HEART AND BLOOD VESSEL DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 224

bling, dizziness, and occasionally numbness of the lips and fingers. The heart rate may
beincreased.Reassurance,rest,andmildsedationareusuallytheonlymeasuresneeded
(see “ Hyperventilation Syndrome ” in Chapter 18: Respiratory Disorders ) .
Chest pain attributable to the chest wall, lungs, or lining of the lungs and heart that is
actually pleuritic pain and worsens with inspiration. Such pain is usually related to in-
flammation and responds to anti-inflammatory agents such as acetaminophen, aspirin,
or ibuprofen. If pleuritic chest pain is associated with marked shortness of breath or
coughingupblood,amuchmoreseriousdisordersuchaspneumoniaorpulmonaryem-
bolus (blood clots carried to the lungs) should be suspected and should prompt rapid
evacuation.
Heartburn. This discomfort typically originates below the breastbone and may extend
to the throat. It is more common after large, fatty meals, excess coffee or alcohol, and
when lying down, in which case antacids usually provide prompt relief. Heartburn may
be difficult to differentiate from angina pectoris. Persons in whom heartburn does not
respond to antacids should be queried and examined for other signs and symptoms of
angina ( Chapter 19: Gastrointestinal Disorders ) .
DISORDERS OF CARDIAC RHYTHM
Cardiac rhythm can change in a number of ways. Speeding up with exercise or slowing
withrestarenormal.Somechangesareofminorsignificance;othersaremoreserious( Fig.
17-2 ) . Ventricular fibrillation is lethal if not halted in minutes.
Paroxysmal Supraventricular Tachycardia
Paroxysmal supraventricular tachycardia (PSVT) is characterized by a very rapid but
regular heart rate, sudden in onset, that is associated with a sensation of pounding in the
chest, weakness, dizziness, and shortness of breath. True syncope (unconsciousness) is
rare. The heart rate is very rapid (150 to 220 or more per minute) and completely regular.
The pulses may be so weak that listening to the heart with a stethoscope is necessary to
determine the rate. (When beating so rapidly, the heart does not have time to fill between
contractions and the amount of blood pumped with each heartbeat decreases.) Individuals
may have previously experienced similar attacks.