Hello.
Thank you for your query at DoctorSpring.com.
I understand your concern.
As you seem to know already, the reason for antibiotics prior to invasive procedures such as dental work, in those with artificial heart valves is to prevent bacterial infection of the heart, termed as Prosthetic Valve Endocarditis (PVE). This is because artificial (prosthetic) valves are more conducive to bacterial colonisation and thus the risk of infection of the inner layer (endothelium) of the heart is higher.
Invasive procedures can result in bacteria such as the normal residents of the mouth etc., to enter the bloodstream (bacteremia), by which they can reach the heart. Antibiotic prophylaxis is given to prevent bacteremia.
The risk is of a fatal infection is in the early post-operative period as the artificial valve is not coated with the endothelium yet. The risk is highest in the first 3 months, remains high for next 6 months. After a year of surgery, the risk keeps falling.
Having a procedure without antibiotic prophylaxis has an infection risk of only about 3-6 percent. The infection in the later periods is less dangerous than early infection. So in your case, there is no reason to panic, just make sure you do not miss the antibiotics again.
When the valve gets infected, the bacteria adhere to the leaflets, forming small growths termed "vegetations". Vegetations can break off and travel with the bloodstream and can block small vessels causing stroke, heart attack etc. Associated inflammation causes thickening of the lining of the leaflets and can lead to narrowing of the valve opening. This can make the heart work extra hard, becoming weak and may lead to heart failure.
Rarely, especially in the early post-op period, infection can spread to the rest of the heart, forming an abscess (collection of pus) or fluid in the sac enclosing the heart which is more dangerous. And Endocarditis is easier to prevent than to treat.
Symptoms can arise from within a few days to weeks. You can watch up to 6 weeks.
PVE can present as fever for more than 9 days not responding to antibiotics, symptoms of a weak heart such as shortness of breath, chest pain, dizziness or fainting spells etc.
The odds in your case are quite less. However, if any such symptom arises, please see your doctor.
I hope this was helpful. Feel free to ask queries.
Regards.