The new "enhanced" filter dramatically improves the readability of an ECG and you can see that by comparing these 2 images:
Here is the Original Filter (click on the image below to magnify):
vs. the new Enhanced Filter (click on the image below to magnify):
After you record an ECG, you can switch views from the Original to Enhanced filter. I'm very impressed by the quality of the ECG readings you're able to capture using the AliveCor Heart Monitor iPhone case.