Key result
Ventricular pacing for microvolt T-wave alternans assessment showed 80% concordance with atrial pacing (kappa = 0.62, P < 0.001), with 93% sensitivity and 71% specificity.
Why the study?
Does ventricular pacing yield concordant results compared to atrial pacing for the assessment of microvolt T-wave alternans in patients evaluated for sudden cardiac death risk?
Cross-Sectional (n=42)
Does ventricular pacing yield concordant results compared to atrial pacing for the assessment of microvolt T-wave alternans in patients evaluated for sudden cardiac death risk?
Effect estimate: kappa 0.62
p-value: p=< 0.001
Ventricular pacing is a feasible alternative to atrial pacing for microvolt T-wave alternans assessment, showing good concordance but generating higher noise and amplitudes.
VP may offer alternative to AP for MTWA testing; leaves open prospective validation for SCD risk stratification.
INTRODUCTION: Assessment of microvolt T-wave alternans (MTWA) by the spectral analysis (SA) method requires the heart rate to be stable within a certain range. This can be achieved by ventricular pacing (VP). We compared MTWA during short-term VP versus atrial pacing (AP). METHODS: Patients presenting for evaluation of risk of sudden cardiac death underwent an invasive electrophysiologic study. The concordance of results of MTWA-VP with MTWA-AP was evaluated, as well as the specificity, sensitivity, negative, and positive predictive values of MTWA-VP versus MTWA-AP. The maximum recorded amplitude of MTWA (MValt) in concordant positive results, as well as noise levels in all, were compared in both pacing modes. RESULTS: We studied 42 consecutive patients, of whom 31 completed both tests (32 by AP, 40 by VP). Compared to AP, VP-MTWA SA had a sensitivity of 93%, specificity of 71%, negative predictive value of 92%, and positive predictive value of 72%. The results were concordant in 25 patients (80%, kappa = 0.62, P < 0.001). The noise level was significantly higher during VP than AP (1.4 +/- 0.8 vs 1 +/- 0.8, P < 0.01), and there was a trend toward a higher amplitude of TWA by VP (10.7 +/- 5.3 vs 7.8 +/- 3.9, P = 0.058). CONCLUSIONS: MTWA SA is more likely to be completed during VP than AP. Overall there was concordance between both tests. VP generates higher amplitudes and noise, and a higher percentage of nonnegative results.
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Shalaby et al. (2007) conducted a cross-sectional in Risk of sudden cardiac death (n=42). Ventricular pacing (VP) vs. Atrial pacing (AP) was evaluated on Concordance of results of MTWA-VP with MTWA-AP (kappa 0.62, p=< 0.001). Ventricular pacing for microvolt T-wave alternans assessment showed 80% concordance with atrial pacing (kappa = 0.62, P < 0.001), with 93% sensitivity and 71% specificity.