Feasibility of physiological pacing rate in cardiac resynchronization therapy.

AIMS: Although cardiac resynchronization therapy (CRT) improves functional capacity in heart failure patients, a blunted heart rate (HR) response remains after treatment. So we aimed to evaluate the feasibility of the physiological pacing rate (PPR) in CRT patients. METHODS: A cohort of 30 clinical mildly symptomatic CRT patients underwent the six-minute walk test (6MWT). During the 6MWT, HR, blood pressure, and maximum walking distance were assessed. The measurements were obtained in a pre to post manner, with CRT at nominal settings and with the physiological phase (CRT PPR), in which HR was increased by 10% above the maximum HR achieved previously. The CRT cohort also comprised a matched control group (CRT CG). In the CRT CG, the 6MWT was repeated after the standard evaluation with no PPR. The evaluations were blinded for patients and for the 6MWT evaluator. RESULTS: During the 6MWT, CRT PPR led to an increase in walking distance of 40.5 m (9.2%; P < 0.0001) when compared with baseline trial. Additionally, CRT PPR increased the maximum walking distance compared with CRT CG 479.3 ± 68.9 m vs. 420.3 ± 44.8 m, respectively, P = 0.001. In the CRT CG, CRT PPR increased the variation in walking distance, compared with baseline trials, respectively 2.40 ± 3.8% vs. 9.25 ± 7.0%, P = 0.007. CONCLUSIONS: In mildly symptomatic CRT patients PPR is feasible, leading to improvements in functional capacity. In this regard, the efficacy of PPR must be confirmed by controlled randomized trials.

Pacemaker-related infection detected by (18)F-fluorodeoxyglucose positron emission tomography-computed tomography.

Lead endocarditis (LE) is one of the most feared complications and remains a challenging diagnosis in cardiology due to the possibility of an obscure clinical course and symptoms, leading to a delayed diagnosis, or even no diagnosis. (18)F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) appears to be a valuable imaging technique and has been shown to have advantages in the diagnosis of patients with fever of unknown origin. We present the case of a 52-year-old man with a 3-year history of intermittent fever, chills, anemia, and weight loss (13kg). He was submitted to an extensive investigation to clarify his symptoms and all results were negative. LE was finally diagnosed by FDG PET/CT. This examination could become a useful noninvasive method for the detection of LE at an earlier stage, thus avoiding repeated tests and reducing the length of hospital stay.

Quality of life and functional capacity after long-term right ventricular pacing in pediatrics and young adults with congenital atrioventricular block.

BACKGROUND: Although several studies have demonstrated deleterious consequences of chronic right ventricular (RV) pacing on ventricular function and synchronicity, its effects on health-related quality of life (HRQoL) and functional exercise capacity remain uncertain. We aimed to evaluate the effect of RV pacing on HRQoL and functional capacity of children and young adults with congenital complete atrioventricular block (CCAVB). METHODS: We included 66 consecutive subjects with RV cardiac pacemaker due to CCAVB and under clinical follow-up for more than 1 year. Multidimensional HRQoL scores were evaluated by Short Form-36 Health Survey (SF-36) and Child Health Questionnaire-Parent Form 50 (CHQ-PF50). Functional capacity was tested by a 6-minute walk distance test (6MWDT). Association analysis was performed to examine if any demographic and clinical characteristics were associated with lower HRQoL scores and shorter distances at the 6MWDT. RESULTS: Domains presenting lower HRQoL scores were vitality (64.0 ± 17.3), mental health (67.3 ± 8.0), role emotional (69.7 ± 35.8) in the SF-36 questionnaire; general health perceptions (61.3 ± 8.3), general behavior (61.9 ± 15.6), parental impact-emotional (67.7 ± 28.7) in the CHQ-PF50. Female gender (P = 0.009), left ventricular ejection fraction lower than 55% (P = 0.013), cardiovascular drugs (P = 0.003) were significantly associated with lower HRQoL scores. Average distance traveled during the 6MWDT was 539.8 ± 82.9 m. The 6MWDT showed significant association with age (P = 0.006) and cardiovascular drugs (P = 0.024). CONCLUSIONS: Chronic RV pacing did not affect the HRQoL and physical capacity of pediatrics and young subjects. Female gender, ventricular function, and cardiovascular drugs were associated with lower HRQoL scores. Older subjects walked shorter distances in the 6MWDT, as well as subjects who were taking cardiovascular drugs.

Glocal clinical registries: pacemaker registry design and implementation for global and local integration--methodology and case study.

BACKGROUND: The ability to apply standard and interoperable solutions for implementing and managing medical registries as well as aggregate, reproduce, and access data sets from legacy formats and platforms to advanced standard formats and operating systems are crucial for both clinical healthcare and biomedical research settings. PURPOSE: Our study describes a reproducible, highly scalable, standard framework for a device registry implementation addressing both local data quality components and global linking problems. METHODS AND RESULTS: We developed a device registry framework involving the following steps: (1) Data standards definition and representation of the research workflow, (2) Development of electronic case report forms using REDCap (Research Electronic Data Capture), (3) Data collection according to the clinical research workflow and, (4) Data augmentation by enriching the registry database with local electronic health records, governmental database and linked open data collections, (5) Data quality control and (6) Data dissemination through the registry Web site. Our registry adopted all applicable standardized data elements proposed by American College Cardiology / American Heart Association Clinical Data Standards, as well as variables derived from cardiac devices randomized trials and Clinical Data Interchange Standards Consortium. Local interoperability was performed between REDCap and data derived from Electronic Health Record system. The original data set was also augmented by incorporating the reimbursed values paid by the Brazilian government during a hospitalization for pacemaker implantation. By linking our registry to the open data collection repository Linked Clinical Trials (LinkedCT) we found 130 clinical trials which are potentially correlated with our pacemaker registry. CONCLUSION: This study demonstrates how standard and reproducible solutions can be applied in the implementation of medical registries to constitute a re-usable framework. Such approach has the potential to facilitate data integration between healthcare and research settings, also being a useful framework to be used in other biomedical registries.

Comparison of quantitative T-wave alternans profiles of healthy subjects and ICD patients.

BACKGROUND: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. METHODS: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values < or = 0.05. Discriminatory performance was evaluated by a binary logistic regression model. RESULTS: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 +/- 2 microV; 8 +/- 9 muV; p < 0.001) and peak TWA values (26 +/- 13 microV; 37 +/- 20 microV; p = 0,009) as well as on baseline TWA heart rate (79 +/- 10 bpm; 67 +/- 15 bpm; p < 0.001) and peak TWA heart rate (118 +/- 8 bpm; 90 +/- 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. CONCLUSIONS: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols.

Incidence of shock and quality of life in young patients with implantable cardioverter-defibrillator.

OBJECTIVES: To analyze the incidence and causes of ICD therapies in children and young adults and verify their impact on the quality of life (QoL). METHODS: From March/1977 to February/2006, 29 patients (15.7+/-5.4 years old) were submitted to ICD implants. Aborted cardiac arrest (41.5%), sustained ventricular tachycardia (27.6%) and primary prophylaxis of sudden cardiac death (30.9%) indicated device therapy. The number of therapies was evaluated by interviewing patients and by ICD diagnostic data. The SF-36 questionnaire was used to measure the QoL and the results were compared to healthy population. The expectative of freedom from ICD therapies were estimated by the Kaplan-Meier method. RESULTS: After 2.6+/-1.8 years follow-up, 8 (27.6%) patients received 141 appropriate ICD shocks due to ventricular tachycardia (6) or ventricular fibrillation (2), and 11 (37.9%) patients received 152 inappropriate ICD shocks due to supraventricular tachyarrhythmias (8) or oversensing (3). Expectative of freedom from appropriate shocks was 74.2+/-9.0% and 66.7+/-10.7% after one and three years, respectively. Compared to healthy population, QoL decreased in physical function (61.7+/-28.7), vitality (64.7+/-19.1), mental health (65.9+/-22.7) and role-emotional domains (66.7+/-38.5). All patients referred fear and concern related to ICD use. CONCLUSION: Despite the efficacy of ICD therapies, the high incidence of appropriate and inappropriate shocks interfered in patients QoL and adaptation to the device.

Body surface potential mapping investigating the ventricular activation patterns in the cardiac resynchronization of patients with left bundle-branch block and heart failure.

Body surface potential mapping assessed mean cardiac electrical activation times displayed by isochronal maps in the right ventricle (RV; right ventricle mean activation time [mRV]), anterior septal area (anterior septal area mean activation time [mAS]), and left ventricle (left ventricle mean activation time [mLV]) of 28 patients (mean, 61.07 years; congestive heart failure class III-IV; ejection fraction, < or =40%; left bundle-branch block [LBBB] QRS, 180.17 milliseconds), before and after biventricular pacemaker implantation, comparing them, using reference values from a control group of healthy individuals with normal hearts (GNL), in (1) baseline native LBBB, where mRV and mAS values were similar (40.99 vs 43.62 milliseconds), with mLV delayed (80.99 milliseconds, P < .01) and dyssynchronous with RV/anterior septal area; (2) single-site RV pacing, where mRV was greater than in GNL (86.82 milliseconds, P < .001), with greater mAS/mLV difference (63.41 vs 102.7 milliseconds; P < .001); and (3) biventricular pacing (BIV-PM), where mLV and mRV were similar (71.99 vs 71.58 milliseconds), mRV was greater than in GNL and native LBBB (71.58 vs 35.1 and 40.99 milliseconds; P < .001), and mAS approached values in GNL and native LBBB (51.28 vs 50.14 and 43.62 milliseconds). Body surface potential mapping showed that similar RV/left ventricle activation times during biventricular pacing, nearing mAS, indicate synchronized ventricular activation pattern in patients with congestive heart failure/LBBB.

Efeitos da mudança de modo de estimulação ventricular para atrioventricular sobre a qualidade de vida em pacientes com cardiopatia chagásica e bloqueio atrioventricular na troca eletiva do gerador de pulsos / Health related quality of life in patients with Chagas cardiomiopathy and complete atrioventricular block at elective pulse generator replacement: effects of pacing mode upgraded from VVI to DDD

Objetivo: Avaliar os efeitos da mudança de modo de estimulação ventricular para atrioventricular sobre a qualidade de vida em pacientes com cardiopatia chagásica e bloqueio atrioventricular, na troca eletiva do gerador de pulsos.Método: No período de 8 de setembro de 2001 a 18 de março de 2004, no Instituto do Coração da Faculdade de Medicina da Universidade de São Paulo e no Hospital Beneficência Portuguesa de Ribeirão Preto, foram estudados comparativamente sob estimulação ventricular e atrioventricular 27 pacientes com cardiopatia chagásica e bloqueio atrioventricular, com indicação de troca eletiva do gerador de pulsos. Os pacientes foram analisados na inclusão doestudo e alternadamente no modo ventricular e atrioventricular em duas fases com duração de 90 dias, considerando-se o comportamento clínico, avaliado pela qualidade de vida. A análise estatística foi realizada na condição basal, modo VVI e modo DDD, utilizando-se o teste de variância para medidas repetidas, considerando-se nível de significância de 0,05.Resultados: Não foram detectadas diferenças de comportamento na qualidade de vida, avaliada pela capacidade funcional pelo estado geral e pela vitalidade, entre os dois modos de estimulação cardíaca estudados. Ocorreram três casos de complicações relacionadas à mudança de modo de estimulação: dois casos de taquiarritmias atriais conduzidas pelo marcapasso e um caso de deslocamento de eletrodo atrial.Conclusões: A análise comparativa da estimulação ventricular com a atrioventricular, na troca eletiva do gerador, demonstrou que não houve diferença de comportamento clínico sobre a qualidade de vida

QT interval dispersion analysis in patients undergoing left partial ventriculectomy (Batista operation).

BACKGROUND: QT interval dispersion (QTd) has been valued as a marker of increased vulnerability for cardiac arrhythmias. QTd was analyzed in patients undergoing the left partial ventriculectomy (LPV) or Batista operation, a palliative surgery for patients in the line for heart transplantation, which is associated with complex arrhythmia and death from sustained ventricular tachyarrhythmia (SVT). METHODS: Pre- and postoperative R-R, QT, QTc, JT (QT - QRS), and aT (apex to end of T wave) intervals were obtained by 87-lead body surface mapping from 24 patients (18 male), mean age 46.4 +/- 9.15 years. Dispersions of QT, QTc, JT, and aT intervals were calculated, and the total number of arrhythmic events were assessed, aiming to verify a possible risk predictor for the occurrence of SVTs. Subgroups of patients who survived and who died after LPV were also compared, aiming to obtain a QTd cutoff value that could be used prognostically. RESULTS: No difference between pre- and postoperative mean values were found, but a very significant difference was seen when comparing QTd and QTcD values for surviving and dead patients: QTd, cutoff value was 95 ms, while QTcD value was 114 ms. CONCLUSION: There were no significant differences between pre- and postoperative variables or the number of arrhythmic events, but there were significant differences between both pre- and postoperative QTd and QTcD data from surviving and dead patients; this enabled the determination of cutoff values that we believe may be useful for the prognosis of the LPV outcome.

Seguimento clínico, dignóstico e tratamento das complicações em portadores de cardioversor-desfibrilador implantável / Clinical follow-up, diagnosis and treatment of complications in patients with implantable cardio defibrilator

O paciente com cardioversor-desfibrilador implantável exige seguimento diferenciado, porque, além de apresentar cardiopatia de alto risco, é portador de dispositivo cuja complexidade aumenta progressivamente, com a evolução tecnológica. Por isso, é imprescindível que esses pacientes sejam incluídos em Programa de Seguimento Sitematizado, cujas etapas são: avaliação clínica do paciente, programação do cardioversor-desfibrilador implantável, avliação eletrônica do sistema e reeducação do paciente e seus familiares. A infra-estrutura mínima para implementação de um Programa de Seguimento Sistematizado inclui recursos logísticos, humanos e tecnológicos específicos e multidisciplinares. Os resultados dessas avaliações devem ser monitorados com periodicidade entre três e seis meses, por meio de um Sistema de Base de Dados para Avaliação de Dispositivos de Estimulação Cardíaca Artificial, com capacidade de operação on line. Neste artigo estão relacionadas as principais complicações dos sistemas de cardioversor-desfibrilador implantável, identificadas por meio de um Programa de Seguimento Sistematizado. Com base nesses achados, é possível realizar ações de tecnovigilância capazes de aperfeiçoar continuamente os protocolos assistenciais e implementar políticas de saúde pública nessa área, geradno melhora da relação custo-efetividade. Com a divulgação do Programa de Seguimento Sistematizado e a utilização em larga escala, deverão ser atingidos, em breve período, os objetivos básicos de um atendimento médico-especializado: reduzir as taxas de complicações, aumentar a longevidade dos dispositivos e melhorar a qualidade de vida dos pacientes

Indicações e técnicas de implante de marcapasso e cardiodesfibrilador implantável na gestação e em crianças / Pacemakers and automatic implantable defibrillator in children and pregnants: indications and implant procedures

O uso de dispositivos implantáveis em grávidas e crianças é controvertido e implica criteriosa avaliação de suas indicações e complicações. Isso porque envolve portadores de arritmias comumente ameaçadoras da vida. Na presença de cardiopatia estrutural ou não, o bloqueio atrioventricular congênito é responsável pela maioria dos implantes de marcapasso definitivo no período gestacional. Por outro lado, taquiarritmia ventricular polifórmica (torsades de pointes) associada a síndrome do QT longo congênito, fibrilação ventricular idiopática e taquiarrtmia ventricular associada a cardiopatias estruturais são as arritmias que mais trazem ameaças às crianças e gestantes candidatas ao implante de cardiodesfibrilador. Foi demonstrado que com o uso de cardiodesfibrilador implantável, por meio de técnicas distintas, respectivamente epicárdica e endocárdica, podem ser obtidos resultados seguros com baixas taxas de complicações. Nos primeiros achados de resultados de crianças submetidas a implante de cardiodesfibrilador, a maioria teve morte súbita recuperada. A incidência de choques apropriados foi superior a quarenta por cento, em seguimento a médio prazo, com baixos índices de complicações clínicas ou cirúrgicas. Esses estudos permitem concluir que o uso de marcapasso definitivo e cardiodesfibrilador implantável é eficaz para crianças e gestantes com arritmias de alto risco de morte súbita e que as técnicas cirúrgicas alternativas são absolutamente factíveis

Transfemoral pediatric permanent pacing: long-term results.

The femoral vein has been used as an alternative conduit to implant pacemakers in children of any weight. Such method associates endocardial pacing and good cosmetics. The aim of this study was to evaluate prospectively, since 1981, the long-term follow-up of 99 children, from newborn to 13 years old (average = 4.1 +/- 3.6 years, 56 girls), who underwent the implantation of pacemakers via the femoral vein. Atrioventricular block was present in 88% of patients, of congenital etiology in 39% and postoperative in 54%. Single chamber pacemakers were implanted in 92% of patients. During a mean follow-up of 5.3 +/- 5.0 years (maximum = 18.2 years), 5 patients died of cardiac causes, 4 of infection, 2 suddenly, and 3 of unknown causes. The 5-, 10- and 15-year actuarial survival rates were 83.7%, 75.7%, and 75.7%, respectively. Transfemoral leads were used for a mean of 48.9 +/- 44.0 months. Reasons for lead explantations were pacing failure in five patients, infection in eight, and elective in nine. The 2-, 5- and 10-year actuarial survivals of transfemoral leads were 87.6%, 73.8%, and 31.8%, respectively. The mean lead survival was 97 months. Overall, 105 reoperations were performed, 38 for battery depletion, 24 for body growth, 14 for infection or pocket revisions, and 27 for miscellaneous reasons. In conclusion, the durability and overall long-term performance of transfemoral leads were excellent.

Efeitos da estimulação biventricular, via minitoracotomia, sobre o comportamento clínico-funcional de pacientes com insuficiência cardíaca avançada / Effects of biventricular pacing, via mini-thoracotomy, on the long-term clinical and functional behavior of advanced heart failure

A estimulação biventricular tornou-se interessante alternativa terapêutica para pacientes com disfunção ventricular e bloqueio de ramo esquerdo (BRE) não controlados pelo tratamento clínico. Os objetivos deste estudo foram avaliar o comportamento clínico e funcional a longo prazo de pacientes submetidos a estimulação biventricular, o comportamento das arritmias ventriculares e dos parâmetros funcionais diastólicos e avaliar as taxas de complicações, internação hospitalar e mortalidade. Vinte e oito pacientes com insuficiência cardíaca (IC) em classe funcional (CF) III ou IV e BRE foram estudados prospectivamentes durante 22 meses. A estimulação biventricular foi realizada por meio da abordagem epicárdica do ventrículo esquerdo, via minitoracotomia. Em 17 pacientes ocorreu melhora funcional significativa da IC, assim como aumento da distância média percorrida no teste de 6 minutos (23 por cento), incremento da fração de ejeção (FE) (26,5 por cento), redução da densidade de extra sístole ventricular (EV)/24 horas (87,2 por cento) e taquicardia ventricular não sustentada (TVNS)/24 horas (90 por cento), com redução do diâmetro diastólico do ventrículo esquerdo (VE) (4,5 por cento) e da duração do QRS (10 por cento. Registrou-se ainda redução significativa do parâmetro tempo para o enchimento diastólico máximo (PFR) (26 por cento) e redução da taxa de internação por IC (63 por cento).A fibrilação atrial foi responsável por descompensação clínica em 16 pacientes e dois apresentaram taquicardia ventricular sustentada. Até o final do seguimento ocorreram sete óbitos, sendo dois súbitos e três por IC progressiva. A análise de regressão logística univariada revelou associação estatística entre FE<16 por cento, PFR<0,560 VDF/s, duração do complexo QRS>188ms e a maior ocorrência de óbitos. o PFR revelou-se um fator independente preditivo da mortalidade

Remoção a laser de cabos-eletrodos de marcapassos e cardioversores-desfibriladores implantáveis / Excimer laser assisted extraction of permanent pacemaker and ICD leads

A remoção de cabos-eletrodos de marcapassos e cardioversores-desfibriladores é um problema técnico de difícil solução, razão pela qual as técnicas usadas no procedimento estão sendo continuamente aperfeiçoadas. A utilização do Excimer LASER representa grande avanço tecnológico, contribuindo decisivamente para o sucesso do procedimento. O objetivo do presente trabalho foi analisar criticamente algumas técnicas utilizadas na retirada de cabos-eletrodos de marcapasso e cardioversor-desfibrilador implantável (CDI) e descrever a experiência inicial do Instituto do Coração com a técnica de extração LASER-assistida (Excimer LASER). Foram operados 36 pacientes, com idade variando de 1,4 a 91 anos, sendo retirados 47 cabos-eletrodos de marcapasso e 9 de desfibrilador. As indicações para a remoção incluíram: 19 pacientes com infecção no sistema, 13 com troca eletiva e 5 com outras causas. Em 54 cabos-eletrodos removidos, obteve-se 96,4 por cento de sucesso. A técnica de remoção com excimer LASER apresentou resultados excelentes, equivalentes aos descritos na literatura

Implante pediátrico de cardioversor-desfibrilador pela via transtorácica transatrial / Pediatric cardioverter-defibrillator

Os autores relatam o caso de uma criança de 23 meses de idade, portadora de síndrome do QT longo congênito,submetida a implante de cardioversor-desfibrilador atrioventricular. A criança apresentou três episódios de fibrilação ventricular revertida após manobras convencionais de ressuscitação cardiopulmonar e desfibrilação transtorácica externa, previamente ao implante. Devido a descontinuidade da fabricação de placas epimiocárdicas, foi utilizado a via transtorácica para o implante dos cabos-eletrodos, com abordagem epimiocárdica para o eletrodo atrial e endocárdica transatrial para o implante do eletrodo ventricular convencional