Cannabis and Myocardial Infarction

It has been noted that there is a five-fold increase risk of Myocardial Infarctions (MI) in the first hour after cannabis use. Traditional risk factors for MI include diabetes, hypertension and dyslipidemia. The rising use of cannabis may have ushered in an additional MI risk factor to be added to the list; that is cannabis. In this review, we discuss the growing use of cannabis and potential link with MI, highlighting the common pathogenic hypotheses linking these risk factors. While Metabolic and Inflammatory effects accrue over time with cannabis use, cardiovascular effects from cannabis use can precipitate to a MI much more acutely. Myocardial effects result from alterations in coronary blood flow and heart rate promoting myocardial ischemia and potential infarction. Several studies have reported that acute THC use may be involved in reducing coronary blood flow.

Additionally, intravascular ultrasoundson patients experiencing THC associated myocardialinfarction usually findno evidence of atherosclerotic CAD.  Coronary angiography usually confirms coronary vasospasm and platelet thrombus formation without underlying atherosclerosis. Moreover, myocardial oxygen supply is further restricted by an increased concentration of carboxyhemoglobin leading to a reduction in oxygen carrying capacity of red blood cells. Further exacerbating the myocardial oxygen supply are elevations in both heart rate and blood pressure, resulting in reductionof diastolic coronary filling and elevated diastolic coronary pressures.

Therefore, the reduction in coronary blood flow in combination with reduced oxygen carrying capacity and potential systemic and coronary vasoconstriction lead to an increase in myocardial oxygen supply-demand mismatch, resulting in ischemia. Patients suffering from preexisting cardiac conditions such as stable angina are especially prone to develop symptoms. Decreased exercise time to angina was reported in volunteers who use THC. Other studies have proposed that the hemodynamicmresponse caused by THC interrupts perfusion in susceptible atherosclerotic plaques. The role of beta blockers in reducing the myocardial oxygen supply-demand mismatch in cannabis users warrants further investigation.

The above Article originally got published at SciFed Journal of Cardiology in 2017, to have a glance please visit: Click Here