I don't have personal experience, but it has been proven that marijuana usage increase the heart rate and blood pressure of the user. Although not always immediate, both of these symptoms eventually may lead to heart attacks in the future. Although it is not toxic, that doesn't mean it is safe.
Medical research has documented the fact that within minutes of smoking marijuana, the heart beats more rapidly, accompanied by a drop in blood pressure.
Researcher's have found that the blood pressure and increased heart rate raise a marijuana smoker's risk for a heart attack by a factor of four, compared to their risk of a heart attack when not smoking.
Marijanana is a mood altering substance. It is not a substitute for proper healthcare. Like any chemical that enters the body it uses up minerals at an accelerated rate. One of those minerals, magnesium, is key to good cardiovascular health. When your magnesium gets low, your chances of having a heart attack increase.
Lots of things can induce heart attacks, anything from being kicked in the leg after a long flight to holding your breath too long, to choking on a peanut. However, eating peanuts, getting kicked, and holding your breath are generally not considered as "causes" of heart attacks. Marijuana use has NEVER been recorded as the necessary and sufficient element of any coronary infarction, thus there is NO support for the resolution.
No, pot cannot cause a heart attack. Smoking is not healthy but pot is an herb, a plant. It is totally natural and does not contain anything toxic that will harm you to that degree. I do not support the use of this drug, but it cannot cause this type of illness.