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Electrocardiographic and electrophysiologic characteristics of midseptal accessory pathways

Shih-Ling Chang1, Shih-Huang Lee, Ching-Tai Tai

  • 1Department of Medicine and Cardiovascular Research Center, National Yang-Ming University, Fu Jen Catholic University, Veterans General Hospital, Taipei, Taiwan, ROC.

Journal of Cardiovascular Electrophysiology
|April 9, 2005
PubMed

Insights

Electrocardiography can differentiate right midseptal (RMS) from left midseptal (LMS) accessory pathways (APs). Delta wave polarity in lead V1 and precordial QRS transition are key indicators for distinguishing these accessory pathways.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Diagnostics

Background:

  • Accessory pathways (APs) can cause tachyarrhythmias.
  • Differentiating right midseptal (RMS) from left midseptal (LMS) APs is clinically important.

Purpose of the Study:

  • To investigate electrocardiographic and electrophysiologic characteristics of RMS and LMS APs.
  • To develop an algorithm for differentiating RMS from LMS APs.

Main Methods:

  • Analysis of delta wave and QRS transition during sinus rhythm.
  • Evaluation of retrograde P wave during orthodromic tachycardia.
  • Review of electrophysiologic characteristics and catheter ablation data from 38 patients with midseptal APs.

Main Results:

  • No significant difference in electrophysiologic characteristics or ablation outcomes between RMS and LMS APs.
  • LMS APs showed a higher incidence of biphasic delta wave in lead V1 (80% vs. 15%).
  • Precordial QRS transition distributions differed significantly between RMS and LMS APs (P=0.03).

Conclusions:

  • Delta wave polarity in lead V1 and precordial QRS transition are valuable for differentiating RMS and LMS APs.
  • A combination of delta wave negativity in V1 or QRS transition in V3/V4 predicted RMS APs with high sensitivity (90%) and specificity (80%).
Abstract

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