A Consideration of Recent Criticisms of the T-wave Amplitude Index of Myocardial Sympathetic Activity.

Because of its ventricular origin, T-wave amplitude (TWA) has been suggested as a plausible candidate index for assessing myocardial sympathetic activity. This idea received some support in the literature but recent (1979-1980) papers from three independent laboratories have criticized the validity of TWA, and have at least implicitly suggested that TWA should he abandoned as a noninvasive sympathetic index. This paper examines these criticisms and finds them to he of questionable validity and certainly not of sufficient strength to support abandoning TWA. Instead, the conclusion drawn here is that we should continue to critically assess both TWA and other noninvasive candidate sympathetic indices by using invasive myocardial indices as criterion measures and both behavioral and pharmacological interventions as manipulations. [ABSTRACT FROM AUTHOR]