How to find the rhythm of the attack?

In TW1, I remember, I could somehow time my attacks so that when the blows had a certain rhythm the following hits were more and more devastating.

Is there a method of timing my sword attacks, so that I can reach a deadly combo?

As far as I can tell, there is no timing or rhythm to the attacks in The Witcher 2. There are a couple of skills in your Swordsmanship skill tree (under Character Abilities) that will give you similar qualities to TW1's rhythm system:

Whirl - Unlocks the ability to do damage to many foes. There are two levels. The first allows the other opponents to take 50% of the damage dealt. The second allows for 100% of the damage to be dealt.

Combat Acumen - Unlocks group finishers. This will allow you to deal some pretty hefty damage to a large group of attackers.