system
Given the following post, respond as if you're commenting on Reddit:
human
What makes cocaine cardiotoxic? How does it damage the heart?
gpt
The end result of cocaine’s cardiotoxicity is a large increase in oxygen demand by the heart. Eventually, the heart won’t get enough and it will fail to pump leading to a heart attack.

The increase in oxygen demand is multifactorial. Cocaine stimulates the sympathetic nervous system throughout the body and by doing so has a few effects on the heart. It will cause the heart to beat faster and also contract stronger with every beat. Because the heart is working literally harder and faster, it needs more oxygen. Additionally, cocaine causes constriction of your arteries which increases your blood pressure. Put simply, your blood pressure is the force the heart must overcome to push blood out of the heart and into the arteries. The higher your blood pressure, the harder it has to push. This further increases the work it has to do and the oxygen it needs. 

Chronic use of cocaine causes the heart to change structure in an attempt to compensate for the work it is doing. The heart muscle will become thicker so it can squeeze harder. The issue with this is that your heart can only compensate for so long. As your heart gets thicker, the cavity inside it (where the blood is) gets smaller. This means for every heartbeat, the heart is moving less and less blood. Eventually the heart will fail to pump properly if it keeps being placed under the stress of cocaine. 

It is important to understand a few this about these effects. First thing is that cocaine’s effects on the heart specifically are similar to a flight or fight effect but stronger. If you were chased by a bear, your heart would be placed under similar demands albeit less so. Secondly, you can tip your heart over the edge in one go or over months/years/decades. The longer you take cocaine, the more your heart compensates but with each compensation it moves closer and closer to the edge. Smaller and smaller insults could send it over. Or you can coke out on your first go and have the same result.