ECG Case 99: Sinus Rhythm with Paroxysmal Ventricular Tachycardia

ECG Interpretation

This ECG looks difficult to interpret because there is a nine-beat run of a broad complex tachycardia which occupies the whole of leads V1–V3.

The key is to identify the rhythm first, from the lead II rhythm strip at the bottom. The ECG shows:

  • The rhythm is basically sinus, with a rate varying between 65/min and 100/min
  • One ventricular extrasystole, at the beginning of the record
  • Broad complex tachycardia with an obviously different morphology from the sinus beats. The QRS complex duration is 160 ms, and in lead V1 the R peak is higher that the R1 peak. These features make it likely that the tachycardia is ventricular in origin
  • Left axis deviation in the sinus beats (left anterior hemiblock)
  • QRS complexes in the sinus beats otherwise appear normal
  • Slight ST segment depression in leads II, III, V5–V6
  • T wave inversion in leads II, III
Sinus Rhythm with Paroxysmal Ventricular Tachycardia
Sinus Rhythm with Paroxysmal Ventricular Tachycardia
Criteria for Discriminating Ventricular Tachycardia from SVT with Aberration
Criteria for Discriminating Ventricular Tachycardia from SVT with Aberration

What to do ?

This patient’s attacks of dizziness may be due to the paroxysmal arrhythmia, which is life-threatening. The results of an ambulatory ECG recording and an exercise test would be interesting, but the patient needs immediate treatment, and amiodarone would probably be the drug of choice.

A coronary angiogram should be considered because there may be one or more critical stenoses amenable to percutaneous coronary intervention (PCI), and this might abolish the ventricular tachycardia.