HEART AND BLOOD VESSEL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 226

evacuated. Unlike PSVT, atrial fibrillation is more often associated with other more signi-
ficant heart disease such as heart failure, coronary disease, valvular disease, or pulmonary
embolus.
Heart Rhythm Medications
Therapy for PSVT and AF in the wilderness should include rest, hydration, and heart
rate control with medications. The most effective drugs for rate control are beta blockers
such as metoprolol, atenolol, or propanolol, although these should not be given to indi-
viduals with asthma or chronic lung disease. Doses should be started low and gradually
increased at six- to eight-hour intervals to achieve a resting heart rate of under 100 beats
per minute.
Syncope (Fainting)
Syncope is a transient loss of consciousness commonly referred to as fainting or
“passing out.” Two general varieties are encountered:
True syncope is complete loss of consciousness. The individual falls down, cannot be
aroused, and may display seizure activity. The duration may be seconds or minutes.
Partial syncope is a condition with which the person feels weak or faint and slumps to
a chair, bed, or floor, but consciousness and communication are maintained. After a few
minutes the person recovers but remains weak and unsteady for several minutes.
Truesyncopeispresentinonly10to20percentoftheindividualsreferredtophysicians
with that diagnosis. Partial or near syncope makes up the rest. True syncope is a serious
symptom,particularlyifithasoccurredmorethanonceandwithoutwarningandshouldbe
investigated in a hospital where sophisticated diagnostic studies can be performed. Many
serious conditions, including brain tumors, heart tumors, and cardiac arrhythmias, may
cause true syncope.
Most instances of partial syncope—and some cases of true syncope—are postural or
vasovagal and situational in origin. Common provocations are a crowded, overheated
room, the sight of blood, recent arrival at high altitude, dehydration, a large meal, or pro-
longed standing. In rare instances, partial syncope may occur during or immediately after
heavy exertion without adequately cooling down.
Anindividualwithvasovagalsyncopetypicallybecomespale,sweaty,nauseated,weak,
and anxious. The pulse is usually slow and regular but may be weak. A history of similar
episodes may be obtained.
Partial syncope can be avoided by having the person lie down with legs elevated. The
person must remain supine until the episode has completely resolved. Fresh air and a cold,
wet towel for the face usually aid recovery. If the individual has no history of cardiac dis-
ease or episodes of true syncope, hospitalization is not necessary. Precautions to prevent
subsequent episodes should be observed.