I have twice have echo stress tests, and
the first time, right after the test my heart
rate dropped rapidly, but irregularly. I was given holter monitor, but nothing meaningful produced. Some arrythmia, but I guess not abnormal. Now, about 18 months later, I'm having still similar problems, but worse. I also seldom get a good night's sleep - wake frequently, sometimes cannot breathe. I have had sleep study, and no results. I am thin, so not likely to be sleep apnea, but I wonder.