R. Pedretti et al., INFLUENCE OF TRANSDERMAL SCOPOLAMINE ON CARDIAC SYMPATHOVAGAL INTERACTION AFTER ACUTE MYOCARDIAL-INFARCTION, The American journal of cardiology, 72(5), 1993, pp. 384-392
In 41 survivors of acute myocardial infarction (AMI) a prospective stu
dy was performed in 2 sequential phases. In phase 1, the role of baror
eflex sensitivity and heart rate variability as predictors of inducibl
e and spontaneous sustained ventricular tachyarrhythmias was evaluated
. In phase 2, the effects of transdermal scopolamine on baroreflex sen
sitivity, spectral and nonspectral measures of heart rate variability
were investigated. At a mean follow-up of 10 +/- 3 months after AMI, 5
of 41 patients (12%) developed a late arrhythmic event. Of these, all
(100%) had inducibility of sustained monomorphic ventricular tachycar
dia at programmed stimulation compared with 3 of 36 patients (8%) with
out events (p <0.0001). At multivariate analysis, baroreflex sensitivi
ty had the strongest relation to both inducibility of sustained monomo
rphic ventricular tachycardia (p <0.0001) and occurrence of arrhythmic
events (p <0.0001). Of 41 patients, 28 (68%) consented to undergo pha
se 2 of the investigation. Baroreflex sensitivity significantly (p <0.
00001) increased after transdermal scopolamine as well as heart rate v
ariability indexes. Of these, the mean of SDs of normal RR intervals f
or S-minute segments (p <0.0001) and the total power (p <0.0001) had t
he most significant improvement after scopolamine. The present investi
gation confirms that assessment of autonomic function is an essential
part of arrhythmic risk evaluation after AMI. Transdermal scopolamine,
administered to survivors of a recent AMI, reverses the autonomic ind
exes that independently predict arrhythmic event occurrence. On the ba
sis of these data, transdermal scopolamine could be a potential useful
tool in the prophylaxis of life-threatening ventricular arrhythmias a
fter AMI.