In:
Circulation: Arrhythmia and Electrophysiology, Ovid Technologies (Wolters Kluwer Health), Vol. 5, No. 3 ( 2012-06), p. 475-483
Abstract:
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 (rs=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 cm 2 . 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.
Type of Medium:
Online Resource
ISSN:
1941-3149
,
1941-3084
DOI:
10.1161/CIRCEP.111.967893
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2012
detail.hit.zdb_id:
2425487-3
