[IN LOWER STRIP,ADD ARROWS SHOWING THE INTERVAL (1.72 SECONDS) SURROUNDING THE VPB.
The ECG strips displayed here were recorded on successive days from a 73 year old male with severe ventricular dysfunction. The PP (and RR) intervals in both are similar (0.88 seconds (rate of 68), in the upper strip, and 0.86 seconds (rate of 71), in the lower). In the upper strip, there is a ventricular premature beat which hides the sinus P wave. The interval between the QRS complexes that precede and follow the premature beat is 1.76 seconds, twice the sinus RR interval of 0.88 seconds.
In the lower strip, there is a pause of 1.72 seconds during which there is a non-conducted sinus P wave. The duration of this pause is twice the sinus RR interval, which in this strip is 0.86 seconds. A ventricular premature beat occurs after the sinus best that terminates the pause and the interval between the QRS complexes that precede and follow this premature beat is also 1.72 seconds. This ECG strip is discussed on the next page