zoloft

I have been diagnosed with Parox Ventric Tachycard and have had  icd for 12 years.im also diagnosed with depression and anxiety which i take 100 mg zoloft once a day for. I also take  various antiarrythmia drugs which seem to be working well for the time being.My heart rate has been going to 90-100 bpm  off and on at rest  for  several weeks . my rate with cardiac meds has been 50-60  at rest for over a year .Ive taken the zoloft 100 mg for 14 months, Do you think if i cut this back to 50 mg daily that this may help my high, irregular rate? My prescriber for the zoloft is retired so i am between Drs. on this. Any suggestions will be much appriciated .i need to get this irregular rate under control,so if i have problems concerning the zoloft dosage i can deal with it then,the irregular rate is my main concern because if it continues,idont need it getting high enough for my device to have to fire .which is my main concern  Thank you for your  time and advice Dr.