Portable handheld ecg monitor?

i have Omron Portable ECG EKG Handheld HCG-801 Monitor. Is it accurate or the same like in the hospital or holter monitor, i mean the ecg strip result no the machine? I usually use it when i feel something wrong with my heart and then print it out and bring it to the doctor. I was just wondering if it can detect every single wrong thing and doctor can read it. (i have heart rhythm problem)