The diagnosis depends a lot on the type of arrhythmia. Atrial premature contractions are usually benign, and an extensive workup is unnecessary unless other physical signs indicate the need for it. Infrequent ventricular premature contractions (VPCs) in otherwise healthy individuals probably can be handled the same way. When VPCs are frequent or multifocal, an exercise tolerance test, echocardiogram, and perhaps coronary angiography are indicated. Runs of ventricular tachycardia require an extensive workup, including coronary angiography, but usually there will be other signs to indicate the need for this.

Atrial tachycardia and fibrillation require a workup of hyperthyroidism and pulmonary disease, systemic hypertension, and congestive heart failure (CHF). Atrial obstruction and dilatation should be excluded by echocardiography. Carotid sinus massage will distinguish rapid atrial arrhythmias from sinus tachycardia.

Any arrhythmia warrants an electrocardiogram (ECG) and possibly repeated ECGs. The Holter monitor should be used if there is doubt about the type of arrhythmia.

The diagnosis of cardiomegaly can be further developed by a good history and the association of other symptoms and signs. Is there a history of hypertension, alcoholism, rheumatic fever, or other systemic disease? Has the patient experienced shortness of breath, angina, fever, joint pains, and so forth? Are there findings of pedal edema, hepatomegaly, or jugular venous distention (CHF)? Are there hypertension and proteinuria (renal disease or essential hypertension)?
Is there a significant heart murmur (congenital heart disease, rheumatic heart disease)?

The diagnostic workup will include a CBC, urinalysis, chemistry panel, sedimentation rate, chest x-ray, and ECG. At this point, it is wise to consult a cardiologist. Echocardiography will be helpful in diagnosing valvular heart disease, myocardiopathy, and pericardial effusion. If CHF is suspected, a venous pressure and circulation time as well as spirometry will support the diagnosis. Echocardiography can diagnose CHF by determining the left ventricular ejection fraction (LVEF). CT angiography will also be helpful. If there is unexplained fever, an antistreptolysin O (ASO) titer or streptozyme test should be ordered to rule out rheumatic fever, and perhaps serial blood cultures should be done to exclude subacute bacterial endocarditis. If there is hypertension, the patient may need a hypertensive workup (see page 237).

A history of diaphoresis, weight loss, or heat intolerance would arouse suspicion of hyperthyroidism. A history of transient hemiplegia, amaurosis fugax, or other intermittent neurologic symptomatology should point to a carotid stenosis or subclavian steal syndrome. Physical findings of pallor or spoon nails would point to anemia. An enlarged thyroid prompts the suspicion of hyperthyroidism. If there is a diminished pulse on the side of the bruit, look for thoracic outlet syndrome or subclavian steal syndrome. The diagnostic workup may need to include a CBC, thyroid panel, and carotid duplex scan.

Consult a neurologist if there are objective neurologic signs. Four-vessel angiography needs to be considered if a carotid stenosis or subclavian steal syndrome is suspected. If the bruit seems to be transmitted from the chest, echocardiography may be needed.

A possible myocardial infarction must be the first consideration in all adults with acute chest pain, especially if there are significant alterations of the vital signs. Consequently, serial ECGs, serial cardiac enzymes including troponins, and hospitalization will often be necessary. Patients with non-STEMI chest pain may be evaluated by coronary CT angiography first. After this condition has been excluded, we can turn our attention to the other possibilities. A tablespoon of Xylocaine Viscous may be administered to rule out reflux esophagitis. Arterial blood gases, chest x-ray, and a lung scan or helical CT scan of the chest may be ordered to exclude a pulmonary embolism. The D-dimer test is sensitive for pulmonary embolism and dissecting aneurysm. Pulmonary angiography may be necessary in some cases. A chest x-ray may be ordered to rule out pneumonia. Acute chest pain related to esophagitis is often relieved by swallowing Lidocaine Viscous, an extremely useful tool in the differential diagnosis. Relief of

the pain with nitroglycerin under the tongue or by spray will support the diagnosis of coronary insufficiency. Tenderness of the costochondral junctions with relief on lidocaine injection into the point of maximum tenderness suggests Tietze syndrome (costochondritis). In cases of chronic chest pain, an exercise tolerance test with thallium scan should be done to rule out coronary insufficiency or myocardial infarction. CT angiography will easily diagnose a dissecting aneurysm. It may be wise to do immediate coronary angiography if the condition deteriorates so that balloon angiography, bypass surgery, or reperfusion therapy may be initiated. Dissecting aneurysm is revealed by CT scan or MRI of the chest. Do not forget that young patients may have an MI due to collagen disease or anomalous coronary circulation.