depends from person to person
for example it's very rare but it happens and it's one of very rare harmful marijuana physical efecets, as weed is mostly not harmful
marijuana can cause arrhythmia, I myself didn't believe this but when I and my cousin had so little tobacco but a lot of weed we got so stoned and it started..
I sat down in a coffe shop and my hearth started pumping and pumping, I felt like it's going to jump out of my chest, and this was going on while I was sitting, I wasn't doing anything, my vision got kind of blurry but nothing to be concerned about, I barely got home and faked that my arrhythmia started there..
got into the hospital and got some sort of a pill altough I don't know what for, and so I was laying down in the hospital bed and your usual hearth rate during lying shouldn't be above 70-80, my was 120
it wasn't just rapid hearth beat, I felt severe pain in my chest, something like I swallowed glass, I only went to the hospital when I felt like I was going to pass out, as my vision started to decay and I heard a beeping noise in my ears until they opened the window..
first I thought it was just my heart and that it didn't have anything to do with weed, hell I smoked a lot before and nothing happened
so a few weeks later I took just 3 hits not even from a bong, it was just 3 hits from a usual joint and I felt nothing bad, but 3-4 hours later around 3am I woke up and my heart started pumping rapidly again..
let's just say I didn't sleep that night..
it's proven that marijuana speeds up your heart, that's why your pupils get dilated because your arteries get wider..
happily the doctor thought it was because I was stressed as I didn't go visit or tell him about the other time and I got away scot free but bear this with you because that trauma..
when you heart starts pumping so hard, a straight line connecting your hearth with the rest of your body starts bloating and you don't know what to do, you stop so you rest but it goes even faster, you lie down but it doesn't stop, you feel an urge to press down on your chest but every few minutes you feel something passing trough and feeling pain inside yourself as you never felt it before, it's a fucking horrifying experience..
I never had much problems with my heart except I was born with a heart murmur but a lot of people are, so it's not a big deal..
it won't get you the first time, or the second time, but once you take it hard few days in a row it might.. if your family has a history of weak hearted people don't do that..
If you ever had even a slightest problem with your hearth, don't do weed!
Could also been a panic attack which can have the same symptoms. Try to stay calm next time and take some sugar, chocolate or other sweets in. It'll help.