This is the same concept as one of my earliest articles when I coined the phrase “Trust Earning Text” for Pure360.
That top two lines of text can help you get the email opened and the images loaded. After than you are left with coding for the preview pane to get that call to action clicked.
Also don’t forget that people’s attention span is smaller and smaller, hence the success or social media – in many way a tweet is an email with a call to action subject line and link. I wonder how many clicks a tweet gets compared to an email?