Heart Blocks lecture.doc - Bob Jones University Division of Nursing Heart Blocks AV Blocks First Degree Not a true block Delay at the AV node Each

Bob Jones UniversityDivision of NursingHeart BlocksAV BlocksFirst DegreeNot a true blockDelay at the AV nodeEach impulse is eventually conductedSecond DegreeType IWenckebachType IIType II Classical Heart Block2:1 AV blockThird DegreeAtria and ventricles are completely dissociatedThere is a total block at the AV nodeFirst Degree Heart BlockAV node holds each impulse longer than normal before conducting it to the ventricles. Each impulse is eventually conducted.First Degree Heart BlockRegularity: Depends on underlying rhythmRate: Depends on underlying rhythmP Wave: Upright and uniform; each P wave followed by QRS complexPRI: Greater than .20 seconds; constant across stripQRS: Less than .12 secondsCausesoCan occur at any age in health or diseased heartodrugs, such as digitalis, β-blockers, or calcium channel blockers; oCADoa variety of infectious diseasesocongenital lesionsTreatmentoNo hemodynamic consequence but can be an indicator of AV conduction problem and can deteriorate into 2ndor 3rd