Noe and Dr Farsalinos agree about not cutting down on nic if there is a risk of vaping more liquid with flavouring in it. http://ecigarette-research.com/web/index.php/research has some research regarding the heart. It is not very technical reading and it might make you feel more comfortable about your nic consumption. Bottom line is that your blood nicotine levels are probably the same as when you were smoking but minus the carbon monoxide which is a plus for the health of you heart. I will believe a cardiologist over a vendor on this subject.