Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
Med Biol Eng Comput. 2021 Nov;59(11-12):2373-2382. doi: 10.1007/s11517-021-02441-8. Epub 2021 Oct 9.
An approach recently proposed to assess ultra-rapid patterns of heart rate variability, namely heart rate fragmentation (HRF), is increased in aging and coronary disease. We aimed to evaluate and to correlate HRF with cardiac functional parameters in a rat model of myocardial infarction (MI). Wistar rats were submitted to MI (n = 18) or sham operation (n = 20), and after 4 or 12 weeks, their arterial pressure was recorded. Subsequently, cardiac function was evaluated by echocardiography. From pulse interval series, HRF patterns with zero, one, two, or three inflection points were estimated, as well as the total percentage of inflection points (PIP). Cardiac function was reduced in MI rats. Ejection fraction was smaller 4 (28 ± 3 vs 68 ± 2%, p < 0.0001) and 12 weeks after MI (38 ± 3 vs 70 ± 3%, p < 0.0001). Fractional shortening was also smaller 4 (13 ± 2 vs 41 ± 2%, p < 0.0001) and 12 weeks after MI (20 ± 2 vs 41 ± 3%, p < 0.0001). PIP was increased in MI rats 4 (74 ± 2 vs 69 ± 1%, p = 0.03) and 12 weeks after surgery (70 ± 2 vs 63 ± 1%, p = 0.02). We found a significant negative correlation between cardiac functional parameters and HRF at both 4 and 12 weeks after MI. These findings reveal that MI increases HRF, reinforcing the importance of this approach to explore pathophysiological conditions. Evaluation of heart rate fragmentation (HRF) in a rat model of myocardial infarction (MI). Wistar rats were submitted to MI (n = 18) or sham operation (n = 20), and after 4 or 12 weeks, their arterial pressure was recorded. Cardiac function was evaluated by echocardiography. From pulse interval series, HRF patterns with zero (W0), one (W1), two (W3), or three (W3) inflection points were estimated, as well as the total percentage of inflection points (PIP). Cardiac function was reduced, while PIP was increased in all MI rats. Fluent patterns (W0 and W1) decreased in MI rats after 12 weeks. Altogether, the findings reveal that MI increases HRF, reinforcing the potential of this approach to explore pathophysiological conditions.
评估心率变异性超快模式（即心率碎片化，HRF）的一种新方法在衰老和冠心病中更为常见。我们旨在评估 HRF 在心肌梗死（MI）大鼠模型中的心脏功能参数，并进行相关性分析。Wistar 大鼠接受 MI（n = 18）或假手术（n = 20），4 或 12 周后记录其动脉压。随后，通过超声心动图评估心功能。从脉搏间隔序列中，评估具有零、一、二或三个拐点的 HRF 模式，以及拐点总数（PIP）。MI 大鼠的心功能降低。射血分数在 MI 后 4 周时更小（28 ± 3%比 68 ± 2%，p < 0.0001），在 12 周时更小（38 ± 3%比 70 ± 3%，p < 0.0001）。短轴缩短率在 MI 后 4 周时也更小（13 ± 2%比 41 ± 2%，p < 0.0001），在 12 周时更小（20 ± 2%比 41 ± 3%，p < 0.0001）。MI 大鼠在 MI 后 4 周时 PIP 更高（74 ± 2%比 69 ± 1%，p = 0.03），在 12 周时更高（70 ± 2%比 63 ± 1%，p = 0.02）。我们发现 MI 后 4 周和 12 周时心脏功能参数与 HRF 呈显著负相关。这些发现表明 MI 增加了 HRF，从而增强了这种方法探索病理生理条件的重要性。在心肌梗死（MI）大鼠模型中评估心率碎片化（HRF）。Wistar 大鼠接受 MI（n = 18）或假手术（n = 20），4 或 12 周后记录其动脉压。通过超声心动图评估心功能。从脉搏间隔序列中，评估具有零（W0）、一（W1）、二（W3）或三个拐点（W3）的 HRF 模式，以及拐点总数（PIP）。MI 大鼠的心脏功能降低，而 PIP 则在所有 MI 大鼠中增加。MI 后 12 周，MI 大鼠的流畅模式（W0 和 W1）减少。总之，这些发现表明 MI 增加了 HRF，从而增强了这种方法探索病理生理条件的潜力。
