Heart patients who catch the flu may face a greater danger than they are aware of. An analysis of 39 previous studies of heart patients found a consistent link between flu and heart attacks. As many as half of all unexpected flu deaths were related to heart disease. The virus is particularly dangerous for heart patients because it can cause inflammation in the heart or coronary arteries, possibly leading to dangerous clots that cause heart attacks. Doctors are recommending that, given the recent swine flu pandemic and the high number of flu viruses that will be circulating this flu season, all heart patients get vaccinated for both seasonal flu and swine flu.