[Mitral valve prolapse. Atrial stimulation, ajmaline test and "pharmacological denervation" in the evaluation of ventricular repolarization].
In patients with mitral valve prolapse syndrome (MVP) various electrophysiological abnormalities occur. There are convergent opinions concerning QT distance variability and the influence of autonomic nervous system on ventricular repolarization in this syndrome. In 38 MVP patients (group I) and 24 subjects without this abnormality (group II) ecg was recorded during transvenous right atrial pacing at baseline, after ajmaline administration and after pharmacological autonomic blockade (atropine + propranolol). The following ventricular repolarization parameters were analysed: QTe (distance to the end of T wave), JTe (distance between J point and the end of T wave--so called "pure repolarization"), QTdys (repolarization dispersion) and the corrected QTc.QTe during 90/min right atrial pacing was significantly shorter than QTc in both groups. QTc was abnormally prolonged (above 440 msec) in MVP group. Ajmaline administration prolonged QTe in group II only, whereas autonomic blockade resulted in marked shortening of QTe in MVP group. QTdys was significantly prolonged only after ajmaline administration in group II. Based on above results, the following conclusions are made: 1) Right atrial pacing technique may be used for calculating standardized QT distance, an alternative to corrected QT. 2) Ajmaline test is useless in ventricular repolarization estimations in MVP patients. 3) In MVP patients the influence of adrenergic system on ventricular repolarization at rest appears to be greater than in non-MVP subjects.
Gil
R
R
Klinika Kardiologii PAM, Szczecinie.
Kaźmierczak
J
J
Kornacewicz-Jach
Z
Z
Zinka
E
E
D000293:Adolescent; D000328:Adult; D000404:Ajmaline; D001285:Atropine; D001340:Autonomic Nerve Block; D001341:Autonomic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology*; D006325:Heart Atria / Q000187:drug effects / Q000503:physiopathology; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008945:Mitral Valve Prolapse / Q000503:physiopathology*; D011433:Propranolol
D000404:Ajmaline; D001285:Atropine; D011433:Propranolol
Zespół wypadania płatka zastawki dwudzielnej. Stymulacja przedsionka, test z ajmalina i "farmakologi czne odnerwienie" w ocenie repolaryzacji komór.