New Delhi : According to a small, but rigorous study led by Johns Hopkins Medicine researchers, adults with abnormal heart metabolism are up to three times more likely to experience life-threatening arrhythmias (an irregular heart rhythm), and MRI techniques could be used to detect the condition and predict future sudden cardiac death (SCD). Sudden cardiac death accounts for 50% of all cardiovascular deaths in the United States, claiming more than 3,00,000 American lives annually, according to the American Heart Association. Currently, an implantable cardioverter-defibrillator (ICD) -- a small, battery-powered device placed in the chest to detect and stop irregular heart rhythms -- is the primary means of preventing SCD in high-risk patients. The device continuously monitors the heart rhythm and delivers electric shocks, when needed, to restore a regular heart rhythm. The battery life of an ICD is typically between five to seven years.