Figure 2.

QTc intervals in patients with obstructive sleep apnea at three different altitudes during discontinuation of continuous positive airway pressure therapy. White boxes with whiskers and dots represent medians, quartiles, 5^th, 10^th, 90^th and 95^th percentiles during placebo treatment, gray boxes represent corresponding values during acetazolamide treatment. Mean QTc intervals during entire nights (meanQTc, lower panel) and mean QTc intervals during minutes with the highest values of the nights (maxQTc, upper panel) are shown. Significant differences (P < 0.05) between values at the higher altitudes versus values at 490 m, and between acetazolamide and placebo are indicated.