Cardiology is the subspecialty of internal medicine involved with the study of diseases and disorders of the heart and blood vessels. Cardiology training generally involves at least five years of postgraduate training including three years of internal medicine training. For board certification in cardiology (or offically, cardiovascular diseases) physicians must first be board certified in internal medicine. Then for cardiologists who began training prior to 1989, two years of subspecialty training in cardiology was required. For physicians beginning training after 1989 board certification in cardiology requires three years of subspecialty training in cardiology. While most cardiologists are trained in all aspects of cardiology, areas of special expertise include cardiac catheterization and coronary angiography, interventional procedures including angioplasty and artherectomy, echocardiography, nuclear cardiology, electrophysiology (diagnosis and treatment of cardiac arrhythmias), exercise testing and cardiac rehabilitation. Cardiologists who perform cardiac catheterization and/or interventional procedures are termed invasive cardiologists whereas cardiologists who do not perform such procedures are termed noninvasive cardiologists.

Cardiologists often manage patients with life-threatening illnesses such as those with acute myocardial infarction or congestive heart failure. Consequently it is not uncommon for cardiology patients to have poor outcomes such as death. It is therefore important to distinguish poor outcome which is a result of the underlying cardiac disease which could not be averted from poor outcome which may be related to deviations from good and accepted standards of care on the part of the treating cardiologist.

Patients Presenting in the Emergency Room:

Patients presenting with chest pain syndrome is a common occurrence in the emergency room. Not all chest pain is due to the heart, but when it is, there may be life-threatening implications. Consequently, emergency room physicians and cardiologists must be alert to search for features which may be consistent with a potentially life-threatening cardiac syndrome and must approach each patient with a high index of suspicion. The character of the chest pain complaint is often helpful in pointing toward or away from a cardiac etiology. Anginal or cardiac quality chest pain generally is described as a pressure, squeezing sensation, or a heaviness on the chest which can last for minutes to hours. Cardiac pain frequently but not always is associated with other features such as shortness of breath, diaphoresis (sweatiness), nausea or vomiting, and radiation of the discomfort into the neck, jaw or arms. Anginal discomfort also generally is precipitated by physical exertion and relieved with rest, although it may occur at rest alone without obvious precipitating factors. Recurrent episodes of anginal quality pain lasting several minutes each, particularly when it occurs in a crescendo pattern of increasing frequency or decreased threshold of physical exertion, may be a manifestation of unstable angina. This is a syndrome which if untreated properly may lead to an acute myocardial infarction or death. However, proper treatment of unstable angina generally has a survival of greater than 90%. Therefore, the standard of care for patients presenting with such symptoms requires immediate hospitalization and institution of appropriate medications, including antanginal medications, aspirin and heparin. If chest pain continues after the patient was hospitalized indicating a refractoriness to medical treatment, then urgent cardiac catheterization and revascularization is generally indicated.

A prolonged episode of anginal quality discomfort lasting for 15 - 20 minutes or longer may indicate a manifestation of an acute myocardial infarction (heart attack). The standard treatment of such a patient requires hospitalization in an intensive care unit setting where constant telemetry of heart rhythm can be secured since patients are at increased risk for life-threatening arrhythmias in the first 48 to 72 hours.

It is important to note that a normal electrocardiogram, especially done in patients with unstable angina at a time when they are not having chest pain, does not rule out a cardiac etiology of the chest pain. Even patients with an acute myocardial infarction may have a normal initial electrocardiogram. therefore, the finding of a normal electrocardiogram should not by itself ordinarily dissuade the necessity for hospitalization of patients presenting with symptoms which otherwise would mandate admission. Similarly, normal cardiac enzymes, which by definition show a rise following acute myocardial infarction, may commonly be normal very early following the myocardial infarction. Typically, it takes at least two hours and often longer before an elevation in cardiac enzymes are noted. Typically, the peak elevation for the most important cardiac enzyme CK (creatine kinase) occurs at 18 to 24 hours following the onset of the myocardial infarction.

There are some chest pain syndormes which are so atypical for a cardiac etiology that it would be within good and accepted standards of care to dismiss a cardiac diagnosis and allow the patient to leave the emergency room. Chest pain which is very fleeting, lasting only for a few seconds is very unlikely to be cardiac related and would not generally require further cardiac evaluation.

Patients Presenting to Their Family Doctor with Complaints of Chest Pain:

In this scenario, issues related to chest pain complaints are similar to that described above for presentation in the emergency room. However, the chest pain syndrome may be more chronic in duration without a crescendo pattern suggestive of unstable angina or prolonged episodes suggestive of myocardial infarction. Nevertheless, recurrent episodes of anginal quality discomfort, particularly exertional in nature, require further cardiology evaluation and treatment. Since a cardiac etiology is almost always more potentially life-threatening than other etiologies of chest pain such as gastrointestinal, the standard of care calls for cardiac evaluation to be carried out first. Primary care physicians could choose to either initiate the evaluation (see below) or refer the patient to a cardiologist. If the patient is stable, initial evaluation generally would include performing a stress test as an outpatient. The stress test may be performed in conjunction with myocardial perfusion imaging (heart scan) or with echocardiography which can increase the diagnostic and prognostic capability of the stress test. If the test is significantly abnormal, then further evaluation with cardiac catheterization and possible revascularization is generally indicated. In addition, when patients present with recurrent chest pain even if stable, the standard of practice calls for institution of antianginal medication presumptively. This generally will be with an oral antianginal medication such as a beta blocker, long acting nitrate, or calcium channel blocker. At the very least, patients would be given sublingual nitroglycerin to take in the event that chest pain recurs. Administration of nitroglycerin in this setting is helpful both diagnostically and therapeutically. If nitroglycerin is found to relieve the patient's chest discomfort, then diagnostically it strongly favors a cardiac etiology.

Chest Pain Syndromes in the Hospital:

In patients who are admitted with presumptive diagnosis of unstable angina or acute myocardial infarction, recurrent chest pain identifies the patient at high risk for life-threatening complications such as acute or recurrent myocardial infarction or cardiac death. When recurrent chest pain recurs in patients who have presented with unstable angina, the standard of care calls for an enhancement of the medical treatment by increasing the dosage or adding additional medications. In general, once recurrent chest pain has occurred with a resasonably adequate medical regimen, a cardiac catheterization and coronary revascularization is indicated. In patients who have been admitted with acute myocardial infarction, recurrent chest pain generally indicates the presence of additional myocardium at risk. Recurrent chest pain is a marker of increased risk of recurrent myocardial infarction and cardiac death. Therefore, generally such patients require cardiac catheterization with an eye toward coronary revascularization. Coronary revascularization can include either coronary angioplasty or coronary artery bypass surgery.