Electronic cigarettes — myocardial infarction, hemodynamic compromise during pregnancy, and systolic and diastolic dysfunction: Minireview

Table 1 Effects of electronic cigarettes on the risk of myocardial infarction and cardiac functional changes from electronic cigarettes

Name of the study	Type of the study	Results	Comments
Chronic intermittent electronic cigarette exposure induces cardiac dysfunction and atherosclerosis in apolipoprotein-E knockout mice	Animal model randomized control study with intervention	ECs with 2.4% nicotine had decreased left ventricular ejection fraction and had increased atherosclerotic lesions compared to ECs without nicotine and saline groups. Mice exposed to 2.4% nicotine vapor had increased atherosclerotic lesions on aorta as well	Mice model with limited implication to humans
Association between electronic cigarette use and myocardial infarction	Cross-sectional; study was based on self-reporting surveys	Increased odds ratio (1.79) of having MI with ECs and even higher odds ratio (4.62) with dual use of ECs and combustible cigarettes relative to never smokers	Number of surveys in 2014 was 36697 and 33028 in 2016
Acute effects of using an electronic nicotine-delivery device (electronic cigarette) on myocardial function: Comparison with the effects of regular cigarettes	Interventional, case-control	Electronic cigarettes caused delayed myocardial relaxation, no effect on systolic function	Small study with total of 76 subjects; the study does not predict long term effects
Association between electronic cigarette use and myocardial infarction	Cross-sectional through surveys	Daily EC use increased the odds of having MI (OR = 1.79) while daily TC smoking had a higher correlation of MI (OR = 2.72)	Large surveys: 36697 in 2014 and 33028 in 2016

ECs: Electronic cigarettes; MI: Myocardial infarction; OR: Odds ratio; TC: Tobacco cigarette.