hudanimations_tf.txt (copy/paste into the relevant parts)

//Health Bonus Pulse
event HudHealthBonusPulse
{
 Animate HPFrameBuff      Alpha       "255"           Accel 0.0 0.0
}

event HudHealthBonusPulseStop
{
 StopEvent HPFrameLow 0.0


 Animate HPFrameBuff      Alpha       "0"           Accel 0.0 0.0
}

//Health Dying Pulse
event HudHealthDyingPulse
{
 Animate HPFrameLow      Alpha       "255"           Accel 0.0 0.0
}

event HudHealthDyingPulseStop
{
 StopEvent HPFrameLow 0.0


 Animate HPFrameLow      Alpha       "0"           Accel 0.0 0.0
{