Correlation between signal-averaged ecg and the histologic evaluation of the myocardial substrate in right ventricular outflow tract arrhythmias

Pasquale Santangeli, Maurizio Pieroni, Antonio Dello Russo, Michela Casella, Gemma Pelargonio, Luigi Di Biase, Andrea Macchione, J. David Burkhardt, Fulvio Bellocci, Pietro Santarelli, Claudio Tondo, Andrea Natale

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Background-The differential diagnosis between idiopathic and cardiomyopathy-related right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs) is crucial. Signal-averaged ECG (SAECG) abnormalities are frequent in cardiomyopathy-related RVOT-VAs, although their pathophysiologic basis and diagnostic value in this setting are undefined. We tested the association between SAECG and the myocardial substrate underlying RVOT-VAs. Methods and Results-Twenty-four consecutive patients (median age, 50 years [42-59]; 12 men) with RVOT-VAs (10 with frequent [>1000/24 hours] premature ventricular contractions, 14 with ventricular tachycardias) underwent SAECG with 40-Hz filtering and electroanatomic mapping (EAM) with EAM-guided biopsy for characterization of the RVOT-VAs substrate. A filtered averaged QRS (fQRS) was obtained and analyzed for fQRS duration, low amplitude signal duration <40 mV (LAS40), and root-mean-square voltage in the last 40 ms of the QRS (RMS40). Standard definition of EAM scar was used. EAM-guided biopsy diagnosed ARVC in 11 (46%), myocarditis in 8 (33%), and idiopathic RVOT-VAs in 5 (21%) patients. Patients with cardiomyopathy-related RVOT-VAs had ≥1 EAM scar (median, 2 [1-2]; all with RVOT scar). EAM of patients with idiopathic RVOT-VAs was normal. Patients with cardiomyopathy-related RVOT-VAs had significantly longer fQRS (106 ms [92-132] versus 83 ms [82-84], P=0.01) and LAS40 (39 ms [36-51] versus 19 ms [18-21], P=0.02), and lower RMS40 (18 μV [9-26] versus 33 μV [32-33], P=0.04). A significant linear correlation was found between the extension (cm2) of the RVOT scar and all 3 SAECG parameters (r s=0.76, P<0.001 for the fQRSd; rs=0.73, P<0.001 for the LAS40; and rs=-0.72, P<0.001 for the RMS40). Using the established 2 of 3 criteria (ie, late potentials), SAECG diagnosed cardiomyopathy-related RVOT-VAs with high positive (100%) but low negative (38%) predictive values and missed 7 of 9 (78%) patients with RVOT scar <8 cm2. Conclusions-In patients with RVOT-VAs, abnormal SAECG parameters reflect the presence of extensive cardiomyopathic involvement of the RVOT. However, a negative SAECG does not reliably rule out cardiomyopathy-related RVOT-VAs in the presence of a small RVOT scar. (Circ Arrhythm Electrophysiol. 2012;5:475-483.)

Original languageEnglish (US)
Pages (from-to)475-483
Number of pages9
JournalCirculation: Arrhythmia and Electrophysiology
Issue number3
StatePublished - Jun 2012
Externally publishedYes


  • Right ventricular outflow tract tachycardia
  • Signal-averaged ECG
  • Three-dimensional electroanatomic mapping

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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