1. Recognition and management of Bradyarrhythmias and Tachyarrhythmias
Ms Lalith Sivanathan

2. OBJECTIVES Recognize unstable conditions requiring urgent intervention
Differentiate supraventricular tachycardia (SVT) from sinus tachycardia
Differentiate initial steps to stabilize the child who is unstable as a result of arrhythmias
Describe indications for vagal maneuvers used for treatment of SVT with adequate perfusion
Describe when and how to provide electrical therapy for arrhythmias with a pulse synchronized cardioversion attempts or pacing

3. BRADYARRHYTHMIAS
Bradycardia is defined as a heart rate that is slow compared with the normal heart rates for the patient’s age.
Primary bradycardia
Is a result of congenital and acquired heart conditions that directly slow the spontaneous depolarisation rate of the normal pacemaker cells
Secondary bradycardia
Is the result of conditions that alter the normal function of the heart (causes – hypoxia, acidosis, hypotension, hypothermia and drug effects)

4. SYMPTOMS Change in the level of consciousness Dizziness Syncope
fatigue
Cardinal signs
Shock with hypotension
Poor end-organ perfusion
Sudden collapse
A very slow heart rate can cause shock from inadequate cardiac output. The child is potentially unstable if deterioration to shock or cardiac arrest is likely

5. ECG CHARACTERISTICS OF BRADYCARDIA
HEART RATE
Slow compared with normal rates for the patient’s age
P waves
May or may not be visible
QRS complex
Narrow or wide (depending on location of intrinsic cardiac pacemaker and location of any injury to the conduction system
P wave and QRS complex
May be unrelated (ie., AV dissociation)
Examples of bradyarrythmias
Sinus bradycardia
Sinus node arrest with atrial, junctional or idioventricular escape rhythms
AV block

6. Sinus bradycardia
Is an incidental finding in otherwise healthy persons, particularly in young adults, sleeping patients and well-conditioned athletes.
It normally develops as a physiologic response to reduced metabolic demand (sleep, rest, hypothermia)
Other pathologic causes include poisoning, electrolyte disorders, infection, sleep apnea, drug effects, hypoglycemia, hypothyroidism and increased ICP

7. Sinus node arrest
It is characterized by absent pacemaker activity in the sinus node, In such care a subsidiary pacemaker in the atrium, AV junction or ventricles may initiate cardiac depolarization, resulting in
Atrial escape rhythm
Impulse arise from subsidiary non sinus atrial pacemaker (late P wave)
Junctional escape rhythm
The rhythm originates in the AV node (narrow QRS complex)
Idioventricular rhythm
The rhythm originates in the ventricles

10. AV Block
AV block is a disturbance of electrical conduction through the AV node. AV block is classified as
First degree
Prolonged PR interval representing slowed conduction through AV node
Second degree
Some but not all atrial impulses are conducted to the ventricles
Mobitz I (Wenckebach) – occurs at the AV node, One P is not followed by QRS
Mobitz II – occurs below the level of AV node
Third degree
None of the atrial impulses is conducted to the ventricle. Complete heart block or complete AV block

13. MANAGEMENT OF BRADYARRHYTHMIAS
Pediatric Bradycardia with a pulse algorithm
Initial Management
AIRWAY
Support airway, Open airway
BREATHING
Provide oxygen in high concentration – use a non rebreathing system
Assist ventilations as indicated
Attach a pulse Oximeter to assess oxygenation
CIRCULATION
Assess perfusion
Peform chest compressions as indicated (HR – below 60/min)
Attach monitor/defibrillator (with trancutaneous pacing capability)
Check electrode pad position and skin contact to ensure no artifacts
Record a 12-lead ECG if available
Establish vascular access
Obtain appropriate lab studies (K, Ca, Mg, Blood gas PH)

14. Pharmacologic agents Epinephrine- indicated in persistent bradycardia
IV/IO
0.01 MG/KG (1:10,000 : 0.1ML/KG)
Endotracheal tube
0.1 mg/kg (1:1000 ; 0.1ml/kg)
Repeat every 3 to 5 mins as needed

15. Atropine – it is a parasympathetic drug that accelerates sinus or atrial pacemakers and enhances AV conduction ( for drug toxicity, increased vagal tone, AV block )
IV/IO
First dose – 0.02 mg/kg, minimum 0.1 mg ( Max single dose 0.5 mg for a child and 1 mg for adolescent)
May repeat dosage in 5 mins, total dose 1 mg for child and 2 mg for an adolescent
Endotracheal tube
0.04 to 0.06 mg/kg

16. Identify and treat underlying cause
REVERSIBLE CAUSE
TREATMENT
Hypoxia
Give supplementary oxygen in high concentration
Hypothermia
Treat with warming techniques. Avoid hyperthermia if the patient has experienced a cardiac arrest
Hyperkalemia
Restore normal potassium concentration
Heart Block
Consider atropine for AV block along with pacing and expert consultation
Toxins/poisons/drugs
Treat with specific antidote and provide supportive care
Trauma
Head trauma – Provide oxygenation and ventilation. If signs of impending herniation develop, provide hyperventilation

17. TACHYARRHTHMIAS
It is defined as a heart rate that is fast compared with normal heart rates for the patient’s age
Cardinal signs:
Respiratory distress/failure often due to pulmonary edema (lung tissue disease)
Shock with hypotension or poor end – organ perfusion
Altered consciouness
Sudden collapse with rapid detectable pulses

18. Tachycardic rhythms It may be classified according to the width of the QRS complex
NARROW COMPLEX
WIDE COMPLEX
Sinus tachycardia
Supraventricular tachycardia
Atrial flutter
Ventricular tachycardia
Supraventricular tachycardia with aberrant intraventricular conduction

19. Sinus tachycardia – is defined as a rate of sinus node discharge faster than normal for the patient’s age (causes – hypoxia, hypovolemia, fever, metabolic stress, injury, pain, anxiety, toxins, drugs, anemia)
Supraventricular tachycardia is abnormally fast rhythm originating above the ventricles. SVT is the most common tachyarrhythmia producing cardiovascular compromise during infancy
Common signs in infants are poor feeding, rapid breathing, irritability, unusual sleepiness, pale or blue skin, vomiting
In older children – palpitations, shortness of breath, chest pain, dizziness, lightheadedness and fainting

20. COMPARISON OF ST AND SVT
CHARACTERISTICS ST
SVT
HISTORY
Gradual onset (H/o fever, pain, dehydration, hemorrhage)
Abrupt onset, Infant : CHF symptoms, Child: palpitations
PHYSICAL EXAM
Signs of underlying cause (fever, hypovolemia, anemia)
Signs of CHF (rales, hepatomegaly, edema)
HEART RATE
Infant - < 220/min, child - <180/min
Infant - > 220/min, child - >180/min
MONITOR
Variability in heart rate with changes in level of activity or stimulation
Minimal variability in heat rate with changes in level of activity or stimulation
ECG
P waves present/ normal
P waves absent/abnormal
CHEST X-RAY
Usually small heart and clear lungs
Signs of CHF (pulm edema may be present)

21. Atrial flutter – is an uncommon narrow-complex tachyarrhythmia in children
Ventricular tachycardia – is a wide complex tachyarrhythmia generated within the ventricles, VT is uncommon in children, most children who develop VT have underlying heart disease
Causes – myocarditis, cardiomyopathy, electrolyte disturbances: hyperkalemia, hypocalcemia, hypomagnesemia and drug toxicity)

22. MANAGEMENT OF TACHYARRHYTHMIAS
Initial Management
Support ABCs and oxygenation as needed
Establish monitoring
Establish vascular access
Obtain lab studies (k, glucose, ca, mg, etc)
Assess neurologic status
Treat hypothermia
Anticipate need for appropriate medications

23. Vagal maneuvers
In normal infants and children the heart rate falls when the vagus nerve is stimulated, In patients with SVT, vagal stimulation may terminate the tachycardia by slowing the conduction through the AV node

24. CARDIOVERSION
Electrical cardioversion can be frightening and painful for a child, establish vascular access and provide preprocedural sedation
For syn cardioversion – use a first dose of 0.5 to 1 J/kg for SVT or VT with pulse. Increase the dose to 2J/kg if initial dose is ineffective, then all remaining shocks at 2 J/kg

25. PHARMACOLOGIC THERAPY
Adenosine (Blocks conduction through AV node temporarily)– 0.1 mg/kg (max first dose 6 mg) by rapid bolus, max second dose 12 mg
Amiadarone(vasodilatation and Av node suppresion) – 5 mg/kg IV over 20 to 60 mins
Procainamide (antiarrhythmic agent) 15 mg/kg IV over 30 to 60 mins
Lidocaine (sodium channel blocker) – 1 mg/kg bolus
Infuse loading doses slowly in a stable patient to avoid hypotension. Monitor blood pressure frequently during administration

26. Summary Recognize unstable conditions requiring urgent intervention
Differentiate supraventricular tachycardia (SVT) from sinus tachycardia
Differentiate initial steps to stabilize the child who is unstable as a result of arrhythmias
Describe indications for vagal maneuvers used for treatment of SVT with adequate perfusion
Describe when and how to provide electrical therapy for arrhythmias with a pulse synchronized cardioversion attempts or pacing

27. Thank you…