Marijuana use may be linked to a weakened heart muscle, a new studyfinds. Researchers found that people who used marijuana were twice as likely to later develop a heart condition called transient ventricular regional ballooning (TVRB) than those who did not use marijuana. TVRB is a form of cardiomyopathy, which is a sudden weakening of the heart muscle that can mimic symptoms of a heart attack. The symptoms can include chest pain, dizziness and shortness of breath, but the condition is often temporary. The most surprising finding from the study was that the marijuana users in the study were the opposite of the people that TVRB tends to strike in several ways, said Dr. Amitoj Singh, a co-author of the study and the chief cardiology fellow at St. Luke’s University Health Network in Pennsylvania. The condition tends to develop in post-menopausal women, he said. In the study, the marijuana users who developed TVRB were 44 years old, on average, and 36 percent were men. Among the non-marijuana users in the study who developed TVRB, the average age was 66, and just 8 percent were men.