each QRS PR interval: steadily lengtheningwith each cycle until QRS complex disappears. PR interval shorter after dropped beat QRS interval: normal PP interval regular RR interval irregular Cause: inferior or anterior wall MI, congenital abnormality, rheumatic fever Treatment: atropine, epinephrine, and dopamine for symptomatic bradycardia. Temporary or permanent pacemaker for symptomatic bradycardia.
May decrease cardiac output 2ndDegree Heart Block: Mobitz Type II HR: Rhythm: slow, irregular rhythm. Not all signals reach the ventricles and some heart beats are dropped P wave: occasionally P wave does not follow QRS PR interval: fixed QRS interval: wide bc the block occurs in the His bundle or bundle branches and conduction through the ventricles is slowed PP interval is regular Causes: ischemia, myocarditis, increased vagal tone, medications that slow AV nodal conduction Treatment: initiate transvenous pacing until a permanent pacemaker is placed 3rddegree Heart Block: complete heart block HR: Rhythm: atrial rhythm regular, ventricles are beating at 20-40 bom P wave: not associated with QRS complex PR interval: none, bc atria and ventricles work independently QRS interval: normal (nodal pacemaker) wide and bizarre (ventricular pacemaker) PP intervals regular RR intervals regular Causes: Ischemia or infarction, heart surgery, cardiomyopathy, congenital abnormality, rheumatic fever Treatment: atropine, epinephrine, and dopamine for symptomatic bradycardia. Temporary or permanent pacemaker for symptomatic bradycardia. transcutaneous pacing