abstract
presented
at the 1995 ACC
New Orleans, Louisiana
March 20-22, 1995
Electrophysiologic
Testing, Electrical Alternans and Signal Averaged Electrocardiography
as Predictors of Arrhythmia-free Survival*
J Am Coll Cardio Feb. 1995; Special Issue: 926-26
Antonias A. Armoundas, David S. Rosenbaum, Jeremy
N. Ruskin, Hasan Garan, Richard J. Cohen. Massachusetts Institute
of Technology, Cambridge MA; Massachusetts General Hospital,
Boston, MA.
Arrhythmia-free survival was analyzed retrospectively
in 47 patients who underwent programmed electrophysiologic (EP)
testing as well as electrical alternans (EA) and signal averaged
electrocardiography (SAECG) measurements.
We compared the accuracy of (i) electrophysiologic
testing (inducible ventricular tachycardia or fibrillation), (ii)
electrical alternans (alternans ratio >3), (iii) signal averaged
ECG (QRS duration >114 msec or LAS>38msec or RMS 40<20uV)
and (iv) the combined use of EA and SAECG (a patient was classified
positive if EA was positive and SAECG was positive or indeterminate)
to predict the arrhythmia-free survival of these patients. SAECG
was deemed indeterminate if the QRS duration of any of the unfiltered
Frank leads was greater that 120 msec (n=11). The accuracy of
predicting arrhythmia-free survival was estimated by computing
actuarial arrhythmia-free survival at 20 months and comparing
20 month survival rates with EP, EA and SAECG testing. The results
are:
p | |||||||
EP | 0.0090 | ||||||
SAECG | 0.3706 | ||||||
EA | <0.0001 | ||||||
EA & SAECG | <0.0001 |
+PV: positive predictive value -PV: negative predictive value
RR: relative risk
p: significance level
Conclusions: EP, EA and
EA & SAECG were significant predictors of arrhythmia-free
survival. SAECG alone was not a significant predictor. In this
patient population, EA or EA combined with SAECG provided a powerful
measure of risk comparable or superior to EP.
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