Quantitative T-wave alternans ≥90 µV during exercise strongly predicted cardiovascular mortality (HR 6.4; P=0.002) and ≥60 µV predicted sudden cardiac death (HR 4.6; P=0.002).
Cohort (n=2,119)
Does quantification of T-wave alternans during routine exercise testing predict total mortality, cardiovascular mortality, and sudden cardiac death in patients undergoing clinically indicated exercise testing?
Quantification of T-wave alternans during routine exercise testing significantly predicts total mortality, cardiovascular mortality, and sudden cardiac death, with the highest prognostic power observed during the exercise phase.
Hazard Ratio: 6.4
p-value: p=0.002
INTRODUCTION: We examined whether quantification of T-wave alternans (TWA) enhances this parameter's capacity to evaluate the risk for total and cardiovascular mortality and sudden cardiac death (SCD). METHODS AND RESULTS: The Finnish Cardiovascular Study (FINCAVAS) enrolled consecutive patients (n = 2,119; 1,342 men and 777 women) with a clinically indicated exercise test with bicycle ergometer. TWA (time domain-modified moving average method) was analyzed from precordial leads, and the results were grouped in increments of 10 microV. Hazard ratios (HR) for total and cardiovascular mortality and SCD were estimated for preexercise, routine exercise, and postexercise stages. Cox regression analysis was performed. During follow-up of 47.1 +/- 12.9 months (mean +/- standard deviation SD), 126 patients died: 62 were cardiovascular deaths, and 33 of these deaths were sudden. During preexercise, TWA >or= 20 microV predicted the risk for total and cardiovascular mortality (maximum HR >4.4 at 60 microV, P or=50 microV, with 90 microV TWA yielding maximum HRs for total and cardiovascular death of 3.1 (P = 0.03) and 6.4 (P = 0.002), respectively. During postexercise, TWA >or=60 microV indicated risk for total and cardiovascular mortality, with maximum HR of 3.4 at 70 microV (P = 0.01) for cardiovascular mortality. SCD was strongly predicted by TWA levels >or=60 microV during exercise, with maximum HR of 4.6 at 60 microV (P = 0.002), but was not predicted during pre- or postexercise. CONCLUSION: Quantification of TWA enhances its capacity for determination of the risk for total and cardiovascular mortality and SCD in low-risk populations. Its prognostic power is superior during exercise compared to preexercise or postexercise.
Minkkinen et al. (2008) conducted a cohort in Clinically indicated exercise test (n=2,119). Quantitative T-wave alternans (TWA) vs. Lower TWA levels was evaluated on Total and cardiovascular mortality and sudden cardiac death (HR 6.4, p=0.002). Quantitative T-wave alternans ≥90 µV during exercise strongly predicted cardiovascular mortality (HR 6.4; P=0.002) and ≥60 µV predicted sudden cardiac death (HR 4.6; P=0.002).