+Bmp7, which have been determined to function as a regeneration inducer in urodele amphibians, could compensate for the effects denervation has on accessory blastema formation. Our findings suggest that regeneration of appendages in axolotls is regulated by common Fgf- and Bmp-signaling cascades.

Dental Management of Ectodermal Dysplasia Syndrome at an Early Age: A Case Report

Objectives: Ectodermal dysplasia (ED) is a relatively common sex-linked dermatitis characterized by congenital dysplasia of one or more ectodermal structures and their accessory appendages. Common manifestations include fragile skin and nails, defective teeth and salivary glands, frontal bossing with prominent supra orbital ridges, nasal bridge depression and protuberant lips. Teeth are often few in number (hypodontia or oligodontia) and have a conical form that results in generalized spacing. In extreme cases, both deciduous and the permanent dentition may fail to form (anodontia) and consequently, hypoplasia of the jaws may happen. This article reports a case of ED with its management protocol.Case report: A 4 year-old boy with hypohydrotic ED was referred to Dental School of shahid Beheshti University of Medical Sciences. Clinical examination revealed classical features of ED, with only a few teeth. He had fine scanty hair, dry skin and depressed nasal bridge. Removable denture was made with particular limitations for his lower jaw to restore esthetics and masticatory function. The existing upper teeth were initially reshaped using composite resin restoration material.Conclusion: Preventive treatments in ED patients are very important to save the existing teeth. In patients with oligodontia, removable dentures can be used as a cost-benefit and pleasant intermediate treatment to restore function and esthetics and improve patient’s psychological status.

Left atrial accessory appendages, diverticula, and left-sided septal pouch in multi-slice computed tomography. Association with atrial fibrillation and cerebrovascular accidents

BackgroundThe aim of this study is to provide a morphometric description of the left-sided septal pouch (LSSP), left atrial accessory appendages, and diverticula using cardiac multi-slice computed tomography (MSCT) and to compare results between patient subgroups. MethodsTwo hundred and ninety four patients (42.9% females) with a mean of 69.4±13.1years of age were investigated using MSCT. The presence of the LSSP, left atrial accessory appendages, and diverticula was evaluated. Multiple logistic regression analysis was performed to check whether the presence of additional left atrial structures is associated with increased risk of atrial fibrillation and cerebrovascular accidents. ResultsAt least one additional left atrial structure was present in 51.7% of patients. A single LSSP, left atrial diverticulum, and accessory appendage were present in 35.7%, 16.0%, and 4.1% of patients, respectively. After adjusting for other risk factors via multiple logistic regression, patients with LSSP are more likely to have atrial fibrillation (OR=2.00, 95% CI=1.14–3.48, p=0.01). The presence of a LSSP was found to be associated with an increased risk of transient ischemic attack using multiple logistic regression analysis after adjustment for other risk factors (OR=3.88, 95% CI=1.10–13.69, p=0.03). ConclusionsIn conclusion LSSPs, accessory appendages, and diverticula are highly prevalent anatomic structures within the left atrium, which could be easily identified by MSCT. The presence of LSSP is associated with increased risk for atrial fibrillation and transient ischemic attack.

Prevalence of left atrial diverticula and accessory appendages and origins of the sinoatrial nodal artery in patients with atrial fibrillation

Background: Considering the importance of knowledge about anatomical variations in the left atrium (LA) and its nearby structures for clinical decision-making and the lack of pertinent studies on Iranian patients, this study was conducted to determine the prevalence of LA diverticula and accessory appendages and the origins of the sinoatrial (SA) nodal artery in patients with atrial fibrillation. Methods: In this observational cross-sectional study, 45 consecutive patients with atrial fibrillation undergoing preprocedural computed tomography angiography were enrolled. The prevalence rates of LA diverticula and accessory appendages and the origins of the SA nodal artery were determined and compared according to the patients' age and gender. Results: The origin of the SA nodal artery was R1 (medial to right auricle) in 30 patients (66.7%), L1 (medial to left auricle) in 11 patients (24.4%), and both R1 and L1 in 1 patient. The origin in the remaining 3 subjects was L2 (posterior to auricle), L3 (posterior to left atrium), and R2 (posterior to right atrium). The prevalence rates of LA diverticula and accessory appendages were 48.9% and 17.8%, respectively. Diverticula were seen in 34.8% and 63.6% of the patients younger and older than 50 years, respectively (P = 0.050). Also, accessory appendages were present in 30.4% and 4.5% of the patients younger and older than 50 years, respectively (P = 0.047). There was no significant association for age (P > 0.05). Conclusions: The findings of the present study show that the main supplying artery of the SA nodal artery was R1 from the right coronary artery. The prevalence rates of LA diverticula and accessory appendages were higher than those reported previously.

Prosthodontic rehabilitation of a pediatric patient affected with anhidrotic ectodermal dysplasia: A rare case report

Ectodermal dysplasia (ED) is a hereditary disease characterized by congenital dysplasia of one or more ectodermal structures and other accessory appendages. The oral manifestations are anodontia and poor bony foundation which impairs both esthetic as well as masticatory function. The prosthodontic management of patients with such dysplastic condition necessitates a multidisciplinary approach. The strong, flexible nature of flexible denture material is perfectly suited to the variety of natural conditions in the mouth, simplifying design and enabling the flexible nylon resin to act as a built-in stress-breaker that provides superior function and stress distribution. Flexible partial dentures certainly offer advantages over conventional partials by way of superior esthetics, better function, durable material, and longevity of the prosthesis. This case report describes the prosthodontic oral rehabilitation of a 14-year-old female pediatric patient with anhidrotic ED using resin flexible prosthesis (Valplast). Clinical Relevance to Interdisciplinary Dentistry A multidisciplinary approach comprising restorative, prosthetic, and periodontal treatment was done to achieve a satisfactory result. The treatment led to significant improvements in appearance, speech, and masticatory function The focus is on the interdisciplinary management of a patient with complex restorative needs An integrated approach that addresses both skeletal and dental issues can provide superior results. In this case, restorative goals guided the overall treatment plan, requiring the integration of restorative services at several stages of care, which involved a team of pedodontist, prosthodontist, and periodontist Although implants are the ideal choice for partial anodontia, this case was treated in a conservative and minimally invasive method. Eventually the patient was satisfied with the prosthesis as function was re-established and esthetics was not compromised. Long-term success depends on regular recall appointments and meticulous maintenance of oral and prosthetic hygiene.

Clinical Significance of Left Atrial Anatomic Abnormalities Identified by Cardiac Computed Tomography

Purpose: The clinical significance of newly identified left atrial anatomic abnormalities (LAAA)— accessory appendages, diverticula, septal pouches—by multidetector CT (MDCT) remains unclear. Similar anatomical outpouchings, i.e., the left atrial appendage, have been associated with cardioembolisms and arrhythmia. To test the hypothesis that LAAA are also associated with increased risk of these events, we performed a retrospective analysis to examine the association of LAAA in patients undergoing CT with embolic events and arrhythmia. Methods: 242 patients (mean age 56 SD 12 years, 41% female) were selected who had CT coronary angiography performed with 64-row MDCT between 2007 and 2012 if complete clinical history records were available. CT images were independently reviewed for the presence of LAAA. Association of cerebrovascular accident (CVA) or transient ischemic attack (TIA), atrial fibrillation, and palpitations to LAAA was calculated using odds ratios (OR) with 95% confidence interval (CI) and Fisher’s exact test. Results: After adjusting for age, sex, hypertension, dyslipidemia and diabetes via multiple logistic regression, patients with accessory appendages are more likely to have reported palpitations (OR: 1.80; CI: 1.03 - 3.16). Patients with diverticula and septal pouches are significantly older than those without these abnormalities (p = 0.01 and p = 0.02, respectively). Septal pouches are associated with diabetes (OR: 2.29; 95%CI: 1.15 - 4.54). Conclusions: Accessory left atrial appendages are associated with palpitations. Patients with septal pouches and diverticula are significantly older than those patients without these anatomic abnormalities, suggesting age dependency of these findings. None of these anatomic abnormalities were associated with thromboembolic events after adjustment for potentially confounding comorbidities.

Ectodermal Dysplasia: Familial Report of Six Cases

Ectodermal dysplasia is a hereditary disease characterized by a congenital dysplasia of one or more ectodermal structures and their accessory appendages. There are two main types, Hypohidrotic/Christ-Seimens-Tourian Syndrome and Hidrotic/Clouston syndrome. Common manifestations include defective hair follicles and eyebrows, frontal bossing with prominent supraorbital ridges, nasal bridge depression and protuberant lips. Intraorally common findings are anodontia or hypodontia and conical shaped teeth. The patient may suffer from dry skin, hyperthermia and unexplained high fever because of the deficiency of sweat glands. The present article reports unique case series of ectodermal dysplasia cases in two families, where three generations in the both the families were affected.

Prosthodontic treatment strategy for patients with ectodermal dysplasia: A literature review

Ectodermal dysplasia (ED) is a congenital syndrome characterized by developmental failure of two or more ectodermal structures and their accessory appendages. ED is commonly a difficult condition to manage with prosthodontics because of the typical oral deficiencies and because the afflicted individuals are quite young when they are evaluated for treatment. It is important that these individuals receive dental treatment at an early age for physiologic and psychosocial reasons. Patient with this disease often need a multidisciplinary approach to treatment planning and dental treatment to regain appropriate function, esthetics, and comfort. The definitive treatment plan may include removable, fixed, or implant-supported prosthesis or a combination of these options. This article reviews the literature that pertains to the prosthodontic treatment of the ED and the review includes considerations in patient management and timing of treatment.

Anatomical features and clinical importance of left atrial diverticula

To assess the anatomical features and clinical importance of left atrial diverticula and atrial accessory appendages in patients undergoing cardiac computed tomography with multidetector computed tomography. A total of 1305 consecutive patients (385 female, 29.5%; 920 male, 70.5%) were assessed using electrocardiogram-gated computed tomography between May 2010 and June 2013. The anatomical features and the prevalences of left atrial diverticula and left atrial accessory appendages were retrospectively assessed by four radiologists. The relationships between the prevalence and size of the diverticula and the age and gender of the patients were assessed. Among the 1305 patients, 610 (46.7%) exhibited 708 left atrial diverticula, and 62 (4.8%) exhibited left atrial accessory appendages. The most common locations of the left atrial diverticula were the right anterior superior wall (n = 328, 46.3%) and the lateral superior wall (n = 96, 13.5%). In addition to classical cystic and tubular diverticula, 49 (3.7%) of the patients exhibited mixed (cystic-tubular), conical, or hook-shaped diverticula and diverticular forms containing mural calcifications. There was no significant relationship between the prevalence of diverticula and the age and gender of the patients (P > 0.05). In addition to tubular and cystic diverticula, the left atrial wall can host different diverticular forms (such as mixed, conical, calcific, and hook shaped). It could be beneficial to assess the left atrium using MDCT to determine the source of emboli in cryptogenic embolism and to reduce complications associated with interventional procedures performed for left atrial arrhythmias.

Presence of left atrial diverticula, accessory appendages, and normal variant pulmonary venous anatomy diagnosed using MDCT and adverse outcomes following radiofrequency catheter ablation therapy in patients with drug-refractory atrial fibrillation: An exploratory study

To determine the frequency of normal variation left atrial anatomy (NVLAA) (diverticula, accessory appendages) and normal variation pulmonary venous anatomy (NVPVA) in patients with atrial fibrillation (AF), and to determine whether the presence of these entities is associated with an increased recurrence of atrial arrhythmias following radiofrequency catheter ablation (RFCA). All cardiac MDCT images performed prior to RFCA between November 2009 and May 2011 in patients with drug-refractory AF were retrospectively evaluated. The presence, type, and location of NVLAA and NVPVA, and outcome of RFCA were recorded. Success was defined as restoration of sinus rhythm. Forty-six consecutive patients with a mean age of 59.8 (±9.7) years (76.1% male) underwent cardiac MDCT for anatomical planning prior to RFCA procedures. Fourteen (30.4%) patients had NVLAA, 35% of patients had NVPVA. Thirty (65%) patients had successful RFCA: 57% of these had a NVLAA, 67% had NVPVA. Sixteen (35%) patients had unsuccessful RFCA: 63% of these had a NVLAA, 56% had NVPVA. There was no significant association between the presence of NVLAA (p = 0.699), NVPVA (p = 0.197), or "NVLAA in the presence of normal pulmonary venous anatomy" (p = 0.589) and the outcome of RFCA. The presence of NVLAA and NVPVA appears unrelated to adverse outcome in patients undergoing RFCA for the treatment of drug-refractory AF.

An unusual association of Goldenhar syndrome

Goldenhar syndrome is well known for its classical triad of epibulbar dermoids or lipodermoids, auricular appendages and pretragal fistulas. Here we report a case of Goldenhar syndrome with an unusual association of a fibroepithelial polyp attached to a limbal dermoid. A case of Goldenhar syndrome in a 5-month-old male infant presented with the features of a fibroepithelial polyp attached to a limbal dermoid, right-sided polydactylia with hypoplastic thumb, and accessory preauricular appendages on the left side. The association of a fibroepithelial polyp attached to a limbal dermoid with Goldenhar syndrome is a rare report in the literature. In these cases, regular follow-up with an ophthalmologist is important to monitor the visual development of the patient. Ideally, a multidisciplinary approach is required to manage the other associated anomalies.

Prevalence of left atrial anatomical abnormalities in patients with recurrent atrial fibrillation compared with patients in sinus rhythm using multi-slice CT

Enlargement of the LA is known to increase the risk of atrial fibrillation (AF) and its associated complications. However, the relation between other left atrial (LA) anatomical abnormalities and the risk of developing AF is less well described. The aim of this study was to compare the prevalence of LA anatomical abnormalities between a group of patients with recurrent AF and a group of patients in sinus rhythm (SR) with the use of cardiac computed tomography (CT). The cardiac CT prevalence, location, and size of LA accessory appendages and diverticula were assessed in 200 patients with recurrent AF referred for radiofrequency catheter ablation and compared with a control group of 200 patients in SR. The prevalence and mean length and width for diverticula were 23.5%, 8.1 mm, and 8.1 mm, in the AF group and 20.5%, 7.8 mm, and 7.2 mm in the SR group, respectively, and for accessory appendages 6.5%, 8 mm, and 6.3 mm in the AF group and 6.5%, 9.4 mm, and 5.7 mm in the SR group, respectively. In both groups, the most common location for a diverticulum or an accessory appendage was the right anterosuperior LA wall. The prevalence, location, and size of accessory appendages and diverticula were not significantly different (P > 0.05) between cohorts. This study found no difference in the prevalence and anatomic characteristics of LA accessory appendages and diverticula between patients in recurrent AF and patients in SR.