EKG of the Week 2017 9-24

This EKG comes courtesy of Dr. Pilat.


A 5 month old boy presented to the ED with intermittent fast heart rate observed by the mother. No change in the level of activity or alertness, normal feeding, no SOB or any other additional complaints. No recent illness. Physical exam revealed a well-appearing, well-nourished baby boy, smiling, playful, active, good eye contact, normal work of breathing, no retractions, lungs CTA b/l, tachycardia, abdomen soft NT/ND, normal skin color and temperature, no cyanosis, capillary refill<2 sec.

V/S: P 148, R 28, BP 85/59

The EKG is below.

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1.      What does the EKG demonstrate?

2.      How would you manage this baby?



The EKG demonstrates a regular narrow complex tachycardia at a rate of approximately 220 with absent P waves. This is consistent with SVT.

Infants in SVT can be managed with vagal maneuvers. If they are unsuccessful, give adenosine 0.1 mg/kg.


This patient received 3 doses of adenosine (0.1, 0.2, 0.2) and then converted.

The post-conversion EKG is below.

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It shows a sinus rhythm with tall P waves (best seen in leads II, III, aVF, V1 and V2) consistent with right atrial enlargement. There is also a short PR interval with a delta wave (best seen in leads V4-V6) consistent with pre-excitation.

This patient had Ebstein’s anomaly. This is a congenital malformation of the tricuspid valve where the valve is located “too low” in the right ventricle. This results in the upper portion of the right ventricle effectively becoming part of the right atrium (known as “atrialization of the right ventricle”). The functional portion of the right ventricle is very small. Most patients with Ebstein’s anomaly also have tricuspid regurgitation and an atrial septal defect.

Patients with Ebstein’s anomaly often present with cyanosis and signs of right-sided heart failure. They are also at risk for arrhythmias including narrow complex SVT, wide complex tachycardia, a-flutter, a-fib, v-tach and sudden cardiac death.

The abnormal tricuspid valve results in direct muscle connection from the right atrium to the right ventricle. This can serve as an accessory pathway which puts the patient at risk for pre-excitation arrhythmias (WPW). 10-25% of patients with Ebstein’s anomaly will have WPW.

Management of arrhythmias in patients with Ebstein’s anomaly is the same as in the general population.

This patient was admitted to the hospital and seen by pediatric cardiology. Her echo showed mild to moderate tricuspid regurgitation, normal RV pressure, dilated right atrium.

She was put on propranolol and discharged home.



(Attenhofer Jost, et al. Ebstein’s Anomaly. Circulation. 2007;115:277-285)

(Loomba et al, Association of Atrial Tachycarrhythmias with Atrial Septal Defect, Ebstein’s Anomaly and Fontan Patients. Expert Review of Cardiovascular Therapy 2011;9:887.)


EKG of the Week 2016 10-2

This EKG comes courtesy of Dr. Benson and Dr. Hardy.

A 60 year old female presents to the ED complaining of palpitations, chest heaviness, right arm pain and shortness of breath.

V/S: P 210, R 20, BP 140/80, O2 sat 98%.

Her EKG is below.

1.       What is the rhythm?

2.       How would you manage this patient?



The rhythm is SVT.

The patient was treated with adenosine. The repeat EKG is shown below.


The initial EKG demonstrates a narrow complex tachycardia at a very rapid rate. At such a fast rate it may be difficult to tell if the rhythm is regular or irregular. This rhythm happens to be regular and there are no P waves or flutter waves. SVT is the diagnosis.

When the rate is this fast it may be difficult to differentiate SVT from rapid a-fib. History may give you a clue. If the patient has a history of one arrhythmia, that may be a clue that they are having the same arrhythmia again. However, remember that is not 100% accurate as patients can have any arrhythmia. In this scenario, when you are unsure if it is SVT or a-fib, adenosine can be diagnostic. Make sure to watch the rhythm on the monitor as the adenosine is administered. The QRS complexes will disappear and the underlying atrial rhythm will become visible. If the rhythm was SVT you may see no atrial activity or you may see P waves, and the arrhythmia may completely terminate. If it was a-fib, you may now see the fibrillatory waves on the monitor and the tachyarrhythmia will come right back.

Tachyarrhythmias with rates above 200 should raise the concern about the possibility of an accessory pathway (i.e. WPW). If the QRS complex is narrow, you can assume the rhythm is orthodromic and it is safe to administer AV nodal blockers. However, if the QRS is wide you must be concerned about an antidromic tachycardia. In that scenario, procainamide is the drug of choice. AV nodal blockers are contraindicated.

Remember the algorithm below to help diagnose tachyarrhythmias: