I have never taken Zoloft so I can't answer that question directly. In addition to the Zoloft, you may want to consider other possibilites for an increased heart rate. For example, do you deal with anxiety issues or panic? Have you recently started the Zoloft? Are there any other medications you take? Just some things to think about. When you start to experience a new symptom or side effect it is helpful to look at everything involved and not narrow in on one aspect.