SCN EKG Review and Strip
Milburn, R.L., & Stech, M. 2015.
Objectives
• Identify regular and irregular neonatal heart rhythms
• Recognize causes of irregular heart rhythms in the neonate
• Match irregular heart rhythms with their appropriate medical treatment
Overview
Basic Neonatal ECG
P wave= atrial depolarization
QRS complex= ventricular depolarization
T wave= ventricular repolarization
Normal Sinus Rhythm
• Heart rate 100-180 bpm• Regular, uniform P wave before each
QRS complex followed by a T wave• No treatments necessary
Sinus Bradycardia
• Heart rate <100 bpm• Slow rate with normal P waves• Caused by:
– Hypoxia– Acidosis– Increased intracranial pressure– Increased vagal tone– Abdominal Distention– Hypoglycemia– Hypothermia– Digoxin
Sinus Bradycardia Treatments
• Treat underlying causes• Administer Oxygen• Resuscitation if appropriate
Sinus Tachycardia
• Heart rate >181 and <220 bpm• Normal P wave that precedes QRS complex• Caused by:
– Heart Failure– Fever– Anemia– Pain– Infections– Hypovolemia
• Treatment:– Treat underlying cause
Atrial Flutter
• “Saw tooth” flutter waves• P waves may be hidden in QRS complex• Heart rate can reach as high as 500 in
neonates• Caused by:
– Damage to Sinus Node– Congenital heart disease– Digoxin Toxicity– Idiopathic
Atrial Flutter Treatments
• If unstable:– Pacing– Electrical cardioversion
• If stable:– Digoxin– Propranolol– Amiodarone
Atrial Fibrillation
• “Irregularly irregular”• No two R to R intervals will look the
same• Absent P waves• Caused by:
– Atrial septal defects– Mitral valve anomalies– Atrial dilatation
Atrial Fibrillation Treatments
• If unstable:– Electrical cardioversion
• If stable:– Digoxin– Propranolol
• Due to risk of thrombus, anticoagulant therapy may be started
Supraventricular Tachycardia(SVT)
• Heart rate >220 bpm• Abnormal P axis• P wave may be seen or hidden• Caused by:
– Cardiac defects– Conduction abnormalities– Myocarditis– Systemic infections– Idiopathic
SVT Treatments
• If unstable:– Adenosine (0.05 mg/kg)– Amiodarone
• If stable:– Propranolol– Amiodarone– Digoxin
• Vagal maneuvers can also treat– Ice
Ventricular Tachycardia
• Lethal arrhythmia• Regular rhythm with no P waves• Wide QRS complex• Caused by:
– Asphyxia– Cardiac Tumors– Hypoxia– Acidosis– Electrolyte Imbalances– Drug toxicity– Cardiac Anomalies– Conduction Disorders
Ventricular Fibrillation
• Lethal Arrhythmia• Chaotic rhythm• Rapid and irregular• Caused by:
– Hypoxia– Acidosis– Electrolyte Imbalances– Cardiac Anomalies
Asystole
• Lethal Arrhythmia• Absence of electrical activity• Rhythm is flat• No P waves or QRS complexes
Treatments for Lethal Arrhythmias
• Defibrillation for Pulseless rhythms (such as Ventricular Tachycardia and Ventricular Fibrillation)
• Cardioversion for rhythms with pulses (such as Ventricular Tachycardia)
Abnormal Beats
• Premature Ventricular Contraction (PVC):• Early with no P wave• Wide QRS complex• T wave inverted• Caused by:
– Acidosis– Electrolyte Imbalances– Cardiac Disease– Irritation from invasive lines (such as UVCs)– May be normal in infants up to 2 months of age
PVC Treatments
• Infant should have cardiac work up including:– BMP– 12 lead EKG– ECHO
References
• Ambulance Technician Study. (2013). ECG rhythms. Retrieved from http://www.ambulancetechnicianstudy.co.uk/rhythms.html.
• New York-Presbyterian Healthcare System. (2011). Neonatal basic dysrhythmia study guide.