E-Cigarette Use and Subclinical Cardiac Effects

ABSTRACTBACKGROUNDElectronic (e-) cigarettes are marketed as a safer alternative to conventional tobacco cigarettes. Although e-cigarettes contain a lower level of nicotine, the delivery method involves delivering an aerosolized bolus of poorly-characterized ultrafine particles that have unknown cardiovascular effects.METHODSWe studied apparently adult volunteers, free of any chronic disease, including: non-smoking controls, chronic e-cigarette users, and chronic tobacco cigarette smokers. After overnight abstinence, we used myocardial contrast echocardiography to measure acute increases in myocardial blood flow (MBF)induced by ischemic rhythmic handgrip stress, which causes sympathetically-mediated increases in myocardial work and oxygen demand and, in turn, shear stress, nitric oxide production, and coronary endothelial-dependent vasodilation.RESULTSIn non-smoking controls, handgrip stress increased myocardial blood flow, reflecting normal endothelial function. Chronic tobacco cigarette smokers demonstrated stress-induced blunting in myocardial blood flow change, when compared to non-smoking controls. Chronic e-cigarette smokers demonstrated a decrease, rather than increase, in myocardial blood flow change.CONCLUSIONChronic e-cigarette users demonstrated substantially impaired coronary microvascular endothelial function, even more pronounced than that seen in chronic tobacco cigarette users. These findings suggest that chronic e-cigarette use leads to measurable and persistent adverse vascular effects that are not directly related to nicotine.