Originally Posted by bad.moshi
Well I was trying to look at things from a neuro standpoint. I'm not particularly familiar with the complete workings of the circulatory system, but i assumed that a stress test would see if his heart was working correctly under stress. I realize stress on your heart from running is different than psychological stress, but still.
By all means, stress from any source (psychological or otherwise) can certainly have negative effects. I'm simply curious about your thoughts
As an example, here'* one approach we use to treat cardiac related chest pain (part of which involves a phychological factor)...
Cardiac CP (for the purpose of this discussion) relates to inadequate oxygenation of the heart muscle with its current workload. When oxygen demand exceeds supply, symptoms may develop. The elderly and diabetics in particular may not have pain in the "traditional" sense. Symptoms that this subgroup of patients might have are called anginal equivalents. If it is truly cardiac chest pain (or an anginal equivalent), we can be looking at either (simple) angina or one of the three acute coronary syndromes (unstable angina, ST Elevation MI or Non-ST Elevation MI). Chest pain may also develop due to hypoperfusion from arrythmias, infections (pericarditis) and others (which I won't touch on here as these are treated differently).
The goal in treating CP is to reduce the oxygen demand on the heart. Often, we see people take nitroglycerin under the tongue. A common misconception is that this dilates the coronary arteries increasing blood flow to the heart muscle and taking the pain away. Nitro does achieve this to some extent, but the major benefit results from peripeheral vasodilation. By dilating vessels elswhere in the body, the heart doesn't have to work as hard to pump blood. When workload decreases, so does the amount of oxygen the heart requires. In the setting of an acute myocardial infarction (heart attack), nitro generally doesn't resolve the pain completely. Here there is a restriction preventing the blood from reaching the heart muscle. Nitro may still of benefit because ultimately it will assist in reducing workload. Nitro can have devastating and potentially fatal effects if not used correctly.
Supplemental oxygen is also beneficial since it helps to ensure hemoglobin is completely saturated with oxygen molecules. This aids in delivering the most possible oxygen to the heart under the current circumstances. Aspirin (especially in the setting of an acute MI) has proven benefits in decreasing mortality. While there is another misconception that ASA is a "blood thinner", it isn't. ASA is a platelet aggregation inhibitor and helps to keep blood platelets from sticking together. This can have huge benefits in controlling the size of a blockage in the process of developing. Too much aspirin however, can have a negative effect. Type of aspirin, correct dosage and delivery method are very important here. The ASA given in this setting generally has little to no benefit in the relief of CP.
Here'* where the psychological factors come into play. What we know is that pain causes anxiety. When we are anxious, this has negative effects on the heart because it will increase the hearts oxygen demand (anxiety causes an increase heart rate, therefore the heart is working harder). More demand can result in more pain. More pain can result in more stress. This can get to be somewhat of a vicious cycle. Unlike traumatic pain where we want to at least make people comfortable, our goal in management of cardiac chest pain is to eliminate it entirely. If we can achieve a decrease in pain, or eliminate it altogether, we can decrease the oxygen demand of the heart. This can actually help to limit the area of damaged tissue (in the setting of a heart attack). We have a variety of analgesics capable of helping us do this, depending on each specific patient and the training of the care provider.
In some cases, we use medications to decrease the heart rate in order to reduce workload. This again can again limit the size of damaged heart muscle and reduce or eliminate pain.
Stress testing is intended to increase the workload of the heart while monitoring various portions of the heart for signs of ischemia (decreased oxygenation). ECG changes in specific areas can indicate which vessels are involved. Physicians typically don't allow individuals with current chest pain felt to be cardiac in nature take a stress test. The risk is simply too high. This test is often done in people who don't immediately have chest pain in order to see if, under stress, chest pain develops or ECG changes occur. This can help to rule out cardiac chest pain from other types of pain amongst other things.
Some of the other types of testing (in fairly basic terms) include a thalium test where it'* possible to see areas of the heart muscle not being adequately oxygenated. An echocardiogram will help to assess pumping action of the heart. A Holter monitor can be used to record unusual electrical activity that isn't always present. Blood tests to check for a variety of cardiac enzymes (looking for signs of damaged heart muscle). The electrocardiogram can show many things including electrical blocks, old or recent heart damage, a heart attack in progress and a variety of other things.