Which is a better anti depressant drug to treat panic attacks, anxiety and depression. Lexapro (escitalopram) or zoloft?

Both Potentially. Lexapro (escitalopram) and zoloft are similar medications and have both been shown to be helpful for panic, anxiety, and depression. There is probably a decreased percentage of side effects with lexapro (escitalopram), (escitalopram) so it might be preferable for that reason. However, plenty of people do well with either medicine, and I have had some patients do well with zoloft after not getting benefit with lexapro (escitalopram).
Panic Tx. All ssris are first line tx for panic/depression, the difference is in tolerability & individual variations, so there really is no 1 best med.
SSRI or SNRI. If you asked 10 doc's, you'd probably get 10 different answers. Any ssri, like zoloft or Lexapro would be good options. I personally choose Paxil tapering up to 40 mg or more or (snri) Effexor (venlafaxine) xr 150 mg to max of 300 mg. They have tended to work best for severe anxiety, but they are not always tolerated well because of nausea, sedation, BP or weight gain. Get a good detail from your practioner.
Nortriptyline. My drug of choice for panic attacks is called nortriptyline. It is an older medication. Many physicians who received their training after the first ssri-prozac came out in the late 80s, are not as comfortable or as familiar with prescribing it. I have used it extensively. It, like all medications, is not for everyone and it does have side-effects. It is usually well tolerated at 25 mgs at bedtime.