Heart failure: more common in IE of the aortic valve (75%) than in mitral valve (50%) or tricuspid valve disease (14%); poor prognostic sign (death rate with vs. without heart failure, 85% vs. 37%).
Embolization: clinically seen in up to 35% of patients; pathologic evidence in up to 65%.
Neurologic manifestations: 40-50% of patients.
Mycotic aneurysm: 3-15% of patients; highest incidence in the proximal aorta.
Renal failure: approximately 5%; dialysis can maintain the patient until bacterial antigens are cleared.
What is the prognosis of IE?
The prognosis depends on organism, type of valve, location, patient age, and complications. Adverse prognostic indicators are heart failure, renal failure, culture-negative disease, gram-negative or fungal infection, prosthetic valve, and abscess. Favorable factors are young age, early diagnosis and treatment, penicillin-sensitive streptococcal infection, and young intravenous drug users with Staphylococcus aureus infection of the tricuspid valve (90% cure rate). Cure is 90% for native valve streptococcal infection, approximately 75-90% for enterococcal infection, and 30-60% for infection with S. aureus. Multiple valve involvement also has a higher mortality rate, as does aortic vs. mitral and left-sided vs. right-sided disease. Left-sided IE due to S. aureus carries a mortality rate of 25-40%. PVE has a worse prognosis; early PVE has a mortality rate of 41-80% and late PVE of 20-50%.
IE involving both aortic and mitral valve.
What does the electrocardiogram (ECG) show in patients with IE? How often should the EKG be repeated?
An ECG should be done at admission for patients in whom IE is suspected and repeated according to response to treatment, initial findings, and echocardiographic data. Findings include possible silent myocardial infarction or ischemia secondary to vegetation embolism involving a coronary artery. A prolonged P-R interval also may suggest extension into the conduction system, focal myocarditis, or abscess close to the conduction system. Other disturbances in conduction also may involve major complications, need for surgery, and worse prognosis.