Hi, I understand your concern. The only diagnosis that could relate a dental infection to a heart failure would be a infective endocarditis. When there is the formation of dental abscess, it is possible that the bacteria that are causing the abscess fall into the bloodstream and become lodged in the heart valves and destroying them. The destruction of any heart valve is a very serious problem and requires a rigorous treatment in hospital, and prolonged use of intravenous antibiotics, arriving in extreme cases to heart surgery for valve replacement destroyed by a new valve. A sign of injury in some cardiac valve is the presence of audible heart murmurs with stethoscope and better diagnosed as the use of transthoracic or transesophageal echocardiography. When there is a valvular destruction by endocarditis, the heart loses performance and led to heart failure. This heart failure is progressive and gets worse. The story you reported is not compatible with a significant destruction of any heart valve to cause heart failure. However, if doubt persists, I suggest you again see your cardiologist and explain your question and if he agrees, you should seek a heart murmur or to request an echocardiogram. Hope I have answered your question. If you have any further questions I will be happy to help you. Wish you good health.