bradycardia is confirmed or suspected in a patient, possible
intrinsic or extrinsic causes must be sought, including obstructive
sleep apnea (absent breathing due to obstruction in the throat
by the uvula), and medications affecting heart rate (see figure
93a). The thyroid should be tested for activity.
must be confirmed by EKG. If the symptoms are intermittent,
a 24 hour EKG Holter test (see figures
96B, 97, 98, 99, 100, 101,
102) may be necessary to assist with the diagnosis and the
correlation of symptoms with the onset of bradycardia.
testing with the EKG while the patient is lying on a tilt table
with a head up position may be used to provoke an episode of
fainting with changes in heart rate and blood pressure. Invasive
electrophysiologic testing is rarely needed, but may be helpful
if the mechanism responsible for bradycardia remains uncertain,
or if symptoms suggest the presence of a life-threathening arrhythmia.