To preempt the unevitable comments blaming COVID vaccines for this: please note that most of the sources used in the article predate the pandemic.
> A 2022 study published in the Journal of Medical Virology found that heart attack deaths increased by 14 percent within the first year of the pandemic.
So if I were to blame the 14% increase on the vaccine instead, sources predating the pandemic wouldn't matter.
To the data: Not sure what period the study is about. Though it's well known, that MRNA vaccines cause heart related problems. Whether the rise in excess death of young people is caused by "long covid"-effects, and/or by the vaccine, is still an open question I guess. But it's a fact, that the pandemic has a long-term impact on peoples health and excess death: https://www.euromomo.eu/graphs-and-maps
Best case scenario, unknowingly publishing with bad sources taints the article, making the article itself unreliable.
Worst case scenario, knowingly publishing with bad sources taints the _publisher_, making them unreliable.