CMP 2 Exam 1

0.12s (3 small boxes) what is normal QRS complex duration men = 0.44s (440ms) women = 0.46s (460ms) what is the normal QTc interval atrial = 60-80/min AV junction= 60-40/min Ventricular = 20-40/min what are the rates of atrial foci, AV junction, and ventricular foci as secondary pacers? count number of large boxes between 2 successive R waves and divide this number into 300 300,150,100,75,60,50,43,37 can only be used for regular rhythms!! how do you use the rule of 300 count and multiply by 6 can be used for irregularly irregular need a rhythm strip!! counting QRS complexes 0-90 degrees lead I and AVF are both POSITIVE deflections normal axis +90 - + 180 AVF positive by lead I is negative right axis deviation -90 - +180 both AVF and lead I are NEGATIVE extreme right axis deviation 0- -90 lead I is positive, AVF is negative left axis deviation - RVH - MI (anterior or lateral) - left posterior fasicular block - ventricular ectopy - pulmonary disease (PE, PH, COPD) - dextrocardia - lead reversal - pre- excitation - vertical heart - tall thin patient - hyperkalemia - newborns Right axis deviation ddx - LVH - MI (right sided or inferior) - left anterior fasicular block - pre-excitation - left bundle branch block - horizontal heart - pregnancy - ascites - hyperkalemia left axis deviation DDX rate is 60-100 rhythm is regular P wave present and similar in appearance (up in lead I, II, AVF, inverted in AVR) P wave with every QRS QRSs look the same Equal time between QRS complexes sinus rhythm is present if rate varies with inspiration (increases) and expiration (decreases) makes the rhythm look irregular -- so keep in DDX list for that sinus arrhythmia the signal coming from somewhere other than the SA node (the AV junction or ventricles, or irritable foci w a-fib) absence of p waves can indicate PAC s PJC s PVC s what are the 3 types of premature beats premature atrial contraction