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

70yr old male presented with chest pain, palpitations and hypotension. He underwent DC cardioversion and this is his post cardioversion ECG.

Rate:

78
Rhythm:

Regular
Sinus rhythm
Axis:

Normal
Intervals:

PR – Normal (~180ms)
QRS – Normal (100ms)
QT – 320ms (QTc Bazett 370 ms)
Segments:

ST Elevation leads V1 & V3 ?? aVF
ST Depression leads II, III, aVF, V5-6
ST segment analysis difficult due to baseline wander
Additional:

Deep symmetrical T wave inversion leads II, III, aVF, V5-6
Interpretation:

Without more clinical information on the case including prior medical history, findings on serial ECG’s, old ECG’s, and result of further investigations post this episode e.g. echo or angio it’s difficult to give a clear conclusion to this case and ECG.

The broad differentials for the findings on this ECG are:

Ischemia
Structural Heart Disease
Cardiac T-wave Memory
T wave memory is an interesting phenomenon that could explain the marked T wave changes seen on this ECG. It results in transient T wave changes following a period of abnormal ventricular conduction e.g. ventricular tachycardia, paced rhythms, intermittent bundle branch block or aberrant conduction.

86 yr old male referred by his General Practitioner with worsening renal failure. He has a history of atrial fibrillation with bradycardia for which he had a PPM inserted. His medications include metoprolol.

ECG ANSWER and INTERPRETATION
Rate:

Mean ventricular rate ~24 bpm
Rhythm:

Irregular ventricular rhythm
No visible P waves
Irregular pacing spikes mean rate of 43 bpm
No evidence of capture
Axis:

Normal
Intervals:

QRS – Prolonged
Additional:

ST depression with T wave inversion leads II, III, aVF
Interpretation:

Pacemaker failure to capture
Underlying marked slow atrial fibrillation

CLINICAL PEARLS
Causes of pacemaker failures

In broad terms there is either a problem with the pacemaker signal generator, the connection to the patient or the patient. These can be further expanded:

Signal generator problems
End-of-life
Battery failure
Programming issue
Over or under sensing
Connection between unit and patient
Lead fracture
Lead malposition
Lead migration
Lead fibrosis
Patient factors
Progression of underlying disease
Ischaemia
Electrolyte / acid-base disturbance
Drug toxicity
Further reading:

61-year-old lady is brought in by ambulance with palpitations and dizziness. GCS 15. HR 190, BP 75/50.