Answer 37

37.   Choice D is the correct answer.  Second Degree Type I AV Block also known as Mobitz Type I or Wenckebach is characterized by increasing PR interval (>0.2 millisec) and the QRS complex eventually drops.  Usually just observe these rhythms.  Third Degree AV block or Complete heart block is characterized by AV dissociation and the P waves and QRS complexes march out but do not have a relationship.  Sinus arrhythmia just shows some variability in strip and varies usually with respiration.  There is no lengthened PR interval or dropped QRS complex.  Sinus bradycardia just has a normal rhythm but a ventricular rate less than 60.