(b) If the patient is experiencing a falling blood pressure, cool and
clammy skin, confusion, or unconsciousness, treatment is directed at slowing the
ventricular rate. In the field, transport the casualty to a medical treatment facility where
he can be monitored. DO NOT use cardioversion for a casualty who has been taking
digitalis or a person who has a ventricular rate of more than 120 to 140 beats per
minute. Cardioversion would not be used if the casualty were experiencing inadequate
cardiac output resulting in hypotension, cold and clammy skin, confusion, or coma.
Cardioversion would be indicated only when it would be a long time before the casualty
could be transported to a medical treatment facility.
Figure 2-18. Atrial flutter.
f. Atrial Fibrillation.
(1) Analysis. In atrial fibrillation, the rhythm is irregularly irregular. The
atrial rhythm is unmeasurable, and the R-R interval is irregularly irregular (ventricular).
In regard to the heartbeat rate, the atrial rate is unmeasurable. If the ventricular rate is
less than 100 beats per minute, it is controlled. If the ventricular rate is greater than 100
beats per minute, it has a rapid ventricular response that is uncontrolled. The atrial
heartbeat rate is unmeasurable. The ventricular heartbeat rate, if controlled, is less
than 100 beats per minute. If the ventricular heartbeat rate is uncontrolled, the rate is
greater than 100 beats per minute. There is either no P wave or there are fibrillatory P
waves in which case there is no depolarization of atria, and the waves at the baseline
have chaotic undulations. The P-R interval cannot be measured. The QRS complex is
less than 0.12 seconds. Atrial fibrillation is usually the result of underlying heart
disease. Occasionally, this problem may occur in a normal patient or in patients with
MI, especially if SA node infarction occurs. Rapid ventricular response reduces
ventricular filling decreasing the stroke volume.
(2) Treatment. Treatment is directed toward eliminating the cause of the
problem and decreasing the rate of ventricular response. In the field, transport the
casualty to a medical treatment facility and monitor him.