the most common pattern of abnormal responses in symptomatic patients with or without mvp was ( 1 ) an increased heart rate and elevated plasma norepinephrine levels while supine and then while standing quietly for five minutes , ( 2 ) an exaggerated increase in heart rate during phase ii of valsalva , ( 3 ) a diminished bradycardic response during phase iv of valsalva , and ( 4 ) an exaggerated heart rate response to administration of isoproterenol .
C0428977
bradycardic
C0022245
isoproterenol