TY - JOUR
T1 - Effects of midodrine on exercise-induced hypotension and blood pressure recovery in autonomic failure
AU - Schrage, William G.
AU - Eisenach, John H.
AU - Dinenno, Frank A.
AU - Roberts, Shelly K.
AU - Johnson, Christopher P.
AU - Sandroni, Paola
AU - Low, Philip A.
AU - Joyner, Michael J.
PY - 2004/11
Y1 - 2004/11
N2 - We tested the hypothesis that the oral α1-adrenergic agonist, midodrine, would limit the fall in arterial pressure observed during exercise in patients with pure autonomie failure (PAF). Fourteen subjects with PAF underwent a stand test, incremental supine cycling exercise (25, 50, and 75 W), and ischemic calf exercise, before (control) and 1 h after ingesting 10 mg midodrine. Heart rate (ECG), beat-to-beat blood pressure (MAP, arterial catheter), cardiac output (Q̇, open-circuit acetylene breathing), forearm blood flow (FBF, Doppler ultrasound), and calf blood flow (CBF, venous occlusion plethysmography) were measured. The fall in MAP after standing for 2 min was similar (∼60 mmHg; P = 0.62). Supine MAP immediately before cycling was greater after midodrine (124 ± 6 vs 117 ± 6 mmHg; P < 0.03), but cycling caused a workload-dependent hypotension (P < 0.001), whereas increases in Q̇ were modest but similar. Midodrine increased MAP and total peripheral resistance (TPR) during exercise (P < 0.04), but the exercise-induced fall in MAP and TPR were similar during control and midodrine (P = 0.27 and 0.14). FBF during cycling was not significantly reduced by midodrine (P > 0.2). By contrast, recovery of MAP after cycling was faster (P < 0.04) after midodrine (∼25 mmHg higher after 5 min). Ischemic calf exercise evoked similar peak CBF in both trials, but midodrine reduced the hyperemic response over 5 min of recovery (P < 0.02). We conclude midodrine improves blood pressure and TPR during exercise and dramatically improves the recovery of MAP after exercise.
AB - We tested the hypothesis that the oral α1-adrenergic agonist, midodrine, would limit the fall in arterial pressure observed during exercise in patients with pure autonomie failure (PAF). Fourteen subjects with PAF underwent a stand test, incremental supine cycling exercise (25, 50, and 75 W), and ischemic calf exercise, before (control) and 1 h after ingesting 10 mg midodrine. Heart rate (ECG), beat-to-beat blood pressure (MAP, arterial catheter), cardiac output (Q̇, open-circuit acetylene breathing), forearm blood flow (FBF, Doppler ultrasound), and calf blood flow (CBF, venous occlusion plethysmography) were measured. The fall in MAP after standing for 2 min was similar (∼60 mmHg; P = 0.62). Supine MAP immediately before cycling was greater after midodrine (124 ± 6 vs 117 ± 6 mmHg; P < 0.03), but cycling caused a workload-dependent hypotension (P < 0.001), whereas increases in Q̇ were modest but similar. Midodrine increased MAP and total peripheral resistance (TPR) during exercise (P < 0.04), but the exercise-induced fall in MAP and TPR were similar during control and midodrine (P = 0.27 and 0.14). FBF during cycling was not significantly reduced by midodrine (P > 0.2). By contrast, recovery of MAP after cycling was faster (P < 0.04) after midodrine (∼25 mmHg higher after 5 min). Ischemic calf exercise evoked similar peak CBF in both trials, but midodrine reduced the hyperemic response over 5 min of recovery (P < 0.02). We conclude midodrine improves blood pressure and TPR during exercise and dramatically improves the recovery of MAP after exercise.
KW - Calf blood flow
KW - Cardiac output
KW - Forearm blood flow
KW - Supine bicycle
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U2 - 10.1152/japplphysiol.00547.2004
DO - 10.1152/japplphysiol.00547.2004
M3 - Article
C2 - 15273244
AN - SCOPUS:7044229627
SN - 8750-7587
VL - 97
SP - 1978
EP - 1984
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 5
ER -