The quad cab has a smaller back seat and a larger bed, the crew cab has a larger back seat and a smaller bed. To compare them you can go to http://www.ramtrucks.com/en/2011/ram_150... and select the Build My Own option from the bottom of the page.
Heart muscle thickening (called cardiac hypertrophy) can be a healthy response to exercise and pregnancy; however, it often occurs in people with high blood pressure, diabetes, heart failure and certain genetic conditions.
Hypertrophic cardiomyopathy (HCM) is associated with thickening of the heart muscle, most commonly at the septum between the ventricles, below the aortic valve. This leads to stiffening of the walls of the heart and abnormal aortic and mitral heart valve function, both of which may impede normal blood flow out of the heart.