Interpret this - EKG...Monitor printout

1 week old, s/p Arterial Switch Operation. 6 hrs postop.
Clue: Arterial trace gives it away.

Narrow Complex Tachycardia/SVT - 3 types of responses to Adenosine

Response 1 - Adenosine terminates SVT to sinus rhythm
Response 2 - Adenosine terminates SVT to sinus rhythm; but, SVT returns
Response 3 - Adenosine decreases ventricular response, enabling the correct diagnosis of Atrial Flutter (This narrow complex tachycardia was not SVT)

Thus, if Adenosine does not treat it. It helps to uncover the correct diagnosis! It is important to record EKG strip during Adenosine administration so that the type of response can be carefully analyzed and documented.


EKG - Interpret this

8-day old, 31 week gestation baby. Recovering from Respiratory distress syndrome.
Consulted for episodes of bradycardia.


EKG: Dextrocardia

Panel 1: EKG recorded with standard lead placements
Panel 2: EKG recorded with reversed lead placement (Illustrates why this should not be done)

It is good exercise to compare the two EKGs and identify how reversing lead positions change the morphology of the complexes.


SVT - Onset & Termination from Holter recording

Is it SVT or AET?
Click on the image to enlarge.


EKG: PR interval

PR interval appears to be shorted after the ectopies. What is the mechanism?


Anatomy: Left Aortic Arch with Right Descending Aorta

Left Aortic Arch with Right Descending Aorta: Possible type
(From Esophagography in anomalies of the aortic arch system by A.C. Klinkhamer. 1969. Williams & Wilkins Company, Baltimore, MD)
See related posting


Vascular Ring - General Rules

From Moss & Adams(Vol. 1) 7th ed. 2008.
Chapter: Aortic Arch Anomalies by Dr. Paul Weinberg.

1) Arch sidedness: Retroesophageal or Isolated vessel always is the vessel on opposite side from the arch.

2) Vascular Ring: Easier to recognize the existence of vascular ring if all components of the ring are patent. The following rule is helpful when the ring is completed by an atretic ligament on one side i.e. Presence of one of the 3 Ds on the opposite side from the aortic arch indicates presence of a vascular ring. (3Ds are Diverticulum, Dimple or Descending aorta).


ICU: Where is the tip of this PA line?

ICU: What's wrong with this picture...

6-mo old. s/p Complete AVSD repair. Immediate postop. Just arrived from operating room.

Hint: The anomaly is the relationship between LA pressure and PA pressure.
Panel 1 - Has a problem/mistake. (Pardon the shaken image)
Panel 2 - The problem/mistake has been rectified.


ICU: Pulsus Alternans

What is the significance of Pulsus Alternans?
6 mo old baby girl, s/p VSD closure, Repair of Cleft mitral valve. Postop. ICU stay. Residual VSD with Pulmonary hypertension. Pulsus alternans is noted in the PA line pressure traces.
Panel 1 - DDD pacing

Panel 2 - Pacing Off

Panel 3 - AAI pacing

Panel 4 - VVI pacing

ICU: Arterial Pressure Trace Distortion

(From Cardiovascular Dynamics by Robert F. Rushmer. 3rd Ed. 1970. W.B. Saunders Company)


Quiz, EKG: What is the rhythm? Junctional vs. Low Atrial rhythm?

11 yr old boy. s/p Repair of Sinus venosus ASD. Started with AAI pacing at 80 bpm in the operating room. You set out to determine the underlying rhythm. The following strips are availabe for analysis. Second-from-the-last panel has atrial lead electrogram in V1. (Click on the images to enlarge).

Last panel image is from Principles of Clinical Electrocardiography by Mervin J. Goldman. Lange Medical Publications. 11th ed. 1982.


ICU: Pericardial Tamponade

Beware of the importance of looking "all-around" when you are doing a "quick" echo when a baby is unstable, in the immediate postoperative period. (Poor image quality is part of the deal!)

The first two panels show no significant effusion. However, in the lower-most panel - angled more posteriorly - there is a localized collection of clot compressing right atrium and part of right ventricle. This was not recognized due to poor images. Chest was opened to cannulate for ECMO! Clot was noted in the pericardial space, compressing right atrium (Lower-most panel). Hemodynamic status improved when the clot was removed. ECMO was not necessary.

Newborn, s/p Arterial switch operation. 3 hrs postop.


EKG: Nomogram / Table: Cycle Length to Heart Rate Table

L = Cycle length (seconds)
R = Heart rate

In pediatrics, it is useful remember the cycle length range of 200-300 ms (0.2 to 0.3 seconds) where most of pediatric arrhythmias occur.

EKG - Normal values, Basics

Kirschoff's Law: Algebraic sum of all the potential differences in a closed circuit equals zero. Based on this law, I + II + III = 0.

But, Einthoven reversed the polarity of II. Instead of connecting RA - LL, he connected it LL - RA. Therefore, the formula becomes I - II + III = 0.

When this equation is solved, it becomes Einthoven's equation: II = I + III.

(To verify, take the net amplitude of QRS complexes respective leads from any EKG and do the calculations)

Relationship between Augmented unipolar limb leads (aVR, aVL, aVF) & Standard bipolar leads (I, II, III):
aVR = (I + II)/2
aVL = (I - III)/2
aVF = (II + III)/2

From Principles of clincal electrocardiography by Mervin J. Goldman. 11th ed. 1982. Lange Medical Publications.


Cath Lab: Artifacts in Pressure Traces...Underdamped waveform

Both panels below have LV pressure trace recorded in the same patient.
Upper panel has artifact (Underdamping of the trace)
This artifact is corrected in the lower panel.

What is the mechanism of this artifact (Underdamping)?
What are the methods that can be used to correct such artifact?


EKG - Quiz

5-mo old, VSD closure, Repair of primum ASD and Cleft Mitral Valve. Postop. Day 4. H/O Junctional Ectopic Tachycardia - controlled with Amiodarone for the 2 days.
What is the rhythm?
What is the differential diagnosis?
How would you differentiate between Junctional Rhythm from Sinus rhythm with First degree AV block?
(Click on the image to enlarge)

Atrial lead is in V1.

A-paced at 150 bpm.


EP: Quiz, Interpret this EKG recording

You are called to consult for irregular heart rate. A newborn who has recovered from severe sepsis was noted to have irregular heart rate on the day of discharge. Therefore, discharge was canceled and you were consulted. A PICC line was removed the day before. Baby is otherwise doing well. Here are the traces. There are no answers for these traces. Your differential diagnosis and discussion is what is expected.


Quiz: EP - Apparent Malfunction of Pacemaker

1 yr old boy, s/p Mitral Valve replacement, Postop. AV block. Epicardial DDD pacemaker. HR range is set at 110-180 bpm.
First panel (24-hr trend) shows pacemaker heart rate decreased to ~110 bpm between 6pm & 10pm, when the patient was febrile.
Second panel shows EKG prior to drop in HR.
Third panel shows EKG during the low HR at ~110 bpm (with fever).
Fourth panel shows EKG after return of HR to higher level (after fever).
Fifth panel shows current EKG at the time of review (next day).

1) What are the possible reasons for the pacemaker not to respond appropriately during a time of need (fever)?
2) What further information is needed regarding pacemaker settings to determine the cause of this pacemaker behavior?
3) What change, if any need to be made in the pacemaker settings?


Wire shape for RPA and LPA

Image from Jim Lock's Cath Book 1987
(Diagnostic and Interventional Catheterization in Congenital Heart Disease.
James E. Lock, John F. Keane, Kenneth E. Fellows First edition 1987. Marinus Nijhoff Publishing, Boston, MA)

My first choice for LPA is just not to put any curves in the wire. But, you may need these wire shapes to enter "postop. LPAs".