BACKGROUND:Exercise performance in heart-transplanted patients increases with respect to pre-transplantation but remains subnormal, and it does not improve with time after surgery. Possible causes include persisting denervation, and sympathetic vasoconstriction inducing functional vascular abnormalities that prevent adequate increase in blood flow to the exercising limbs. We tested the effects of physical training on baroreceptors-mediated control of heart rate and blood pressure in recently heart-transplanted subjects. METHODS: Patients were randomly allocated to physical training (n=13, 30 min cycling at 60-70% of peak oxygen consumption for 5 days/week for 6 months) or to control (n=11). Upright exercise test to exhaustion was performed at the beginning of the study after 3 and 6 months. Reflex changes in RR interval and blood pressure in response to sinusoidal neck suction (6 and 12 cycles/min 0 to -30 mm Hg swing) were considered as evidence of reinnervation and baroreflex control of blood pressure, respectively. RESULTS: After 6 months peak oxygen consumption (p<0.001), exercise time (p<0.01) and workload (p<0.01) increased in trained patients. Before training RR interval and blood pressure were not modified by neck suction. After physical training systolic (p<0.01) and diastolic blood pressure decreased, RR interval and blood pressure could be modulated (p<0.05) by slow (6 cycles/min) neck suction, indicating initial cardiac sympathetic reinnervation and restored sensitivity to autonomic modulation on the arteries. No changes were observed in controls. CONCLUSIONS:Physical training improved exercise performance and the control exerted by the autonomic nervous system through the sympathetic nerves at both cardiac and vascular level.
RCT Entities:
BACKGROUND: Exercise performance in heart-transplanted patients increases with respect to pre-transplantation but remains subnormal, and it does not improve with time after surgery. Possible causes include persisting denervation, and sympathetic vasoconstriction inducing functional vascular abnormalities that prevent adequate increase in blood flow to the exercising limbs. We tested the effects of physical training on baroreceptors-mediated control of heart rate and blood pressure in recently heart-transplanted subjects. METHODS:Patients were randomly allocated to physical training (n=13, 30 min cycling at 60-70% of peak oxygen consumption for 5 days/week for 6 months) or to control (n=11). Upright exercise test to exhaustion was performed at the beginning of the study after 3 and 6 months. Reflex changes in RR interval and blood pressure in response to sinusoidal neck suction (6 and 12 cycles/min 0 to -30 mm Hg swing) were considered as evidence of reinnervation and baroreflex control of blood pressure, respectively. RESULTS: After 6 months peak oxygen consumption (p<0.001), exercise time (p<0.01) and workload (p<0.01) increased in trained patients. Before training RR interval and blood pressure were not modified by neck suction. After physical training systolic (p<0.01) and diastolic blood pressure decreased, RR interval and blood pressure could be modulated (p<0.05) by slow (6 cycles/min) neck suction, indicating initial cardiac sympathetic reinnervation and restored sensitivity to autonomic modulation on the arteries. No changes were observed in controls. CONCLUSIONS: Physical training improved exercise performance and the control exerted by the autonomic nervous system through the sympathetic nerves at both cardiac and vascular level.
Authors: Justin M Bachmann; Ashish S Shah; Meredith S Duncan; Robert A Greevy; Amy J Graves; Shenghua Ni; Henry H Ooi; Thomas J Wang; Randal J Thomas; Mary A Whooley; Matthew S Freiberg Journal: J Heart Lung Transplant Date: 2017-05-23 Impact factor: 10.247
Authors: George E Billman; Kristen L Cagnoli; Thomas Csepe; Ning Li; Patrick Wright; Peter J Mohler; Vadim V Fedorov Journal: J Appl Physiol (1985) Date: 2015-03-06
Authors: Lindsey Anderson; Tricia T Nguyen; Christian H Dall; Laura Burgess; Charlene Bridges; Rod S Taylor Journal: Cochrane Database Syst Rev Date: 2017-04-04
Authors: Morcos Awad; Lawrence S C Czer; Margaret Hou; Sarah S Golshani; Michael Goltche; Michele De Robertis; Michelle Kittleson; Jignesh Patel; Babak Azarbal; Evan Kransdorf; Fardad Esmailian; Alfredo Trento; Jon A Kobashigawa Journal: J Am Heart Assoc Date: 2016-11-01 Impact factor: 5.501