I'm having my second TCH (Taxotere, cyclophosphamide and Herceptin) tomorrow. I had a MUGA heart scan a week before my first chemo. I am also a bit worried about heart problems on herceptin but you will continue to have your heart monitored throughout treatment and can have a break if necessary. Are you having herceptin injections or IV? I have my herceptin by injection at the same appointment as my chemo. The injection stings slightly as they put it in quite slowly but only for a few mins.