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:

Sens.
Spec.
+PV
-PV
RR
Accy.
p
EP
71%
78%
36%
94%
5.89
77%
0.0090
SAECG
50%
72%
18%
92%
2.27
69%
 0.3706
EA
89%
82%
53%
97%
17.08
83%
<0.0001
EA & SAECG
88%
91%
68%
97%
24.61
90%
<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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