Arrhythmias

ECG ECG is a graphic representation of the sequence of myocardial depolarisation and repolarisation. Each noarmal cardiac cycle consists of a P wave QRS complex T wave

Anatomy of the conduction system in relation to ECG

Normal Heart Rate by Age

Placement of electrodes for ECG Monitoring

Cardiac Rhythm Disturbances Recognize that rhythm disturbances are an uncommon cause of cardiovascular arrest in children Define 3 classes of rhythm disturbances Assess and manage rhythm disturbances associated with shock (unstable)

Treatment - Stable Versus Unstable Unstable rhythms require emergency therapy Rhythms that cause circulatory instability Rhythms that may deteriorate and cause circulatory instability

Assessment of Cardiovascular Function Assess Ventilation, Heart rate, Peripheral pulses, End organ perfusion, Blood pressure. Is CPR needed? Is cardiovascular instability present? Compensated shock Hypotensive shock Cardiopulmonary arrest

Definition of Rhythm Groups by Pulse (central) Rate Fast pulse = Tachyarrhythmia Slow pulse = Bradyarrhythmia Absent pulse = Collapse rhythms Rate Infant Child Fast >220 >180 Slow <80 <60

Development of Shock From Pulse Rate Disturbances Cardiac Output = Heart Rate X Stroke Volume HR X SV FAST Low High SLOW Normal , High or Low ABSENT

Assessment of Cardiac Rhythm Group Is the pulse rate slow, fast or absent? Is the perfusion compromised? Are the ventricular complexes wide or narrow? Is there a diagnostic pattern to the ECG?

Assessment Of Tachycardia ( Fast Pulse ) Tachycardia appropriate for clinical condition= Sinus tachycardia Tachycardia excessive for clinical condition= Tachyarrhythmia Narrow QRS Complex Sinus Tachycardia Supraventricular Tachycardia Wide QRS Complex Ventricular Tachycardia

Supraventricular Tachycardia Sinus Tachycardia Supraventricular Tachycardia History Possible history of fever, pain, or volume loss (eg. Diarrhea, vomiting, bleeding) Nonspecific history of irritability, lethargy, poor feeding, tachypnea, sweating, pallor, or hypothermia Heart Rate P waves present and normal Variable RR with constant PR Infants rate <220bpm Children <180bpm P waves absent or abnormal Abrupt rate change to or from normal Infants rate usually>220bpm Children >180bpm

Sinus Rhythm

Supraventricular Tachycardia

Ventricular Tachycardia

SUMMARY - FAST RATE Etiology Treatment Narrow QRS (Probable SVT) Vagal Maneuver Adenosine (if IV access) Synchronized Cardio version Wide QRS (Probable VT) Amiodarone / Lidocaine / Procaineamide / Magnesium Sulphate

Drug Treatment of SVT- Adenosine 0.1 to 0.2 mg/kg Maximum single dose:12 mg

Bradyarrhythmia

Etiology of Bradycardia Hypoxia Hypothermia Head injury Heart Block Heart Transplant Toxins/poisons/drugs

What Is the Rhythm? BRADYCARDIA

Management of Bradycardia Oxygenation (FiO2 = 1.00) and ventilation Chest Compressions Epinephrine Dose: IO/IV, 0.1 ml /kg of 1:10000 ET, 0.1 ml /kg of 1:1000 Atropine Dose : IO/IV: 0.02 mg/kg, Minimum 0.1 mg Maximum Single Dose (may repeat once) Child: 0.5mg, Adolescent: 1 mg ?? Pacing

Treat potential reversible causes of Bradycardia

Case Study 8 year old submersion victim with Apnea No palpable pulses What Arrhythmias could be present?

Absent Pulse Asystole Ventricular fibrillation Pulseless ventricular tachycardia Pulseless electrical activity / electromechanical dissociation

ASYSTOLE

Absent Pulse (Collapse Rhythms)-Asystole Treatment CPR Secure airway Ventilate with 100% oxygen Obtain IV or IO access Epinephrine q 3-5 min

VENTRICULAR FIBRILLATION

Defibrillation - updates First dose – 2 J / kg Second & subsequent dose – 4 J / kg Superiority & greater safety of biphasic over monophasic shocks & less energy requirement Drug administration during CPR Minimum interruptions in Chest Compressions

Defibrillation

starting with chest compression needed in all 3 post shock situations High quality CPR starting with chest compression needed in all 3 post shock situations

Case Study A 2 year old child was struck by an automobile Respiratory rate = 0 Central pulse = absent

What are the priorities for treatment? PULSELESS ELECTRICAL ACTIVITY Rhythm 60 beats/min What are the priorities for treatment?

Treat Cause

SUMMARY: Rx by Pulse Rate in a Child with Shock TREATMENT FAST Synchronized Cardioversion Adenosine (in SVT if IV access +) SLOW Ventilation, oxygenation, compressions, epinephrine ABSENT CPR (beginning with chest compressions) VF/VT: immediate defibrillation PEA/EMD: Identify and treat the cause Epinephrine

Questions to answer in order to identify an unknown arrhythmia: : Is the rate slow (<60 bpm) or fast (>100 bpm)? Slow - Suggests sinus bradycardia, sinus arrest, or conduction block Fast -Suggest increased/abnormal automaticity or reentry 2. Is the rhythm irregular? Irregular -Suggests atrial fibrillation, 2nd degree AV block, Multifocal atrial tachycardia, or atrial flutter with variable AV block 3. Is the QRS complex narrow or wide? Narrow - Rhythm must originate from the AV node or above Wide - Rhythm may originate from anywhere

Questions to answer in order to identify an unknown arrhythmia: : 4. Are there P waves? Absent P waves - Suggests atrial fibrillation, ventricular tachycardia, or rhythms originating from the AV node 5. What is the relationship between the P waves and QRS complexes? More P waves than QRS complexes - Suggests 2nd or 3rd degree AV block More QRS complexes than P waves - Suggests an accelerated junctional or ventricular rhythm 6. Is the onset/termination of the rhythm abrupt or gradual? Abrupt - Suggests reentrant rhythm Gradual - Suggests altered automaticity

Treat The Patient Not The Rhythm