Cannabis and Heart Disease

If you’re really following the discussion about cannabis, you may have noted that cannabis can potentially affect heart problems.  While this can be a serious issue, there are details that we should discuss so that you know whether cannabis poses a risk to you and what you can do about it. 

Understanding Cannabis’s Potential Effects on Heart Health

Let’s start by breaking down heart disease into a few categories that will help us understand the effects and risks of cannabis. 

An Overview of Coronary Artery Disease

First, there’s coronary artery disease.  The heart is a muscle and requires oxygen from the blood stream to be able to contract and pump blood.  The heart muscle is fed by arteries called the Coronary Arteries.  If these get blocked and not enough blood can get through, then the heart muscle can die.  This is called a heart attack, or Myocardial Infarction. 

While most heart attacks happen abruptly due to an acute obstruction, typically the development of a tiny blood clot on a fatty deposit in the artery, sometimes we can have a heart attack just from the gunk in the artery narrowing the pipe so that the heart can’t get enough blood when it’s working hard.  This is called Demand Ischemia – meaning the demand for oxygen is greater than can be supplied by the artery.  This demand goes up when the heart beats faster, like if you’re running. 

Cannabis and Heart Rate

Cannabis causes a brief and usually harmless increase in heart rate.  For most people, they don’t even notice.  For some, they can feel the increased rate and report “palpitations”.  This is important to know as some people experience these palpitations as anxiety.  But with forewarning, it can be a minor nuisance. 

However, in patients with narrowed coronary arteries, this increased heart rate could lead to insufficient blood getting through.  Typically this leads to pain in the chest and/or shortness of breath.  It’s important to discuss your cardiac health with your cannabinoid specialist doctor.  It may be that cardiac testing is important for you and a visit to the Cardiologist is in order prior to starting cannabis treatment.  There are fairly few studies on how often this actually occurs and those studies that we do have on this topic weren’t all that well done.  Our best understanding at this time is about 20% increased risk.

In the worst case scenario, this could lead to a heart attack so it’s important to take any symptoms seriously and call 911. 

Heart Rhythm Problems and Cannabis

The next category of heart disease is rhythm problems.  Our hearts beat in an orderly manner that leads to proper propulsion of blood out of the heart and around our body.  There are a range of problems that can lead to discoordinated beating.  One such odd rhythm is called Atrial Fibrillation.  The main risk from Atrial Fibrillation is the formation of blood clots that can be propelled out of the heart and can block blood flow in other organs like your brain, causing a stroke. 

Cannabis seems to be able to provoke Atrial Fibrillation.  Again, the studies on this are few and not very well done.  The increased risk appears to be again about 20%.  However, it is unusual for it to cause new Atrial Fibrillation and people who have ongoing Atrial Fibrillation should already be on medication to control it. 

Congestive Heart Failure

Last, as we’ve discussed, the heart is a muscle and after enough heart attacks or other insults, it may simply not pump very effectively any more.  This leads to a condition where the blood backs up though the heart into the lungs causing difficulty breathing and swelling in the legs.  This is called Congestive Heart Failure. 

Cannabis can make the strength of the heart contractions less.  This is just not a problem in a normal heart, but in a damaged heart with a history of heart failure, cannabis can make that heart failure worse.  This can be a minor issue or it can be life-threatening.  Again, discussing your symptoms and history with your cannabis expert is really crucial. 

In most cases, the decrease in pump function is so little as to have no noticeable effect, but for patients with severe CHF at baseline, this poses risk.  I’ve found that patients with severe heart failure who need cannabis for pain management, for example, are often so sick that any positive intervention is worth the risk.  However, consulting with your cardiologist to be sure we’re all in agreement is important and there are steps that can be taken to minimize this risk. 

Evaluating Cannabis Use in Heart Patients

Overall, heart disease, of any type, is a major consideration when evaluating whether cannabis is a safe medication for a patient.  Your medical history and current state of cardiac health will be the determining factors.  Hence, it’s crucial to discuss your full health history and any ongoing symptoms with your cannabis specialist who can, with the advice of your cardiologist if needed, help you understand and minimize any risk.