WILDERNESS MEDICINE: ADVENTURE AND CARDIAC RISK
By Frank Hubbell, D.O.

Adventure programs are considered "adventurous," at least in part, because they may require a fair amount of unusual physical or emotional responses. Activities in adventure programs are often exciting, potentially producing fear and anxiety while demanding a higher level of physical exertion. Obviously some adventure opportunities are more anxiety provoking than others-high elements on ropes courses, climbing or rappelling, white water rafting, and kayaking, to name a few. Part of the learning and team building process is discovering how to harness this anxious emotional energy and make it work for you, not against you.

Adventure programs are available to anyone. However, not everyone is physically or emotionally capable of performing well in these situation and, as a result, some individuals may be putting themselves at risk of having an acute cardiac event, such as a potentially lethal heart attack. Is there a relatively simple way to predict who is at risk of an acute heart attack? In the opinion of this author, the answer to the question is "yes," there are predictors that can be used to identify individuals who have significant carcliac risk factors and who would therefore be at increased risk.

Heart disease is a very common medical condition in this country. The term "heart disease" includes hypertension, coronary heart disease, angina pectoris, congestive heart failure, and a history of myocardial infarction (heart attack). Heart disease is the number one cause of death in the U.S., but quite often remains undiagnosed until an acute event such as a myocardial infarction occurs unexpectedly.

The heart is a muscle. Like any muscle, it requires constant blood flow to maintain a supply of oxygen and nutrients and to carry away waste products. The heart responds to demands placed on the rest of the body. During periods of physical exertion, it increases the cardiac output, or blood flow, to meet the increased oxygen demands of the working muscle groups.

The heart can also be stressed to increase cardiac output by certain hormones produced by the body. One of these hormones is adrenaline, also known as epinephrine. Adrenaline, produced and stored by the adrenal gland, is the hormone used for flight or fight responses. When the brain perceives a dangerous or frightening situation, the adrenal glands secrete adrenaline into the bloodstream. This adrenaline then provides the burst of added strength needed to survive the situation. As part of this process, adrenaline also increases heart rate and the strength of contraction of the heart muscle to dramatically increase cardiac output and supply more blood and oxygen to the muscle groups utilized in that particular situation.

As mentioned above, adventure sports participants may find themselves not only in a physically demanding activity but also in one that is frightening or anxiety provoking. As a result, their heart, driven by adrenaline, must work twice as hard. Individuals with underlying heart disease may suddenly find that this demand is too great for their diseased hearts and suffer an acute cardiac event like a heart attack.
The problem for adventure programs is how to identify those individuals with underlying heart disease that could become a problem under times of extreme cardiac stress from the combination of physical exertion and fear. Obviously, it would be virtually impossible to identify every individual at risk. However, we can identify those with definite risk factors (see Table 1 below). These identifiers can be incorporated into a standard form that each individual completes before participating in a activity that is going to stress the heart. Some of these risk factors are better indicators than others.

The first and most obvious questions are historical. Does this person have a known history of coronary artery disease? Do they have angina pectoris? Have they had a previous myocardial infarction? Have they had open heart surgery or a coronary artery bypass? Do they have anginapectoris? Have they had a previous myocardial infarction? Have they had open heart surgery or a coronary artery bypass? Do they have hypertension? Have they ever had a stroke? Are they currently taking any cardiac medications? If so, these individuals should be advised to confer with their physician/cardiologist to help determine the recommended level of participation. Most individuals in this situation can then be offered the opportunity to participate in a modified program as deemed appropriate.

Individuals who have chest pain with exertion, especially if associated with the chest pain is shortness of breath and sweating, also need to be evaluated by a cardiologist because these constellations of symptoms are very strong indicators of underlying coronary artery disease.

There are other risk factors which alone indicate that the person has potential risk for heart disease, but do not indicate if the person currently has heart disease. However, several of the factors combined are strong indicators that the person most likely does have underlying heart disease and should be questioned more closely and given the option to participate in the program.

The following is an example of a CARDIAC RISK ASSESSMENT form:

1. Previous Cardiac History: Do you have a history of any heart disease? Have you ever had a heart attack or a stroke? Have you ever had open heart surgery? Do you have hypertension? Do you take any cardiac medications? Do you have chest pains with physical exercise?

2. Cardiac Risk Factors: Do you have diabetes. NIDDM or IDDM? Do you have elevated blood cholesterol or triglycerides? Do you smoke? Do you consume more than one alcoholic beverage per day? Do you have a family history of heart disease? Do you have a daily exercise routine?

If any of the part one questions are answered "yes," then the person should be advised to confer with their physician/cardiologist.

If three or more risk factors in part two are positive, then the participant should be questioned in more depth as to any current signs or symptoms of heart disease (such as chest pain or shortness of breath with exertion) and should be given the recommendation to participate in a modified program. More importantly, if an individual who has been identified as having risk factors of potential heart disease suddenly develops chest pain or shortness of breath while participating in the program, they should immediately be treated as if they were having a myocardial infarction.

As stated earlier, it is impossible to identify every individual who might possibly have an acute cardiac event while participating in an adventure program. However, it is very possible to identify those at significant risk and offer them modified programs to minimize that risk. In addition, it is most prudent to suggest they pursue further evaluation by a cardiologist.

The policies that a particular adventure program develops to handle the processing of these forms and the presentation o f the information to the individual are important and need to be customized to the particular program. The role of the adventure program is to advise the participant so that he or she is able to make an informed choice. In the rare event that an individual is given the information about risk factors. and still desires to pursue higher stress activities, the program may decide to allow that individual to accept the risk as part of their release form procedure. But that individual will be informed as to the risk in a way that conforms to acceptable current practice in the adventure field. A corollary to the recognition of cardiac risk factors is the provision of rapid care in the case of a cardiac event. All adventure program trainers should have first aid and CPR training appropriate to the level of activity and distance from definitive care. There are organizations available that can provide specific training in cardiac risk assessment for adventure programs.

TABLE 1 - RISK FACTORS FOR HEART DISEASE

The currently identified risk factors include any person who:

• has a known history of coronary artery disease, or a previous myocardial infarction
• has a history of hypertension or currently takes medications for hypertension or cardiac disease.
• has diabetes, either insulin dependent (IDDM) or non-insulin dependent (NIDDM).
• has a history of elevated blood cholesterol or triglycerides.
• is or once was a smoker
• consumes more than one alcoholic beverage per day
• has a family history of heart disease
• is overweight and has no exercise routine
• has a history of chest pain with exertion.