Effects of procainamide on transmural ventricular repolarisation.
To investigate the pharmacological effect of procainamide on transmural ventricular repolarisation in normal heart, the transmural activation-recovery intervals (ARI) and their responses to procainamide (20 mg/min i.v. for 20 min) were studied in 6 open-chest, pentobarbitone-anaesthetised sheep. ARI was measured from the unipolar ECGs acquired with 4 plunge needles inserted into the basal and apical parts of the left ventricular wall. During sinus rhythm (cycle length 500-700 ms), there was no significant difference in the pooled ARI between the epicardium (266.0 +/- 30.5 ms), midmyocardium (265.0 +/- 28.9 ms) and endocardium (265.7 +/- 28.1 ms) (p > 0.05). Procainamide prolonged ARI in all myocardial layers. The pooled ARI prolongation from the epicardium, midmyocardium and endocardium of the 6 animals was 66.8 +/- 18.3, 70.3 +/- 14.7 and 65.3 +/- 15.7 ms (p > 0.05), respectively. In conclusion, sodium channel blocker procainamide results in a similar repolarisation prolongation in the left ventricular epicardium, midmyocardium and endocardium of a healthy heart.
Wang
Lexin
L
School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia. lwang@csu.edu.au
Yong
Ah Chot
AC
Kilpatrick
David
D
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D004562:Electrocardiography; D004699:Endocardium / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D010496:Pericardium / Q000187:drug effects / Q000502:physiology; D011342:Procainamide / Q000494:pharmacology*; D012756:Sheep; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects* / Q000502:physiology
D000889:Anti-Arrhythmia Agents; D011342:Procainamide