Structural Heart Disease

Aortic Insufficiency

Epidemiology/Pathophysiology

• Aortic insufficiency may be acute or chronic.
• Acute aortic insufficiency is due to aortic root disease with dissection or valvular destruction secondary to endocarditis. Acute aortic insufficiency causes a rapid increase in cardiac afterload secondary to the regurgitant blood volume as well as an acute increase in pulmonary vascular pressure. Symptoms include severe dyspnea with signs of pulmonary edema. Other symptoms are those of the underlying disease such as tearing chest pain in patients with aortic dissection.
• Chronic aortic insufficiency is most likely secondary to rheumatic heart disease. The damaged valve leads to a backflow of blood during diastole, thus increasing the stroke volume. This increases afterload as the ventricle attempts to push the increased blood volume against the regurgitant flow. Preload is also increased as the regurgitant flow significantly increases the volume load of the left ventricle. Early in the disease, the left ventricle is able to compensate with hypertrophy and dilatation, with minimal symptoms. However, as the disease progresses, the ventricle is unable to compensate, ejection fraction decreases, and symptoms of heart failure develop. Other symptoms include anginal chest pain as the hypertrophied heart outgrows its blood supply or palpitations from the increased systolic outflow.

Diagnosis and Evaluation

• The murmur of aortic insufficiency is a "blowing" diastolic murmur heard best at the left sternal border of the heart. There may be an accompanying systolic ejection murmur heard as the increased volume is expelled during systole. Other findings include a "water-hammer" pulse with a fast upstroke and an abrupt collapse.
• The electrocardiogram is variable in acute disease, often reflecting the underlying cause.
  Chronic aortic insufficiency will cause signs of LVH to be present on the EKG.
• The diagnostic test of choice is the echocardiogram, which can assess the severity of the valvular dysfunction as well the left ventricular function. In acute disease, the echocardiogram is also important for evaluation of concurrent life threatening complications of the underlying disease, especially pericardial tamponade associated with aortic dissections.

  ED Management

• Treatment of aortic insufficiency is surgical.
• Acute disease is a cardiothoracic surgical emergency requiring immediate operative repair of both the valve and often the aortic root.
• Chronic disease develops over years with surgical correction suggested for most symptomatic patients and most patients with severe disease and/or concurrent left ventricular dysfunction despite clinical symptoms.
• Medical management includes the use of afterload reducing agents in order to decrease the regurgitant volume, hopefully retarding the onset of left ventricular dysfunction. However, medical management is not a replacement for surgical valve replacement or repair. Other medical management issues include the treatment of concurrent diseases including coronary artery disease, atrial fibrillation, and the prevention of endocarditis.

  Mitral Stenosis
  Epidemiology/Pathophysiology

• The most common cause of mitral stenosis is rheumatic heart disease.
• The mitral valve becomes thickened, calcified, and fused. The increased pressure required to force blood across the stenotic valve leads to an elevation of left atrial pressures and subsequent left atrial dilatation. With progression of disease, the pressure column backs into the pulmonary circulation, leading to pulmonary hypertension, tricuspid valve dysfunction, and right heart failure. The disease progresses slowly over years but may be accelerated by conditions increasing the demand for flow across the damaged valve, such as atrial fibrillation, pregnancy, infection, or other stressors.

  Diagnosis and Evaluation

• Mitral stenosis presents with symptoms of congestive heart failure and pulmonary hypertension usually in the fifth to sixth decade of life.
• Patients may also present with complications of previously unrecognized disease. This includes atrial fibrillation in 30-40% of patients, hemoptysis secondary to pulmonary hypertension and erosion of bronchial veins, chest pain (despite the lack of concurrent coronary artery disease), or embolic disease in 10-20% of patients.
• The murmur of mitral stenosis is a low-pitched diastolic rumble best heard at the apex of the heart. Other findings include an opening snap. Auscultatory findings are best heard with the patient in the left lateral position with the bell of the stethoscope.
• Electrocardiographic findings include "P-mitrale," a widened p-wave in the limb leads.
  Echocardiography is the test of choice to visualize the abnormal mitral valve, assess the severity of valvular obstruction and evaluate its effect on the pulmonary circulation.

  ED Management

• Treatment for mitral stenosis is surgical via mitral valve replacement or balloon valvotomy.
• Medical treatment is reserved for the treatment of concurrent diseases including atrial fibrillation with rate control medications and anticoagulation, as well as antibiotic prophylaxis against endocarditis.

  Mitral Regurgitation
  Epidemiology/Pathophysiology

• Mitral regurgitation may be acute or chronic.
• Acute mitral regurgitation is secondary to infective endocarditis with erosion of the valve or acute ischemia of the chordae tendinae/papillary muscle support system. Acute mitral regurgitation causes an abrupt increase in the pulmonary vascular pressure leading to acute pulmonary edema. This often progresses to cardiogenic shock and cardiac arrest.
• Chronic mitral regurgitation has multiple etiologies, most commonly rheumatic heart disease. Chronic mitral regurgitation leads to a compensatory enlargement of both the left atrium and ventricle in order to handle the regurgitant blood volume. Early in the course of the disease, the contractile force of the left ventricle is preserved and stroke volumes are supranormal with both the normal stroke volume and the regurgitant volume expelled during systole. With disease progression, the left ventricle enlarges to a point that compromises the contractile function, lowering the ejection fraction. The decrease in forward flow leads to an increase of pulmonary pressures and symptoms of heart failure.

  Diagnosis and Evaluation

• The murmur of mitral regurgitation is holo-systolic at the apex of the heart that radiates to the axillae. In acute mitral regurgitation, the murmur is typically harsh with signs of pulmonary edema present. In chronic mitral regurgitation, there may also be a diastolic murmur heard at the apex indicative of the increased regurgitant flow across the valve.
• Physical signs of cardiac enlargement are usually present.
• The electrocardiogram typically demonstrates LVH and LAE in mitral regurgitation.
  However, these may be absent in cases of acute valvular dysfunction.
• The diagnostic test of choice is the echocardiogram, which can assess the severity of the valvular dysfunction as well as the left ventricular function.

  ED Management

• Treatment of acute mitral regurgitation is surgical.
• Medical support is geared toward treatment of acute pulmonary edema and the underlying etiology of the dysfunction (i.e., ischemia).
• Surgical repair is indicated in most patients with decompensated chronic mitral regurgitation.
• Medical treatment options for patients with chronic mitral regurgitation are complex.
• Afterload reduction with ACE inhibitors and other vasodilators may reduce the regurgitant flow and thusdecrease symptoms and prolong the time between diagnosis and the need for operative repair. Medical treatment is also geared toward the prophylaxis and treatment of potential complications including atrial fibrillation and endocarditis.

  Mitral Valve Prolapse
  Epidemiology/Pathophysiology

• Mitral valve prolapse is the most common form of valvular disease.
• Etiologies include congenital valve degeneration and connective tissue disorders.
• The overall prognosis for most patients with mitral valve prolapse is excellent, with most symptoms being benign.
• Sudden death is a rare complication, occurring in 1-2% of patients.

  Diagnosis and Evaluation

• The presentation of mitral valve prolapse is diverse. Patients are usually asymptomatic, with the diagnosis made on auscultatory findings alone. Common symptoms include chest pain and palpitations. The chest pain is often times atypical, nonanginal type chest pain but can occasionally have angina-like characteristics. The palpitations of mitral valve prolapse are usually due to occasional premature ventricular complexes but can occasionally be due to more troubling dysrhythmias such as SVT or rarely ventricular tachycardias.
• Mitral valve prolapse is also associated with autonomic hyperactivity symptoms. Patients may present with anxiety, panic attacks, or other symptoms of concurrent psychiatric disease.
• Neurologic complications such as TIAs and migraine headaches are also associated with mitral valve prolapse. The auscultatory finding of mitral valve prolapse is a midsystolic click. Mitral valve prolapse can progress to significant mitral regurgitation at which time the systolic murmur of MR is heard.
• Diagnosis is confirmed by echocardiography.

  ED Management

• Treatment is focused on the relief of symptoms and the prevention of complications.
• Beta-blockers are used to control palpitations and anxiety symptoms.
• Antibiotics are used for the prevention of endocarditis.
• Aggressive rhythm control is required for patients with more severe dysrhythmias.

  Tricuspid Valve Disease
  Epidemiology/Pathophysiology

• Tricuspid valve disease is usually found with concurrent left-sided valvular diseases and pulmonary hypertension.
• Congenital abnormalities and endocarditis, seen most commonly in abusers of intravenous drugs, cause isolated right-sided valvular disease.
• Weight loss medications may also result in tricuspid valve disease.

  Diagnosis and Evaluation

• In patients with tricuspid disease and associated left-sided valve dysfunction or pulmonary hypertension, symptomatology is dominated by the concurrent diseases.
• Isolated tricuspid disease presents with symptoms of right-sided heart failure including hepatomegaly, ascites, and peripheral edema.
• The murmur of tricuspid regurgitation is pansystolic at the left lower sternal border.
• Tricuspid stenosis inconsistently produces a high-pitched diastolic murmur. Prominent jugular venous pulsations are present in both abnormalities.
• Diagnosis is confirmed by echocardiography.

  ED Management

• Treatment is geared toward concurrent disease processes and prevention of complications such as endocarditis.
• Surgical correction may be needed.

  Prosthetic Valve Dysfunction and Complications

• Valve replacement surgery is very common with more than 40,000 replacements done per year.
• Prosthetic heart valves are either bioprosthetic (usually bovine, porcine, or human cadaveric) or mechanical.
• The evaluation of a patient with a prosthetic valve begins with an understanding of the type of valve placed and the reason for placement. Patients are instructed to carry a card describing the prosthetic valve.
• Mechanical valves have a mechanical click and systolic murmurs. Bioprosthetic valves normally have only slight murmurs.
• Any change in clinical status or auscultatory findings in patients with prosthetic valves requires an evaluation of the valve including echocardiography.
• Complications of prosthetic valves include valve thrombosis, infection, and degeneration of the valve or surgical site.
• Thrombosis of a prosthetic valve can be acute or chronic and is much more common in mechanical valves. Acute valvular thrombosis is a cardiothoracic surgical emergency, presenting with acute heart failure and cardiogenic shock. Thrombi may also occur chronically and present with either progressive valvular dysfunction and symptoms of worsening valvular disease, or with embolic phenomena. Treatment includes valve replacement but may also include fibrinolytic therapy.
• Endocarditis is common in prosthetic valves. Within the first 2 mo after placement, Staph species are common. After the first 2 mo, the etiology is similar to native valve endocarditis. Treatment with antibiotics as in patients with native valve endocarditis is required. Surgical valve replacement may be required.
• Valve dysfunction occurs more commonly with bioprosthetic valves with approximately 30% requiring replacement within 10 yr. All prosthetic valves have some regurgitation and stenosis inherently. Degeneration of the valve itself, the perivalvular surgical site, or the diseased myocardium can lead to worsening regurgitation or stenosis. Valve failure presents with symptoms of either the stenosis or regurgitation of the diseased valve. It is often difficult to distinguish valve dysfunction from progression of underlying cardiac disease in these patients, thus requiring liberal use of echocardiography in the evaluation of these patients.
• Mechanical prosthetics may also cause chronic hemolysis and subsequent anemia.
  Hemolysis from mechanical valves or perivalvular degeneration is usually compensated and asymptomatic. Severe dysfunction may lead to a more severe anemia and subsequent symptoms.