GUIDELINES AND CRITICAL PATHWAYS FOR ACUTE CHEST PAIN
Guidelines for the initial evaluation for patients with acute chest pain have been developed by the American College of Emergency Physicians (ACEP) and other organizations. The ACEP statement describes rules and guidelines about the data that should be recorded as part of the evaluation, and the actions that should follow from certain findings. In the ACEP framework, rules are actions that are general principles of good practice, while guidelines are actions that should be considered but are not always followed. Hence, failure to follow a guideline is not necessarily improper care.
Other organizations, including the Agency for Health Care Policy and Research (AHCPR) and the National Heart Attack Alert Program, have also issued guidelines for management of patients with a high probability of acute ischemic heart disease. In these and other guidelines, patients with possible or probable acute myocardial infarction as suggested by the description of their pain or electrocardiographic findings are expected to be admitted to the hospital. The AHCPR guidelines for unstable angina note that not all patients with that syndrome require admission but recommend that patients with unstable angina be monitored electrocardiographically during their evaluation; that those with ongoing rest pain should be placed at bed rest during the initial phase of stabilization. The ACEP policy statement indicates that patients who are discharged should be given a referral for follow-up care and instructions regarding treatment and circumstances that require a return to the emergency department.
Many medical centers have adopted critical pathways and other forms of guidelines to increase efficiency. These guidelines emphasize two strategies:
· Triage to non-coronary care unit monitored facilities such as intermediate care units or chest pain units of patients with a low risk for complications, such as patients without new ischemic changes on their electrocardiograms and without ongoing chest pain. Such patients can usually be safely observed in non-coronary care unit settings, undergo early exercise testing, or be discharged home. Risk stratification can be assisted through use of prospectively validated multivariate algorithms that have been published for acute ischemic heart disease and its complications.
· Shortening lengths of stay in the coronary care unit and hospital. Recommendations regarding the minimum length of stay in a monitored bed for a patient who has no further symptoms have decreased in recent years to 12 h or less if exercise testing or other risk stratification technologies are available.
NONACUTE CHEST DISCOMFORT
The management of patients who do not require admission to the hospital or who no longer require inpatient observation should seek to identify the cause of the symptoms and the likelihood of major complications. Cost-effectiveness analyses support use of noninvasive testing for coronary disease, such as exercise electrocardiography and stress echocardiography. These tests serve both to diagnose coronary disease and to identify patients with high-risk forms of coronary disease who may benefit from revascularization. Gastrointestinal causes of chest pain can be evaluated via endoscopy or radiology studies. Emotional and psychiatric conditions warrant appropriate evaluation and treatment; randomized trial data indicate that cognitive therapy and group interventions lead to decreases in symptoms for such patients.
PALPITATIONS
Palpitations are characterized by an awareness of the beating of the heart. Patients commonly describe "pounding" or "fluttering" heart beats or report a sensation that the heart is stopping or skipping beats. These symptoms may be caused by a change in the heart's rhythm or rate or by an increase in the force of its contractions. In many cases, this awareness reflects lack of competing sensory stimuli, such as when a person is lying in bed, unable to sleep.
Palpitations are often manifestations of psychiatric conditions, the most common of which are depression and panic disorder. For example, in one study of outpatients referred for ambulatory electrocardiographic monitoring to evaluate palpitations, 19% were found to have a psychiatric disorder. Patients with psychiatric disorders were more likely than other patients to report that their palpitations lasted longer than 15 min or were accompanied by ancillary symptoms. In this study, physicians usually recognized the emotional basis of the patients' symptoms but frequently did not refer the patient for specific therapy.
Palpitations can also be caused by virtually any cardiac arrhythmia as well as by other cardiac and noncardiac conditions. A markedly enlarged left ventricle can cause awareness of the heart beat by contact with the chest wall. Any condition associated with increased catecholamine levels can lead to palpitations both by increasing the forcefulness of cardiac contractions and by increasing the rate of premature beats.
Palpitations can be intermittent or sustained and regular or irregular. Patients with this complaint should be asked to describe their palpitations' onset, duration, associated symptoms and the circumstances in which they occur. Abrupt onset and termination after several minutes may reflect a sustained ventricular or supraventricular tachyarrhythmia. Gradual onset and termination of a pounding heart beat is more consistent with sinus tachycardia. Patients should try to replicate the rhythm of their palpitations by tapping on a table. This maneuver can help the physician determine the nature of any cardiac arrhythmia. Patients should also be taught to take their pulse so that they can more accurately report their approximate heart rate and whether the rhythm was regular.
DIFFERENTIAL DIAGNOSIS
Patients who report "skipped" beats or a "flopping" sensation often have atrial or ventricular extrasystoles. These premature beats are followed by a compensatory pause, and the first heart beat after the pause may be unusually strong due to increased left ventricular volume and enhanced contractility (a phenomenon called postextrasystolic potentiation). Sustained bursts of rapid heart beats may be due to ventricular or supraventricular tachyarrhythmias. A sustained irregular rhythm suggests atrial fibrillation.
Conditions that cause marked left ventricular enlargement such as aortic regurgitation can cause an awareness of the heart beat that is sometimes positional. Presumably because of associated arrhythmias, hypertrophic cardiomyopathy, mitral valve prolapse, and other cardiac structural abnormalities are also associated with palpitations.
Palpitations can also be a prominent symptom in noncardiac conditions, including thyrotoxicosis, hypoglycemia, pheochromocytoma, and fever. The physiologic basis of palpitations with these conditions is either arrhythmia or increased catecholamine levels leading to greater myocardial contractility. Drugs that can precipitate arrhythmias and palpitations include tobacco, coffee, tea, alcohol, epinephrine, ephedrine, aminophylline, and atropine.
Approach to the Patient
The first goal in the evaluation of patients with palpitations is to exclude the possibility of life-threatening arrhythmias. The risk for such arrhythmias is highest in patients with coronary artery disease, congestive heart failure, or other structural cardiac abnormalities. The history, physical examination, and electrocardiogram should therefore be focused on stratifying patients according to the risk of such conditions. Palpitations are also more likely to reflect serious arrhythmias if they are associated with symptoms that suggest hemodynamic compromise, such as syncope, light-headedness, dizziness, or shortness of breath.
The most common first test after the initial evaluation of palpitations is continuous electrocardiographic (Holter) monitoring. This test is especially useful if patients have palpitations on a daily basis. For patients with more sporadic palpitations, a variety of new technologies have become available to allow capture of electrocardiographic tracings at the time of their symptoms. These technologies include loop recorders, that can freeze the last several minutes of data when the patient presses a button, and telephonic monitors, which can be used to "call in" tracings when symptoms occur. If episodes are associated with physical stress, exercise electrocardiography can be used in an attempt to elicit an arrhythmia.
Most patients with palpitations do not have evidence of major arrhythmias or abnormal physiologic conditions associated with increased catecholamine levels. Patients with emotional or psychological causes of palpitations should be evaluated for possible cognitive and pharmaceutical therapy. Drugs and medications that may precipitate palpitations should be eliminated or reduced. A trial of beta blockers is often successful in reducing premature beats and symptoms. Regardless of the cause and treatment, the clinician should remain aware that palpitations are extremely bothersome symptoms for patients. Reassurance that a comprehensive evaluation has been performed and that the palpitations do not adversely affect the patient's prognosis is a critical part of the patient's care.
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