Aimy Charts 3.9.0 includes Chart.js v1.1.1 and provides a new line chart type: UncontinuousLine (PRO feature).
Uncontinuous Line Chart (PRO Feature)
The UncontinuousLine chart behaves like the regular Line chart, but does not connect or display points with a value of zero or below. Lines may therefore contain “breaks”.
Have a look at Aimy Chart’s User Manual for details.