Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Faculty of Medicine, University of Oslo, Oslo, Norway.
Transplantation. 2021 Sep 1;105(9):2086-2096. doi: 10.1097/TP.0000000000003580.
Heart transplantation (HTx) surgically transects all connections to the heart, including the autonomic nerves. We prospectively examined signs, timing and consequences of early sympathetic and parasympathetic sinoatrial reinnervation, as well as explored indirect evidence of afferent cardiopulmonary reinnervation.
Fifty HTx recipients were assessed at 2.5, 6, and 12 mo after HTx. For comparison, 50 healthy controls were examined once. Continuous, noninvasive recordings of hemodynamic variables and heart rate variability indices were performed at supine rest, 0.2 Hz controlled breathing, 60° head-up-tilt, during the Valsalva maneuver and during handgrip isometric exercise.
In HTx recipients, supine low-frequency heart rate variability gradually increased; supine high-frequency variability did not change; heart rate variability indices during controlled breathing remained unaltered; heart rate responses during tilt and isometric exercise gradually increased; the tachycardia response during Valsalva maneuver increased, while the bradycardia response remained unchanged; and indices of baroreflex sensitivity improved. Responses remained low compared to healthy controls. A negative correlation between indices of preload and heart rate response during head-up tilt emerged at 12 mo.
Results suggest that sympathetic reinnervation of the sinoatrial node starts within 6 mo after HTx and strengthens during the first year. No evidence of early parasympathetic reinnervation was found. Indirect signs of afferent reinnervation of cardiopulmonary low-pressure baroreceptors emerged at 12 mo. Better sympathetic sinoatrial control improved heart rate responsiveness to orthostatic challenge and isometric exercise, as well as heart rate buffering of blood pressure fluctuations.
心脏移植（HTx）手术切断了与心脏的所有连接，包括自主神经。我们前瞻性地检查了早期交感神经和副交感神经窦房结再神经支配的迹象、时间和后果，以及探索了传入心肺再神经支配的间接证据。
50 例 HTx 受者在 HTx 后 2.5、6 和 12 个月进行评估。为了比较，50 例健康对照者仅检查一次。在仰卧位休息、0.2Hz 控制呼吸、60°头高位倾斜、瓦尔萨尔瓦动作和握力等长运动期间，对血流动力学变量和心率变异性指数进行连续、非侵入性记录。
在 HTx 受者中，仰卧位低频心率变异性逐渐增加；仰卧位高频变异性无变化；控制呼吸期间的心率变异性指数保持不变；倾斜和等长运动期间的心率反应逐渐增加；瓦尔萨尔瓦动作期间的心动过速反应增加，而心动过缓反应保持不变；压力反射敏感性指数改善。与健康对照组相比，这些反应仍然较低。12 个月时，仰卧位前负荷指数与头高位倾斜时心率反应之间出现负相关。
结果表明，窦房结的交感神经再支配在 HTx 后 6 个月内开始，并在第一年加强。没有发现早期副交感神经再支配的证据。12 个月时出现心肺低压压力感受器传入再神经支配的间接迹象。更好的交感神经窦房控制改善了对直立挑战和等长运动的心率反应性，以及血压波动的心率缓冲。
