you can die from heart failure at any age.
If you have some undiagnosed flaw, or if you just overdo it, you can die suddenly. I'm not saying 20 or 50 or 70 deadlifts can kill you. But it is something to take into consideration when lifting. I don't know all the details of Jesse Maurande's death in July... but he was 27, wasn't he?
Marunde had some form of cardiomyopathy. Most likely HOCM/IHSS or some other sort of hypertrophy. There is rumors of excessive "stimulant" use, which would potentiate an ICMP like dilated cardiomyopathy. Either one would greatly predispose someone to risk of cardiac arrest.
The abnormal musculature of the heart in these cases increases the risk for abnormal ventricular rhythms.
Normal people have little to no risk of this.
If you're worried about dying of a cardiac arrest without any pre-existing cardiomyopathy (a trivial murmur some doctor may have heard doesn't count. Everyone has some level of regurgitation across every valve), then you should be equally worried of dying by lightning strike or spontaneous combustion as there is pretty equal chances of all three.
Don't be such a fucking pussy that you're scared to train hard, then instead blame it on the chance of cardiac arrest.
Especially when you know absolutely nothing about its etiology.