-year-old female with intentional polypharmacy overdose. HR 72 reg, BP 100/62, GCS 15.

Sinus rhythm, rate 72 bpm
1st degree AV block (PR interval ~210ms)
Northwest axis
Dominant R’ wave in aVR reflects terminal right axis deviation of the QRS
There is marked intraventricular conduction delay (IVCD) with QRS duration ~160ms
Absolute QT interval is 460ms
This patient has three important toxicological ECG manifestations — there are features of AV blockade, sodium channel blockade, and potassium efflux blockade.

Such marked QRS widening places them at risk of both seizures and ventricular arrhythmias. An absolute QT interval of 460ms is on the borderline of the tox nomogram — this patient is likely at risk of Torsades de Pointes (TdP).

QT interval: Measure from the Q wave to the intersection of T wave maximum slope with the isoelectric line

“12 mg of adenosine x 2 did not work, and neither did Electrical Cardioversion at 200J x 2

Diagnosis ?

The presence of supraventricular tachycardia is required to diagnose a Wolff-Parkinson-White (WPW) pattern on ECG.
A. True
B. False

Rate:

102 bpm
Rhythm:

Regular
Sinus Rhythm
Alternating QRS Morphologies
See annotated ECG below

54 year old lady attends with 2 month history of ‘chest flutterings

Axis:

Normal
All complexes
Intervals – QRS Complexes Labelled in Red

PR – Short at ~110ms
QRS – Normal at 100ms
QT – 340ms
Intervals – QRS Complexes Labelled in Green

PR – Normal at ~140ms
QRS – Normal at 80ms
QT – 320ms
Additional:

Alternating variation in QRS voltages
Alternating variation in T wave voltages in right precordial leads
Subtle delta waves seen in the complexes labelled red in the right precordial and inferior leads
Interpretation:

Alternating pre-excitation / accessory pathway conduction with sinus conduction

The EP members of our team agree this is likely a weak left sided pathway with classical intermittent pre-excitation which usually confers a benign prognosis in the setting of atrial fibrillation.

For a great overview article on pre-excitation and paroxysmal SVT check out:

Almendrala J, Castellanosa E, Ortiza M. Paroxysmal Supraventricular Tachycardias and Preexcitation Syndromes

ممكن تعزيز القناه حتي يتم فتح الحظر عليها