abstract

presented

at the 1995 ACC

New Orleans, Louisiana

March 20-22, 1995

Electrical Alternans During Rest and Exercise as Predictors of Vulnerability to Ventricular Arrhythmias

J Am Coll Cardio Feb. 1995; Special Issue:1027-39N. A. Mark Estes, Douglas P. Zipes, Nabil El-Sherif, Ferdinand J. Venditti, *David S. Rosenbaum, *Paul Albrecht, *Paul J. Wang, Philip C. Krause, *Richard J. Cohen. Tufts University, New England Medical Center, Boston, MA, Massachusetts Institute of Technology, Cambridge MA.

Electrical alternans representing visually inapparent beat-to-beat alternating amplitude on the electrocardiogram, has been reported to predict vulnerability to ventricular arrhythmias during atrial pacing. We hypothesized that electrical alternans recorded during sinus rhythm and with the heart rate elevated by exercise would be similarly predictive. In the pilot phase of a multicenter study, electrical alternans recordings were made at rest, during a bicycle protocol to maintain the heart rate 100-110 bpm, and analyzed using a spectral method incorporating noise reduction software. Ventricular vulnerability was defined by prior episodes of clinical ventricular tachycardia(VT) or ventricular fibrillation(VF) or by VT or VF induction at electrophysiology study. The results are:

Sens.
Spec.
+PV
-PV
RR
p
Rest
50%
91%
80%
71%
2.8
0.14
Exercise
80%
91%
89%
84%
5.3
0.005
Rest/Exer
100%
91%
91%
100%
>10
 <0.005

+PV: positive predictive value -PV: negative predictive value

RR: relative risk p: significance level

Conclusions: Electrical alternans can be measured during exercise and is an accurate predictor of vulnerability to ventricular arrhythmias. Electrical alternans measured during sinus rhythm at rest is not as accurate a predictor. Combining rest and exercise electrical alternans results is more predictive of arrhythmia vulnerability than rest or exercise alone.



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