In recent months, researchers in Philadelphia and beyond have reported success using gene therapy to treat cardiac problems including heart failure, hardened arteries and atrial fibrillation. Although these successes occurred in animal models — with results in humans being inconclusive, researchers believe the field is close to a breakthrough. "I think cardiac gene therapy has great promise," said Steven Houser, director of the Independence Blue Cross Cardiovascular Research Center at Temple's School of Medicine. "I think you'll see lots of things over the next few years."