Chest Pain Part 1 - What Is It, and What Are Its Causes?

From Richard N. Fogoros, M.D.
Few symptoms are more alarming than chest pain. In the minds of many people, chest pain equals heart pain. And while many other conditions can cause chest pain, cardiac disease is so common – and so dangerous – that the symptom of chest pain should never be dismissed out of hand as being insignificant.

What is chest pain?
“Chest pain” is an imprecise term. It is often used to describe any pain, pressure, squeezing, choking, numbness or any other discomfort in the chest, neck, or upper abdomen, and is often associated with pain in the jaw, head, or arms. It can last from less than a second to days or weeks, can occur frequently or rarely, and can occur sporadically or predictably. With such a broad definition the term “chest pain” is itself of little help to doctors.

What medical problems cause chest pain?
Chest pain is merely a symptom, not a diagnosis. Many medical problems can cause chest pain, and before the chest pain can be adequately treated, the actual underlying cause needs to be identified. The following is a list of the more common causes of chest pain, roughly in order of the frequency in which they are seen in the emergency room.
1. angina due to coronary artery disease
2. heart attack
3. heartburn
4. benign chest wall pain
5. anxiety or panic disorder
6. asthma, bronchitis, pneumonia, pleuritis
7. mitral valve prolapse
8. pericarditis
9. recent chest trauma
10. peptic ulcer
11. angina due to coronary artery spasm
12. angina due to cardiac syndrome X
13. aortic dissection
In young, healthy people presenting with chest pain, the condition "benign chest wall pain" is particularly common. This is a diagnosis that doctors do not understand very well, and consequently neither do their patients. Because this condition is completely harmless, the lack of understanding on the part of patients as to what is causing the pain often leads to months or years of needless worry or anxiety.

Chest Pain Part 2 - Evaluating the Cause of Chest Pain

From Richard N. Fogoros, M.D.
How should chest pain be evaluated?
If the chest pain is acute in onset: When you arrive in the emergency room with chest pain, doctors can usually get to the root of your problem quite rapidly by
1) taking a directed medical history,
2) performing a physical examination,
3) getting an ECG and cardiac enzymes.
If the diagnosis is still in doubt, further testing will be needed, depending on which conditions are being considered.
The first order of business is to rule out a potentially life-threatening cardiac problem – heart attack usually being the main concern (aortic dissection - a tearing of the wall of the aorta - is also life-threatening, but far less common). Rapidly diagnosing heart attack is especially important since immediate treatment can significantly limit the heart damage that occurs, and can prolong overall survival. Almost as important is the diagnosis of unstable angina, since rapid and aggressive treatment of this condition is also necessary to prolong survival.
Once a life-threatening problem is ruled out, most emergency room doctors will make a presumptive diagnosis and refer you to your own physician for follow-up evaluation and treatment.
If the chest pain is a more chronic, recurrent, or non-acute problem: Angina due to coronary artery disease is the chief concern here. Often, stress testing with thallium will be needed to rule out this diagnosis, and not infrequently a cardiac catheterization will also be necessary. The importance of diagnosing angina is not to relieve your pain, but instead to deal with the long-term implications of angina. Namely, the coronary artery disorder that causes angina is a progressive disease process that gets worse over time, and – if untreated – often leads to heart attacks, disability, and death. It is vitally important to make the diagnosis so that treatment can be optimized not only to relieve the pain, but also to slow or halt the progression of the underlying coronary artery disease.
When something other than “routine” coronary artery disease is causing your chest pain a diagnosis also needs to be made before the pain can be adequately treated. Depending on which problems might be suspected by your doctor, you may need x-rays, endoscopy of your GI tract, or pulmonary (lung) function tests.

When is chest pain an emergency?
As we have seen, the term “chest pain” encompasses many different kinds of symptoms and many different kinds of medical disorders. Some of these disorders are quite benign and trivial, but some are dangerous and life-threatening. So when you have chest pain, how do you know when to treat it as an emergency?
There are no hard and fast rules here. Sometimes even minor chest symptoms can turn out to be due to coronary artery disease (evidenced by the fact that up to 30% of heart attacks are accompanied by symptoms so trivial that the patient does not notice them). And you should tell your doctor about any chest pain you experience. But here are some general guidelines that are useful for deciding whether you need to go to the emergency room.
Chest pain is relatively likely to represent a dangerous cardiac disorder - and should be treated as an emergency - if any of the following are true:
1. You are 40 years old or older, and have one or more risk factors for coronary artery disease (family history, smoking, obesity, sedentary lifestyle, elevated cholesterol, diabetes
2. You are any age and have a very strong family history of early heart disease.
3. The pain can best be described by the terms tightness, squeezing, heaviness, or crushing.
4. The pain is accompanied by weakness, nausea, shortness of breath, sweating, dizziness or fainting.
5. The pain “radiates” to the shoulders, arms, or jaw.
6. The pain is more severe than any you have had before.
7. The pain is accompanied by the uncontrollable feeling that something is horribly wrong
8. The pain gets continually worse over the first 15 or 20 minutes.
9. The pain is new – you have never experienced anything like it before.
On the other hand, chest pain is relatively unlikely to represent a dangerous cardiac disorder - and is less likely to be a medical emergency - if any of the following are true:
1. The pain changes with changes in body position.
2. The pain worsens with a deep breath or with coughing.
3. You have had similar pains in the past, and a cardiac disorder was ruled out.

Technology gives rise to diagnostic breakthroughs (Part – I)

Several technologies are being combined in novel ways to address previously intractable problems
By: GREG FREIHERR
Engineering advances over the last decade have resulted in clinical technology that may permit physicians to use their ultrasound scanners in ways they have previously only dreamed about.
Myocardial perfusion imaging with ultrasound can sometimes replace traditional techniques, with harmonic and sub-harmonic imaging generating better images of the coronaries and other parts of the body. While 3-D has yet to reach its potential in real-time image presentation, many mainstream systems generate volumetric images in less than a minute, opening the door to new diagnostic opportunities.
In achieving these capabilities, no single technological advance stands alone; several techniques are combined in novel ways to address previously intractable problems.
No better example arises than the evolution of micro-bubble contrast agents. Several years ago, these agents were designated as the best approach for visualizing myocardial perfusion . Micro-bubbles improve image quality, partly because their shells and the gas inside strongly reflect ultrasound waves. This reflectivity vastly increased signal strength, but clinical tests found the agents lacking-until ultrasound technology was adapted especially for use with micro-bubbles. This innovation changed the picture in myocardial perfusion .
Harmonic imaging and micro-bubble contrast agents, possibly in combination with pulse inversion and power Doppler, have produced clinical results comparable to those of nuclear medicine. At Northwick Park Hospital in Harrow, U.K., researchers studied power Doppler harmonic imaging in the assessment of myocardial perfusion. They compared ultrasound using micro-bubble contrast with single-photon emission computed tomography with technetium-99m sestamibi in 15 patients.

Technology gives rise to diagnostic breakthroughs (Part – II)

Several technologies are being combined in novel ways to address previously intractable problems
By: GREG FREIHERR
Using a five-segment model by two blinded observers, perfusion was determined to be present or absent for each modality. The research team reported a high concordance (93%) between the two modalities for the presence as well as the location of the defects: 96% for the antero-septal region, 93% for the infero-posterior region, and 87% for the apical region.
"Potentially, contrast echo has similar accuracies to SPECT, although it is certainly not a clinically proven technique," said Dr. Avijit Lahiri , director of cardiac research at the hospital.
A larger study comparing the two modalities was performed at the University of Texas Southwestern, where harmonic power Doppler imaging (HPDI) and SPECT were performed during rest and pharmacological stress in 123 patients known or suspected to have coronary heart disease . Myocardial perfusion by HPDI was graded for each coronary territory as absent, patchy, or full.
Persistently absent or patchy myocardial perfusion by HPDI between rest and adenosine was interpreted as a fixed defect, whereas any decrease in perfusion grade was interpreted as a reversible defect. Ultrasound and SPECT produced the same conclusions in 83 of 103 (81%) for normal versus abnormal perfusion. Discrepancies occurred mostly in imaging the circumflex, where HPDI identified fixed defects in 33% of patients but SPECT identified only 14%.
"The next stage of development is to assess real-time perfusion, and that is even more exciting because we can watch the contrast agent come and then wash out," said Dr. Sheila K. Heinle, an assistant professor of medicine at the university. "That will possibly give us additional information about coronary flow reserve in conjunction with pharmacologic agents."
Harmonic imaging alone offers substantial advantages over fundamental imaging, with or without micro-bubble contrast. It increases contrast between vessels and background tissues, has spatial and temporal resolution similar to that of gray-scale imaging, and is unaffected by flash artifact. Harmonic imaging also allows increased penetration without loss of detail. The advantage of artifact reduction and greater intrinsic contrast sensitivity is especially apparent when heightening low-contrast lesions.

Technology gives rise to diagnostic breakthroughs (Part – III)

Several technologies are being combined in novel ways to address previously intractable problems
By: GREG FREIHERR
Harmonic imaging may be less useful in some circumstances than others. Research conducted at Hutzel Hospital/Wayne State University in Detroit found that harmonic imaging improved resolution in at least one fetal structure in only 51.4% of patients studied. Differences were most evident for four-chamber views of the heart , but in those cases improved visualization was seen in only 30.5% of patients. Patient weight and gestational age were found to be major factors, as the researchers concluded that obese patients during the second trimester benefited the most.
"Women with a normal body mass index did not have improvement in visualization rates with harmonic tissue imaging, and in fact there seemed to be some image deterioration in normal-weight patients when we used harmonic tissue imaging instead of traditional fundamental imaging," said Dr. Marjorie C. Treadwell, director of obstetric ultrasound at Hutzel.
The improved resolution that came with deeper penetration worked, but only in patients who needed the deeper look.
Capturing a volume of data enables the diagnostician to see all relevant data at once and in context. Pathologies are frozen in time and place, and reproducibility is absolute, since the same data set could be reconfigured into volumes or slices from any perspective or angle. Faster heart scans and less operator error boosts productivity and patient throughput; lower cost and increased revenue will follow. And patient recalls would become a thing of the past.
Real-time imaging, while preferred, may not be necessary. Delays in image processing, which may be no more than a few seconds, allow computing engines built into scanners to do some powerful processing. The Voluson 530 D Digital Volume Sonography system from Medison acquires a volume of data that can be sliced in planes, which is otherwise difficult if not impossible to achieve. The system, which requires a six-second scan to obtain the data for a 3-D image, has been used in ob/gyn, abdominal, pelvic, vascular, and endocavitary applications. Harmonic imaging is offered as an option.

Technology gives rise to diagnostic breakthroughs (Part – IV)

Several technologies are being combined in novel ways to address previously intractable problems
By: GREG FREIHERR
Echocardiography presents the ultimate challenge and promises the greatest patient benefits for volumetric sonography. Instantaneously capturing the beating heart at stop-action speeds would dramatically reduce exam time and improve the diagnostic value of the data. The Model One-and still experimental-V360 Real-time Volumetric Ultrasound system from Volumetrics Medical Imaging incorporate many features found in conventional 2-D imaging, as well as real-time volumetric acquisition. Interactive capabilities allow retrospective multi-view analysis of the heart. A work-in-progress shown at the 1999 annual meeting of the American Heart Association featured on-the-fly viewing of 3-D volumes of the heart.
"Based on our market research, within three to five years every company will have to offer 3-D capability," said Jim Mundell, general manager at Volumetrics.
3D echocardiography is especially suited to imaging the fetal heart, which for obvious reasons is not a candidate for nuclear medicine . Researchers at the University of California, San Diego, evaluated 10 human fetuses in-utero, four of whom had congenital heart disease. They performed freehand trans-abdominal scanning, using a real-time, 3-D echocardiography system from Volumetrics.
Four scans, lasting just 1.5 seconds and acquiring 20 volumes per second, were obtained for each fetal heart and stored for off-line analysis. Two-dimensional images displayed simultaneously in four planes were reconstructed in real-time during the acquisition, providing the operator with enough feedback to ensure that an adequate 3-D volume was being captured. Off-line reconstructions allowed the heart to be slowed, stopped, or viewed at its original speed.
The researchers consistently visualized most structures and views, as well as cardiac function and they could readily detect abnormal structures.
Yet the current of clinical medicine is hampered by clinical and economic realities. While the technologies necessary to make volumetric imaging a reality are almost at hand, the perceived clinical value of volumetric imaging has not resulted in widespread adoption of the technology. Some kinks remain to be worked out, such as exactly demonstrating blood flow.
Despite the perception of 3-D as leading-edge technology, 2-D imaging is serving as the pathfinder for new types of data acquisition and processing, both qualitative and quantitative. Researchers at Thomas Jefferson University in Philadelphia have been exploring ways to get around some of the limitations of harmonic imaging, especially the problems caused by second harmonic generation and harmonic frequency accumulation within the tissue itself. They are attempting to create sub-harmonic images by transmitting at the fundamental frequency and receiving at half that frequency.8 This technique brings better lateral resolution as well as improved scanning of deep-lying structures. The latter are better visualized with the higher transmit frequency and smaller attenuation of scattered sub-harmonic signals.