In the study of the human body, there are what are known as anatomical or sectional planes. These are used to make communication of reference points standardized and easier among medical personnel and the like. In other words, anatomical planes are there so we know organs are located. Anatomical planes are like points-of-views where the body is cut and the organs are viewed. They are called: the sagittal view, transverse view, or coronal view.
For this particular question the heart and lungs can be viewed using the sagittal cut or sagittal view. This view is made by making an imaginary cut or line along the middle most vertical axis of the body. Imagine a line at the very middle of your body starting from your head down to your feet, dividing your left and right sides. That is the sagittal view.
The transverse view is cutting the body in half with a horizontal plane dividing your upper body and lower body. While the coronal view is cutting the body in the middle but this time dividing your front and back. When you think of coronal, think of the "crown" of the head being cut. Picture added to make understanding easier.