1) Ventricular rate ~181/min (Measure R-R Cycle length is 660 ms. Divide this by 2, because the paper speed is 50 mm/sec, i.e. 340 ms. 60/0.34 = 176/min).
2) Atrial rate ~363/min (Cycle length measured is 320 ms. Correcting for paper speed, i.e 160 ms. 60/0.16 = 363/min).
3) Diagnosis: Atrial flutter with 2:1 conduction
4) Treatment: Because the patient is somewhat unstable, synchronized DC cardioversion. May follow with a medication (probably Amiodarone) to prevent recurrence at least until patient improves hemodynamics and out of ICU.
Arrows indicate the waves recognizable as P wave. I have put arrows close together in the middle only. The presumption is one P wave hiding inside each QRS; thus preventing us from recognizing the rhythm.
When it is a 2:1 conduction, recognition alternate P waves may be difficult. A spontaneous break in the QRSs will helpful in recognizing the rhythm. 2:1 conduction with HR in 170s need not always cause hemodynamic instability because there is 2:1 conduction with apparent A-V synchrony though only in every 2nd P wave. But, this patient is slowly deteriorating. Therefore, treating this will be necessary – esp. in postoperative period.
