Other Cardiac Emergencies

Patients entering an emergency unit with chest pain, a common event, are preferentially evaluated for possible acute myocardial infarction. A diagnosis of infarction calls for immediate intervention, and the relief of pain may have to take second place to prompt diagnosis. If the cause of the pain is identified as myocardial ischemia (diminished blood supply to the heart muscle), the medical

staff must consider whether the problem is reversible and temporary (angina pectoris) or the heart muscle has sustained permanent damage (myocardial infarction). This question may not be answerable in the emergency unit, in which case it is usually necessary to admit the patient to the hospital for observation and further evaluation.

Other cardiovascular conditions causing sudden onset of severe chest pain include pulmonary embolism, pericarditis, and aortic dissection. Noncardiac conditions associated with chest pain severe enough to bring a patient to an emergency unit include gastrointestinal disease (hiatus hernia, esophageal spasm) and pulmonary disease (pleurisy, pneumonia, pneumothorax). Such pain may also originate in various structures of the chest wall—nerves, muscles, or the junction between the ribs and the sternum.

As explained in this chapter, arrhythmias are responsible for the majority of cases of cardiac arrest or cardiac syncope. However, patients are often sufficiently alarmed about less-serious arrhythmias to seek emergency medical care. A common condition in this category is paroxysmal tachycardia or atrial fibrillation, which may be perceived as severe pounding of the heart, even though it may not produce any abnormality in the cardiac or circulatory function. The emergency unit must decide whether to admit the patient to the hospital or administer drugs and send the patient home. Most supraventricular tachycardias can be promptly terminated by appropriate intervention, and if no underlying heart disease is present, hospitalization is usually unnecessary. Atrial flutter or fibrillation may or may not respond to treatment in the emergency unit. If the ventricular rate is above 150 beats a minute, hospitalization is frequently advisable. Ventricular tachycardia requires prompt intervention and, because of its implications, admission to the hospital.