Feasibility study of using bridging temporary permanent pacemaker in patients with high-degree atrioventricular block after TAVR / 中华心血管病杂志

Objective: To determine the feasibility of using temporary permanent pacemaker (TPPM) in patients with high-degree atrioventricular block (AVB) after transcatheter aortic valve replacement (TAVR) as bridging strategy to reduce avoidable permanent pacemaker implantation. Methods: This is a prospective observational study. Consecutive patients undergoing TAVR at Beijing Anzhen Hospital and the First Affiliated Hospital of Zhengzhou University from August 2021 to February 2022 were screened. Patients with high-degree AVB and TPPM were included. Patients were followed up for 4 weeks with pacemaker interrogation at every week. The endpoint was the success rate of TPPM removal and free from permanent pacemaker at 1 month after TPPM. The criteria of removing TPPM was no indication of permanent pacing and no pacing signal in 12 lead electrocardiogram (EGG) and 24 hours dynamic EGG, meanwhile the last pacemaker interrogation indicated that ventricular pacing rate was 0. Routinely follow-up ECG was extended to 6 months after removal of TPPM. Results: Ten patients met the inclusion criteria for TPPM, aged (77.0±11.1) years, wirh 7 females. There were 7 patients with third-degree AVB, 1 patient with second-degree AVB, 2 patients with first degree AVB with PR interval>240 ms and LBBB with QRS duration>150 ms. TPPM were applied on the 10 patients for (35±7) days. Among 8 patients with high-degree AVB, 3 recovered to sinus rhythm, and 3 recovered to sinus rhythm with bundle branch block. The other 2 patients with persistent third-degree AVB received permanent pacemaker implantation. For the 2 patients with first-degree AVB and LBBB, PR interval shortened to within 200 ms. TPPM was successfully removed in 8 patients (8/10) at 1 month without permanent pacemaker implantation, of which 2 patients recovered within 24 hours after TAVR and 6 patients recovered 24 hours later after TAVR. No aggravation of conduction block or permanent pacemaker indication were observed in 8 patients during follow-up at 6 months. No procedure-related adverse events occurred in all patients. Conclusion: TPPM is reliable and safe to provide certain buffer time to distinguish whether a permanent pacemaker is necessary in patients with high-degree conduction block after TAVR.

Bloqueo auriculoventricular de alto grado idiopático en la infancia: reporte de caso y revisión de literatura / High-grade idiopathic atrioventricular block in childhood: case report and literature review

Los bloqueos auriculoventriculares son aberraciones cronotrópicas producidas por alteraciones de índole multifactorial en el sistema de inervación cardíaco. Específicamente se localizan entre las vías internodales que conducen el potencial de acción desde el nodo sinusal hasta el nodo auriculoventricular. Estos representan el 2,3% de las alteraciones cardíacas en la vida intrauterina, registrándose un caso por cada 20 000 a 25 000 nacidos vivos. Sin embargo, su ocurrencia en la infancia temprana y la edad escolar es desconocida. Asimismo, el porcentaje de causas idiopáticas de bloqueos auriculoventriculares en esta etapa de la vida es desconocido hasta el momento en Colombia. Dentro de las posibles etiologías se han documentado causas congénitas y adquiridas. Algunos ejemplos son casos aislados producto de isoinmunización materna, en hijo de madre lúpica o en coexistencia con alteraciones estructurales como anomalías del septo interventricular de índole neoplásico, defectos relacionados al ostium y la tabicación de las cámaras cardíacas. También se han descrito casos secundarios a infección por virus sincitial respiratorio y miocarditis vírica concomitante, incluyendo cardiomiopatías de origen inmune, reumático, infeccioso, tumoral, estructural, además de aquellas con compromiso mitocondrial en el cardiomiocito (síndrome de Kearns Sayre) con presentación más tardía con afectación multiorgánica. Todas ellas destacan por un fenómeno en común a nivel celular, referente a la inflamación crónica con reparación fibrótica en el sistema de conducción cardíaco, que conlleva alteraciones de la transmisión del potencial de acción y bradicardia con asíncrona auriculoventricular. También se han reportado causas idiopáticas descritas en el debut de una disautonomía primaria. Se presenta el caso de una paciente de 11 años con crisis de cefalea y síntomas vegetativos paroxísticos asociados a lipotimias a repetición, con posteriores estudios de extensión sin identificación de alteraciones estructurales ni hallazgos autoinmunes. A la niña se le diagnosticó bloqueo auriculoventricular completo, idiopático por lo que recibió manejo expectante por parte del servicio de electrofisiología.

Atrioventricular blocks are chronotropic abnormalities produced by multifactorial alterations in the cardiac innervation system, specifically between the internodal pathways between the sinus node and the atrioventricular node. These bradyarrhythmias represent 2.3% of cardiac alterations in intrauterine life, registering one case for every 20 000 to 25 000 live births. However, its occurrence in childhood and adolescence is unknown. Likewise, the percentage of idiopathic atrioventricular blocks in this group in Colombia is unknown to date. Among the possible etiol-ogies, congenital and acquired causes have been documented. Some examples are isolated cases found in pregnancies with maternal isoimmunization, from carriers with lupus, and in coexis-tence with structural alterations, such as anomalies of the interventricular septum due to cardiac tumors and defects in the ostium and septation of the cardiac chambers. Atrioventricular blocks are also associated with respiratory syncytial virus infection and concomitant viral myocarditis and with cardiomyopathies of immune, rheumatic, infectious, tumoral, and structural origin, in addition to mitochondrial diseases such as Kearns Sayre syndrome, presenting with multi- organ involvement. These etiologies lead to chronic inflammation with fibrotic repair in the cardiac conduction system, which alters the transmission of the action potential and bradycardia with atrioventricular asynchrony. Idiopathic causes described in the onset of primary dysautonomia have also been reported. We present the case of an 11- year- old patient with a headache crisis and paroxysmal vegetative symptoms associated with repeated fainting, with subsequent studies where no structural alterations or autoimmune findings were identified. The patient was diag-nosed with idiopathic complete atrioventricular block and received expectant management by the electrophysiology service.

The success rate of His-Purkinje system pacing in patients with various sites of atrioventricular block / 中华心血管病杂志

Objective: To evaluate the success rate of His-Purkinje system pacing (HPSP) in patients with various sites of atrioventricular block (AVB) and provide clinical evidence for the selection of HPSP in patients with AVB. Methods: This is a retrospective case analysis. 637 patients with AVB who underwent permanent cardiac pacemaker implantation and requiring high proportion of ventricular pacing from March 2016 to September 2021 in the Department of Cardiology, General Hospital of Northern Theater Command were enrolled. The site of AVB was determined by electrophysiological examination. His bundle pacing (HBP) was performed in the first 130 patients (20.4%) who were classified as the HBP group and HPSP included HBP and/or left bundle branch pacing (LBBP) was performed in later 507 patients (79.6%) and these patients were classified as the HPSP group. The basic clinical information such as age and sex of the two groups was compared, and the success rates of HBP or HPSP in patients with different sites of AVB and QRS intervals were analyzed. Results: The age of HBP group was (66.4±15.9) years with 75 males (57.7%). The age of HPSP group was (66.8±13.6) years with 288 (56.8%) males. Among 637 patients, 63.0% (401/637) had atrioventricular node block; 22.9% (146/637) had intra-His block; 14.1% (90/637) had distal or inferior His bundle block. Totally, the success rate of HPSP was higher than that of HBP [93.9% (476/507) vs. 86.9% (113/130), P<0.05]. In each group of patients with various AVB sites, the success rate of HPSP was higher than that of HBP respectively and both success rates of HBP and HPSP showed a declining trend with the distant AVB site. The success rate of HBP in patients with atrioventricular node block and intra-His block was higher than that in patients with distal or inferior His bundle block [95.2% (79/83) vs. 47.1% (8/17), P<0.001; 86.7% (26/30) vs. 47.1% (8/17), P=0.010]. The success rate of HPSP was higher than that of HBP in patients with distal or inferior His bundle block [87.7% (64/73) vs 47.1% (8/17), P=0.001]. In patients with QRS<120 ms, 94.9% (520/548) of AVB sites were in atrioventricular node or intra-His, and HBP had a similar high success rate with HPSP [95.6% (109/114) vs. 96.3% (418/434), P=0.943] in these patients. In patients with QRS ≥ 120 ms, 69.7% (62/89) of AVB sites were at distal or inferior His bundle, and the success rate of HBP was only 25.0% (4/16), while the success rate of HPSP was as high as 79.5% (58/73), P<0.001. Conclusions: In patients with QRS<120 ms and atrioventricular node block or intra-His block, success rates of HBP and HPSP are similarly high and HBP might be considered as the first choice. In patients with QRS ≥ 120 ms and AVB site at distal or inferior His bundle, the success rate of HPSP is higher than that of HBP, suggesting LBBP should be considered as the first-line treatment option.

Crisis hipercalcémica, presentación inusual de adenoma paratiroideo: reporte de 2 casos / Hypercalcemic crisis, unusual presentation of parathyroid adenoma

La crisis hipercalcémica (CH) es una emergencia endocrina inusual, definida por la presencia de calcemia > 14 mg/dl asociada a disfunción renal, alteraciones cardiovasculares, gastrointestinales y del sensorio; también podría considerarse en pacientes con síntomas graves y calcemia menor. El hiperparatiroidismo primario (HPTP) y las neoplasias malignas son las etiologías más comunes de la hipercalcemia (90% de los casos); sin embargo, rara vez el primero se presenta como CH. Debido a la alta mortalidad asociada a esta entidad, es de gran importancia establecer diagnóstico y tratamiento precoces. Presentamos dos pacientes con crisis hipercalcémica como primera manifestación del HPTP, el 1.° con bloqueo auriculoventricular (AV) completo y el 2.° con pancreatitis aguda. La anatomía patológica (AP) reveló adenoma oxifílico en ambos casos, que es una variante histológica poco frecuente y puede manifestarse clínicamente de forma grave. Conclusiones: los adenomas paratiroideos son causa poco frecuente de CH. Consideramos el tipo histológico observado (adenoma oxifílico) como probable factor condicionante. La pancreatitis y especialmente el bloqueo AV son manifestaciones poco frecuentes de la CH. Resaltamos la importancia de la determinación de los niveles de calcio dentro de la evaluación inicial de todo paciente con bloqueo AV. (AU)

Hypercalcemic crisis (HC) is an unusual endocrine emergency, defined as the presence of serum calcium > 14 mg/dl related to kidney dysfunction, cardiovascular, gastrointestinal and sensory disturbances. It could also be considered in patients with severe symptoms and lower serum calcium levels. Primary hyperparathyroidism (PHPT) and malignant neoplasms are the most common hypercalcemia etiologies (90% of cases), nevertheless, the former hardly ever occurs as HC. Due to the high mortality associated with HC, it is crucial to establish early diagnosis and treatment.We report two patients with HC as the first manifestation of PHPT; the former with atrioventricular (AV) block and the latter with acute pancreatitis. Pathology revealed oxyphilic adenoma in both cases, which is an infrequent histological variant that can have a severe clinical manifestation. Conclusions: parathyroid adenomas are a rare cause of HC. We consider the histological type observed (oxyphilic adenoma) as a probable conditioning factor. Pancreatitis and especially AV block are rare manifestations of HC. We emphasize the importance of determining calcium levels in the initial evaluation of all patients with AV block. (AU)

Initial Experience with Fractionation Mapping in the Identification of Vagal Ganglionated Plexus During Cardioneuroablation

This is a series case report of five symptomatic patients presented with diagnosis of sinus bradycardia, first and second degrees atrioventricular (AV) blocks, that were referred to pacemaker implantation. During the screening, a functional cause for the bradycardia and AV blocks were documented by treadmill stress test, 24-hour Holter monitoring and atropine test. After the confirmation of the diagnosis, patients were submitted to cardioneuroablation on an anatomical basis supported by a tridimensional electroanatomical fractionation mapping software. The technique and the acute and short-term results of the cardioneuroablation are described.

Cardiac dysrhythmias in systemic sclerosis / Alteraciones del ritmo cardíaco en esclerosis sistémica

Systemic sclerosis is an immunological disorder characterized by tissue fibrosis and multi-organ dysfunction.1 The accompanying images exhibit electrocardiographic changes in severe systemic sclerosis. Advanced 3:1 atrioventricular block, best observed in Lead Vi, suggests extensive fibrosis of the conduction system (Image A). While one P wave is buried in the T wave (black arrows), two are evident (red arrows) along the isoelectric line. Bradyarrhythmia related prolonged QT interval, best measured in Lead II represents increased risk for torsades-de-pointes, a polymorphic ventricular tachyarrhythmia. Additionally, right bundle branch block with giant T wave inversions (T wave depth > 10 mm) in precordial leads V2- 4 suggests pulmonary hypertension. Post-induction the rhythm abruptly changes to torsades-de-pointes (Image B) necessitating defibrillation.

La esclerosis sistémica es un trastorno inmunológico caracterizado por fibrosis tisular y disfunción multiorgánica. 1 Las imágenes adjuntas muestran cambios electrocardiográficos en la esclerosis sistémica grave. El bloqueo auriculoventricular avanzado 3: 1, que se observa mejor en la derivación VI, sugiere una fibrosis extensa del sistema de conducción ( Imagen A ).Mientras que una onda P está enterrada en la onda T (flechas negras), dos son evidentes (flechas rojas) a lo largo de la línea isoeléctrica. El intervalo QT prolongado relacionado con bradiarritmia, mejor medido en la derivación II, representa un mayor riesgo de torsades-de-pointes, una taquiarritmia ventricular polimórfica. Además, el bloqueo de la rama derecha del haz con inversiones de la onda T gigante (profundidad de la onda T> 10 mm) en las derivaciones precordiales V2- 4 sugiere hipertensión pulmonar. Después de la inducción, el ritmo cambia abruptamente a torsades-de-pointes ( Imagen B ), lo que requiere desfibrilación.

Infección por trypanosoma cruzi y bloqueo cardíaco del nodo auriculoventricular en el salvador / Trypanosoma cruzi infection and atrioventricular-nodal heart block in El Salvador

Resumen La enfermedad de Chagas es endémica en América Latina y sigue siendo un problema regional a pesar de que su frecuencia ha disminuido gracias a importantes avances en salud ambiental. Para determinar su frecuencia en pacientes con enfermedades miocárdicas de El Salvador, se llevó a cabo una in vestigación observacional retrospectiva en nuestro hospital que es un centro de referencia de nivel nacional. Se revisó el registro del Laboratorio de Chagas en el período 2013-2015 para conocer cuántos individuos internados en la Unidad Cardiológica eran positivos por serología para infección chagásica y cuáles fueron sus diagnósticos. Se realizó un total de 1472 pruebas a pacientes individuales durante los 36 meses del período de estudio. De los 557 pacientes con serología positiva para Chagas, 97 (17.4%) fueron eventualmente hospitalizados en la Unidad Cardiológica. A su vez, estos 97 pacientes representaron el 33.7% de los 288 pacientes con cardiopatías. Entre los 97 con cardiopatía chagásica, 40 (41.2%) cumplieron criterios para colocación de marcapaso permanente, mientras que solo 13 de 191 (6.8%) enfermos con cardiopatías no chagásicas cumplieron esos criterios. La frecuencia de bloqueos auriculoventriculares asociados a infección por Trypanosoma cruzi resultó mucho mayor que las publicadas en estudios previos realizados en Sudamérica.

Abstract Chagas disease is endemic in Latin America and remains a regional problem despite improvements in en vironmental health conditions that have helped to control its transmission. To know more about its prevalence in heart disease patients, we carried out a survey in our national (El Salvador) reference hospital. We reviewed the Chagas Lab´s records 2013-2015 to find out how many of the patients admitted to the Hospital´s Heart Unit were serologically positives for Trypanosoma cruzi infection and which the associated diagnoses were. A total of 1472 patients were tested along the 36-month study period. Out of 557 (37.8%) patients with positive serology for Chagas infection, 97 (17.4%) were eventually admitted to the Heart Unit. Among these 97 Chagas infected patients with heart disease, 40 (41.2%) met the criteria for permanent pacemaker placement, while only 13 of 191 (6.8%) patients with non-chagasic heart disease met these criteria. The frequency of heart atrioventricular block associated with Trypanosoma cruzi infection was higher than frequencies reported in South American studies.

Intoxicación por adelfa, un caso poco frecuente / Oleander poisoning, a rare case

Introducción: Las intoxicaciones por plantas son infrecuentes, de complicada orientación diagnóstica, que en general, se dificulta la identificación de la planta, su potencial tóxico y el tratamiento específico. Entre ellas la adelfa, capaz de producir cuadros de intoxicación grave, como un caso consultado a la guardia del Centro Nacional de Toxicología. Objetivos: Presentar un caso clínico de intoxicación grave por adelfa. Caso clínico: Paciente adulto, con intranquilidad, vómitos, dolores abdominales, tensión arterial 150/90 mmHg, frecuencia cardiaca y respiratoria normales, refirió que había consumido vía oral y rectal una poción elaborada con una planta, como tratamiento antiparasitario. El médico de guardia decidió comunicarse con el Centro Nacional de Toxicología. Se identificó la planta como adelfa. A pesar de la aplicación de reposición de volumen, lavado gástrico y la administración de carbón activado; presentó bloqueo auriculoventricular, extrasístoles aisladas y bradicardia. Se suministró atropina endovenosa, luego se trasladó hacia la unidad de cuidados intensivos y posteriormente egresó. Conclusiones: El caso presentó una intoxicación aguda grave por adelfa, con un correcto diagnóstico y tratamiento, que requirió de la labor conjunta de los médicos del cuerpo de guardia del hospital, la terapia intensiva y del Centro Nacional de Toxicología(AU)

Introduction: Poisoning by plants is infrequent, with a complicated diagnostic orientation, which in general makes it difficult to identify the plant, its toxic potential and specific treatment. Among them the oleander, capable of producing serious intoxication, as a case consulted to the National Toxicology Center. Objectives: To present a clinical case of severe oleander poisoning. Clinical case: Adult patient with restlessness, vomiting, abdominal pain, blood pressure 150/90 mmHg, normal heart and respiratory rates, and reported that he had consumed orally and rectally a potion made with a plant, as an antiparasitic treatment. The doctor who assisted him decided to communicate with the National Toxicology Center. The plant was identified as oleander. Despite the application of volume replacement, gastric lavage and the administration of activated charcoal; the patient presented atrioventricular block, isolated extrasystoles and bradycardia, intravenous atropine was administered, and subsequent transfer to the intensive care unit, and later he was discharged. Conclusions: The case presented a severe acute oleander poisoning, there was correct diagnosis and treatment, which required the joint work of the doctors from hospital emergency, the intensive care unit and the National Toxicology Center(AU)

Syncope in patients with cardiac pacemakers

Abstract Introduction: It is challenging to diagnose syncope in patients with pacemakers. Because these patients have increased morbidity and mortality risks, they require immediate attention to determine the causes in order to provide appropriate treatment. This study aimed to investigate the causes and predictive factors of syncope as well as the methods used to diagnose syncope in cardiac pacemaker patients. Methods: Patients with pacemakers implanted owing to sinus node disease or atrioventricular block were evaluated with standardized questionnaires, endocavitary electrograms, and other tests based on the suspected causes of syncope. Mann-Whitney U tests were used to analyze continuous variables and Chi-squared or Fisher's exact tests were used for categorical variables. Logistic regression was used for multivariate analyses. Statistical significance was P<0.05. Results: The study included 95 patients with pacemakers: 47 experienced syncope in the last 12 months and 48 did not. Of the 100 documented episodes of syncope, 48.9% were vasovagal syncopes, 17% had cardiac-related causes, 10.6% had unknown causes, and 8.5% had pacemaker failure. The multivariate analysis showed that a New York Heart Association (NYHA) Functional Class II was a significant factor for developing syncope (P<0.01). Conclusion: While the most common type of syncope in pacemaker patients was neurally mediated, it is important to perform detailed evaluations in this population as the causes of syncope can be life-threatening. The best diagnostic methods were stored electrogram analysis and the tilt table test. NYHA Functional Class II patients were found to have a higher risk for syncope.

Amiloidose cardíaca: cardiomiopatia infiltrativa com comportamento hemodinâmico restritivo ­ relato de caso / Cardiac amyloidosis: infiltrative cardiomyopathy with restrictive hemodynamic behavior ­ case report

A amiloidose é uma condição rara que descreve um grupo heterogêneo de distúrbios que cursam com a deposição extracelular de agregados proteicos fibrilares em tecidos e órgãos. Relata-se aqui o caso de paciente do sexo masculino, com 76 anos de idade, que, há 2 meses, iniciou quadro progressivo de dispneia aos mínimos esforços. Na investigação, observou-se aumento cardíaco global, e o ecocardiograma evidenciou cardiopatia restritiva infiltrativa e derrame pericárdico. Pela elevada suspeição clínica, foi solicitada ressonância magnética cardíaca, que foi altamente sugestiva de amiloidose cardíaca. Dessa forma, assim como no caso relatado, o acometimento cardíaco possui como principal forma de manifestação o tipo miocardiopatia restritivo, sendo um quadro de insuficiência cardíaca crônica com etiologia de difícil diagnóstico em pacientes acima de 50 anos, com prognóstico bastante reservado. Assim, apesar de permanecer como um desafio diagnóstico para o clínico, sua hipótese deve sempre ser aventada na ausência de outra causa que justifique tais achados (AU)

Bloqueo aurículo-ventricular transitorio por dengue complicado: Presentación de un caso / Transient Atrioventricular Block due to Complicated Dengue: Case Report

RESUMEN Las manifestaciones cardiológicas del dengue son muy variadas, el virus puede penetrar al miocardio y producir una miocarditis aguda que, en ocasiones, puede pasar inadvertida y cursar de manera asintomática, con una evolución benigna; y en otras, puede producir alteraciones electrocardiográficas de trastornos del ritmo y la conducción o signos de disfunción ventricular que pueden llegar a la insuficiencia cardíaca grave. Se presenta el caso de un hombre de 21 años de edad, estudiante, con historia previa de salud, que ingresó en el Servicio de Cardiología con diagnóstico de dengue, confirmado por serología, complicado con un trastorno de la conducción (bloqueo aurículo-ventricular de grado avanzado 2:1) en relación a una miocarditis aguda por dengue. Este problema puede observarse en áreas en las que el dengue constituye un problema emergente, por lo que es de vital importancia su conocimiento para diseñar estrategias de prevención y tratamiento de las complicaciones.

ABSTRACT Dengue's cardiological manifestations are diverse; the virus is able to enter the myocardium and cause acute myocarditis that sometimes may go unnoticed and be asymptomatic, with benign outcomes; while in others, it may produce electrocardiographic rhythm and conduction disturbances or signs of ventricular dysfunction that could lead to severe heart failure. We present the case of a 21-year-old man, a student, previously healthy, who was admitted to the Department of Cardiology with a diagnosis of dengue confirmed by serology and complicated with conduction disorders (2:1 advanced atrioventricular block) related to acute myocarditis due to dengue. This problem can be seen in areas where dengue is an emerging problem. Therefore it is critical to be aware of it in order to design strategies for prevention and treatment of complications.

Serum elabela level significantly increased in patients with complete heart block

Abstract Objective: To investigate the change in serum Elabela level, a new apelinergic system peptide, in patients with complete atrioventricular (AV) block and healthy controls. Methods: The study included 50 patients with planned cardiac pacemaker (PM) implantation due to complete AV block and 50 healthy controls with similar age and gender. Elabela level was measured in addition to routine anamnesis, physical examination, and laboratory tests. Patients were divided into two groups, with and without AV block, and then compared. Results: In patients with AV block, serum Elabela level was significantly higher and heart rate and cardiac output were significantly lower than in healthy controls. Serum Elabela level was found to be positively correlated with high-sensitive C-reactive protein and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, but negatively correlated with heart rate, high-density lipoprotein cholesterol, and cardiac output. In linear regression analysis, it was found that these parameters were only closely related to heart rate and NT-proBNP. Serum Elabela level was determined in the patients with AV block independently; an Elabela level > 9.5 ng/ml determined the risk of complete AV-block with 90.2% sensitivity and 88.0% specificity. Conclusion: In patients with complete AV block, the serum Elabela level increases significantly before the PM implantation procedure. According to the results of our study, it was concluded that serum Elabela level could be used in the early determination of patients with complete AV block.

Cardiac conduction defects and complete heart block in myotonic dystrophy / Defectos de conduccion cardiaca y bloqueo cardiaco completo en la distrofìa miotonica

Classic myotonic dystrophy is a multisystem disorder that results from RNA toxicity and is one of the commonest adult onset muscular dystrophies. Patients often present with muscle stiffness from myotonia and dysphagia or dysarthria from laryngopharyngoesophageal muscle weakness. Benign electrocardiogram changes such as first degree atrioventricular block are commonly present and rarely merit further work up. Occasionally, patients develop advanced conduction defects which can unexpectedly progress to complete heart block perioperatively

La distrofia miotonica clásica es un trastorno multi-sistémico que resulta de la toxicidad del RNA y es una de las distrofias musculares más comunes en adultos. Los pacientes suelen presentar rigidez muscular por la miotonía, así como disfagia o disartria por debilidad muscular laringo-faríngea-esofágica. Los cambios benignos en el electrocardiograma, como el bloqueo auriculoventricular de primer grado, suelen estar presentes y rara vez merecen un análisis más profundo. Ocasionalmente, los pacientes desarrollan defectos de conduccion avanzados que pueden progresar inespera-damente para completar el bloqueo cardiaco perioperatorio.

Características diferenciales del bloqueo interauricular avanzado típico y atípico / Differential characteristics of the typical and atypical advanced interatrial block

Resumen Objetivo: Se denomina bloqueo interauricular avanzado (BIA) a la existencia de una onda P ≥ 120 ms y bifásica +/- en las derivaciones inferiores (II-III-VF) del electrocardiograma (ECG) de superficie, el cual constituye un factor predictivo significativo del desarrollo de fibrilación auricular. En fecha reciente se han descrito cuatro patrones de BIA atípicos (BIA-At) con base en la morfología y la duración de la onda P, sin conocer si comparten patogenia y características clínicas similares. Método: Estudio observacional, descriptivo y retrospectivo de pacientes, visitados en el Servicio de Cardiología, en ritmo sinusal y con BIA. Las variables analizadas se obtuvieron de la historia clínica informatizada. El análisis de la onda P se efectuó al aumentar el tamaño del electrocardiograma y mediante calipers electrónicos. El análisis estadístico se realizó con SPSS 19.0, con nivel de significación de p < 0.05. Resultados: Se incluyó a 75 pacientes con media de edad de 74.4 ± 11.7 años, con 62.7% de varones. Se compararon los grupos de pacientes con BIA típico (BIA-T) y BIA-At. El primero se relacionó con la existencia de diabetes mellitus (p = 0.001), enfermedad renal crónica estadio ≥ 3 (p = 0.036), bloqueo auriculoventricular (p = 0.006) y una menor fracción de expulsión ventricular media (p = 0.025); no hubo diferencias respecto de la prevalencia de fibrilación auricular/flúter o accidente cerebrovascular. Sólo la diabetes se acompañó de riesgo de ser un BIA-T (OR: 6.4; p = 0.002; IC 95%: 2.0-21.1). Conclusiones: La diabetes mellitus constituye el único factor de riesgo de que un BIA sea típico. Los pacientes con BIA-T y BIA-At presentan similar prevalencia de fibrilación auricular y accidente cerebrovascular, por lo que son objeto de un mismo tratamiento clínico.

Abstract Objective: It is called advanced interatrial block (IAB) to the existence of a P wave ≥ 120 ms and biphasic ± in the lower leads II-III-VF of the surface electrocardiogram (ECG), which constitutes a significant predictive factor for the development of atrial fibrillation. Recently, four patterns of atypical aIAB (At-IAB) have been described based on the morphology and duration of the P wave, but it’s unknown if they share the same pathogenesis and clinical characteristics. Method: An observational, descriptive and retrospective study was performed with patients, visited in cardiology, who have a sinus rhythm and with aIAB. The analyzed variables were obtained from the computerized clinical history. The analysis of the P wave was made by increasing the size of the ECG and by electronic calipers. Statistical analysis was performed with SPSS 19.0; level of significance: p < 0.05. Results: A total of 75 patients with an average age of 74.4 ± 11.7 years and with a 62.7% males, were included. It was compared the group of patients with typical aIAB (T-aIAB) and with At-aIAB. The first one was associated with the existence of diabetes mellitus (p = 0.001), chronic kidney disease stage ≥ 3 (p = 0.036), atrioventricular block (p = 0.006) and a lower mean ventricular ejection fraction (p = 0.025); there were no differences regarding the prevalence of atrial fibrillation/flutter or stroke. Only diabetes was associated with the risk of T-aIAB (odds ratio: 6.4; p = 0.002; 95% confidence interval: 2.0-21.1). Conclusions: Diabetes mellitus is the only risk factor for an aIAB to be typical. Patients with T-aIAB and At-aIAB have a similar prevalence of atrial fibrillation and stroke, so they must follow the same clinical management.