PMC7436781_01
PMC7436781_02
Flow diagram illustrating the steps adopted during literature evaluation that led to the selection of the literature evaluated in this report. This process applies to literature evaluated up to October 2019. PubMed IDs for the eight articles excluded are: Prescrire Int, 2006 (PMID: 16764099); Riepe, 2014 (PMID: 24717382); Livio et al., 2011 (PMID: 21309181); Hadano et al., 2013 (PMID: 30546746); Burry et al., 2019 (PMID: 31479532); Zarowitz and Tisdale, 2019 (PMID: 30747995); Heranval et al., 2016 (PMID: 27063094); Sasaoka et al., 2016 (PMID: 27723808).
10.1177_2042098620942416-fig1.jpg
PMC7436781_02_10.1177_2042098620942416-fig1.jpg
fig1-2042098620942416
Figure 1 shows the data from the case reports examined here.
QT interval nomogram. The figure contains plots of uncorrected QT intervals against corresponding heart rate for donepezil, galantamine and rivastigmine. With this nomogram, points plotted above the line indicate QT interval prolongation. For a number of the studies, uncorrected QTc interval values were not available, but heart rate and QTc interval values were. This allowed uncorrected QT interval values to be derived. QT intervals were required to be calculated from QTc and rate information in one galantamine case and five donepezil cases. As the correction formula used was unspecified in most reports, we derived uncorrected QT intervals where this was necessary using both Bazett's and Fridericia's rate correction formulae, plotted in panels A and B, respectively (Y axis labels in A also apply to B). For the sole rivastigmine case, both QT and QTc intervals were given in the case report, but heart rate was not. However, the very close proximity of QT and QTc intervals in that case yielded the same heart rate value with both correction formulae.
10.1177_2042098620942416-fig2.jpg
PMC7436781_02_10.1177_2042098620942416-fig2.jpg
fig2-2042098620942416
Therefore, where it was necessary to calculate QT intervals in the absence of correction formula information, we calculated these using both Bazett's and Fridericia's formulae (Figure 2A and B, respectively).