Shortness of breath or dyspnea is a very common symptom observed in the general population. About 25% of patients seen by a care team in the ambulatory setting present with a complaint of shortness of breath. There certainly are a number of different causes of shortness of breath but the initial workup generally begins in the primary care setting. Once acute issues such as reactive airway disease (asthma), pneumonia, and bronchitis have been effectively ruled out, the primary team may request that the patient be seen by a cardiology or pulmonary specialist. In the cardiology setting is often important that we rule out underlying coronary artery disease especially in patients who are risk for this treatable condition. Moreover, shortness of breath may be caused by cardiac issues such as valvular disease, cardiomyopathy/heart failure, rhythm disturbance, pericarditis (an inflammation of the sac in which the heart sits). Another condition that may be involved is pulmonary vascular disease or pulmonary hypertension. A special blog will be devoted to this condition but it involves elevated blood pressures in the lungs that may result in significant shortness of breath as well as a special type of heart failure.
While the testing involved for working up patients with shortness of breath must be tailored to the individual we will highlight a few tests that may be performed at the cardiology office.
Stress testing. This is a test devoted to evaluating whether or not the patient may have blockages of the coronary arteries (coronary artery disease). While some patients present with coronary artery disease with classic symptoms of chest pain, some patients present with shortness of breath as their “angina equivalent". There are a number of different ways to perform a stress test. The most common type of test in ambulatory patients is the treadmill test. This test evaluates the patient's electrocardiogram during exercise. In some cases, an injection of an “indicator” may be given intravenously to provide further assessment of the patient's blood flow within the heart. For patients who cannot walk on a treadmill there is a chemical alternative in which medication is given intravenously to allow for assessment of blood flow in the heart.
Echocardiogram: An echocardiogram is a noninvasive ultrasound of the heart which provides information related to how well it squeezes, how well it relaxes, assessment of the size of the chambers, assessment of the valves, and assessment of its overall structure. This test allows the patient's care team to determine the likelihood of their shortness of breath being secondary to valvular disease, heart failure, another structural abnormality, or pulmonary hypertension.
Cardiopulmonary exercise test (CPET): this is a robust test that allows for functional assessment of the patient's cardiopulmonary system. In this test, the patient is given a mouthpiece through which to breathe from the mouth. The patient's oxygen saturation and electrocardiogram are continuously monitored. The test measures how much oxygen the body consumes and how much carbon dioxide it gives off. This allows us to determine whether or not the patient's shortness of breath is from a cardiac cause, a pulmonary cause, a problem with how the heart and lungs are interacting, or whether or not the patient’s shortness of breath is most likely from deconditioning. In addition to allowing for a workup for shortness of breath, this test allows us to give the patient an exercise “prescription" for physical activity.
Summary: We have a number of noninvasive testing and modalities that allow for the workup of the symptom of shortness of breath. In some cases, the patient has shortness of breath that is not secondary to a cardiac issue but more likely related to a pulmonary issue. In these cases it is recommended that the patient have further workup performed by pulmonologist in which case functional testing and imaging may be used to determine if the patient has a condition such as COPD/emphysema, asthma, pulmonary fibrosis or another lung condition. In cases such as these we work very well with the patient's primary care physician and pulmonologist in an effort to treat the patient in an attempt to relieve them of their shortness of breath.