New variants of ALMS1 gene and familial Alström syndrome case series.

OBJECTIVES: To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome. REPORT: This paper is a multi-disciplinary diagnostic evaluation, with genetic and audiological analysis that aims to report two new variants of the ALMS1 gene and to discuss the audiological evolution and clinical phenotype in a case series of patients with familial Alström syndrome. Therefore, we describe 4 cases presenting a complete audiometric profile of two pairs of unrelated siblings, to provide a better understanding of this very rare disease. Additionally, the present study identified two heterozygous mutations in the ALMS1 gene. CONCLUSION: This Clinical Capsule Report highlights the importance of audiological monitoring throughout the development of patients with Alström syndrome. The two variants found were not previously reported in the literature, which expands the spectrum of ALMS1 variants in Alström syndrome.

Middle Ear Cholesteatoma and Vestibular Schwannoma Resection Followed by Cochlear Implant: Surgical Challenges and Audiological Outcomes.

(1) Background: The occurrence of vestibular schwannoma (VS) associated with cholesteatoma is rare. A hearing impairment is one of the most significant issues in such cases. Moreover, the presence of middle and inner ear pathologies combined may represent a surgical challenge. No studies have described a combined surgical approach for these coexisting conditions (VS and cholesteatoma), nor the hearing rehabilitation outcomes of using cochlear implants for these patients. (2) Case Report: This paper is on a female patient who underwent simultaneous surgical treatments for VS and middle ear cholesteatoma in the right ear followed by a cochlear implant, describing the technique and the audiological results. (3) Conclusions: The surgical approach was successful and enabled the resection of lesions with the auditory nerve and cochlea preservation. Cochlear implantation in the right ear showed positive postoperative results, with an improvement in the results with the CI in silent and noisy environments.

Novel cochlear implant assessment tool: Comparative analysis of children and adults.

Objectives: To analyse the results of children and adults with cochlear implants (CIs) in pure tone audiometry (PTA) and speech perception tests. Tests were performed in two ways: using loudspeakers in the sound booth (SB) and with direct audio input (DAI) employing the Cochlear Latin America BOX (CLABOX). Methods: Fifty individuals (33 adults and 17 children) participated in the study, including children aged between 8 and 13 years; of these, 15 users had bilateral CIs, 35 had unilateral CIs, and all had severe to profound bilateral sensorineural hearing loss. All participants were evaluated in the SB with loudspeakers and the CLABOX with DAI. The following evaluations were conducted: PTA, speech recognition tests with the hearing in noise test (HINT). Results: The results for PTA and HINT conducted in SB and with CLABOX presented no significant difference between children and adults. Conclusion: The CLABOX tool presents a new possible method to evaluate PTA and speech recognition tests in adults and children, with results comparable to the conventional evaluation in the SB.

Developmental Disruptions of the Human Stapes.

OBJECTIVE: To evaluate and classify developmental malformations of the human stapes. METHODS: Twenty-five temporal bone specimens from 18 patients with congenital stapes malformations were identified in the Mass Eye and Ear temporal bone collection. Serial sections stained with hematoxylin and eosin were examined by light microscopy and the morphology of the stapes was compared to age-matched controls. RESULTS: Each case of stapes malformation could be classified into one of four malformation types based on our current understanding of the embryologic origin of the subunits of the stapes and timing of development. Twenty-seven percent of stapes malformations had a Type I morphology characterized by a hypoplastic or absent inner footplate and hypoplastic to absent mesoderm footplate or oval window. The crura and capitulum may be absent, monopodal or dysmorphic. Eleven percent expressed a Type II malformation with dysmorphic or monopodal capitulum and crura and a fixed footplate. Twenty-seven percent were of Type III with a dysmorphic or monopodal capitulum and or crura. The footplate, and thereby oval window is present and without fixation. The most common malformation, Type IV, was isolated footplate fixation observed in 33% of cases. CONCLUSIONS: Malformations of the human stapes follow consistent patterns of early or late disruptions of the stapes subunits of mesodermal and/or neural crest origin. While the molecular events, including temporal coordination, that lead to a normally formed stapes are not yet fully understood, the observed patterns of human stapes malformation can be consistently classified into one of four patterns of developmental disruption.

Bilateral Sudden Sensorineural Hearing Loss: A Distinct Phenotype Entity.

OBJECTIVE: To investigate the clinical phenotype and hearing prognosis of patients with unilateral and bilateral (simultaneous and nonsimultaneous) sudden sensorineural hearing loss (SSNHL). STUDY DESIGN: Retrospective cohort. SETTING: Otology outpatient clinic of a tertiary university hospital. PATIENTS: Three hundred eighty-five medical records from patients with SSNHL. MAIN OUTCOME MEASURES: Comparison of demographic, clinical, and audiometric (pretreatment and posttreatment) data of patients with unilateral and bilateral SSNHL. RESULTS: Our final analysis comprised of 239 medical records of patients with SSNHL. Most patients had unilateral SSNHL (186, 77.82%). We identified a potential underlying cause for the SSNHL in 105 (43.9%) of the cases, being more frequent in cases of bilateral simultaneous SSNHL (100%) as compared with unilateral (45.6%) and nonsimultaneous bilateral SSNHL (22.7%). Cases of simultaneous bilateral SSNHL presented more frequently with severe or profound hearing loss (89%; unilateral SSNHL 50.5%; nonsimultaneous bilateral SSNL, 59.1%) and had a significantly worse hearing recovery prognosis as compared with unilateral or nonsimultaneous bilateral SSNHL (p = 0.002). CONCLUSION: We observed a high heterogeneity of clinical presentations of SSNHL, the most common being unilateral SSNHL. Our results demonstrate that the clinical and audiological prognosis of simultaneous bilateral SSNHL differed significantly from unilateral and nonsimultaneous bilateral SSNHL, suggesting that simultaneous cases of bilateral SSNHL may be a part of a different disease process. The presence of a simultaneous, bilateral SSNHL indicates the need to investigate the presence of an underlying systemic disease.

Evaluation of Oxidative-Stress Pathway and Recovery of Sudden Sensorineural Hearing Loss.

Introduction Although the pathogenesis of sudden sensorineural hearing loss (SSNHL) has been discussed in the literature, many unclear points remain. Several authors have hypothesized that oxidative stress plays a role in the pathogenesis of noise-related hearing loss, as well as in drug- and aging-related hearing loss. Reactive oxygen species (ROS) may contribute to the pathogenesis of SSNHL in a similar way as in cases of ototoxicity, noise-induced hearing loss and presbyacusis. Objective The aim of the present study was to find potential peripheral biomarkers to show the levels of oxidative stress in samples of peripheral blood collected from SSNHL patients with and withouth metabolic disease. Methods In total, 80 consecutive patients with SSNHL were evaluated in the otolaryngology emergency room and outpatient clinic of a tertiary hospital between May 2017 and May 2019. All patients underwent detailed anamnesis, physical examination, audiometry, magnetic resonance imaging (MRI) of the inner ears, and blood tests for serum lipids and plasma activity of thiobarbituric acid reactive species (TBARS). Results No significant effect of malondialdehyde (MDA) activity was observed regarding the hearing recovery of patients who developed SSNHL. Conclusion We did not observe a significant correlation between the concentration of TBARs in the peripheral blood or the presence of arterial hypertension and the severity of the initial hearing loss or the prognosis of hearing recovery in patients with SSNHL. The concentration of TBARs in the peripheral blood may not adequately represent the abnormalities that occur in the intracoclear environment.

Evaluation of vestibular symptoms and postural balance control in patients with chronic otitis media.

BACKGROUND: Evidence to support potential links between chronic otitis media (COM) and vestibular impairment/postural balance control issues is lacking. OBJECTIVE: To investigate whether COM associates with vestibular symptoms, balance problems, and abnormalities in vestibular function tests. METHODS: We selected 126 patients with COM and excluded patients with any identifiable underlying causes for vestibular dysfunction. Fifty-two healthy volunteers were included as controls. All subjects underwent anamnesis, physical examination, posturography, and video-head impulse tests. RESULTS: We found a high prevalence of vestibular symptoms (58.4%) among patients with COM, while only 2% of the controls had vestibular symptoms. There was a positive correlation between COM activity with the presence of tinnitus and vestibular symptoms (P < 0.05). Clinical vestibular tests were abnormal in 63% of patients with COM, and those positively associated with presence of vestibular symptoms. Posturography results shown worse postural balance control in patients with COM as compared with controls, especially in the limit of stability (LOS) (Mean LOS, COM = 157.56 cm2; controls = 228.98 cm2; p < 0.001) and worse results in the test with eyes closed while standing on a foam mattress (sway area, COM = 10.91 cm2; controls = 5.90 cm2; p < 0.001) in patients with COM as compared with controls. We did not observe differences in the average vestibuloocular reflex gains in the video-head impulse test between our COM and control groups. CONCLUSIONS: Our results show that COM associates with higher prevalence of vestibular symptoms and abnormalities in clinical vestibular function tests, and worse postural control as compared with controls. Among patients with COM, the activity of the middle-ear inflammation seemed to positively associate with the severity of hearing and balance problems.

Different clinical presentation of intralabyrinthine schwannomas - a systematic review.

INTRODUCTION: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. OBJECTIVE: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. METHODS: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. RESULTS: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. CONCLUSION: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.

New variants of ALMS1 gene and familial Alström syndrome case series

Abstract Objectives To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome. Report This paper is a multi-disciplinary diagnostic evaluation, with genetic and audiological analysis that aims to report two new variants of the ALMS1 gene and to discuss the audiological evolution and clinical phenotype in a case series of patients with familial Alström syndrome. Therefore, we describe 4 cases presenting a complete audiometric profile of two pairs of unrelated siblings, to provide a better understanding of this very rare disease. Additionally, the present study identified two heterozygous mutations in the ALMS1 gene. Conclusion This Clinical Capsule Report highlights the importance of audiological monitoring throughout the development of patients with Alström syndrome. The two variants found were not previously reported in the literature, which expands the spectrum of ALMS1 variants in Alström syndrome.

The human leukocyte antigen G molecule (HLA-G) expression in patients with nasal polyposis.

INTRODUCTION: Sinonasal polyposis (NP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. HLA-G molecules are a kind of no classic class I antigen with anti-inflammatory and tolerogenic properties. Little attention has been paid to the role of HLA-G chronic inflammatory disorders. OBJECTIVE: The aim of this study is to investigate the expression of HLA-G in the NP. MATERIALS AND METHODS: Prospective study involving samples of patients presenting with nasal polyposis that were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups and classified as asthmatic or non-asthmatic. RESULTS: Immunohistochemical staining demonstrated a higher expression of the HLA-G molecule in samples from nonatopic than in those from atopic patients, and was significantly lower in the non-asthmatic patients. CONCLUSION: These results indicate that HLA-G may play an important role in the pathology of nasal polyposis. Considering the anti-inflammatory properties of HLA-G, this study suggests that it could reduce susceptibility to atopy and asthma.

Different clinical presentation of intralabyrinthine schwannomas - a systematic review / Diferentes apresentações clínicas do schwannoma intralabiríntico --- uma revisão sistemática

Abstract Introduction: Intralabyrinthine schwannoma is a rare, benign tumor that affects the most terminal portions of the vestibular and cochlear nerves. This tumor can be classified into 10 subtypes, according to its inner ear location. Objective: To carry out a comprehensive review of the most frequent auditory manifestations secondary to the intralabyrinthine schwannoma, describing the possible underlying pathophysiological mechanisms. Methods: Systematic review of the literature until October 2017 using the PubMed, Web of Science and Scopus databases. The inclusion criteria were clinical manifestations of the intralabyrinthine schwannoma. Three researchers independently assessed the articles and extracted relevant information. The description of a case of an intravestibular subtype intralabyrinthine schwannoma with multiple forms of clinical presentations was used as an example. Results: Twenty-seven studies met our inclusion criteria. The most common intralabyrinthine schwannoma subtype was the intracochlear, followed by the intravestibular type. All the cases demonstrated hearing loss, usually progressive hearing loss. Conclusion: The diagnosis of intralabyrinthine schwannomas is based on high-resolution magnetic resonance imaging and should be included in the differential diagnosis of patients with vestibulocochlear complaints. Although there are approximately 600 cases in the literature, we still lack a detailed description of the clinical evolution of the patients, correlating it with MRI findings of temporal bones and tumor subtype.

Resumo Introdução: Schwannoma intralabiríntico é um tumor benigno, raro, que afeta as porções mais terminais dos nervos vestibular e coclear. Este tumor pode ser classificado, de acordo com sua localização na orelha interna, em 10 subtipos. Objetivo: Realizar uma revisão abrangente das manifestações auditivas mais frequentes secundárias ao schwannoma intralabiríntico e descrever os possíveis mecanismos fisiopatológicos subjacentes. Método: Revisão sistemática da literatura até outubro de 2017 nas bases de dados PubMed, Web of Science e Scopus. O critério de inclusão foi manifestações clínicas do schwannoma intralabiríntico. Três pesquisadores avaliaram de forma independente os artigos e extraíram informações relevantes. Exemplificamos com a descrição de um caso de schwannoma intralabiríntico subtipo intravestibular com múltiplas formas de apresentações clínicas. Resultados: Vinte sete estudos contemplaram nossos critérios de inclusão. O subtipo do schwannoma intralabiríntico mais comum encontrado foi o intracoclear, seguido pelo intravestibular. Todos os casos apresentaram alteração auditiva, normalmente perda auditiva progressiva. Conclusão: O diagnóstico de schwannomas intralabirínticos baseia-se em exames de ressonância magnética de alta resolução e deve ser incluído no diagnóstico diferencial de pacientes com queixas vestibulococleares. Apesar de termos aproximadamente 600 casos na literatura, ainda nos falta descrição detalhada da evolução clínica dos pacientes em correlação com achados na ressonância magnética de ossos temporais e o subtipo tumoral.

Interleukin-17A expression in patients presenting with nasal polyposis.

UNLABELLED: Sinonasal polyposis (SNP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation of nasal/paranasal sinus mucosa in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. Interleukin-17A (IL-17A) is a key inflammatory cytokine in many disorders. Little attention has been paid to the role of IL-17A in chronic inflammatory disorders. OBJECTIVE: To investigate the expression of IL-17A in the SNP and verify if this expression is a marker of good or bad prognosis. METHOD: Prospective study with 25 patients presenting with SNP were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups, and asthmatic or non-asthmatic. RESULTS: The IL-17A expression was observed in both atopic and nonatopic patients. The numbers of IL-17A positive cells were greater in nasal polyps of atopic patients than nonatopic (p = 0.0128). CONCLUSION: These results indicate that IL-17A may play an important role in the pathology of SNP. Considering the inflammatory properties of IL-17A, this study suggests that it could increase susceptibility to atopy and asthma.

The human leukocyte antigen G molecule (HLA-G) expression in patients with nasal polyposis / A expressão do antígeno humano leucocitário G (HLA-G) em pacientes com polipose nasossinusal

INTRODUCTION: Sinonasal polyposis (NP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. HLA-G molecules are a kind of no classic class I antigen with anti-inflammatory and tolerogenic properties. Little attention has been paid to the role of HLA-G chronic inflammatory disorders. OBJECTIVE: The aim of this study is to investigate the expression of HLA-G in the NP. MATERIALS AND METHODS: Prospective study involving samples of patients presenting with nasal polyposis that were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups and classified as asthmatic or non-asthmatic. RESULTS: Immunohistochemical staining demonstrated a higher expression of the HLA-G molecule in samples from nonatopic than in those from atopic patients, and was significantly lower in the non-asthmatic patients. CONCLUSION: These results indicate that HLA-G may play an important role in the pathology of nasal polyposis. Considering the anti-inflammatory properties of HLA-G, this study suggests that it could reduce susceptibility to atopy and asthma. .

INTRODUÇÃO: Polipose nasossinusal (PNS) é uma patologia inflamatória crônica das cavidades nasais/paranasais que afeta 1%-4% da população. Embora os pólipos pareçam ser uma manifestação de inflamação crônica em ambos os indivíduos alérgicos e não alérgicos, a patogênese da polipose nasal permanece desconhecida. Moléculas HLA-G são antígenos não clássicos da classe I com propriedades anti-inflamatórias e tolerogênicas. Pouca atenção tem sido dada ao papel do HLA-G em doenças inflamatórias crônicas. OBJETIVO: Investigar a expressão de HLA-G na PNS. MATERIAIS E MÉTODOS: Estudo prospectivo de pacientes com polipose nasal que foram submetidas à técnica de imuno-histoquímica. Após realizarem teste cutâneo, os pacientes foram divididos em grupos atópicos e não atópicos e classificados como asmáticos ou não asmáticos. RESULTADO: A coloração imuno-histoquímica mostrou uma maior expressão da molécula HLA-G em pacientes não atópicos do que naqueles atópicos e foi significativamente inferior nos pacientes não asmáticos. CONCLUSÃO: Os resultados indicam que o HLA-G pode ter um papel importante na patologia da polipose nasal. Considerando as propriedades anti-inflamatórias do HLA-G, este estudo sugere que ele poderia reduzir a susceptibilidade a atopia e asma. .

Expressao de interleucina-17A em pacientes com polipose nasossinusal / Interleukin-17A expression in patients presenting with nasal polyposis

Polipose nasossinusal (PNS) é uma afecção inflamatória crônica das cavidades nasais/paranasais que afeta 1%-4% da população. Pólipos parecem ser uma manifestação inflamatória crônica da mucosa do seio nasal/paranasal em indivíduos alérgicos e não alérgicos; porém, a patogênese da PNS permanece desconhecida. A interleucina-17A (IL-17A) é uma citocina chave em muitas doenças inflamatórias. Pouca atenção tem sido dada ao papel da IL-17A em distúrbios inflamatórios crônicos. OBJETIVO: Investigar a expressão da IL-17A na PNS e verificar se ela é um marcador de bom ou mau prognóstico. MÉTODO: Estudo prospectivo de 25 pacientes com PNS foram submetidas à técnica de imuno-histoquímica. Após realizarem teste cutâneo, todos os pacientes foram divididos em grupos atópicos e não atópicos e classificados em asmáticos ou não asmáticos. RESULTADOS: A expressão de IL-17A foi observada nos pacientes atópicos e não atópicos; porém, o número de células positivas com IL-17A foi maior nos pólipos nasais de pacientes atópicos que nos não atópicos (p = 0,0128). CONCLUSÃO: Os resultados indicam que a IL-17A pode desempenhar papel importante na patologia da PNS. Considerando as propriedades inflamatórias da IL-17A, este estudo sugere que a IL-17A pode aumentar a susceptibilidade a atopia e asma. .

Sinonasal polyposis (SNP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation of nasal/paranasal sinus mucosa in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. Interleukin-17A (IL-17A) is a key inflammatory cytokine in many disorders. Little attention has been paid to the role of IL-17A in chronic inflammatory disorders. OBJECTIVE: To investigate the expression of IL-17A in the SNP and verify if this expression is a marker of good or bad prognosis. METHOD: Prospective study with 25 patients presenting with SNP were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups, and asthmatic or non-asthmatic. RESULTS: The IL-17A expression was observed in both atopic and nonatopic patients. The numbers of IL-17A positive cells were greater in nasal polyps of atopic patients than nonatopic (p = 0.0128). CONCLUSION: These results indicate that IL-17A may play an important role in the pathology of SNP. Considering the inflammatory properties of IL-17A, this study suggests that it could increase susceptibility to atopy and asthma. .

Mecanismos arritmogênicos deflagadores de choque em chagásicos portadores de cardioversor-desfibrilador implantável / Arrhythmogenic mechanics triggering shock in patients with Chagas' disease and implantable cardioverter defibrillator

A cardiopatia chagásica crônica (CCC) ainda é um importante problema de saúde pública no Brasil. A principal causa de óbito é a morte súbita por taquiarritmia e o cardioversor-desfibrilador implantável (CDI) tornou-se importante opção terapêutica nessa doença. Objetivos: Identificar os pacientes com CCC, portadores de CDI, que receberam terapia de choque e reconhecer o principal mecanismo arritmogênico deflagrador. Metodologia: Estudo descritivo, retrospectivo, com amostra de 81 pacientes portadores de CDI. Os dados relacionados a eventos arrítmicos e terapias foram obtidos retrospectivamente pela análise dos eletrocardiogramas endocavitários (EGM) de cada paciente. Os resultados foram expressos em valores absolutos, médias e porcentagem, em tabelas e gráficos. Resultados: Foram documentadas terapias apropriadas em 68 (83,9%) pacientes, com um total de 5.336 eventos. Desses, 4.585 (85,9%) foram apenas trem de pulso (ATP) e 741 (14,1%), choques subsequentes ou não à falência do ATP. A taquicardia ventricular monomórfica (TVM) foi a arritmia mais diagnosticada nos EGM, com 4.783 (89,6%) eventos, seguida de taquicardia ventricular polimórfica (TVP) em 480 (8,9%) e fibrilação ventricular (FV) em apenas 63 (1,5%). Conclusões: Demonstrou-se elevada prevalência (83,9%) de pacientes chagásicos portadores de CDI submetidos a terapias por esse dispositivo. Além disso, detectou-se que o principal mecanismo arritmogênico deflagrador de choque foi a TVM na zona de taquicardia rápida, secundária à aceleração da frequência cardíaca após terapia por ATP ineficaz...

Chronic Chagas’ cardiomyopathy remains a major public health problem in Brazil. Tachyarrhythmia is the leading cause of sudden death and the implantable cardioverter defibrillator (ICD) has become an important therapeutic option. Objectives: Identify patients with CCC and ICD who have received shock therapy and identify the main arrhythmogenic mechanism triggering shock in these patients. Method: Retrospective descriptive study, with a sample of 81 patients undergoing CDI implantation from January 2004 to December 2007. Data were obtained retrospectively by analysis of patients’ intracavitary electrocardiograms (iECM). Results were expressed as absolute numbers, mean and percentage values, using tables and graphs. Results: Appropriate therapy was documented in 68 (83.9%) patients, with a total of 5,336 events. Of these, 4,585 (85.9%) were only train of pulse (ATP) and 741 (14.1%) were shocks subsequent or not to failure of ATP. Monomorphic ventricular tachycardia (MVT) was the most frequently diagnosed arrhythmia in the iECGs with 4,783 (89.6%) events, followed by polymorphic ventricular tachycardia (TVP) with 480 (8.9%) and ventricular fibrillation (VF) with only 63 (1.5%). Conclusion: This study demonstrated a high prevalence (83.9%) of chagasic patients receiving ICD therapy. Furthermore, the main arrhythmogenic mechanism triggering shock in these patients was MVT in the zone of fast tachycardia secondary to heart rate acceleration after failure of ATP therapy...