For many years
ischemic heart disease involving the right ventricle had received little attention. During the last 15 years, the initial works of Cohn, Isner, and others spawned a number of clinical and experimental studies that extended the understanding of the pathophysiology of
ischemia in the right ventricle. Most of the work has been done in the setting of acute
myocardial infarction, and information is still lacking in other conditions, such as chronic
ischemic heart disease and perioperative
right ventricular dysfunction. Acute right ventricular
infarction rarely occurs in the absence of left ventricular
necrosis and in most cases is the extension of an inferior left ventricular
infarct. The majority of patients with right ventricular
infarction only exhibit subtle signs of ischemic dysfunction. Elevated right atrial pressure is found only in the typical syndrome of elevated venous pressure; low output syndrome can be found only in 20% of the cases, and
cardiogenic shock secondary to right ventricular
necrosis is found only in 10%. It is also important to note that there is not a clear correlation between the severity of ischemic
right ventricular dysfunction and the necrotic area. The discrepancy may be due to
ischemia without
necrosis of the right ventricular wall (
stunned myocardium), but the intact pericardium and the
necrosis of the interventricular septum may also play an important role. In the most severe form of ischemic
right ventricular dysfunction, the entire right ventricular wall is akinetic. Right atrial, right ventricular, and pulmonary artery pressures become similar in magnitude and shape, and the pulmonary valve is opened during diastole, demonstrating a passive blood flow from the right atrium to the left ventricle through the low resistance pulmonary capillary bed. Volume loading, administration of
dopamine or
dobutamine, and careful use of
vasodilators under hemodynamic monitoring are the therapeutic measures to control the severe forms of acute ischemic
right ventricular dysfunction. The use of
thrombolytic agents has decreased the incidence of
right ventricular dysfunction after acute
myocardial infarction. Mortality is high in the severe forms of acute ischemic
right ventricular dysfunction, but after discharge from hospital the prognosis is good and right
heart failure is unusual, even in those patients with
shock during the first days of evolution of the
infarct.