Electrophysiological effects of nicainoprol in patients with paroxysmal supraventricular tachycardias.
The electrophysiological effects of nicainoprol, a new class I antiarrhythmic drug, were evaluated in 29 patients with supraventricular reentrant tachycardias, due to accessory pathways in 15 and dual atrioventricular nodal pathways in 14 patients. Nicainoprol was administered intravenously as a bolus followed by continuous infusion of 1.5 mg/kg in two and of 2 mg/kg in 27 patients over one hour. Nicainoprol was given as a bolus of 1.5-2 mg/kg during sinus rhythm in 11 patients or during induced supraventricular tachycardia in 18. The drug successfully terminated the tachycardia in 17 patients due to block in the retrograde tachycardia limb in 15 and the antegrade limb in 2 patients. Prolongation of the cycle length preceded the termination in each case. In one case, the termination could not be achieved despite the administration of 3 mg/kg. The sinus cycle length, heart rate corrected QT interval as well as right atrial and right ventricular effective refractory periods remained unchanged. In contrast, the intranodal and infranodal conduction times, as well as QRS duration, were prolonged significantly. In patients with dual atrioventricular nodal pathways, there was a significant (P less than 0.05) increase of the effective refractory periods of the anterograde slow pathways. The changes of the anterograde fast pathways, however, did not reach significance level. More pronounced effects were found on effective refractory periods of the retrograde pathways, which were blocked in 4 patients and significantly (P less than 0.05) prolonged in the remainder. Similarly, in patients with accessory pathways the effect on the retrograde conduction was more marked with complete block in 5 patients and significant prolongation of effective refractory periods and shortest paced cycle lengths in the remainder.(ABSTRACT TRUNCATED AT 250 WORDS)
Sen
S
S
Medizinische Universitätsklinik, Innere Medizin III, (Kardiologie), Homburg/Saar, F.R.G.
Rettig
G
G
Heisel
A
A
Ozbek
C
C
Schieffer
H
H
D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004562:Electrocardiography / Q000187:drug effects; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011412:Propanolamines / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control*; D013617:Tachycardia, Supraventricular / Q000188:drug therapy* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D011412:Propanolamines; C047768:nicainoprol