Hello and thank you for using HCM. I carefully read your question and i totally understand your concern. But you should not worry. These premature beats have to do with some electrical issues in the heart. Some electrical impulses that generate in a part of the heart different from normal sinusal rhythm cause a premature heart contraction that you feel like a skipped beat, because its not a normal one. This extra-sistolik beats generally are followed by a pause till the next normal heart contraction. If this are not frequent, in Young and normal heart, it is nothing to worry about. There are different factors that might cause this skipped beats like emotional stress, excessive coffee consumption , coca-cola or energy drinks, so you have to avoid them. As you explain you have experienced this premature beats even before taking Zoloft. So my opinion is that Zoloft is not the cause of your palpitations. In general it helps to treat anxiety problems that do cause extra-systolic beats. Only in a small category of people zoloft might have a side effect to increase heart beats, but it is not your case, as it has happen before. Pathology like anemia or hyperthyroidism might be other causes of premature contractions. So, if I was your treating doctor i would say that you have nothing to worry if this happen once a wile, its normal. But if they begin to bother you and interfere in your live we can decide to do some examinations like a blood analyze, your thyroid hormones, an electrocardiogram, echo-cardiography and of course a holter rhythm monitoring to have a full view of your rhythm and the extra-sistolik beat frequencies. Only than we can decide what we should do and if it is necessary to stop zoloft. Hope I was helpful. Best regards.