EVIDENCE FOR AN INTRINSIC MECHANISM REGULATING HEART-RATE-VARIABILITY IN THE TRANSPLANTED AND THE INTACT HEART DURING SUBMAXIMAL DYNAMIC EXERCISE
EVIDENCE FOR AN INTRINSIC MECHANISM REGULATING HEART-RATE-VARIABILITY IN THE TRANSPLANTED AND THE INTACT HEART DURING SUBMAXIMAL DYNAMIC EXERCISE
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DOI：
10.1093/cvr/24.12.969
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发表时间：
1990-12-01
影响因子：
10.8
通讯作者：
RICCIARDI, L
中科院分区：
文献类型：
--
作者：
BERNARDI, L;SALVUCCI, F;RICCIARDI, L
研究目的-的目的是评估交感迷走神经平衡的变化，发生与exercise.Design -RR间期波动（低频[LF]和高频成分[HF]的功率谱测定之前，期间和之后分级的工作负荷运动的自行车测力计。还评价了呼吸信号的功率谱、氧消耗量和呼吸量。在所有受试者中，HF被认为是呼吸性窦性心律失常的指标。在正常受试者中，HF和LF分别被认为是相对迷走神经和交感神经活动的指标，而在心脏移植受试者中，HF被认为是固有心率的呼吸调节，并且不依赖于自主神经张力。心率变异性被评价为RR间期方差。测量和主要结果-在运动的第一部分，心率增加，RR间期方差减少，HF减少，LF的相对量在久坐和运动受试者中均增加，表明交感神经张力相对增加。而接近运动峰值时，心率进一步增加，方差略有下降，LF的相对比例下降，HF的相对比例增加。在运动高峰期，HF占运动受试者心率变异性的99.9%，占久坐受试者心率变异性的88.9%（两组的基线和LF均为p < 0.001）。在心脏移植受试者中，从运动开始，方差和HF均增加（p < 0.05），并显示与解释变量正相关，与心率负相关（r = 0.794，p < 0.001，多元回归分析）。在这些受试者中无法获得可测量的LF成分。在恢复过程中，虽然心率下降，RR间期方差增加，但正常受试者（久坐或运动）的LF相对增加，HF相对减少。同样，在心脏移植受试者中，HF恢复率降低。因此，正常受试者在运动高峰时HF的增加与所有其他数据形成对比，这些数据表明在整个运动和早期恢复期间交感神经紧张的流行，但似乎与心脏移植受试者中观察到的HF增加相似，这是由于运动期间通气增加的影响。可能是心肌固有的，可以确定与完整的以及去神经支配的人心脏中的通气同步的心率波动。
Study objective - The aim was to assess the changes in sympatho-vagal balance which occur with exercise.Design - The power spectrum of RR interval fluctuations (low frequency [LF] and high frequency components [HF] was determined before, during, and after graded work load exercise on a cycle ergometer. The power spectrum of the respiratory signal, oxygen consumption, and respiratory volumes were also evaluated. In all subjects HF was considered to be an index of respiratory sinus arrhythmia. In normal subjects HF and LF were considered to be indices of relative vagal and sympathetic activity, respectively, whereas in heart transplant subjects HF was considered as a respiratory modulation of the intrinsic heart rate, and not dependent on autonomic tone. Heart rate variability was evaluated as RR interval variance.Subjects - 15 normal subjects (six trained cyclists and nine healthy sedentary subjects) and six orthotopic heart transplant recipients took part in the study.Measurements and main results - During the first part of exercise, heart rate increased, RR interval variance decreased, HF decreased, and the relative amount of LF increased both in sedentary and athletic subjects, suggesting a relative increase in sympathetic tone. However, when approaching peak exercise, while heart rate further increased and the variance slightly decreased, the relative proportion of LF decreased and HF proportionally increased. At peak exercise HF accounted for 99.9% of heart rate variability in athletic subjects and for 88.9% in sedentary subjects (p < 0.001 upsilon-baseline and upsilon-LF in both groups). In heart transplant subjects both the variance and the HF increased from the beginning of exercise (p < 0.05), and showed a direct correlation with ventilatory variables and an inverse correlation with heart rate (r = 0.794, p < 0.001, multiple regression analysis). No measurable LF components could be obtained in these subjects. During recovery, while the heart rate decreased and the RR interval variance increased, there was a relative increase in LF and a relative decrease in HF in normal subjects (either sedentary or athletic). Similarly, in heart transplant subjects, there was a decrease in HF recovery. Thus the increase in HF at peak exercise in normal subjects contrasts with all the other data which suggest a prevalence in sympathetic tone during the entire exercise and the early recovery period, but appears similar to the increase in HF observed in heart transplant subjects due to the effect of increased ventilation during exercise.Conclusions - These findings suggest that at peak exercise a non-autonomic mechanism, possibly intrinsic to the heart muscle, may determine heart rate fluctuations in synchrony with ventilation in the intact as well as in the denervated human heart.