W Brian Chiu1, Johan de Bie2, David W Mortara3. 1. Mortara Instrument, Inc., 7865 North 86th St., Milwaukee, WI 53204, USA. Electronic address: brian.chiu@mortara.com. 2. Mortara Instrument, Inc., Via Cimarosa 103, 40033 Casalecchio di Reno, BO, Italy. 3. University of California, San Francisco, Box 0610, 2 Koret Way, 631, San Francisco, CA 94143, USA.
Abstract
OBJECTIVES: To evaluate performance of J-to-T-peak (JTP) measurements of 12-lead ECGs, in a five-arm study using drugs with various levels of electrolyte channel block. METHODS: The novel evaluation method distinguishes between different aspects of measurement. "Random noise" is the variability among repeated measurements made without changing the conditions. "Context noise" is the variability of changes in context of the measurement, e.g. T-wave morphology, autonomic nervous system state. RESULTS: The average random noise of our RR-corrected JTPc measurements in standard deviations was 3.0 ms and not dependent on the drug. The average context noise was 4.0 ms for ranolazine, verapamil, and placebo, and 8.8 ms for dofetilide and quinidine. Measurement consistency is corroborated by linear fit confidence intervals of baseline- and placebo-corrected JTPc versus drug concentration. CONCLUSIONS: Systematic differences were found in JTPc drug response between the Mortara method and published data. Residual signal component in the context noise may influence future study design.
OBJECTIVES: To evaluate performance of J-to-T-peak (JTP) measurements of 12-lead ECGs, in a five-arm study using drugs with various levels of electrolyte channel block. METHODS: The novel evaluation method distinguishes between different aspects of measurement. "Random noise" is the variability among repeated measurements made without changing the conditions. "Context noise" is the variability of changes in context of the measurement, e.g. T-wave morphology, autonomic nervous system state. RESULTS: The average random noise of our RR-corrected JTPc measurements in standard deviations was 3.0 ms and not dependent on the drug. The average context noise was 4.0 ms for ranolazine, verapamil, and placebo, and 8.8 ms for dofetilide and quinidine. Measurement consistency is corroborated by linear fit confidence intervals of baseline- and placebo-corrected JTPc versus drug concentration. CONCLUSIONS: Systematic differences were found in JTPc drug response between the Mortara method and published data. Residual signal component in the context noise may influence future study design.
Authors: Jean-Philippe Couderc; Shiyang Ma; Alex Page; Connor Besaw; Jean Xia; W Brian Chiu; Johan de Bie; Jose Vicente; Martino Vaglio; Fabio Badilini; Saeed Babaeizadeh; Cheng-Hao Simon Chien; Mathias Baumert Journal: J Electrocardiol Date: 2017-09-01 Impact factor: 1.438
Authors: Jose Vicente; Robbert Zusterzeel; Lars Johannesen; Jay Mason; Philip Sager; Vikram Patel; Murali K Matta; Zhihua Li; Jiang Liu; Christine Garnett; Norman Stockbridge; Issam Zineh; David G Strauss Journal: Clin Pharmacol Ther Date: 2017-11-16 Impact factor: 6.875