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A 50-year-old patient with type IV Wolff-Parkinson-White (WPW) syndrome is shown, who presents with a crisis of atrial fibrillation (A) and atrial flutter (B)
that mimics ventricular tachycardia. The diagnosis of atrial fibrillation is supported by the history (knowing that the patient has WPW syndrome) and the
following characteristics of the ECG: (1) the wide complexes have a very irregular rhythm and are more or less wider (present more or less pre-excitation);
and (2) the narrow complexes (the sixth and the last one on the top) are sometimes close (the last complex) and sometimes far (sixth complex) to the
previous QRS. In sustained ventricular tachycardia, the QRS complexes are regular, and in the presence of narrow complexes, the QRS complexes are
always close to the previous one (capture beats). B. In WPW syndrome with flutter, the differential diagnosis with sustained ventricular tachycardia based
Source: Chapter 15. Surface Electrocardiography, Hurst's The Heart, 13e
only on ECG is more difficult because the RR are regular. C. Patient with crisis of atrial fibrillation with a very fast response of the ventricles (>300 ×′) and,
Citation:
Fuster
Walsh RA,
Harrington
RA.
TheR-R
Heart,
13e; 2011
Available
at: http://mhmedical.com/
Accessed:
Maywhich
03, 2017
sometimes, very
narrow
R-RV,intervals
(<200
ms). After
a Hurst's
very short
interval,
a crisis
of ventricular
fibrillation was triggered
(arrow),
had to be
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2017
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resolved by electric cardioversion. D. Patient with reciprocating tachycardia. The conduction in this circuit is retrograde over the accessory AV pathway
and anterograde via the normal AV conduction. The RP′ ratio is smaller than P′R ratio, which is typical for reciprocating tachycardia that involves an
accessory AV pathway.