The study controlled for general health but I would note that the odds-ratio reported for cannabis use (4-6) is not so different from the odds-ratio associated when studying high vs. low income cohorts (3-5). This study is not a random blinded clinical trial it's reporting a trend present in ~5 million electronic health records which I assume record yes/no to patients ever telling a doctor they have used cannabis.

I would assume that cannabis use correlates with a few other important heart health variables and we would expect the odds ratio to be lower when accounting for those (alcohol doesn't have an OR more than 1.0, tobacco smoking ~1.5)

I'm sure that cannabis use is bad for cardio health but the reported odds ratio is very high. I personally do not use cannabis.