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

• Left anterior fascicular block
• Left ventricular hypertrophy
• Left bundle branch block

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

• Ventricular tachycardia.
• Positive deflection wide QRS
• R-wave peak time (RWPT) >50 ms
  

• Ventricular tachycardia.
• Negative deflection wide QRS
• R-wave peak time (RWPT) >50 ms
  

• Supraventricular tachycardia with aberrancy.
• Negative deflection wide QRS
• R-wave peak time (RWPT) <50 ms
  

References

• Pava LF, Perafán P, Badiel M, Arango JJ, Mont L, Morillo CA, Brugada J. R-wave peak time at DII: A new criterion for differentiating between wide complex QRS tachycardias. Heart Rhythm. 2010 Jul;7(7):922-6
• Datino T, Almendral J, Avila P, González-Torrecilla E, Atienza F, Arenal A, Fernández-Avilés F. Specificity of electrocardiographic criteria for the differential diagnosis of wide QRS complex tachycardia in patients with intraventricular conduction defect. Heart Rhythm. 2013 Sep;10(9):1393-401
• Yu M et al. R-Wave Peak Time at Lead II in Adults With Ventricular Premature Beats, Bundle Branch Block and Left Anterior Fascicular Block. Am J Med Sci. 2018 Jan;355(1):44-47
  

Advanced Reading

Online

• Wiesbauer F, Kühn P. ECG Yellow Belt online course: Become an ECG expert. Medmastery
• Wiesbauer F, Kühn P. ECG Blue Belt online course: Learn to diagnose any rhythm problem. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog.

Textbooks

• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
• Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
• Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
• Hampton J. The ECG Made Practical 7e, 2019
• Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
• Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography 1e, 2009
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
• Mattu A, Brady W. ECG’s for the Emergency Physician Part I 1e, 2003 and Part II
• Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

LITFL Further Reading

• ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
• ECG A to Z by diagnosis – ECG interpretation in clinical context
• ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
• 100 ECG Quiz – Self-assessment tool for examination practice
• ECG Reference SITES and BOOKS – the best of the rest