I am 48 years and have been suffering from an anxiety disorder since I was 19, I am on zoloft and xanax. Recently I have started having heart palpatations of 215 that last for 15 minutes. This has only happened twice and they were 3 months apart. My cardiologist has put me on cardizem la 120 mg to see if that will keep my heart rate from becoming too high. I have had a heart cath, stress test, echocardiogram and every test that can be done has. Are my palpations of 215 coming from my anxiety disorder? What do I need to do if I have another attack?