An official cause of death for actor-producer Patrick Muldoon has been confirmed. The “Melrose Place” and “Days of Our Lives” veteran suffered a myocardial infarction — a heart attack — according to a death certificate reviewed by People. Muldoon, 57, died April 19 at his Beverly Hills home. Muldoon’s sister, Shana Muldoon Zappa, told TMZ that his girlfriend found him unconscious on the bathroom floor when he didn’t return promptly after having his morning coffee and going to take a shower. Pulmonary embolism and hereditary coagulopathy — an arterial blockage in the lungs and issues with blood clotting either too much or too little — contributed to his death, People said. Muldoon, who was from San Pedro, played football in high school and at USC, where he acquired two Rose Bowl rings. He grew up in “a family of lifeguards,” which he described to The Times in 2012 as “such a competitive athletic environment.” His smaller size, however, led him to consider acting as a career rather than pro ball after he got run over …