US Monetary Transmission Mechanism
From a presentation by Jonathan McCarthy of the NY Fed .back in March. Neither the Fed funds target nor the change of reserves directly impact aggregate demand.
McCarthy identifies six channels by which monetary policy changes can indirectly impact demand: interest rats, exchange rates, wealth effect, balance sheet, bank lending and portfolio balance.
ECB Monetary Policy Transmission Mechanism
And how the ECB understands the transmission mechanism of its monetary policy.
A compare and contrast essay of the two is stuff that a dissertation is made of. For our purposes here, note that the output for the ECB is price developments. For US monetary policy it is aggregate demand.
Many of the components and factors are indeed the same, though the Federal Reserve has a more significant role for policy communication and commitment.
Perhaps from another perspective, the US transmission mechanism is about what policy can do, while the ECB's transmission mechanism seems more to do with the limits of monetary policy.