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Observational Study
. 2015 Jul-Sep;30(3):311-5.
doi: 10.5935/1678-9741.20150035.

Chronotropic incompetence in Chagas disease: effectiveness of blended sensor (volume/minute and accelerometer)

Antonio da Silva Menezes Junior  1 , Aline Pereira da Silva  1 , Giovana Gurian Batista Profahl  1 , Catarine Ottobeli  1 , Jutay Fernando Silva Louzeiro  1
Affiliations
Observational Study

Chronotropic incompetence in Chagas disease: effectiveness of blended sensor (volume/minute and accelerometer)

Antonio da Silva Menezes Junior et al. Rev Bras Cir Cardiovasc. 2015 Jul-Sep.

Abstract
in English, Portuguese

Introduction: Technological progress of pacemakers has allowed the association of two or more sensors in one heart rate system response. The accelerometer sensor measures the intensity of the activity; it has a relatively rapid response to the beginning of it, however, it may present insufficient response to less strenuous or of less impact exercise. The minute ventilation sensor changes the pacing rate in response to changes in respiratory frequency in relation to tidal volume, allowing responses to situations of emotional stress and low impact exercises.

Objective: To evaluate the cardiorespiratory response of the accelerometer with respect to the blended sensor (BS=accelerometer sensor+minute ventilation sensor) to exercise in chagasic patients undergoing cardiopulmonary exercise test.

Methods: This was a prospective, observational, randomized, cross-sectional study. Patients who met the inclusion criteria were selected. The maximum heart rate of the sensor was programmed by age (220-age). The results were analyzed through t test with paired samples (P<0.05).

Results: Sample was comprised of 44 patients, with a mean age of 66±10.4 years, 58% were female, 54% as first implant, in 74% were functional class I and 26% were functional class II, left ventricular ejection fraction was 58±7. As for the cardiopulmonary test, maximum expected heart rate and VO2 were not achieved in both the accelerometer sensor and the blended sensor, however, metabolic equivalent in the blended sensor was higher than the expected, all data with P<0.001.

Conclusion: Even though the maximal heart rate was not reached, the blended sensor provided a physiological electrical sequence when compared to the accelerometer sensor, providing better physical fitness test in cardiopulmonary hemodynamics and greater efficiency.

Introdução: O progresso tecnológico dos marca passos permitiu a associação de dois ou mais sensores em um único sistema de resposta de frequência cardíaca. O sensor acelerômetro afere a intensidade da atividade, possui uma resposta relativamente rápida ao início da mesma, porém pode apresentar respostas insuficientes a exercícios físicos menos intensos ou de menor impacto. O sensor volume-minuto altera a taxa de estimulação cardíaca em resposta à variação da frequência respiratória quanto ao volume corrente, permitindo, assim, respostas a situações de estresse emocional e exercícios de baixo impacto.

Objetivo: Avaliar a resposta cardiorrespiratória do acelerômetro em relação ao duplo sensor ao exercício em pacientes chagásicos submetidos ao teste ergoespirométrico.

Métodos: Pesquisa prospectiva, observacional, randomizada e cruzada. Foram selecionados pacientes que preenchiam os critérios de inclusão. A frequência cardíaca máxima do sensor foi programada por idade (220-idade). Os resultados obtidos foram analisados pelo Teste T com amostras pareadas (P<0,05).

Resultados: Amostra de 44 pacientes, com idade média de 66±10,4, com 58% do sexo feminino, 54% como primeiro implante, classe funcional I em 74% e II em 26%, fração de ejeção do ventrículo esquerdo de 58±7. Quanto ao ergoespirométrico, a frequência cardíaca máxima prevista e a VO2 máxima prevista não foram atingidas tanto no sensor acelerômetro quanto no sensor volume-minuto, contudo, o equivalente metabólico no sensor volume- minuto foi superior à prevista, todos os dados com P<0,001.

Conclusão: Apesar da frequência cardíaca máxima não ter sido atingida, o duplo sensor proporcionou uma sequência elétrica mais fisiológica quando comparado ao sensor acelerômetro.

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Figures

Fig. 1
Fig. 1
Averages obtained in the erogoespirometry test. ACCEL=Accelerometer; MET=Metabolic equivalent; DS=Double Sensor
Fig. 2
Fig. 2
Maximal Heart Rate and standard deviation (in bpm) obtained in the ergoespirometry test.
Fig. 3
Fig. 3
VO2 max: value in the ergoespirometry test in the different groups (average and standard deviation).
Fig. 4
Fig. 4
Average and standard deviation of metabolic equivalent in the different groups.
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