[Changes in heart rate after ventricular stimulation; correlations with vagal tone].
The authors report a new method of studying the autonomic nervous system, especially vagal tone, during endocavitary electrophysiological studies. After termination of fixed ventricular pacing at incremental rates to 200/min, an initial acceleration of the heart rate is observed followed about 5 seconds later by a sudden slowing. This phenomenon was studied in 278 patients. Ninety seven patients had no cardiac disease: the variation in heart rate was 33 +/- 18%. In the 181 other patients with cardiac disease (ejection fraction 35 +/- 16%) the variation was only 21 +/- 16% (p < 0.01). When the ejection fraction was less than 30%, the variation was only 13 +/- 4%. When the heart rate variation was less than 10%, the prognosis was poor because, of the 48 patients with this sign, 13 died, whereas there were only 2 deaths in the 133 other patients with cardiac disease and preserved adaptation. In 14 patients without cardiac disease the injection of 2 mg of atropine suppressed all adaptation of the heart rate, whilst in 18 other patients, oral betablockers reduced the variation but it persisted to a significant degree. The authors conclude that the adaptation of the heart rate after rapid ventricular stimulation is probably a reflection of vagal tone and may be used to assess the prognosis of subjects undergoing electrophysiological investigations.
Brembilla-Perrot
B
B
Service de cardiologie, CHU Brabois, Vandoeuvre.
Beurrier
D
D
Alsagheer
S
S
Suty-Selton
C
C
Terrier de La Chaise
A
A
Thiel
B
B
Louis
P
P
Hadjaj
B
B
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001341:Autonomic Nervous System / Q000503:physiopathology; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D014630:Vagus Nerve / Q000503:physiopathology*
Variations de la fréquence cardiaque à l'arrêt de la stimulation ventriculaire; corrélations avec le tonus vagal.