allergy and increased bacterial resistance) of taking antibiotics that may outweigh the benefits.Antibiotics were historically commonly recommended to prevent IE in those with heart problems undergoing dental procedures (known as dental antibiotic prophylaxis). There is, however, insufficient evidence to support whether antibiotics are effective or ineffective at preventing IE when given prior to a dental procedures in people at high risk. They are less commonly recommended for this procedure.In some countries e.g. the US, high risk patients may be given prophylactic antibiotics such as penicillin or clindamycin for penicillin-allergic people prior to dental procedures. Prophylactics should be bactericidal rather than bacteriostatic. Such measures are not taken in certain countries e.g. Scotland due to the fear of antibiotic resistance. Because bacteria are the most common cause of infective endocarditis, antibiotics such as penicillin and amoxicillin (for beta lactamase-producing bacteria) are used in prophylaxis. Treatment
High-dose antibiotics are the cornerstone of treatment for infective endocarditis. These antibiotics are administered by the intravenous (IV) route to maximize diffusion of antibiotic molecules into vegetation(s) from the blood filling the chambers of the heart. This is necessary because neither the heart valves nor the vegetations adhering to them are supplied by blood vessels. Antibiotics are typically continued for two to six weeks depending on the characteristics of the infection and the causative microorganisms.
Third-degree atrioventricular block
Third-degree AV block occurs when the signal between the atria and ventricles is completely blocked, and there is no communication between the two. None of the signals from the upper chambers makes it to the lower chambers. On ECG, there is no relationship between P waves and QRS complexes, meaning the P waves and QRS complexes are not in a 1:1 ratio.Third-degree AV block is the most severe of the AV blocks. Persons with third-degree AV block need emergency treatment including but not limited to a pacemaker. Etiology
There are many causes of AV block, ranging from a normal variant among people to the result of a heart attack.First-degree AV block and Mobitz I second-degree block are often thought to be just normal, benign, conditions in people, and do not often result from a severe underlying condition.Mobitz II second-degree block and third-degree AV block are not normal variants and are associated with an underlying condition. Common causes include ischemia (lack of blood flow and oxygen to the heart muscle) or progressive fibrosis (excessive scaring) of the heart. It is also possible that a high degree block can result after cardiac surgery during which the surgeon was in close proximity to the electrical conduction system and accidentally injured it. Reversible causes of Mobitz II and third-degree heart block include untreated Lyme disease, hypothyroidism, hyperkalemia (high levels of potassium), and drug toxicity.