Relias Assessments Assistance Material
DYSRHYTHMIAS with Accurate Solutions
Premature Junctional Contraction
Premature Junctional Contraction (PJC) occurs when some regions of the heart
becomes excitable than normal. It has the following characteristics.
PR interval less than 0.12 seconds if P wave precedes QRS complex
QRS complex configuration and duration is normal
P wave is inverted
Atrial and ventricular rhythms irregular
Causes of PJC may include myocardial infarction or ischemia, digoxin toxicity,
excessive caffeine or amphetamine use. Management includes correction of
underlying cause, discontinuation of digoxin if appropriate.
Atrioventricular Blocks
AV blocks are conduction defects within the AV junction that impairs conduction of
atrial impulses to ventricular pathways. The three types are first degree, second
degree and third degree.
First Degree AV Block
Rate is usually 60 to 100 bpm
PR intervals are prolonged for usually 0.20 seconds
QRS complex is usually normal
Rhythm is regular
, First degree AV block is asymptomatic and may be caused by inferior wall MI or
ischemia, hyperkalemia, hypokalemia, digoxin toxicity, calcium channel
blockers, amiodarone and use of antidysrhythmics. Management includes
correction of underlying cause. Administer atropine if PR interval exceeds 0.26
second or symptomatic bradycardia develops.
Second Degree AV Block Mobitz I (Wenckebach)
Atrial rhythm is regular
Ventricular rhythm is irregular
Atrial rate exceeds ventricular rate
PR interval progressively but only slightly, longer with each cycle until QRS
complex disappears (dropped beat)
PR Interval shorter after dropped beat.
Clinical manifestations include vertigo, weakness, and an irregular pulse. This may be
caused by Inferior wall MI, cardiac surgery, acute rheumatic fever, vagal stimulation.
Treatment includes correction of underlying cause, atropine or temporary pacemaker
for symptomatic bradycardia and discontinuation of digoxin if appropriate.
Second Degree AV Block Mobitz II
Atrial rhythm is regular
Ventricular rhythm maybe regular or irregular depending on the degree of
block P-P interval constant
QRS complex periodically absent or disappears
Clinical manifestations same as Mobitz I. Causes includes: severe coronary artery
diseases, anterior wall MI, acute myocarditis and digoxin toxicity. Treatment includes:
atropine, epinephrine, and dopamine for symptomatic bradycardia. Discontinuation of
digoxin if appropriate. Installation of pacemaker.
DYSRHYTHMIAS with Accurate Solutions
Premature Junctional Contraction
Premature Junctional Contraction (PJC) occurs when some regions of the heart
becomes excitable than normal. It has the following characteristics.
PR interval less than 0.12 seconds if P wave precedes QRS complex
QRS complex configuration and duration is normal
P wave is inverted
Atrial and ventricular rhythms irregular
Causes of PJC may include myocardial infarction or ischemia, digoxin toxicity,
excessive caffeine or amphetamine use. Management includes correction of
underlying cause, discontinuation of digoxin if appropriate.
Atrioventricular Blocks
AV blocks are conduction defects within the AV junction that impairs conduction of
atrial impulses to ventricular pathways. The three types are first degree, second
degree and third degree.
First Degree AV Block
Rate is usually 60 to 100 bpm
PR intervals are prolonged for usually 0.20 seconds
QRS complex is usually normal
Rhythm is regular
, First degree AV block is asymptomatic and may be caused by inferior wall MI or
ischemia, hyperkalemia, hypokalemia, digoxin toxicity, calcium channel
blockers, amiodarone and use of antidysrhythmics. Management includes
correction of underlying cause. Administer atropine if PR interval exceeds 0.26
second or symptomatic bradycardia develops.
Second Degree AV Block Mobitz I (Wenckebach)
Atrial rhythm is regular
Ventricular rhythm is irregular
Atrial rate exceeds ventricular rate
PR interval progressively but only slightly, longer with each cycle until QRS
complex disappears (dropped beat)
PR Interval shorter after dropped beat.
Clinical manifestations include vertigo, weakness, and an irregular pulse. This may be
caused by Inferior wall MI, cardiac surgery, acute rheumatic fever, vagal stimulation.
Treatment includes correction of underlying cause, atropine or temporary pacemaker
for symptomatic bradycardia and discontinuation of digoxin if appropriate.
Second Degree AV Block Mobitz II
Atrial rhythm is regular
Ventricular rhythm maybe regular or irregular depending on the degree of
block P-P interval constant
QRS complex periodically absent or disappears
Clinical manifestations same as Mobitz I. Causes includes: severe coronary artery
diseases, anterior wall MI, acute myocarditis and digoxin toxicity. Treatment includes:
atropine, epinephrine, and dopamine for symptomatic bradycardia. Discontinuation of
digoxin if appropriate. Installation of pacemaker.
