Efeitos da estimulação ventricular convencional em pacientes com função ventricular normal

Impacto dos Modos de Estimulação DDD e VVIR na Capacidade Funcional e Qualidade de Vida de Pacientes Chagásicos

Introdução: A estimulação atrioventricular propicia benefícios hemodinâmicos em relação à ventricular isolada, mas essa vantagem não está completamente estabelecida em pacientes chagásicos com disfunção sistólica. Objetivo:Avaliar a infl uência dos modos de estimulação DDD e VVIR na capacidade funcional, qualidade de vida (QV) e alterações laboratoriais de peptídeo natriurético em pacientes chagásicos com disfunção ventricular submetidos a implante de marcapasso. Métodos: Estudaram-se prospectivamente 20 pacientes (55% do sexo masculino) com média de idade de 62,7(± 9,9 anos) e média da fração de ejeção de 41,8% (± 2,8). Alternadamente, os pacientes receberam a estimulação nos modos DDD e VVIR por um período de três meses sob cada programação. O mínimo percentual de estimulação ventricular admitido foi de 80%. Após cada período, o paciente foi submetido ao teste de caminhada de seis minutos (TC6M), avaliação de QV pelo Minnesota Living with Heart Failure Questionnaire (MLHFQ) e pelo Assesment of QUAlity of life and RELated events (AQUAREL). A avaliação laboratorial foi realizada com a dosagem da fração N-terminal do peptídeo natriurético cerebral (N-terminal pro b-type natriuretic peptide – NT-proBNP). Resultados: A média da distância percorrida no TC6M nos modos DDD e VVIR foram respectivamente 390,60 (± 52,71) e 396,30 (± 52,71) metros (p = 0,160). Verifi caram-se resultados de QV inferiores, considerando o domínio físico do MLHFQ (p = 0,03) e os domínios dispneia de esforço(p = 0,05) e arritmia (p < 0,001) do AQUAREL, com o modo VVIR. Os níveis de NT-proBNP aumentaram signifi cativamente com a estimulação no modoVVIR (p < 0,001). Conclusão: Após três meses de estimulação com omodo VVIR, houve piora da QV dos pacientes chagásicos e aumento dos níveis de NT-proBNP (registro de ensaio clínico: ReBEc RBR-53x476)

Impact of DDD and VVIR Stimulation Modes on Functional Capacity and Quality of Life of Chagasic Patients

Introduction: Atrioventricular stimulation provides hemodynamic benefits over the isolated ventricular rate, but this advantage is not completely established in chagasic patients with systolic dysfunction. Objectives: To evaluate the influence of DDD and VVIR stimulation modes on functional capacity, quality of life (QoL) and laboratory abnormalities of a natriuretic peptide in chagasic patients with ventricular dysfunction submitted to pacemaker implantation. Methods: Twenty patients (55% male) with a mean age of 62.7 (± 9.9 years) and a mean ejection fraction of 41.8% (± 2.8) were prospectively studied. Alternately, patients received pacing in the DDD and VVIR modes for a period of three months under each schedule. The minimum percentage of ventricular pacing was 80%. After each period, the patient was submitted to the six-minute walk test (6MWT), QOL assessment by the Minnesota Living with Heart Failure Questionnaire (MLHFQ) and the Assay of QUAlity of life and RELated events (AQUAREL). Laboratory evaluation was performed with the N-terminal fraction of the brain natriuretic peptide (N-terminal pro b-type natriuretic peptide - NT-proBNP). Results: The mean distance walked on the 6MWT in the DDD and VVIR modes were 390.60 (± 52.71) and 396.30 (± 52.71) meters respectively (p = 0.160). Results of lower QOL were found, considering the physical domain of the MLHFQ (p = 0.03) and the domains of effort dyspnea (p = 0.05) and arrhythmia (p <0.001) of the AQUAREL with the VVIR mode. NT-proBNP levels increased significantly with stimulation in VVIR mode (p < 0.001). Conclusion: After three months of stimulation with the VVIR mode, there was worsening of the QoL of the chagasic patients and increase of the levels of NT-proBNP (clinical trial record: ReBEc RBR-53x476).

Is conventional cardiac pacing harmful in patients with normal ventricular function?

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).

One-year cardiac morphological and functional evolution following permanent pacemaker implantation in right ventricular septal position in chagasic patients

INTRODUCTION

The septal position is an alternative site for cardiac pacing (CP) that is potentially less harmful to cardiac function.

METHODS

Patients with Chagas disease without heart failure submitted to permanent pacemaker (PP) implantation at the Clinics Hospital of the Triângulo Mineiro Federal University (UFTM), were selected from February 2009 to February 2010. The parameters analyzed were ventricular remodeling, the degree of electromechanical dyssynchrony (DEM), exercise time and VO2 max during exercise testing (ET) and functional class (NYHA). Echocardiography was performed 24 to 48 h following implantation and after one year follow-up. The patients were submitted to ET one month postprocedure and at the end of one year.

RESULTS

Thirty patients were included. Patient mean age was 59 ± 13 years-old. Indication for PP implantation was complete atrioventricular (AV) block in 22 (73.3%) patients and 2nd degree AV block in the other eight (26.7%). All patients were in NYHA I and no changes occurred in the ET parameters. No variations were detected in echocardiographic remodeling measurements. Intraventricular dyssynchrony was observed in 46.6% of cases and interventricular dyssynchrony in 33.3% of patients after one year.

CONCLUSIONS

The findings of this work suggest that there is not significant morphological and functional cardiac change following pacemaker implantation in septal position in chagasic patients with normal left ventricular function after one year follow-up. Thus, patients may remain asymptomatic, presenting maintenance of functional capacity and no left ventricular remodeling.

A review of cardiopulmonary research in Brazilian medical journals: clinical, surgical and epidemiological data

Research in the field of cardiopulmonary disease in Brazil has been very active in recent decades. The combination of PUBMED, SCieLO, open access and online searching has provided a significant increase in the visibility of Brazilian journals. This newly acquired international visibility has in turn resulted in the appearance of more original research reports in the Brazilian scientific press. This review is intended to highlight part of this work for the benefit of the readers of "Clinics." We searched through PUBMED for noteworthy articles published in Brazilian medical journals included in the Journal of Citation Reports of the Institute of Scientific Information to better expose them to our readership. The following journals were examined: "Arquivos Brasileiros de Cardiologia," "Arquivos Brasileiros de Endocrinologia e Metabologia," "Brazilian Journal of Medical and Biological Reviews," "Jornal Brasileiro de Pneumologia," "Jornal de Pediatria," "Revista Brasileira de Cirurgia Cardiovascular," "Revista da Associação Médica Brasileira," Revista da Escola de Enfermagem U.S.P." and "São Paulo Medical Journal." These journals publish original investigations in the field of cardiopulmonary disease. The search produced 71 references, which are briefly examined.