R Wave Peak Time RWPT

R Wave Peak Time (Intrinsicoid deflection)

The time from the onset of the earliest Q or R wave to the peak of the R wave in the lateral leads (aVL, V5-6).

  • Represents the time taken for excitation to spread from the endocardial to the epicardial surface of the left ventricle.
  • R-wave peak time is said to be prolonged if > 45ms.
  • Additionally used in Lead II in the differentiation of Ventricular Tachycardia (VT) and Supraventricular Tachycardia (SVT) with aberrancy.
Causes of Prolonged RWPT
Prolonged R-wave peak time aVL

Prolonged R-wave peak time in aVL due to left anterior fascicular block

RWPT in wide QRS complex tachycardia

R-wave peak time (RWPT) can be used in differentiating ventricular tachycardia (VT) from supraventricular tachycardia (SVT) in patients with wide QRS complex tachycardia

RWPT duration is measured in Lead II from the onset of QRS depolarization until the first change of polarity (with both positive or negative QRS deflection)

Studies in 2010 and 2013 demonstrated RWPT ≥ 50 ms in lead II to be a simple, reproducible, sensitive and specific for ventricular tachycardia.

However, more recent studies suggest RWPT of 50 ms may be optimal to differentiate between VT and SVT with RBBB and LAFB, but not with LBBB

R-Wave Peak Time (RWPT) Lead II
  • Ventricular tachycardia.
  • Positive deflection wide QRS
  • R-wave peak time (RWPT) >50 ms

R-Wave Peak Time (RWPT) Lead II negative
  • Ventricular tachycardia.
  • Negative deflection wide QRS
  • R-wave peak time (RWPT) >50 ms

R-Wave Peak Time (RWPT) Lead II SVT
  • Supraventricular tachycardia with aberrancy.
  • Negative deflection wide QRS
  • R-wave peak time (RWPT) <50 ms


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Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

One comment

  1. Marek Jastrzebski
    Marek Jastrzebski

    RWPT in WCT diagnosis? Neither specific [85.3% (80.6–89.3)] nor sensitive [62.0% (57.6–66.2)]. But useful when combined with other criteria in VT SCORE method. Europace (2016) 18, 578–584.
    Congratulation on your web page., Marek

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