Cars and the human body metabolize use to carbon compounds to obtain energy. They both need oxygen to complete this chemical process. Human beings breath oxygen into their lungs which hand it off to the hemoglobin that transports it to all parts of the body. Typically when the heart starts to fail, it's not getting sufficient oxygen to work correctly. So, this is some what like having an extremely clogged up air filter in your car. All the dirt and crap are diminishing the amount of oxygen that gets mixed in with gas to make the car run.