Your conclusion about cardiac abnormalities is wrong, that's not what the study measured. They only looked at male patients aged 52-74, who were bad enough to

Your conclusion about cardiac abnormalities is wrong, that's not what the study measured. They only looked at male patients aged 52-74, who were bad enough to be in hospital, and who had already been given an echocardiogram because there was an indicator, i.e. it's the subgroup that doctors deemed in need of a heart check because they were exhibiting symptoms like chest pain. The study indicates prevalence of abnormalities within those echoes - echoes from very ill people with symptoms of heart failure. They didn't take echoes for the study and they didn't run echoes on a random population.