A-Textbook-of-Clinical-Pharmacology-and-Therapeutics-5th-edition

SELECTED ANTI-DYSRHYTHMIC DRUGS 229
Case history
A 24-year-old medical student arrives at the Accident and
Emergency Department complaining of rapid regular palpitations
coming on abruptly while he was studying in the
library for his final examinations which start next week.
There is no relevant past history. He looks pale but otherwise
well, his pulse is 155 beats per minute and regular, his
blood pressure is 110/60mmHg and the examination is otherwise
unremarkable. The cardiogram shows a supraventricular
tachycardia.
Question
Decide whether initial management might reasonably
include each of the following:
FURTHER READING
Delacretaz E. Clinical practice: supraventricular tachycardia. New
England Journal of Medicine 2006; 354: 1039–51.
Goldberger Z, Lampert R. Implantable cardioverter-defibrillators:
expanding indications and technologies. Journal of the American
Medical Association 2006; 295: 809–18.
Hall MC, Todd DM. Modern management of arrhythmias.
Postgraduate Medical Journal 2006; 82: 117–25.
Nattel S, Opie LH. Controversies in atrial fibrillation. Lancet 2006; 367:
262–72.
(a) i.v. amiodarone;
(b) vagal manoeuvres;
(c) i.v. digoxin;
(d) reassurance;
(e) DC shock;
(f) overnight observation;
(g) specialized tests for phaeochromocytoma.
Answer
(a) False
(b) True
(c) False
(d) True
(e) False
(f) True
(g) False
Comment
Students who are studying for examinations often consume
excessive amounts of coffee and a history of caffeine intake
should be sought. The rhythm is benign and the patient
should be reassured. Vagal manoeuvres may terminate the
dysrhythmia but, if not, overnight observation may see the
rhythm revert spontaneously to sinus. Intravenous amiodarone
or initial DC shock would be inappropriate, and i.v.
digoxin (while increasing vagal tone) could render subsequent
DC shock (if necessary) more hazardous.