61 - Cardiac Valvular Disorders

Of the four heart valves, three are tricuspid (aortic, pulmonic, and tricuspid) and one is bicuspid (mitral). Failure of normal function of these valves is due to lesions that make them incompetent and allow backward flow (regurgitation) or to lesions that decrease orifice size and cause restriction of flow (stenosis). In addition, combinations of these lesions may occur within the same valve, and multiple valves may be involved (commonly the aortic and mitral valves with rheumatic heart disease). Cardiac murmurs result from (1) increased blood flow across a normal or abnormal valve orifice, (2) turbulent flow across a narrow or irregular orifice into a dilated blood vessel or cardiac chamber, or (3) backward flow across an incompetent valve or other cardiac defect. However, most systolic murmurs are related to a physiologic increase in blood velocity and are not pathologic. Physical examination establishes where the murmur occurs within the cardiac cycle and its location, duration, and intensity. Murmurs are classified as systolic, diastolic, and continuous. Systolic murmurs are further subclassified into holosystolic (pansystolic), midsystolic, early systolic, and late systolic. Clicks can be heard from the snapping shut of diseased valves. Diastolic and continuous murmurs are nearly always pathologic and require investigation, even in the absence of symptoms. Although many systolic murmurs merit investigation, especially those associated with symptoms, the majority of systolic murmurs do not signify valvular disease. A summary of the typical findings in the major valvular abnormalities is presented in Table 61.1. A heart affected by valvular pathology has the ability to compensate over time, and symptoms are commonly absent for decades. Emergency physicians need to be able to identify when certain valvular lesions have progressed to the point that they are clinically important and responsible for the patient’s symptom complex. Shortness of breath, arrhythmias, and heart failure are common reasons why patients with VHD seek treatment at an ED. Other clinical scenarios include valve infection, myocardial infarction with papillary muscle dysfunction, and failure of a prosthetic device, which can cause rapid heart failure and shock. It should be kept in mind that valvular pathology is in the differential diagnosis of patients with congestive heart failure, shock, and angina. The clinician should perform a careful cardiac examination with attention • In patients evaluated in the emergency department for chest pain, dyspnea, syncope, arrhythmia, or shock, the possibility of valvular heart disease should be considered. • Emergency echocardiography is essential in elucidating whether acute valvular pathology is responsible for hemodynamic collapse in a patient with cardiogenic shock. • An asymptomatic patient with a grade 2/6 systolic murmur needs no further work-up. • Diastolic murmurs are always pathologic and require echocardiography. • Endocarditis prophylaxis is recommended only for dental procedures and no longer needed for gastrointestinal or genitourinary procedures. KEY POINTS