Management should begin with general supportive measures designed to relieve ongoing ischemic pain and anxiety, correct electrolyte imbalances, and provide adequate oxygenation. Insertion of indwelling intra-arterial and pulmonary artery catheters is essential to define hemodynamics and monitor cardiac function during pharmacologic interventions. Continuous ECG monitoring is also essential because atrial and ventricular arrhythmias are commonly observed and may contribute to persistence of a low-output state. Cardiac performance is generally optimal after acute myocardial infarction, when the pulmonary arterial wedge pressure is between 15 and 18 mm Hg. Intravenous vasodilators, particularly nitroprusside, are potentially useful when shock is further complicated by mitral regurgitation.
Extreme caution is needed to avoid precipitating a further decline in blood pressure, however.
Intra-aortic balloon support has proved to be a useful temporary measure because it enhances coronary perfusion and augments forward cardiac output. Counterpulsation does not reduce overall hospital mortality unless a surgically correctable mechanical lesion is present or coronary revascularization can be performed. Coronary angiography should be considered in most patients with shock and ECG evidence of an acute evolving myocardial infarction. Direct angioplasty, coronary stenting, or both should be considered the most effective forms of reperfusion therapy. In hospitals that cannot provide primary angioplasty, patients in shock should receive a thrombolytic agent and be transferred urgently for coronary angiography and intervention.