Endocarditis, Pericarditis, Tamponade and Cardiac Trauma

Infective Endocarditis and Myocarditis

Infective endocarditis is an infection of the endocardial surface that damages cardiac valves. In the general adult population, infective endocarditis most commonly affects the mitral and aortic valves. Conversely, tricuspid valve endocarditis is most frequently associated with intravenous drug use and central venous catheter infections. In any febrile patient, the auscultation of a new or worsening regurgitant murmur is an important clinical finding that warrants prompt evaluation for valvular infection.

Complications of infective endocarditis depend heavily on which valve is infected. Left-sided endocarditis carries a high risk of systemic arterial embolization to the brain, spleen, kidneys, and extremities. Because of this risk, frequent neurological assessments are essential in left-sided endocarditis to rapidly detect embolic stroke, cerebral mycotic aneurysm rupture, or intracranial hemorrhage. In contrast, right-sided endocarditis vegetations embolize directly into the pulmonary circulation, causing septic pulmonary infarcts, abscesses, or pneumonia. Systemic immunologic and vascular signs also assist in clinical recognition: Osler nodes are painful, erythematous nodules on the pads of fingers and toes caused by immune complex deposition; Janeway lesions are painless, hemorrhagic macules on the palms and soles caused by septic emboli; and splinter hemorrhages present as linear, dark-red subungual streaks visible under the nail beds.

Diagnostic protocols require that the nurse obtain two to three blood-culture sets from separate venipuncture sites before antimicrobial therapy when feasible, without delaying treatment in an unstable patient. Continuous cardiac monitoring is vital because a new prolonged PR interval or atrioventricular block in a patient with aortic valve endocarditis raises concern for an invasive perivalvular abscess and warrants urgent evaluation. Furthermore, acute valvular destruction can trigger catastrophic hemodynamic instability; heart failure resulting from acute valvular destruction is the leading indication for urgent surgical intervention.

Myocarditis represents inflammation of the myocardium and is most often associated with viral infection, but it can also be caused by autoimmune disease or certain medications and other toxins. Patients with fulminant myocarditis can present with acute cardiogenic shock, life-threatening ventricular dysrhythmias, and elevated serum troponin. In managing these patients, the critical care nurse must recognize that individuals with acute myocarditis exhibit heightened sensitivity to digoxin and carry an increased risk of digoxin toxicity. When pharmacologic support is insufficient, mechanical circulatory support, such as intra-aortic balloon pumps, percutaneous ventricular assist devices, or ECMO, may be required as a bridge to recovery.