|Year : 2015 | Volume
| Issue : 1 | Page : 72-73
Department of Cardiology, PGIMER, Chandigarh, India
|Date of Web Publication||22-May-2015|
Dr. Parag Barwad
Department of Cardiology, PGIMER, Chandigarh - 160 012
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Barwad P. Electrocardiography quiz. J Pract Cardiovasc Sci 2015;1:72-3
| ECG Quiz|| |
Question - analyze the ECG [Figure 1].
| Clinical Details|| |
A 32-year-old male patient had an episode of palpitation lasting for 3 h. The onset was abrupt, but there was no hemodynamic compromise. There is a history of similar episodes since last 2 years, lasting for few hours with spontaneous termination. However, required intravenous verapamil for termination on few occasion. The echocardiogram done was normal.
- Regular tachycardia with right bundle branch block (RBBB) morphology, QRS duration of 120 ms
- Left axis deviation
- Inverted P waves are seen, best in lead III (red arrow)
- Constant QRS and P relationship (red arrow).
Interpretation [Figure 2]
- Broad, complex regular tachycardia in young patients is usually supraventricular tachycardia with aberrancy
- However, any broad complex tachycardia not fulfilling the criteria for a typical bundle branch block (RBBB or left bundle branch block), may be a tachycardia of ventricular origin
- RBBB usually has an associated right axis deviation
- Thus, the present patient has a ventricular tachycardia (VT) arising from the left posterior fascicle (fascicular VT)
- Though atrioventricular dissociation is a diagnostic feature for VT, this is seen in only 50% of patients. In fact, up to 25% of patients in VT may have 1:1 ventriculoatrial conduction, as shown, in this case.
Further case details: The patient was taken-up for electrophysiological study, which showed recurrently inducible left posterior fascicular VT, for which a successful radiofrequency ablation was performed.
- Fascicular VT is a relatively benign variety of VT arising from the left ventricle with re-entry within the posterior left fascicle as the possible mechanism
- Electrocardiography characteristics of fascicular VT are RBBB with left axis deviation/northwest axis, with relatively narrow QRS
- This tachycardia usually does not cause hemodynamic compromise and occur in younger population
- However, in few patients incessant tachycardia may cause left ventricular dysfunction
- Verapamil/Diltiazem is effective in terminating this VT; Adenosine is ineffective
- Radiofrequency ablation has a success rate of 90%
- Early recognition and differentiating it from other VTs is important in view of its treatment strategy.
[Figure 1], [Figure 2]