Uncontrolled Diabetes with Underlying Structural Changes in the Atrioventricular Node / Diabetes no Controlada con Cambios Estructurales Subyacentes en el Nodo Atrioventricular

SUMMARY: Diabetic cardiomyopathy, characterized by diabetes mellitus (DM) -induced cardiac muscular abnormalities, is a strong inducer of impaired cardiac contraction and arrhythmia. Atrioventricular block, a serious type of arrhythmia resulting from interruption of cardiac impulse conduction via the atrioventricular node (AVN), frequently occurs among diabetic patients. However, details of structural changes in AVN in DM remain poorly explained. Here, this study defined the effects of DM on the morphological remodeling of the AVN in male Sprague Dawley rats induced by intraperitoneal injection of streptozotocin (60 mg/kg body weight). At 24 weeks, the pathological changes in the AVN were assessed by light microscopy (LM) and transmission electron microscopy (TEM). Under LM, the AVN in diabetic rats became a less compact mass and exhibited the intracellular vacuolation. The nodal cells were more varied in sizes with the absence or shrinkage of nuclei and clear cytoplasm compared to the control. The collagen content significantly increased in relation to the presence of myofibroblasts. Consistent with LM, TEM images of the diabetic nodal cells revealed several signs of cell damage, such as mitochondrial changes, deterioration of cell organelles, gap junction internalization, and cell separation. Furthermore, changes in AVN innervation, evidenced by damaged Schwann cells and axons, were also found. These results indicated alterations in important components in the AVN during diabetic condition, which may lead to the impairment of electrical conduction, causing abnormal cardiac functions in diabetic patients.

La miocardiopatía diabética, caracterizada por anomalías musculares cardíacas inducidas por diabetes mellitus (DM), es un fuerte inductor de alteración de la contracción cardíaca y arritmia. El bloqueo atrioventricular, un tipo grave de arritmia resultante de la interrupción de la conducción del impulso cardíaco a través del nodo atrioventricular (NAV), se produce con frecuencia entre los pacientes diabéticos. Sin embargo, los detalles de los cambios estructurales en NAV en DM siguen estando pobremente explicados. Aquí, este estudio definió los efectos de la DM en la remodelación morfológica del NAV en ratas macho Sprague Dawley inducidas por inyección intraperitoneal de estreptozotocina (60 mg/kg de peso corporal). A las 24 semanas, los cambios patológicos en el NAV se evaluaron mediante microscopía óptica (MO) y microscopía electrónica de transmisión (MET). Bajo MO, el NAV en ratas diabéticas se convirtió en una masa menos compacta y exhibió la vacuolización intracelular. Las células nodales tenían tamaños más variados con ausencia o contracción de núcleos y citoplasma claro en comparación con el control. El contenido de colágeno aumentó significativamente en relación con la presencia de miofibroblastos. De acuerdo con MO, las imágenes MET de las células nodales diabéticas revelaron varios signos de daño celular, como cambios mitocondriales, deterioro de los orgánulos celulares, internalización de uniones comunicantes y separación celular. Además, también se encontraron cambios en la inervación del NAV, evidenciados por schwannocitos y axones dañados. Estos resultados indicaron alteraciones en componentes importantes en el NAV durante la condición diabética, lo que puede conducir al deterioro de la conducción eléctrica, causando funciones cardíacas anormales en estos pacientes.

Prevalence of Atrial Fibrillation in Pacemaker Patients

Abstract Background: Current pacemakers allow for the continuous recording of the occurrence of arrhythmic events. One of the most frequent arrhythmias after implantation of a device is atrial fibrillation (AF), an important risk factor for embolic events. The frequency of this arrhythmia in pacemaker patients has not been widely studied. Objectives: This study aimed to evaluate the prevalence, incidence, and predictors of the occurrence of AF in patients with double-chamber pacemakers and without a history of atrial fibrillation prior to implantation. Methods: A dynamic, retrospective, and prospective cohort study was carried out with 186 patients undergoing biannual follow-up of the double-chamber pacemaker, without previous AF, in a single service, between 2016 and 2018. Clinical data were collected from the medical records and the telemetry of the device and the prevalence, incidence rate, relative risk by univariate analysis (by chi-square), and risk ratio were calculated by multivariate analysis (by Cox regression); values of p<0.05 were considered significant. Results: There was a prevalence of 25.3% FA, with an incidence of 5.64 cases / 100 persons-year. The median time for the development of arrhythmia was 27.5 months. Multivariate analysis identified 5 statistically significant predictors: male gender, OR: 2.54 [1.04-6.15]; coronary artery disease, OR: 2.98 [1.20-7.41]; hypothyroidism, OR: 3.63 [1.46-9.07]; prior heart surgery, OR: 2.67 [1.01-7]; and left atrial enlargement, OR: 2.72 [1.25-5.92]. Conclusions: The prevalence and incidence of AF in this population are high. Risk factors for AF were: male gender, coronary artery disease, hypothyroidism, prior heart surgery, and left atrial enlargement.

Mortality rates of surgical techniques for correcting atrioventricular disjunction

Abstract We compared the mortality rates of two surgical techniques for correction of atrioventricular disjunction in 10 out of 720 patients who underwent mitral valve replacement from 2005 to 2012. In group I, the mitral annulus was fixed with bovine pericardial strips; in group II, a 'patch' of bovine pericardium was sutured and extended from the base of the lateral and medial papillary muscles, covered the posterior wall of the left ventricle, went through the posterior mitral annulus, and ended in the posterior wall of the left atrium adjacent to the mitral ring. The group II technique showed a lower mortality.

Avaliação da Dinâmica do Acoplamento da Condução Atrioventricular à Variação dos Intervalos RR em Atletas e Indivíduos Sedentários / Assessing Dynamic Atrioventricular Conduction Time to RR-interval Coupling in Athletes and Sedentary Subjects

Resumo Fundamento O tempo de condução atrioventricular (TCAV) é influenciado pelo estímulo autonômico e sujeito a remodelação fisiológica. Objetivo Avaliar a variabilidade da TCAV batimento-a-batimento e o intervalo RR em atletas e indivíduos sedentários saudáveis. Métodos Vinte adultos, incluindo 10 indivíduos sedentários saudáveis (controles) e 10 corredores de elite de longa distância (atletas), com idade, peso e altura ajustados foram submetidos à avaliação do equivalente metabólico máximo (MET) e registro de ECG em repouso supino de 15 minutos sete dias depois. O intervalo entre os picos da onda P e da onda R definiu o TCAV. Foram calculadas a média (M) e o desvio padrão (DP) de intervalos RR consecutivos (RR) e TCAV acoplados, bem como as linhas de regressão de RR vs. TCAV (RR-TCAV). A condução AV concordante foi definida como o slope RR-AVCT positivo e, caso contrário, discordante. Um modelo de regressão linear multivariada foi desenvolvido para explicar o MET com base nos parâmetros de variabilidade do TCAV e intervalo RR. Nível de significância: 5%. Resultados Nos atletas, os valores de M-RR e DP-RR foram maiores que nos controles, enquanto M-TCAV e DP-TCAV não foram. Os slopes RR-TCAV foram, respectivamente, 0,038 ± 0,022 e 0,0034 ± 0,017 (p < 0,05). Utilizando um valor de corte de 0,0044 (AUC 0,92 ± 0,07; p < 0,001), o slope RR-TCAV mostrou 100% de especificidade e 80% de sensibilidade. Em um modelo multivariado, o slope DP-RR e RR-TCAV foram variáveis explicativas independentes do MET (razão F: 17,2; p < 0,001), apresentando especificidade de 100% e sensibilidade de 90% (AUC: 0,99 ± 0,02; p < 0,001). Conclusão Em corredores de elite, o acoplamento dinâmico de TCAV para intervalo RR apresenta condução AV discordante espontânea, caracterizada por slope na linha de regressão TCAV negativa vs. intervalo RR. O desvio padrão dos intervalos RR e o slope da linha de regressão do TCAV vs. intervalo RR são variáveis explicativas independentes do MET. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Atrioventricular conduction time ( AVCT ) is influenced by autonomic input and subject to physiological remodeling. Objective To evaluate beat-by-beat AVCT and RR-interval variability in athletes and healthy sedentary subjects. Methods Twenty adults, including 10 healthy sedentary (Controls) and 10 elite long-distance runners (Athletes), age, weight and height-adjusted, underwent maximal metabolic equivalent (MET) assessment, and 15-min supine resting ECG recording seven days later. The interval between P-wave and R-wave peaks defined the AVCT . Mean (M) and standard deviation (SD) of consecutive RR-intervals (RR) and coupled AVCT were calculated, as well as regression lines of RR vs. AVCT (RR-AVCT) . Concordant AV conduction was defined as positive RR-AVCT slope and discordant otherwise. A multivariate linear regression model was developed to explain MET based on AVCT and RR-interval variability parameters. Significance-level: 5 %. Results In Athletes, M-RR and SD-RR values were higher than in Controls, whereas M-AVCT and SD-AVCT were not. RR-AVCT slopes were, respectively, 0.038 ± 0.022 and 0.0034 ± 0.017 (p < 0.05). Using a cut-off value of 0.0044 (AUC 0.92 ± 0.07; p < 0.001), RR-AVCT slope showed 100% specificity and 80% sensitivity. In a multivariate model, SD-RR and RR-AVCT slope were independent explanatory variables of MET (F-ratio: 17.2; p < 0.001), showing 100% specificity and 90% sensitivity (AUC 0.99 ± 0.02; p < 0.001). Conclusion In elite runners, AVCT to RR -interval dynamic coupling shows spontaneous discordant AV conduction, characterized by negative AVCT vs. RR -interval regression line slope. RR -intervals standard deviation and AVCT vs. RR -interval regression line slope are independent explanatory variables of MET (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Longitudinal Shortening of the Left Ventricle by Cine-CMR for Assessment of Diastolic Function in Patients with Aortic Valve Disease / Encurtamento Longitudinal do Ventrículo Esquerdo por Cine-RMC para Avaliação da Função Diastólica em Pacientes com Doença Valvar Aórtica

Abstract Background: Diastolic dysfunction, commonly evaluated by echocardiography, is an important early finding in many cardiomyopathies. Cardiac magnetic resonance (CMR) often requires specialized sequences that extends the test time. Recently, feature-tracking imaging has been made available, but still requires expensive software and lacks clinical validation. Objective: To assess diastolic function in patients with aortic valve disease (AVD) and compare it with normal controls by evaluating left ventricular (LV) longitudinal displacement by CMR. Methods: We compared 26 AVD patients with 19 normal controls. Diastolic function was evaluated as LV longitudinal displacement in 4-chamber view cine-CMR images using steady state free precession (SSFP) sequence during the entire cardiac cycle with temporal resolution < 50 ms. The resulting plot of atrioventricular junction (AVJ) position versus time generated variables of AVJ motion. Significance level of p < 0.05 was used. Results: Maximum longitudinal displacement (0.12 vs. 0.17 cm), maximum velocity during early diastole (MVED, 0.6 vs. 1.4s-1), slope of the best-fit line of displacement in diastasis (VDS, 0.22 vs. 0.03s-1), and VDS/MVED ratio (0.35 vs. 0.02) were significantly reduced in AVD patients compared with controls, respectively. Aortic regurgitation showed significantly worse longitudinal LV shortening compared with aortic stenosis. Higher LV mass indicated worse diastolic dysfunction. Conclusions: A simple linear measurement detected significant differences on LV diastolic function between AVD patients and controls. LV mass was the only independent predictor of diastolic dysfunction in these patients. This method can help in the evaluation of diastolic dysfunction, improving cardiomyopathy detection by CMR, without prolonging exam time or depending on expensive software.

Resumo Fundamentos: A disfunção diastólica, comumente avaliada por ecocardiografia, é um importante achado precoce na maioria das cardiomiopatias. A ressonância magnética cardíaca (RMC) frequentemente requer sequências específicas que prolongam o tempo de exame. Recentemente, métodos de imagens com monitoramento de dados (feature-tracking) foram desenvolvidos, mas ainda requerem softwares caros e carecem de validação clínica. Objetivos: Avaliar a função diastólica em pacientes com doença valvar aórtica (DVA) e compará-la a controles normais pela medida do deslocamento longitudinal do ventrículo esquerdo (VE) por RMC. Métodos: Nós comparamos 26 pacientes com DVA com 19 controles normais. A função diastólica foi avaliada como uma medida do deslocamento longitudinal do VE nas imagens de cine-RMC no plano quatro câmaras usando a sequência steady state free precession (SSFP) durante todo o ciclo cardíaco com resolução temporal < 50 ms. O gráfico resultante da posição da junção atrioventricular versus tempo gerou variáveis de movimento da junção atrioventricular. Utilizamos nível de significância de p < 0,005. Resultados: Deslocamento longitudinal máximo (0,12 vs. 0,17 cm), velocidade máxima em início de diástole (0,6 vs. 1,4s-1), velocidade máxima na diástase (0,22 vs. 0,03s-1) e a razão entre a velocidade máxima na diástase e a velocidade máxima em diástole inicial (0,35 vs. 0,02) foram significativamente menores nos pacientes com DVA em comparação aos controles normais, respectivamente. Pacientes com insuficiência aórtica apresentaram medidas de encurtamento longitudinal do VE significativamente piores em comparação aqueles com estenose aórtica. O aumento da massa ventricular esquerda indicou pior disfunção diastólica. Conclusões: Esta simples medida linear detectou diferenças significativas na função diastólica do VE entre pacientes com DVA e controles normais. A massa ventricular esquerda foi o único preditor independente de disfunção diastólica nesses pacientes. Este método pode auxiliar na avaliação da disfunção diastólica, melhorando a detecção de cardiomiopatias por RMC sem prolongar o tempo de exame ou depender de caros softwares.

Ectopias atriais e associação com fibrilação atrial / Atrial ectopes and atrial fibrillation association

Instabilidade elétrica atrial é um termo recentemente incorporado na prática médica para descrever o amplo espectro de arritmias atriais que se sobrepõem. Essa relação já era intuitiva entre flutter atrial e fibrilação atrial (que deu berço ao anteriormente chamado "fibrilo-flutter"), e, mais recentemente, associou taquicardias atriais e fibrilação atrial. Essa relação é de suma importância, posto que o diagnóstico de fibrilação atrial implica estratégias para prevenção de eventos embólicos. Com novos métodos de rastreio, o diagnóstico de fibrilação atrial se mostrou mais frequente (monitorização prolongada, monitores implantáveis, telemetria de marcapassos). A presença de extrassistolia atrial e taquicardia atrial se torna um desafio: apesar da relação intuitiva de maior risco para fibrilação atrial e eventos cerebrovasculares, a evidência científica para tal se tornou mais robusta recentemente. Este artigo tem a intenção de agregar a evidência de melhor qualidade disponível para facilitar a seleção da estratégia adequada ante um paciente portador de taquicardia e extrassistolia atrial e avaliar adequadamente seu risco

Atrial electrical instability is a recently incorporated term in medical practice to describe the broad spectrum of overlapping atrial arrhythmias. This relationship was already intuitive between atrial flutter and atrial fibrillation (which gave birth to the so-called "fibril-flutter"), and has more recently been related to atrial tachycardias and atrial fibrillation. This relationship is extremely important, since the diagnosis of atrial fibrillation implies in strategies to prevent embolic events. With new screening methods, the diagnosis of atrial fibrillation has become more frequent (prolonged monitoring, implantable monitors, pacemaker telemetry). The presence of atrial extrasystoles and atrial tachycardia is a challenge: despite the intuitive relationship of higher risk for atrial fibrillation and cerebrovascular events, the scientific evidence became more robust recently. This article intends to aggregate the best quality evidence available to facilitate the choice of an appropriate strategy for a patient with tachycardia and atrial extrasystoles and to adequately assess their risk

Associação entre bloqueio de ramo esquerdo e bloqueio divisional ântero-superior: revisitando as evidências / Association between left bundle branch block and anterosuperior hemiblock: revisiting evidences

diagnóstico concomitante de bloqueio de ramo esquerdo e bloqueio divisional ântero-superior esquerdo é motivo de controvérsias entre cardiologistas, principalmente quando há desvio do eixo vetorcardiográfico do coração para a esquerda. Em uma breve revisão da literatura, descrevemos a anatomia do feixe de His e sua natureza trifascicular, apresentamos a teoria tetrafascicular de Medrano e relembramos os critérios diagnósticos dessas duas entidades eletrocardiográficas. Concluímos que o bloqueio concomitante pode ser encontrado em casos de bloqueios pós-divisionais bifasciculares com maior acometimento do bloqueio divisional ântero-superior. Por outro lado, o cardiologista precisa ter em mente que existem outras causas de desvio do eixo para a esquerda em vigência de bloqueio de ramo esquerdo, entre elas: bloqueio de ramo esquerdo com infarto inferior, bloqueio de ramo esquerdo com infarto agudo do miocárdio ântero-septal e lateral, e vias acessórias atípicas

The concomitant diagnosis of left bundle branch block and anterosuperior hemi-block is controversial among cardiologists, especially when there is left vectorcardiographic axis deviation. In a brief literature review, we describe His bundle's anatomy and its trifascicular nature, we present Medrano's quadrifascicular theory and revise the diagnostic criteria of these two electrocardiographic entities. We conclude that concomitant block might be found in cases of post-divisional bifascicular blocks with greater involvement of the anterosuperior hemiblock. On the other hand, the cardiologist must keep in mind that there are other causes of left axis deviation in the presence of left bundle branch block, such as: inferior infarction, anterior-septal and lateral infarction, and atypical bypass tracts

Unsolved Questions on the Anatomy of the Ventricular Conduction System

We reviewed the anatomical characteristics of the conduction system in the ventricles of human and ungulate hearts and then raised some questions to be answered by clinical and anatomical studies in the future. The ventricular conduction system is a 3-dimensional structure as compared to the 2-dimensional character of the atrial conduction system. The proximal part consisting of the atrioventricular node, the bundle of His and fascicles are groups of conducting cells surrounded by fibrous connective tissue so as to insulate from the underlying myocardium. Their location and morphological characters are well established. The bundle of His is a cord like structure but the left and right fascicles are broad at the proximal and branching at the distal part. The more distal part of fascicles and Purkinje system are linear networks of conducting cells at the immediate subendocardium but the intra-mural network is detected at the inner half of the ventricular wall. The papillary muscle also harbors Purkinje system not in the deeper part. It is hard to recognize histologically in human hearts but conducting cells as well as Purkinje cells are easily recognized in ungulate hearts. Further observation on human and ungulate hearts with myocardial infarct, we could find preserved Purkinje system at the subendocardium in contrast to the damaged system at the deeper myocardium. Further studies are necessary on the anatomical characteristics of this peripheral conduction system so as to correlate the clinical data on hearts with ventricular arrhythmias.

Ablação por cateter de taquicardia por reentrada nodal com degeneração para fibrilação atrial: abordagem resolutiva de quatro casos clínicos / Catheter ablation for nodal reentry tachycardia with degeneration for atrial fibrillation: problem solving approach of four clinical cases

A fibrilação atrial é a arritmia mais comumente diagnosticada nos dias atuais. Estima-se que sua prevalência seja de 0,5-1% na população geral. O número de indicações de ablação para tentativa de manutenção do ritmo sinusal tem crescido a cada ano. Não obstante a também crescente experiência dos centros especializados, as complicações inerentes ao procedimento ainda continuam altas, quando comparadas às da ablação convencional. Constatamos a ocorrência de desorganização elétrica atrial consequente a taquicardia por reentrada nodal em quatro pacientes encaminhados inicialmente para ablação de fibrilação atrial

Atrial fibrillation is the most common arrhythmia diagnosed today. It is estimated that its prevalence is around 0.5% to 1% in the general population. The number of indications for ablation procedure, as an attempt to maintain sinus rhythm, grows every year. Nevertheless, the growing experience of specialized centers, the inherent procedurecomplications are still high when compared to conventional ablation. We have noticed the occurrence of atrial electrical disorganization resulting from AV nodal reentry tachycardia in four patients initially referred for atrial fibrillation ablation

P wave

The electrical impulses of atrium arise from the sinus node, subsequently pass through the right and left atrium, and finally arrive at the atrioventricular node. The P wave is the summation of the electrical current generated by depolarization due to its passage through the atrial conduction pathway. It provides many clinical clues that may be useful for diagnosis of atrial, ventricular, or valvular heart diseases. This review article briefly describes the clinical implications, mechanism of genesis, and normal and pathologic features of the P wave.

Supraventricular Tachycardia by Concealed Bypass Tract

Concealed bypass tract (CBT) results from incomplete development of the atrioventricular (AV) annulus. CBT conducts only in a retrograde direction, and therefore does not cause pre-excitation on standard electrocardiograms. The most common tachycardia associated with CBT is an orthodromic atrioventricular reentrant tachycardia (AVRT): a pathway involving anterograde circuitry through the AV node and His Purkinje system and retrograde conduction over the accessory pathway. Orthodromic AVRT accounts for approximately 90%-95% cases of AVRT. Most incidences of CBT occur at the left free wall. Vagal maneuvers and/or intravenous (IV) adenosine are recommended for first line acute management of AVRT. However, pharmacological therapy with IV diltiazem, verapamil, or beta blockers can also be effective for acute treatment for orthodromic AVRT in patients who do not show pre-excitation on their resting ECG during sinus rhythm. The first-line ongoing therapy for AVRT is catheter ablation of CBT; when catheter ablation is not indicated or preferred, oral beta blockers, diltiazem, verapamil, flecainide, propafenone, or amiodarone are recommended.

Radioterapia supradiafragmática y bloqueo auriculoventricular completo / Supradiaphragmatic radiotherapy and complete atrioventricular block

El uso de la radioterapia ha contribuido a mejorar la supervivencia de pacientes con diversos tumores malignos relacionados con la región torácica. No obstante, la irradiación cardíaca a una dosis suficientemente alta puede dañar prácticamente cualquier componente del mismo, incluyendo el sistema de conducción. Se describe el caso de un paciente que desarrolló bloqueo auriculoventricular completo, más de veinte años después de recibir radioterapia supradiafragmática para el tratamiento de un linfoma de Hodgkin.

The use of radiotherapy has contributed to improving the survival in patients with diverse malignancies related to the thoracic region. Nevertheless, cardiac radiation in sufficiently high dose can damage virtually any of its components, including the conduction system. We describe the case of a patient who developed a complete atrioventricular block more than twenty years after receiving supradiaphragmatic radiotherapy for Hodgkin lymphoma.

Spontaneous Transition of Double Tachycardias with Atrial Fusion in a Patient with Wolff-Parkinson-White Syndrome

Among patients with Wolff-Parkinson-White syndrome, atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) can coexist in a single patient. Direct transition of both tachycardias is rare; however, it can occur after premature atrial or ventricular activity if the cycle lengths of the two tachycardias are similar. Furthermore, persistent atrial activation by an accessory pathway (AP) located outside of the AV node during ongoing AVNRT is also rare. This article describes a case of uncommon atrial activation by an AP during AVNRT and gradual transition of the two supraventricular tachycardias without any preceding atrial or ventricular activity in a patient with preexcitation syndrome.

Changes in Atrioventricular Node Physiology Following Slow Pathway Modification in Patients with AV Nodal Re-entrant Tachycardia: The Hypothetical Suggestion of Mechanism of Noninducibility of AVNRT

BACKGROUND AND OBJECTIVES: In cases of radiofrequency catheter ablation (RFCA) for patients with atrioventricular nodal re-entrant tachycardia (AVNRT), complete elimination of slow pathway is not always achievable. Furthermore, in situations of the so-called modified slow pathway, the underlying mechanism of tachycardia elimination remains unclear. SUBJECTS AND METHODS: Patients who underwent RFCA for AVNRT, and showed persistence of dual atrioventricular nodal physiology but no induction of AVNRT after ablation were enrolled. We measured electrophysiologic parameters before and after the ablation procedure. RESULTS: The study subjects included 31 patients (39% men; mean age 43±19 years). The RR interval, Wenckebach cycle length of AV node, slow pathway effective refractory period, maximal AH interval of fast pathway and slow pathway showed no significant changes before and after ablation. However, fast pathway effective refractory period (360±67 vs. 304±55, p<0.001) and differences between slow pathway effective refractory period and fast pathway effective refractory period (90±49 vs. 66±35, p=0.009) were decreased after slow pathway ablation. CONCLUSION: We suggest a possible relationship between the mechanism of tachycardia elimination in AVNRT and an alteration of the re-entrant circuit by removal of the atrial tissue in Koch's triangle. This may be a critical component of providing the excitable gap for the maintenance of tachycardia rather than the electrical damage of slow pathway itself.

A Patient Presenting with Elevations of Cardiac Enzyme Levels after Veratrum Oxysepalum Ingestion

Veratrum patulum has toxicological relevance because of the potential for misidentification of this plant as mountain garlic. Veratrum patulum has an ester-alkaloid that provokes cardiac arrhythmias by excessive vagal stimulation and depression of the sinoatrial and atrioventricular nodes of the heart and hypotension, cardiomegaly. We report on a retrospective case of successful outcome in patients with veratrum patulum poisoning through active treatment from the early phase after ingestion. We report on a case involving a patient who experienced dizziness, dyspnea, hypotension, and elevation of cardiac enzyme, cardiomegaly. These cases were kept under observation and generally recovered with supportive care. We report on cases of veratrum patulum poisoning with review of literature.

Aspectos comparativos da localização, distribuição e irrigação do nó atrioventricular em suínos (Sus domesticus) da raça Landrace / Comparatives aspects of localization, distribution and irrigation of the atrioventricular node in pigs (Sus domesticus) of the Landrace race

A análise morfológica buscou verificar a localização do nó e do fascículo atrioventriculares, bem como sua distribuição sob o endocárdio dos ventrículos e descrever as artérias responsáveis pela nutrição do nó, comparando tais aspectos com características já descritas em seres humanos. Foram coletados 30 corações de suínos Landrace, sendo fêmeas com idade entre 2,5 a 3 anos. Inicialmente, 10 corações foram dissecados a fresco, e outros 20 corações foram injetados com solução de neoprene látex, posteriormente fixados em formaldeído a 10% por 72 horas, para então serem dissecados. Foi observado que o nó atrioventricular localiza-se na região caudoventral do septo interatrial, próximo à abertura do seio coronário. Também foram observadas quatro tipos de irrigações, sendo que a principal irrigação encontrada nos suínos trata-se do primeiro ramo septal caudal, proveniente da artéria coronária direita. O fascículo atrioventricular atravessou o esqueleto fibroso em direção ao septo interventricular e se dividiu em dois ramos. O ramo direito desceu em direção ao ápice do coração sob o endocárdio, se distribuindo na parede lateral do ventrículo direito e o ramo esquerdo permaneceu único ou se dividiu em dois e três ramos, que se distribuíram na parede do ventrículo esquerdo. A localização e irrigação do nó atrioventricular, assim como a divisão e a distribuição do fascículo atrioventricular são semelhantes à anatomia humana, podendo ser viável a utilização de suínos como modelo experimental em estudos comparativos que investiguem esse sistema.

Morphological analysis aimed to verify the location of the node and the atrioventricular fasciculus, and its distribution in the endocardium of the ventricles and describe the arteries responsible for nourishing the node, comparing these aspects with features in humans. Were collected 30 Landrace pig hearts, females, 2.5 to 3 years. Initially, 10 hearts were fresh dissected, and in 20 others hearts were injected with neoprene latex solution, later fixed in 10% formaldehyde for 72 hours, then were dissected. It was observed that the atrioventricular node was located in the caudoventral region of the atrial septum, near the opening of the coronary sinus. It was also observed four types of irrigation, and the main irrigation found in pigs was the first septal branch caudal coming from the right coronary artery. The atrioventricular fascicle crossed the fibrous skeleton into the interventricular septum and split into two branches. The right branch came down towards the apex of the heart under the endocardium, up by distributing itself in the lateral wall of the right ventricle, and the left branch remained single or divided in two and three branches, which are distributed in the wall of the left ventricle. Location and irrigation of the atrioventricular node, as well as the division and distribution of fascicle, are similar to Human Anatomy, being viable the use of pigs as an experimental model in comparative studies to investigate this system.

Pacemaker-Related Tricuspid Regurgitation: An Uninvited Menace of an Invited Guest / 대한내과학회지

A permanent pacemaker is a mainstay treatment for symptomatic bradyarrhythmia, including atrioventricular node blocks and sick sinus syndrome. Although this device was introduced to aid electrical recovery, pacemakers can cause mechanical dysfunction of the tricuspid valve, resulting in significant tricuspid regurgitation (TR). Because pacemaker-related TR is a correctable cause of right heart failure, it is of paramount importance to assess the presence or severity of TR and its association with pacemakers. However, acoustic shadowing from the pacemaker wire hampers the accurate visualization of TR jets, and increases the risk of failing to detect severe TR. Accordingly, goal-directed imaging with a high index of clinical suspicion should be performed when patients present with right heart failure after pacemaker implantation. In this issue of the Journal, the authors sought to investigate the frequency of aggravated TR in patients after pacemaker implantation. They also explored the predictors of TR aggravation, which might provide valuable information for identification of patients who require meticulous follow-up to allow timely intervention. These data regarding the predictive variables for pacemaker-related TR can serve as a roadmap for future studies to identify strategies for reducing the risk of significant TR, such as a tailored approach based on heart rhythm (bradyarrhythmia only vs. combined atrial fibrillation), pacemaker mode (VVI vs. DDD), the location of the pacemaker lead (apical vs. base), and the use of state-of-the art techniques (classical lead vs. leadless).

A estimulação cardíaca convencional é prejudicial em pacientes com função ventricular normal? / Is conventional cardiac pacing harmful in patients with normal ventricular function?

FUNDAMENTO: A estimulação de ventrículo direito pode ser deletéria em pacientes com disfunção ventricular, porém, em pacientes com função normal, o impacto desta estimulação desencadeando disfunção ventricular clinicamente relevante não é completamente estabelecido. OBJETIVOS: Avaliar a evolução clínica, ecocardiográfica e laboratorial de pacientes, com função ventricular esquerdapreviamente normal, submetidos a implante de marca-passo. MÉTODO: Estudo observacional transversal em que foram acompanhados de forma prospectiva 20 pacientes submetidos a implante de marca-passo com os seguintes critérios de inclusão: função ventricular esquerda normal definida pelo ecocardiograma e estimulação ventricular superior a 90%. Foram avaliados: classe funcional (CF) (New York Heart Association), teste de caminhada de 6 minutos (TC6), dosagem do hormônio natriurético tipo B (BNP), avaliação ecocardiográfica (convencional e parâmetros de dessincronismo) e questionário de qualidade de vida (QV) (SF-36). A avaliação foi feita com dez dias (t1), quatro meses (t2), oito meses (t3), 12 meses (t4) e 24 meses (t5). RESULTADOS: Os parâmetros ecocardiográficos convencionais e de dessincronismo não apresentaram variação estatística significante ao longo do tempo. O TC6, a CF e a dosagem de BNP apresentaram piora ao final dos dois anos. A QV teve melhora inicial e piora ao final dos dois anos. CONCLUSÃO: O implante de marca-passo convencional foi associado à piora da classe funcional, piora do teste de caminhada, aumento da dosagem de BNP, aumento da duração do QRS e piora em alguns domínios da QV ao final de dois anos. Não houve alterações nas medidas ecocardiográficas (convencionais e medidas de assincronia).

BACKGROUND: Right ventricular pacing may be deleterious in patients with left ventricular dysfunction, but in patients with normal function the impact of this stimulation triggering clinically relevant ventricular dysfunction is not fully established. OBJECTIVES: To evaluate the clinical, echocardiographic findings of patients with previously normal left ventricular function underwent implantation of a pacemaker. METHODS: Observational, cross-sectional study with 20 patients, who underwent implantation of pacemaker, prospectively followed-up, with the following inclusion criteria: normal left ventricular function defined by echocardiography and ventricular pacing higher than 90%. Were evaluated functional class (FC) (New York Heart Association), 6-minute walk test (6MWT), B-type natriuretic peptide (BNP), echocardiographic assessment (conventional and dyssynchrony parameters), and quality of life questionnaire (QLQ) (SF-36). The assessment was performed at ten days (t1), four months (t2), eight months (t3), 12 months (t4) and 24 months (t5). RESULTS: Conventional echocardiographic parameters and dyssynchrony parameters showed statistically significant variation over time. The 6MWT, FC, and BNP showed worsening at the end of two years. QLQ showed initial improvement and worsening at the end of two years. CONCLUSION: The implantation of conventional pacemaker was associated with worsening in functional class, worsening in walk test, increased BNP levels, increased duration of QRS, and worsening in some domains of the QLQ at the end of two years. There were no changes in echocardiography measurements (conventional and asynchrony measures).