HEART AND BLOOD VESSEL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 228

Extrasystoles (“Skipped Beats”)
Normal individuals may notice occasional irregular thumping sensations in their chests,
particularly at rest or during the night. They may feel their pulse and notice occasional
pauses between beats. Such irregular beats are called extrasystoles and are of no signi-
ficance unless the person clearly has heart disease manifested by angina, myocardial in-
farction, or cardiac dyspnea. Rest and reassurance are usually the only measures needed.
Avoiding stimulants such as coffee and tea or tobacco often entirely eliminates the ex-
trasystoles. Sometimes the number of extrasystoles an individual experiences is increased
at altitude ( Chapter 25: Altitude and Common Medical Conditions ) .
If a bothersome irregularity of the heartbeat persists, or if such irregularities have never
been experienced before, evacuation to a physician's care may be desirable.
DEVICES FOR HEART RHYTHM MANAGEMENT
Implanted devices for the management of cardiac rhythm disturbances include pacemakers
and defibrillators. The indications for these devices and their utilization are steadily in-
creasing. Some backcountry adventurers are likely to have one of these devices. Pace-
makersaregenerallyimplantedforabnormallyslowrhythmsorheartfailure.Defibrillators
(or ICDs: implantable cardioverter-defibrillators) are implanted to shock the heart out of
more malignant fast rhythms from the lower chambers (ventricles) of the heart. Both types
ofdevicesaretypicallylocatedbeneaththecollarbone,usuallyontheleftside.Pacemakers
usuallyaresmaller,aboutthesizeofasilverdollar.Defibrillators,becausetheyhavehigher
energyneeds,arelarger,abouttwo-thirdsthesizeofaniPodNano®.Thepresenceofade-
fibrillator implies the individual has much more serious structural heart disease. Any per-
son with one of these devices should have the device thoroughly interrogated in a physi-
cian's office prior to departure to ensure appropriate settings and function.
HIGH BLOOD PRESSURE (HYPERTENSION)
Thirty percent of adult Americans have high blood pressure. Many individuals with high
blood pressure pursue wilderness activities. For such individuals to be safe, the following
guidelines should be observed:
Persons with mild or drug-controlled hypertension should partake in wilderness activ-
ities only after consulting a sympathetic physician knowledgeable about wilderness en-
vironments. On an outing, such individuals must supply their own medications and fol-
low their physician's recommendations carefully. Fluid intake should be adequate, and
they should maintain a diet modest in sodium.
Individuals with severe, uncontrolled hypertension or complications of hypertension
should not venture into remote wilderness areas. The complications of uncontrolled hy-
pertension—strokes, heart failure, coronary artery disease, decreased visual acuity, and
kidney failure—could be disastrous in such situations.