TLDR;
Alright, so this video is basically a simplified explanation of pediatric ECGs. Dr. Dhukram Walasa talks about how to read ECGs, especially in kids, and busts some myths around it. He covers everything from the basics of ECG waves to identifying different heart rhythm problems and what to do in those situations. Key takeaways include understanding normal ECG changes with age, differentiating between sinus arrhythmia and pathological arrhythmias, and recognizing common SVT patterns in children.
- Understanding ECG basics and application in pediatric patients.
- Differentiating normal and abnormal ECG findings in children.
- Management of common arrhythmias in pediatric OPD settings.
Presidential Address [0:16]
Shankana ma'am welcomes everyone and emphasizes that ECG is a handy and easily available investigation, especially in pediatric emergencies. She points out that ECG knowledge is super important for early intervention. ECG is not a replacement for echocardiography.
Introduction [1:06]
Dr. Lata welcomes Dr. Dhukram Walasa, who will be sharing his knowledge on pediatric ECGs. Dr. Prajapati emphasizes that ECGs can be tricky for pediatricians because they don't get as much training in it as MD medicine folks do. He suggests incorporating ECG training more into MD pediatrics programs so future doctors won't be so scared of them and might even consider cardiology.
What is ECG? [5:20]
ECG is a graphical representation of the heart's electrical activity. The electrical current passes through the conduction system of the heart, which includes the SA node, AV node, bundle of His, and Purkinje fibers. This electrical activity causes the atria and ventricles to contract in a coordinated manner, maintaining cardiac output. The P wave represents atrial depolarization (atrial contraction), the QRS wave represents ventricular depolarization (ventricular contraction), and the T wave represents ventricular repolarization (ventricular relaxation).
ECG Leads [8:38]
ECG leads are sensors placed on the body to detect the direction of electrical current in the heart. Limb leads (like lead 1, 2, 3, AVR, AVL, AVF) help determine the heart's axis, while precordial leads (V1-V6) placed on the chest indicate which ventricle is dominant. For instance, positive waves in left-sided precordial leads (V5, V6) suggest left ventricle dominance, while positive waves in V1 and V2 suggest right ventricle dominance, which is common in fetal and neonatal life.
How to Read ECG [12:09]
When reading an ECG, first look at the heart rate. Calculate it accurately by counting the smallest squares between two R waves and dividing 1500 by that number. A quicker, rough method involves counting the large squares and dividing 300 by that number. Next, determine the rhythm: is it a normal sinus rhythm or an ectopic rhythm? Sinus rhythm means the electrical discharge starts from the SA node, which is normal. Also, check the P wave and QRS wave axes by looking at leads one and AVF to see if the waves are positive or negative.
Sinus Rhythm [14:14]
To determine if the rhythm is sinus rhythm, every P wave should be followed by a QRS complex with a constant PR interval, and the P wave axis should be normal (positive in lead one and AVF). If the rhythm originates from the AV node, it's a junctional rhythm (no P wave). If it's from atrial cells outside the SA node, it's an ectopic atrial rhythm. If it's from ventricular cells, it's a ventricular ectopic rhythm.
QRS Axis [19:08]
The QRS axis can be determined by looking at the QRS morphology in leads one and AVF. If both are positive, it's a normal QRS axis. If lead one is negative and AVF is positive, it's right axis deviation. If lead one is positive and AVF is negative, it's left axis deviation. If both are negative, it's extreme left axis deviation.
ECG Changes with Age [21:19]
In newborns, expect right axis deviation and positive R waves in right precordial leads (V1-V3) due to right ventricle dominance. T wave inversion in right precordial leads is also common. After one month, the axis shifts to normal, but right ventricle dominance and T wave inversion can persist up to 3 years. From 3 to 16 years, the ECG resembles a normal adult ECG, but T wave inversion in right precordial leads can still be normal and not necessarily a sign of ischemia.
Case 1: Sinus Arrhythmia [25:16]
A 4-year-old boy with a cough has an irregular heartbeat. An ECG shows a normal sinus rhythm with RR variability related to respiration. This is sinus arrhythmia, which is physiological and common in kids, indicating good cardiac reserve.
Case 2: Ventricular Premature Contraction (VPC) [28:27]
Another child with a similar presentation shows an ECG with occasional absence of P waves, wide QRS complexes, and T wave inversion, indicating ventricular premature contractions (VPCs). These disappear with exercise, suggesting they are physiological and don't need treatment. Occasional VPCs that disappear on exercise are generally benign.
Irregular Heartbeat [32:23]
Irregular heartbeats can be due to sinus arrhythmia, atrial premature contractions (different P wave morphology, incomplete pause), or ventricular premature contractions (absent P wave, wide QRS, inverted T wave, full compensatory pause).
Extreme Tachycardia or Bradycardia [32:36]
Symptoms of rhythm abnormalities range from no symptoms to serious issues like loss of consciousness. Infants may show lethargy, poor feeding, or irritability, while older kids may have palpitations, fainting, or fatigue. Tachycardia in a child being treated for bronchiolitis can be either due to the infection (myocarditis) or supraventricular tachycardia (SVT). Heart rate variability makes SVT less likely.
Types of Fast Heartbeat Problems [35:15]
Fast heartbeats can originate in the atria (narrow QRS) or ventricles (wide QRS). Narrow QRS tachycardias include sinus tachycardia, SVT, atrial flutter, atrial fibrillation, and multifocal atrial tachycardia. Wide QRS tachycardia is usually ventricular tachycardia.
Sinus Tachycardia vs. SVT [36:39]
Sinus tachycardia has a P wave followed by a QRS complex, a constant PR interval, and a normal P wave axis. Heart rate gradually increases and decreases, varying with time. SVT, on the other hand, has a constant, high heart rate.
Mechanisms of Arrhythmia [38:12]
In ectopic atrial tachycardia, the P wave originates from atrial cells other than the SA node, leading to a different P wave morphology. Multifocal atrial tachycardia involves multiple atrial cells discharging electrical signals, resulting in varying P wave morphologies. Atrial flutter involves a circular movement of electrical current, creating flutter waves with a sawtooth pattern. AV nodal re-entrant tachycardia (AVNRT) involves a circular current within the AV node, often embedding the P wave in the QRS complex. Accessory pathway tachycardia involves an extra pathway, leading to AVRT.
Supraventricular Tachycardia (SVT) [42:55]
SVT is common in infants (0-3 months) and older children (8-10 years). The most common mechanisms are AVRT and AVNRT. SVT is classified as short RP tachycardia (P wave immediately after QRS) or long RP tachycardia (P wave before QRS).
SVT Classification [43:55]
SVT is characterized by a high heart rate, narrow QRS complex, and constant RR interval. P waves may occur before, after, or be hidden within the QRS complex. The onset is usually abrupt.
AVNRT, AVRT, and Multifocal Atrial Tachycardia [47:29]
AVNRT involves a circular rhythm within the AV node, often hiding the P wave. AVRT involves an accessory pathway, with the P wave appearing immediately after the QRS wave. Multifocal atrial tachycardia has multiple P wave morphologies and irregular RR intervals.
Atrial Flutter and Fibrillation [50:40]
Atrial flutter shows a sawtooth pattern of F waves, with varying degrees of block. Atrial fibrillation, more common in older adults, shows irregular RR intervals and difficult-to-identify P waves.
Ventricular Tachycardia (VT) [53:01]
Ventricular tachycardia involves a wide QRS complex due to the rhythm originating from ventricular cells. Monomorphic VT has similar QRS morphologies, while polymorphic VT has varying QRS morphologies and is more dangerous.
Approach to ECG Interpretation [53:53]
When interpreting an ECG, consider the rate, rhythm, QRS width, atrial activity, and the relationship between the P wave and QRS complex. Newborns can have sinus rates up to 220, while most SVTs range from 150-250. Atrial flutter can reach 300, and multifocal atrial tachycardia can be as low as 160.
Regular vs. Irregular Tachycardias [54:57]
Sinus tachycardia and SVT are regular, while atrial flutter with fixed blocks is regularly irregular. Atrial fibrillation, multifocal atrial tachycardia, polymorphic VT, and atrial flutter with varying blocks are irregularly irregular.
P Wave Morphology and Relationship to QRS [55:32]
Upright P waves in leads one and AVL indicate sinus rhythm. Inverted P waves suggest SVT. Flutter waves are best seen in leads 2, 3, and AVF. The relationship of the P wave to the QRS (before, after, short RP, long RP) helps differentiate types of SVT.
Management of SVT [56:55]
Vagal maneuvers can cause transient AV block, helping to diagnose and sometimes terminate re-entrant tachycardias. Adenosine can also help diagnose and treat SVT. If there's no change with adenosine, the dose may be inadequate, or it could be VT. Transient slowing suggests sinus tachycardia, prompt termination suggests re-entrant tachycardia (AVRT or AVNRT), and unmasking of P waves or flutter waves suggests atrial flutter or ectopic atrial tachycardia.
ECG Exercises [59:02]
A 1-month-old with a heart rate of 250 likely has SVT. If a P wave is seen immediately after the QRS, it suggests AVRT. Acute management involves synchronized cardioversion if unstable, vagal maneuvers if stable, and adenosine as the first-line drug.
Case 3: Ectopic Atrial Tachycardia [1:02:36]
An 8-year-old with dyspnea and poor weight gain has a heart rate of 220-230 and a negative P wave in lead one, suggesting ectopic atrial tachycardia. This can lead to tachycardia-induced cardiomyopathy.
Case 4: Normal Sinus Rhythm [1:04:32]
An ECG with a heart rate of 120, P waves followed by QRS complexes, constant PR intervals, and positive P waves in leads one and AVF indicates normal sinus rhythm.
Case 5: Monomorphic Ventricular Tachycardia [1:06:14]
A wide QRS complex with T wave inversion suggests ventricular tachycardia. If all QRS complexes have similar morphology, it's monomorphic VT.
Case 6: Atrial Flutter [1:06:43]
A sawtooth pattern of flutter F waves with varying blocks indicates atrial flutter.
Case 7: Polymorphic Ventricular Tachycardia [1:07:15]
Different morphologies of wide QRS complexes indicate polymorphic ventricular tachycardia.
Case 8: SVT [1:07:26]
A rhythm that starts slow and suddenly becomes fast, with absent P waves during the fast phase, suggests SVT.
Case 9: Multifocal Atrial Tachycardia [1:07:54]
Different P wave morphologies with RR variability suggest multifocal atrial tachycardia.
Case 10: Atrial Fibrillation [1:08:40]
RR variability and difficult-to-see P waves with small fibrillary waves indicate atrial fibrillation.
Heart Blocks [1:08:53]
First-degree heart block involves prolonged PR intervals. Second-degree heart block involves some P waves not being conducted (Mobitz type 1 with gradual PR prolongation, Mobitz type 2 with constant PR interval). Third-degree heart block involves no P waves being conducted, leading to complete AV dissociation.
Q&A: Lead Placement [1:13:12]
To ensure correct lead placement, remember that AVR should always be negative. If it's positive, the limb leads are likely reversed. Also, in adults, expect positive QRS in V5 and V6 and negative QRS in V1 and V2.
Q&A: AVRT and Fentanyl [1:16:19]
AVRT may resolve on its own, especially in the first 3 years of life or between 8-10 years, so waiting until one year is reasonable. There's no clear evidence that fentanyl causes incomplete RBBB.
Q&A: Radiofrequency Ablation (RFA) [1:17:47]
Indications for RFA include refractory arrhythmias not controlled by medication and recurrent AVRT causing ventricular dysfunction. The decision is subjective and depends on the individual patient.
Q&A: Long QT and Down Syndrome [1:19:43]
Differentiate between pre-existing long QT and new-onset long QT by reviewing previous ECGs. Surgical repair usually doesn't cause long QT. Maintain electrolyte balance and avoid QT-prolonging medications.
Q&A: Danger Signs and Direction Diagram [1:22:51]
Anything moving towards a lead is seen as positive, and anything moving away is seen as negative. This helps explain the different QRS morphologies in different leads.
Q&A: P Wave Morphology and Ventricular Fibrillation [1:26:14]
Right atrial dilation can cause tall P waves, while left atrial dilation can cause M-shaped P waves. Ventricular fibrillation shows chaotic, undulatory movements without clear PQRST complexes.
