I .Sinus Rhythms and Sinus Arrhythmias. 1. ECG of Sinus Rhythms Sinus rhythm must originate in the sino-atrial node. 1) .Regularly recurring sequences of P waves, QRS complexes,and T waves.P-P or R-R interval establishes a specific interval which should not vary more than 0.12 second.
(1) 1) .2) .3)and 4)
(2) P-P or R-R interval varies in duration by at least 0.12 second
1).There are no P waves in ECG 2).Presence of saw-tooth flutter wave.3).F waves always uniform in size ,shape and frequency.4).Regular atrial rhythm with a rate of 250-3505).Ventricular response of 1:1,2:1,3:1,4:1,or higher.6).Absence of isoelectric line.
1).Absence of P waves2).P waves replaced by f waves.3).f waves : irregular in size ,shape ,and spacing. Rate between 350 and 6004). Irregularly irregular ventricular rhythm, best seen in Ⅱ,Ⅲ,Avf,V1 or V2.
independent of one another .2).There is no P-R to QRS relationship.3).The atrial rate is more rapid than the ventricular rate.4).regular P-P interval .5).rugular R-R interval
1).QRS 0.12 sec or wider2).Rsr’(M)pattern in V1 and V2 and deep ,wide S wave in Ⅰ,V5-6.3).The ST segment is slight depressure with negative T wavesWhen incomplete RBBB is present ,the pattern is similar, but the QRS width is less than 0.12sec.