Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

Sinus Bradycardia

Sinus Tachycardia

Sinus Dysrhythmia

Sinus Arrest

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

RegularRhythm

Less than 60Rate

Sinus Bradycardia

Rules of Interpretation

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

Sinus Bradycardia– Etiology

Increased parasympathetic (vagal) tone, intrinsic disease of the SA node, drug effectsMay be a normal finding in healthy, well-conditioned persons

– Clinical SignificanceDecreased cardiac output, hypotension, angina, or CNS symptomsIn healthy, well-conditioned person, may have no significance

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Sinus Bradycardia

Treatment– Treat if hypotension or ventricular irritability is

present– Prepare for transcutaneous pacing

Atropine may be considered if delay in pacing

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Bradycardia Algorithm

Click here to view the Bradycardia Algorithm.Reproduced with permission from “2005 American Heart Association Guidelines for Cardiopulmonary

Resuscitation and Emergency Care,” Circulation 2005, Volume 112, IV-68. © 2005 American Heart Association.

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

RegularRhythm

Greater than 100Rate

Sinus Tachycardia

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

Sinus Tachycardia– Etiology

Results from an increased rate of SA node discharge

Potential causes include exercise, fever, anxiety, hypovolemia, anemia, pump failure, increased sympathetic tone, hypoxia, or hypothyroidism

– Clinical SignificanceDecreased cardiac output for rates >140

Very rapid rates can precipitate ischemia or infarct

– TreatmentTreatment is directed at the underlying cause

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

IrregularRhythm

60–100Rate

Sinus Dysrhythmia

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

Sinus Dysrhythmia– Etiology

Often a normal finding, sometimes related to the respiratory cycle

May be caused by enhanced vagal tone

– Clinical SignificanceNormal variant

– TreatmentTypically, none required

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

IrregularRhythm

Normal to slowRate

Sinus Arrest

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Dysrhythmias Originating in the SA Node

Sinus Arrest– Etiology

Occurs when the sinus node fails to dischargeMay result from ischemia of the SA node, digitalis toxicity, excessive vagal tone

– Clinical SignificanceFrequent or prolonged episodes may decrease cardiac output and cause syncopeProlonged episodes may result in escape rhythms

– TreatmentNone if patient is asymptomaticTreat symptomatic bradycardia

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normal

P Waves

SA nodePacemaker Site

IrregularRhythm

Normal to slowRate

Sinus Block

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Sinus Block– Etiology

Occurs when the sinus node fires on time but the impulse is blocked before it exits the sinus node Ischemia, digitalis toxicity, excessive vagal tone

– Clinical significanceProlonged episodes may compromise cardiac output Escape rhythms may develop

– TreatmentNone if patient is asymptomaticTreat symptomatic bradycardia

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

IrregularRhythm

Normal to slowRate

Sinus Pause

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Sinus Pause– Etiology

Occurs when the sinus node fails to discharge for a brief period Ischemia, digitalis toxicity, excessive vagal tone

– Clinical significanceMay compromise cardiac output Escape rhythms

– TreatmentNone if patient is asymptomaticTreat symptomatic bradycardia

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

NormalQRS

NormalPRI

Upright and normalP Waves

SA nodePacemaker Site

IrregularRhythm

Extremely variableRate

Sick Sinus Syndrome

Rules of Interpretation

Dysrhythmias Originating in the SA Node

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 3: Medical Emergencies, 3rd Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Sick Sinus Syndrome– Etiology

A combination of dysrhythmias

Occurs when the sinus node is diseased or ischemic

Ischemia, digitalis toxicity

– Clinical significanceMay compromise cardiac output

Escape rhythms

– TreatmentNone if patient is asymptomatic

Treat symptomatic bradycardia

Dysrhythmias Originating in the SA Node