Estimulação do Ramo Esquerdo do Sistema His-Purkinje: Experiência Inicial / Left Bundle Branch Pacing of His-Purkinje Conduction System: Initial Experience

Resumo Fundamento A estimulação ventricular direita convencional aumenta o risco de fibrilação atrial e insuficiência cardíaca em portadores de marca-passo. A estimulação do ramo esquerdo (RE) do sistema His-Purkinje pode evitar os desfechos indesejados da estimulação ventricular direita. Objetivo Analisar retrospectivamente os desfechos intraoperatórios, eletrocardiográficos e os dados clínicos do seguimento inicial de pacientes submetidos à estimulação do RE. Métodos Foram avaliados os parâmetros eletrônicos do implante e eventuais complicações precoces de 52 pacientes consecutivos submetidos à estimulação do sistema de condução. O nível de significância alfa adotado foi igual a 0,05. Resultados 52 pacientes foram submetidos a estimulação do RE do sistema His-Purkinje, obtendo sucesso em 50 procedimentos. 69,2% dos pacientes eram do sexo masculino e a mediana e intervalo interquatil da idade no momento do implante foi de 73,5 (65,0-80,0) anos. A duração do QRS pré-implante foi de 146 (104-175) ms e de 120 (112-130) ms após o procedimento. O tempo de ativação do ventrículo esquerdo foi de 78 (70-84) ms. A amplitude da onda R foi de 12,00 (7,95-15,30) mV, com limiar de estimulação de 0,5 (0,4-0,7) V × 0,4 ms e impedância de 676 (534-780) ohms. O tempo de procedimento foi de 116 (90-130) min e o tempo de fluoroscopia foi de 14,2 (10,0-21,6) min. Conclusão A estimulação cardíaca do sistema de condução His-Purkinje por meio da estimulação do ramo esquerdo é uma técnica segura e factível. Nesta casuística, apresentou alta taxa de sucesso, foi realizada com tempo de procedimento e fluoroscopia baixos e obteve medidas eletrônicas adequadas.

Abstract Background Conventional right ventricular pacing increases the risk of atrial fibrillation and heart failure in pacemaker patients. Stimulation of the left bundle branch (LBB) of the His-Purkinje system can prevent the unwanted outcomes of right ventricular pacing. Objective To retrospectively analyze the intraoperative outcomes, electrocardiographic and clinical data from the initial follow-up of patients submitted to stimulation of the LBB. Methods The electronic parameters of the implant and of possible early complications of 52 consecutive patients submitted to stimulation of the conduction system were evaluated. The adopted significance level was 0.05. Results Fifty-two patients underwent left bundle branch stimulation, with 50 successful procedures; 69.2% of the patients were male, and the median and interquartile range of age at the time of implantation was 73.5 (65.0-80.0) years. The pre-implant QRS duration was 146 (104-175) ms and 120 (112-130) ms after the procedure. The left ventricle activation time was 78 (70-84) ms. The R-wave amplitude was 12.00 (7.95-15.30) mV, with a stimulation threshold of 0.5 (0.4-0.7) V x 0.4 ms and impedance of 676 (534-780) ohms. The procedure duration was 116 (90-130) min, and the fluoroscopy time was 14.2 (10.0-21.6) min. Conclusion Cardiac stimulation of the His-Purkinje conduction system through the stimulation of the left bundle branch is a safe and feasible technique. In this study, it showed a high success rate, with low procedure and fluoroscopy periods, achieving adequate electronic measurements.

Sincronia Ventricular na Estimulação Cardíaca Parahissiana: Alternativa por Ativação Cardíaca Fisiológica (Estimulação Indireta do Feixe de His)? / Ventricular Synchrony in Para-Hisian Cardiac Pacing as an Alternative for Physiological Cardiac Activation (Indirect Recruitment of the His Bundle?)

Resumo Fundamento A estimulação cardíaca artificial (ECA) por captura direta ou indireta do feixe de His resulta em contração ventricular sincrônica (ECA fisiológica). Objetivos Comparar sincronia cardíaca, características técnicas e resultados de parâmetros eletrônicos entre duas técnicas de ECA indireta do feixe de His: a não seletiva e a parahissiana. Métodos Intervenção experimental (novembro de 2019 a abril de 2020) com implante de marca-passo definitivo (MPd) DDD em pacientes com fração de ejeção ventricular esquerda > 35%. Foram comparadas a sincronia cardíaca resultante mediante algoritmo de análise eletrocardiográfica da variância espacial do QRS e as características técnicas associadas a cada método entre ECA hissiana não seletiva (DDD-His) e parahissiana (DDD-Var). Resultados De 51 pacientes (28 homens), 34 (66,7%) foram alocados no grupo DDD-Var e 17 (33,3%), no grupo DDD-His, com idade média de 74 e 79 anos, respectivamente. No grupo DDD-Var, a análise da variância espacial do QRS (índice de sincronia ventricular) mostrou melhora após o implante de MPd (p < 0,001). Ao ECG pós-implante, 91,2% dos pacientes do grupo DDD-Var mostraram padrão fisiológico de ECA, comprovando ativação similar à do DDD-His (88,2%; p = 0,999). O eixo do QRS estimulado também foi similar (fisiológico) para ambos os grupos. A mediana do tempo de fluoroscopia do implante foi de 7 minutos no grupo DDD-Var e de 21 minutos no DDD-His (p < 0,001), favorecendo a técnica parahissiana. A duração média do QRS aumentou nos pacientes do DDD-Var (114,7 ms pré-MPd e 128,2 ms pós-implante, p = 0,044). A detecção da onda R foi de 11,2 mV no grupo DDD-Var e de 6,0 mV no DDD-His (p = 0,001). Conclusão A ECA parahissiana comprova recrutamento indireto do feixe de His, mostrando-se uma estratégia eficaz e comparável à ECA fisiológica ao resultar em contração ventricular sincrônica similar à obtida por captura hissiana não seletiva.

Abstract Background Artificial cardiac pacing by direct or indirect His bundle capture results in synchronous ventricular contraction (physiological pacing). Objectives To compare cardiac synchronization, technical characteristics, and electronic parameters between two techniques of indirect His-bundle pacing: non-selective (NS-HBP) vs para-Hisian pacing (PHP). Methods The experimental intervention (between November 2019 and April 2020) consisted of implanting a DDD pacemaker in patients who had left ventricular ejection fraction (LVEF) > 35%. The resulting cardiac synchronization was compared using an electrocardiographic algorithm that analyzed QRS variation and the technical characteristics of non-selective Hisian pacing (DDD-His) and para-Hisian pacing (DDD-Var). Results Of 51 total patients (men: 28), 66.7% (34) were allocated to the DDD-Var group and 33.3% (17) to the DDD-His group. The mean ages in each group were 74 and 79 years, respectively. In the DDD-Var group, QRS variation (ventricular synchrony) improved after implantation (p < 0.001). In post-implantation ECG, 91.2% of the DDD-Var group presented a physiological pacing pattern, which was similar to the DDD-His group (88.2%; p = 0.999). The paced QRS axis was also similar (physiological) for both groups. Intraoperative fluoroscopy time (XRay) during implantation was lower for the para-Hisian technique (median 7 min in the DDD-Var group vs 21 min in the DDD-His group, p < 0.001). The mean QRS duration increased in the DDD-Var group (114.7 ms pre-implantation vs 128.2 ms post-implantation, p = 0.044). The mean post-implantation R-wave amplitude was 11.2 mV in the DDD-Var group vs 6.0 mV in the DDD-His group, p = 0.001. Conclusion Para-Hisian pacing appears to indirectly recruit the His bundle, which would make this an effective and comparable strategy for physiological pacing, resulting in synchronous ventricular contraction similar to that of non-selective Hisian pacing.

Importancia de la sincronía aurículo-ventricular para el gasto cardíaco en un paciente con insuficiencia cardíaca y fracción de eyección reducida / Importance of atrioventricular synchrony for cardiac output in a patient with heart failure and reduced ejection fraction

RESUMEN Hombre de 80 años de edad, con antecedentes de miocardiopatía dilatada de origen isquémico, con disfunción sisto-diastólica del ventrículo izquierdo, que inicialmente presentó flutter auricular con inestabilidad hemodinámica y se realizó cardioversión eléctrica, luego de la cual se obtuvo un ritmo no precedido de onda P a 40 latidos por minuto, que fue interpretado como fibrilación auricular bloqueada; razón por la que se le colocó un marcapasos externo. Durante su evolución se realizó electrocardiograma de 12 derivaciones, donde se evidenció estimulación ventricular permanente con conducción retrógrada (ventrículo-auricular). Se disminuyó la frecuencia de estimulación para priorizar el ritmo espontáneo del paciente y se obtuvo marcada mejoría de la curva de presión arterial.

ABSTRACT An 80-year-old male patient is presented, with previous dilated cardiomyopathy of ischemic etiology, with systo-diastolic left ventricular dysfunction, who initially presented atrial flutter and hemodynamic instability, thus, an electrical cardioversion was performed. After this procedure, a blocked atrial fibrillation was observed. Thus, an external pacemaker was placed. During the evolution, a 12 lead electrocardiogram was performed, showing permanent ventricular stimulation with retrograde conduction (ventriculo-atrial). The pacing rate was diminished for prioritizing the patient's spontaneous rhythm resulting in an improvement of the blood pressure curve.

Intervención de enfermería para la aceptación del paciente al cardiodesfibrilador aplicada en el preimplante / Nursing intervention for the acceptance of the patient to the cardioverter defibrillator applied in the pre-implantation

Antecedentes: El cardiodesfibrilador mejora la supervivencia tratando los eventos arrítmicos fatales. La implementación de la terapia se acompaña de cambios importantes a nivel físico, psicológico y social y modifica el estilo de vida, lo que supone nuevos retos para el cuidado de la salud. El objetivo de esta investigación fue evaluar los efectos de la intervención de enfermería sobre: el nivel de aceptación, el tiempo de ajuste y las consecuencias de integrar la tecnología a la vida cotidiana. Diseño y métodos: Estudio cuantitativo de tipo cuasiexperimental con dos grupos de intervención y uno de control; en total se asignaron aleatoriamente 72 sujetos (n=24). La encuesta de caracterización sociodemográfica y el "Cuestionario de Florida para la aceptación del paciente" versión en español permitieron la recolección de los datos. Se realizó la intervención de enfermería "Aceptación en Personas con Estimulación Cardíaca Cardiodesfibrilador" (APECC) con el protocolo clínico. Resultados: Los hallazgos evidenciaron un aumento estadísticamente significativo en el nivel de aceptación global en las mediciones efectuadas a la semana y al mes (valor de la estadística Z= -3,186, valor-p<0,01) Adicionalmente las comparaciones entre los grupos intervención y control demostraron que la intervención APECC disminuye el tiempo de ajuste dados los mejores niveles de aceptación en el tiempo de los grupos de intervención (valor de la estadística Z= -3,860, valor-p<0,000). Conclusiones: La intervención de enfermería aplicada en el periodo de preimplantación tiene efectos positivos sobre la aceptación de la persona al cardiodesfibrilador y disminuye el tiempo de ajuste y las consecuencias físicas, psicológicas y sociales.

Background: Defibrillators improve survival by treating fatal arrhythmic events. Therapy implementation is accompanied by important changes at physical, psychological, and social levels and it modifies lifestyle, which represents new challenges for health care. The objective of this research was to evaluate the effects of a nursing intervention on acceptance level, time of adjustment, and consequences of integrating technology into daily life. Design and methods: A quantitative quasi-experimental study with two intervention groups and a control group, in total 72 subjects were randomly assigned (n = 24). Sociodemographic characteristics survey and the Spanish version of the "Florida Patient Acceptance Survey" enabled data collection. The nursing intervention Acceptance in Patients with Defibrillator Cardiac Pacing (APECC in Spanish) was applied with the clinical protocol. Results: Findings showed a statistically significant increase in the overall acceptance level for weekly and monthly measurements (statistic value Z=-3.186, p<0.01). Additionally, comparisons between intervention and control groups showed that the APECC intervention decreases the adjustment time given better acceptance levels over time in the intervention groups (statistic value Z = -3,860, p <0.000). Conclusions: Nursing intervention applied during preimplantation period has positive effects on patient acceptance of defibrillators and decreases adjustment time as well as physical, psychological and social consequences.

Electrical approach to improve left ventricular activation during right ventricle stimulation

Coronary sinus mapping is commonly used to evaluate left atrial activation. Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular activation times (R-LVtime) and the narrowest QRS widths. Three study groups were defined: 54 controls without intraventricular conduction disturbances; 15 patients with left bundle branch block, and other 15 with right bundle branch block. Left ventricular activation times and QRS widths were evaluated among groups under sinus rhythm, right ventricular apex, right ventricular outflow tract and high output septal zone (SEPHO). Left ventricular activation time was measured as the time elapsed from the surface QRS onset to the most distal left ventricular deflection recorded at coronary sinus. During the above stimulation modalities, coronary sinus mapping reproduced electrical differences that followed mechanical differences measured by tissue doppler imaging. Surprisingly, 33% of the patients with left bundle branch block displayed an early left ventricular activation time, suggesting that these patients would not benefit from resynchronization therapy. SEPHO improved QRS widths and left ventricular activation times in all groups, especially in patients with left bundle branch block, in whom these variables became similar to controls. Left ventricular activation time could be useful to search the optimum pacing site and would also enable detection of non-responders to cardiac resynchronization therapy. Finally, SEPHO resulted the best pacing modality, because it narrowed QRS-complexes and shortened left ventricular activations of patients with left bundle branch block and preserved the physiological depolarization of controls.

El mapeo del seno coronario se utiliza comúnmente para evaluar la activación de la aurícula izquierda. Aquí, investigamos su utilidad para evaluar qué modalidad de estimulación ventricular derecha produce los menores tiempos de activación ventricular izquierda (R-LVtime). Se definieron tres grupos: 54 controles; 15 pacientes con bloqueo de rama izquierda y 15 con bloqueo de rama derecha. El ancho de QRS y los tiempos de activación fueron evaluados en cada grupo bajo las siguientes modalidades: ritmo sinusal, ápex del ventrículo derecho, tracto de salida del ventrículo derecho y alta salida en septum (SEPHO). El R-LVtime se midió como el tiempo transcurrido desde el inicio del QRS de superficie y la deflexión ventricular izquierda más distal del seno coronario. Durante las distintas modalidades de estimulación, el mapeo del seno coronario reprodujo diferencias eléctricas acompañadas por diferencias mecánicas que fueron evaluadas mediante Tissue Doppler Imaging. El 33% de los pacientes con bloqueo de rama izquierda mostró R-LVtime tempranos, lo que sugiere que estos pacientes no se beneficiarían con terapia de resincronización. SEPHO mejoró el ancho de QRS y el R-LVtime de todos los grupos, especialmente en los pacientes con bloqueo de rama izquierda. En conclusión, el R-LVtime serviría para identificar el sitio óptimo de estimulación y permitiría detectar ciertos no respondedores a la terapia de resincronización. Además, el SEPHO resultó la mejor modalidad de estimulación porque estrechó el QRS y acortó el R-LVtime de los pacientes con bloqueo de rama izquierda pero no alteró la despolarización fisiológica de los controles.

Cardiac resynchronization therapy for patients with aggravated right ventricle-Paced heart failure: A report of operation strategy and technique in 6 cases / 第二军医大学学报

Objective To discuss the timing of surgery, operation strategy and technique of upgrading chronically right ventricle-paced heart failure patients to cardiac resynchronization therapy. Methods Six chronically right ventricle-paced heart failure patients underwent surgery of upgrading to CRT in our department between March 2009 to February 2014. The clinical characteristics, surgical techniques and follow-up data were retrospectively analyzed. Results Six patients, including single-chamber pacemaker (VVI) 2 cases, dual-chamber pacemaker (DDD) 4 cases, were successfully complete the upgrade operation, no complications. In two cases which original pacemaker pockets were on the left, the left ventricular electrodes were implanted through the left subclavian vein, without subcutaneous tunnel. In 4 cases which original pacemaker pockets were on the right, the left ventricular electrodes implanted through the right internal jugular vein in 2 patients, running in the subcutaneous tunnel from right internal jugular vein to the right chest, while in other 2 cases, the left ventricular electrodes implanted through Left subclavian vein, running in the subcutaneous tunnel from the right chest to the left chest. There were a total of 10 primary electrode wires, the two wires were removed, the eight were continued to use. Follow-up data showed that in the postoperative 3 days, compared with admission, CRT significantly reduced the mean ORS duration(P0.05)and BNP(P0.05),while left ventricular end-diastolic diameter, ejection fraction and NYHA class no significant changes. In the postoperative 3 months, CRT significantly reduced the mean ORS duration and BNP, and increased the LV ejection fraction, left ventricular end-diastolic diameter were reduced significantly, the patients cardiac function was improved by an average of one grade of NYHA functional class. Conclusion Correct preoperative operation strategy and intraoperative operation skills is the key of upgrading chronically right ventricle-paced to cardiac resynchronization therapy,Upgrade surgery can significantly improve the synchronization of left and right ventricular contraction, improve heart function and quality of life.

Avaliação da estimulação ventricular direita crônica em crianças e adultos jovens com bloqueio atrioventricular congênito isolado / Evaluation of chronic right ventricular pacing in children and young adults with isolated congenital complete atrioventricular block

Introdução: O bloqueio atrioventricular congênito isolado (BAVCi) é raro e tem múltiplas apresentações clínicas. O implante de marca-passo cardíaco permanente (MP) é o tratamento de escolha, resultando em evolução clínica satisfatória para a maioria dos casos, porém, aproximadamente 10% deles apresentam remodelamento ventricular e insuficiência cardíaca grave. Objetivos: Estudar a evolução tardia de crianças e adultos jovens com BAVCi e estimulação crônica do ventrículo direito (VD), visando determinar: a prevalência de sinais clínicos e laboratoriais de insuficiência cardíaca e de remodelamento ventricular; a capacidade funcional; a qualidade de vida e fatores preditores de alterações clínicas, funcionais ou ecocardiográficas. Métodos: Estudo transversal realizado em coorte de portadores de BAVCi e MP implantado antes de 21 anos de idade com estimulação no VD há mais de um ano. Todos os indivíduos foram submetidos a avaliação clínica e laboratorial, da capacidade funcional, da qualidade de vida e a ecocardiograma. Mães e sujeitos da pesquisa foram investigados para doenças reumatológicas. Os dados foram armazenados no sistema REDCap (Research Electronic Data Capture) e analisados pelos programas SAS (Statistical Analysis System), SPSS (Statistical Package for the Social Sciences) e R Studio. A análise dos dados incluiu: análise univariada para pesquisa de associações entre variáveis preditoras e desfechos, coeficiente de correlação de Pearson e modelo de regressão linear multivariado. Resultados: De março/2010 a dezembro/2013, foram avaliados 63 indivíduos, 68% do sexo feminino, com idade de 1 a 40 anos, com MP por 13,4 ± 6,5 anos e estimulação do VD por 10,0 ± 5,4 anos. O modo de estimulação era atrioventricular em 55,6%, o percentual de estimulação de VD de 97,9 ± 4,2% e a duração do complexo QRS estimulado de 152,4 ± 20,1 ms. A maioria (88,9%) era assintomática e não utilizava medicamentos de ação cardiovascular. Maior tempo de MP...

Introduction: Isolated congenital atrioventricular block (iCAVB) is a rare condition with multiple clinical presentations. Permanent cardiac pacing is the most effective therapy for this population resulting in satisfactory long-term outcomes. However, approximately 10% of patients may have ventricular remodeling and severe heart failure. Objectives: To study the long-term effects of chronic right ventricular (RV) pacing in children and young adults with iCAVB in order to determine: prevalence of clinical and laboratory signs of heart failure and ventricular remodeling, functional capacity, quality of life and predictors of clinical, functional or echocardiographic abnormalities. Methods: Cross-sectional study of a cohort of iCAVB patients with <= 21 years old at initial pacemaker (PM) implantation and single or dual-chamber pacing in a unique RV site for a minimum of one year. All subjects underwent clinical and laboratory assessment, functional capacity, quality of life and echocardiogram. Mothers and research subjects were investigated for rheumatic diseases. Data were stored in REDCap (Research Electronic Data Capture) system and analyzed by SAS (Statistical Analysis System), SPSS (Statistical Package for the Social Sciences) and R Studio programs. Data analysis included: univariate analysis for associations between predictor variables and outcomes, Pearson correlation coefficient and linear regression multivariate model. Results: Between March/2010 and December/2013, we evaluated 63 subjects aged 1-40 years old, 68% female, under PM for 13.4 ± 6.5 years and under RV pacing for 10.0 ± 5.4 years. Pacing mode was atrioventricular in 55.6%, percentage of RV pacing was 97.9 ± 4.2% and paced QRS duration was 152.4 ± 20.1 ms. Overall, the majority (88.9%) were asymptomatic and did not use cardiovascular drugs. Longer time under PM (P= 0.013), or even under RV pacing (P= 0.005), higher age at study inclusion (P= 0.032) and lower left ventricular...

Quality of life of patients with implanted cardiac devices: a transversal study

Objective: Evaluate the quality of life (QL) of patients with implanted cardiac devices and describe the recognition of electromagnetic sources, and symptoms, in the event of failure of the device. Methods: This is a transversal study that used the SF-36 questionnaire and an instrument developed to observe other variables. Results: The research included 56 patients, 58±13 years of age, predominantly male. In relation to QL, scores were: functional capacity = 58±26; pain = 65±32; vitality = 58±26; social aspects = 72±31; mental health = 69±26; physical aspects = 12.5(0-50); emotional aspects = 33(0-100); general health status = 49±25. The majority of the patients (91%) know that the device could suffer from interference. Conclusions: The sample of this study showed low QL scores in physical and emotional aspects, and in general health status. Besides that, patients were aware that the devices could suffer from magnetic interference, but they could not name the main sources of that interference.

Efficacy of stent smplantation using a rapid artificial cardiac pacing technique on ostial lesions of left anterior descending artery / 中国综合临床

Objective To evaluate the safety and clinical efficacy of stent implantation using a rapid artificial cardiac pacing technique on ostial lesions of left anterior descending artery (LAD).Methods From Jun 2008 to Nov 2010,38 patients with ostial lesions of LAD were recruited and randomly divided into two groups:patients with stent implantation using a rapid artificial cardiac pacing technique (pacing group,n =19 ) and patients with direct stent implantation (no-pacing group,n =19 ).Post-stenting examination was performed.Patients were followed-up for 9 months and coronary angiography was reviewed.The immediate success rate,major adverse cardiac events including death,reinfarction and target vessel revascularization,late lumen loss,sent thmmbosisin,rent-restenosis were compared between these two groups.Results There were no significant differences in the baseline values,disease characteristics and instant response to surgery between pacing and no-pacing groups(P ＞ 0.05 ).The time cost for stent placement was significantly shorter in the pacing group than that in the no-pacing group ( [ 16.5 ± 0.5 ] s vs.[46.6 ± 1.4 ] s,t =88.256,P =0.004 ).After surgery,there was no acute or subacute thrombosis,in-stent restenosis or occlusion for patients in the pacing group.In the no-pacing group,one patient developed acute thrombosis.The symptoms disappeared after thrombus aspiration and balloon dilatation by emergency percutaneous coronary intervention.Patients were followed up for 270 -275 days,and patients in the pacing group received post-stenting coronary angiography 9 months after stent implantation using a rapid artificial cardiac pacing technique,and no in-stent re-stenosis was found.During this period,nobody had adverse events such as death,myocardial infarction or target lesion revascularization,while five cases with in-stent restenosis (50％ -60％ )were found in the no-pacing group,without further target lesion reconstruction due to symptomless.Conclusion Compared with previous positioning technique,stent implantation using a rapid artificial cardiac pacing technique on treatment of ostial lesions of LAD is safer,and more effective.It is a favorable method for accurate positioning of bracket and can improve the prognosis,reduce the occurrence of acute thrombosis and in-stent restenosis.

Estimulación paraseptal permanente: Indicaciones y seguimiento / Permanent Para-Hisian Pacing: Indications and Follow-Up

Introducción Se ha demostrado que la estimulación definitiva en el ápex del ventrículo derecho provoca disincronía ventricular izquierda y eventualmente deterioro contráctil y ello ha llevado a la búsqueda de otros sitios alternativos de estimulación. Las indicaciones y los resultados de la estimulación septal, así como las dificultades técnicas del implante, se encuentran actualmente en estudio. Objetivos Analizar la indicación, la factibilidad y el seguimiento en un grupo de pacientes con estimulación septal parahisiana. Material y métodos Se evaluaron 22 pacientes con edades entre 27 y 68 años, con complejo QRS angosto sin trastorno de conducción intraventricular, con indicación de marcapasos. Se utilizaron catéteres comunes para la aurícula con fijación activa y catéteres con vaina deflectable para la estimulación septal. Durante el implante y el seguimiento se midieron los umbrales y la amplitud de la onda R. Resultados Los umbrales durante el implante fueron menores de 2 voltios/0,50 mseg y la onda R mayor de 5 m V. El tiempo de implante promedio de los catéteres convencionales fue de 30 ± 10 min y el de los catéteres especiales, de 15 ± 5 min. El seguimiento promedio fue de 24 meses. Los umbrales crónicos fueron de 2,5 ± 1,5 voltios con una amplitud de onda R media de 5 ± 2 voltios. Hubo un desplazamiento durante el seguimiento. Conclusiones La estimulación septal parahisiana presentó un índice bajo de complicaciones. El uso de catéteres y vainas especiales redujo el tiempo de implante. La ubicación parahisiana se caracterizó por umbrales más altos y amplitud de la onda R menor que en la comunicada durante estimulación convencional. La estimulación septal parahisiana sería una alternativa válida para evitar la disincronía producida por la estimulación del ventrículo derecho en pacientes sin trastornos de la conducción intraventricular.

Background It has been demonstrated that permanent right ventricular apical pacing produces left ventricular dyssynchrony and decreases contractile function. For this reason other sites of stimulation have been explored. The indications, outcomes and technical difficulties of para-hisian pacing are currently under investigation. Objectives To analyze the indications, feasibility and follow-up in a group of patients undergoing para-hisian pacing. Material and Methods A total of 22 patients between 27 and 68 years with indication of permanent pacing, narrow QRS complexes and preserved intraventricular conduction were evaluated. Activefixation atrial leads and ventricular leads with a deflectable sheath for parahisian stimulation were used. Pacing thresholds and R-wave amplitude were measured during implantation and follow-up. Results During implantation, pacing thresholds were <2 V/0.50 ms and R-wave amplitude was >5 m V. The average duration of placement of conventional leads and special leads were 30±10 min and 15±5 min, respectively. Mean follow-up was 24 months. Chronic thresholds were 2.5±1.5 Volts, and mean R-wave amplitude was 5±2 Volts. One lead displacement was reported during follow-up. Conclusions Para-hisian pacing presented a low rate of complications. The use of special leads and sheaths reduced the implantation time. Compared to conventional pacing, para-hisian pacing presented higher thresholds and lower R-wave amplitude. Para-hisian pacing would be a valid option to avoid ventricular dyssynchrony related to right ventricular pacing in patients with preserved intraventricular conduction.

Assessment of longitudinal segmental myocardial strain and displacement of left ventricle in patients with dual chamber pacing by velocity vector imaging / 中华医学超声杂志（电子版）

Objective To assess longitudinal segmental myocardial strain and displacement of left ventricle (LV) in patients with dual chamber pacing (DDD) using velocity vector imaging (VVI) and to explore the clinical application value of VVI in assessing left ventricular motion.Methods A total of 23 patients before and after DDD pacemaker implantation were enrolled in this study.The peak systolic strain and displacement of ventricular segments were measured with VVI and compared before and after pacemaker implantation.Results Compared to the values at the baseline,the strain and displacement of lateral,interventricular septum,anterior and posterior wall of LV in patients with pacing were significantly decreased.The strain,displacement of basal and mid segments with pacing were decreased as well(P＜0.01).The left ventricular strain and displacement in patients with pacing were significantly decreased than those of patients at the baseline(P＜0.05).Left ventricular longitudinal displacement before and after DDD pacing was significantly decreased from basal,mid to apical segments.But no significant difference was found in longitudinal strain from basal,mid to apical segments of LV.Conclusions (1) Left ventricular strain and displacement in patients with pacing were different between those before and after DDD pacing.(2) VVI can accurately assess left ventricular strain and displacement in patients with DDD pacing,and can become a powerful mean to assess the regional myocardial function.

Pacemaker malfunction related to insulation break according to position change in a patient with complete AV block / 대한내과학회지

A 53 year-old woman presented with intermittent dizziness and palpitation. She had received VVI type pacemaker due to complete AV block in 1990, and exchanged by VVIR type pacemaker thirteen years later. 1 year later, she suffered intermittent dizziness and palpitation in erect position, not in supine position. Intermittent pacing failure and sensing failure was observed in pacemaker test, especially in erect position, not in supine position. Pacing threshold was increased in erect position, but lead impedance was not changed. Insulation break was observed in bipolar lead by fluoroscope. Initially we tried a new lead implantation by cephalic access to prevent lead related complication, but failed. So, we implanted a new bipolar lead by subclavian access. Finally, she was treated by a new bipolar lead implantation.