R Wave Peak Time RWPT

• 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

RWPT in wide QRS complex tachycardia

R-wave peak time (RWPT) may be useful 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

Example 1

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

Example 2

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

Example 3

• 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 Mastery: 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
• Smith SW. The ECG in Acute MI. 2002 [PDF]

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