<prompt> A 30-year-old man presents with recurrent attacks of feeling dizzy. ECG was done. What is the diagnosis?Atrial fibrillationPSVTMobitz I hea blockComplete hea block  <response>: HR is regularly irregular due to change in rhythm. Axis is normal. Progressive lengthening of PR interval followed by dropped beat is seen. PR interval before the dropped beat is more than PR interval in subsequent beats. Dx: Mobitz I hea block. 