Relias Assessments Assistance Material DYSRHYTHMIAS
EKG interpretation - One of the most useful and commonly used diagnostic tools is electrocardiography
(EKG) which measures the heart's electrical activity as waveforms. An EKG uses electrodes attached to
the skin to detect electric current moving through the heart. These signals are transmitted to produce a
record of cardiac activity. Arrhythmia or dysrhythmia are disturbances in the normal cardiac rhythm of
the heart which occurs as a result of alterations within the conduction of electrical impulses. These
impulses stimulate and coordinate atrial and ventricular myocardial contractions that provide cardiac
output.
Sinus Tachycardia - Sinus tachycardia is a heart rate greater than 100 beats per minute that originated
from the sinus node.
Rate: 100 to 180 beats per minute
P Waves precede each QRS complex
PR interval is normal
QRS complex is normal
Conduction is normal
Rhythm is regular
Causes of sinus tachycardia may include exercise, anxiety, fever, drugs, anemia, heart failure,
hypovolemia and shock. Sinus tachycardia is often asymptomatic. Management however is directed at
the treatment of the primary cause. Carotid sinus pressure (carotid massage) or a beta blocker may be
used to reduce heart rate.
Sinus Bradycardia - Sinus bradycardia is a heart rate less than 60 beats per minute and originates from
the sinus node (as the term "sinus" refers to sinoatrial node). It has the following characteristics
Rate is less than 60 beats per minute
P Waves precede each QRS complex
PR interval is normal
QRS complex is normal
Conduction is normal
Rhythm is regular
, Causes may include drugs, vagal stimulation, hypoendocrine states, hypothermia, or sinus node
involvement in MI. This arrhythmia may be normal in athletes as they have quality stroke volume. It is
often asymptomatic but manifestations may include: syncope, fatigue, dizziness. Management includes
treating the underlying cause and administering anticholinergic drugs like atropine sulfate as prescribed.
Premature Atrial Contraction - Premature Atrial Contraction are ectopic beats that originates from the
atria and they are not rhythms. Cells in the heart starts to fire or go off before the normal heartbeat is
supposed to occur. These are called heart palpitations and has the following characteristics:
Premature and abnormal-looking P waves that differ in configuration from normal P waves
QRS complex after P waves except in very early or blocked PACs
P waves often buried in the preceding T wave or identified in the preceding T wave.
Causes includes coronary or valvular heart diseases, atrial ischemia, coronary artery atherosclerosis,
heart failure, COPD, electrolyte imbalance and hypoxia. Usually there is no treatment needed but may
include procainamide and quinidine administration (antidysrhythmic drugs) and carotid sinus massage.
Atrial Flutter - Atrial flutter is an abnormal rhythm that occurs in the atria of the heart. Atrial flutter has
an atrial rhythm that is regular but has an atrial rate of 250 to 400 beats/minute. It has sawtooth
appearance. QRS complexes are uniform in shape but often irregular in rate.
Normal atrial rhythm
Abnormal atrial rate: 250 to 400 beats/minute
Sawtooth P wave configuration
QRS complexes uniform in shape but irregular in rate
Causes includes heart failure, tricuspid valve or mitral valve diseases, pulmonary embolism, cor
pulmonale, inferior wall MI, carditis and digoxin toxicity.
Management if the patient is unstable with ventricular rate of greater than 150 bpm, prepare for
immediate cardioversion. If patient is stable, drug therapy may include calcium channel blocker, beta-
adrenergic blockers, or antiarhythmics. Anticoagulation may be necessary as there would be pooling of
blood in the atria.
Atrial Fibrillation - Atrial fibrillation is disorganized and uncoordinated twitching of atrial musculature
caused by overly rapid production of atrial impulses. This arrhythmia has the following characteristics:
Atrial Rate: 350 to 600 bpm
Ventricular Rate: 120 to 200 bpm
P wave is not discernible with an irregular baseline
EKG interpretation - One of the most useful and commonly used diagnostic tools is electrocardiography
(EKG) which measures the heart's electrical activity as waveforms. An EKG uses electrodes attached to
the skin to detect electric current moving through the heart. These signals are transmitted to produce a
record of cardiac activity. Arrhythmia or dysrhythmia are disturbances in the normal cardiac rhythm of
the heart which occurs as a result of alterations within the conduction of electrical impulses. These
impulses stimulate and coordinate atrial and ventricular myocardial contractions that provide cardiac
output.
Sinus Tachycardia - Sinus tachycardia is a heart rate greater than 100 beats per minute that originated
from the sinus node.
Rate: 100 to 180 beats per minute
P Waves precede each QRS complex
PR interval is normal
QRS complex is normal
Conduction is normal
Rhythm is regular
Causes of sinus tachycardia may include exercise, anxiety, fever, drugs, anemia, heart failure,
hypovolemia and shock. Sinus tachycardia is often asymptomatic. Management however is directed at
the treatment of the primary cause. Carotid sinus pressure (carotid massage) or a beta blocker may be
used to reduce heart rate.
Sinus Bradycardia - Sinus bradycardia is a heart rate less than 60 beats per minute and originates from
the sinus node (as the term "sinus" refers to sinoatrial node). It has the following characteristics
Rate is less than 60 beats per minute
P Waves precede each QRS complex
PR interval is normal
QRS complex is normal
Conduction is normal
Rhythm is regular
, Causes may include drugs, vagal stimulation, hypoendocrine states, hypothermia, or sinus node
involvement in MI. This arrhythmia may be normal in athletes as they have quality stroke volume. It is
often asymptomatic but manifestations may include: syncope, fatigue, dizziness. Management includes
treating the underlying cause and administering anticholinergic drugs like atropine sulfate as prescribed.
Premature Atrial Contraction - Premature Atrial Contraction are ectopic beats that originates from the
atria and they are not rhythms. Cells in the heart starts to fire or go off before the normal heartbeat is
supposed to occur. These are called heart palpitations and has the following characteristics:
Premature and abnormal-looking P waves that differ in configuration from normal P waves
QRS complex after P waves except in very early or blocked PACs
P waves often buried in the preceding T wave or identified in the preceding T wave.
Causes includes coronary or valvular heart diseases, atrial ischemia, coronary artery atherosclerosis,
heart failure, COPD, electrolyte imbalance and hypoxia. Usually there is no treatment needed but may
include procainamide and quinidine administration (antidysrhythmic drugs) and carotid sinus massage.
Atrial Flutter - Atrial flutter is an abnormal rhythm that occurs in the atria of the heart. Atrial flutter has
an atrial rhythm that is regular but has an atrial rate of 250 to 400 beats/minute. It has sawtooth
appearance. QRS complexes are uniform in shape but often irregular in rate.
Normal atrial rhythm
Abnormal atrial rate: 250 to 400 beats/minute
Sawtooth P wave configuration
QRS complexes uniform in shape but irregular in rate
Causes includes heart failure, tricuspid valve or mitral valve diseases, pulmonary embolism, cor
pulmonale, inferior wall MI, carditis and digoxin toxicity.
Management if the patient is unstable with ventricular rate of greater than 150 bpm, prepare for
immediate cardioversion. If patient is stable, drug therapy may include calcium channel blocker, beta-
adrenergic blockers, or antiarhythmics. Anticoagulation may be necessary as there would be pooling of
blood in the atria.
Atrial Fibrillation - Atrial fibrillation is disorganized and uncoordinated twitching of atrial musculature
caused by overly rapid production of atrial impulses. This arrhythmia has the following characteristics:
Atrial Rate: 350 to 600 bpm
Ventricular Rate: 120 to 200 bpm
P wave is not discernible with an irregular baseline
