Hercepton starts with paclitaxol usually and is given 3 weekly for 17 cycles. You will be monitored for side effects including either an echo cardiogram or a muga scan (or also known as gated blood pool scan)...usually 3 monthly initially and before treatment starts.
Once you've finished the chemo part you will have much less side effects. I just had a bit of tiredness the week of treatment but thst was all. I needed mine stopped early due to issues that was picked up with the monitoring. But I have made full recovery since.