Vritti is our thoughts and feelings, Samskaras are the latent impressions which are created by our thoughts and feelings. These latent impressions then give rise to thoughts and feelings which we can view as sometimes being positive and sometimes negative.This was described to me quite beautifully with the example of chocolate cake. We eat a chocolate cake and it’s delicious! This leave a latent impression (samskara) so the next time we see a chocolate cake we automatically desire it because of the delicious latent impression.
This is all fine and well but you may have health problems which make chocolate cake a bad thing though your latent impressions are so strong you cannot stop eating it so when thoughts and feelings around chocolate cake arise we can use yogic techniques such as pranayama, meditation or asana to break this Vritti-Samskara chakra (wheel or cycle).
Chocolate cake is maybe a light hearted example (unless you’re struggling with weight or diabetes) but replace the chocolate cake with insomnia, stress, self harm, drugs/alcohol, violent thoughts or actions and you can see the importance of interrupting this cycle.