Browsing by Subject "arrhythmogenesis"

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    Possible contribution of leukotrienes in the arrhythmogenic effects of digoxin on isolated guinea-pig hearts
    (1998) Gök Ş.; Ülker S.; Evinç A.
    The effect of a leukotriene D4 (LTD4) receptor antagonist, L-648,051, was investigated in digoxin-induced cardiac toxicity in isolated guinea-pig hearts (Langendorff preparation). Digoxin infusion (25 μg.ml-1, 0.5 ml.min-1) increased perfusion pressure and contractile force initially, but decreased them later. The onset of first ventricular premature beats (VPBs) matched the increase phase, but the decrease phase was accompanied by ventricular tachycardia (VT) and fibrillation (VF). In the presence of L-648,051 (5 μmol.l-1), the initial phase was similar to that observed with digoxin alone, but the marked reduction was inhibited. This drug increased the concentration of digoxin required for VBSs and cardiac arrest, but it could not prevent the formation of VT and VF. The duration of VT was significantly decreased by L-648,051. It is concluded that the leukotriene receptor antagonist might have beneficial effects on digoxin-induced arrhythmias. Whether this effect depends on direct or indirect actions is uncertain.
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    Lower arrythmogenic risk of low dose albuterol plus ipratropium
    (The Indian Journal of Pediatrics, 2001) Yuksel H.; Coskun S.; Polat M.; Onag A.
    Objective: Wheezy infants are in need of urgent bronchodilatation owing to their intermittent bronchoconstriction. β2 agonists are frequently used in emergencies and have previously shown to increase the QT dispersion (QTd), which may be associate with high risk of cardiac arrhythmia, in asthmatics. However, effect of low dose β2 agonist therapy in combination with the anticholinergic agents on QTd in wheezy infants is not known. This study aimed to assess the effect of standard dose of nebulized albuterol (NAB) and low doses of NAB combined with ipratropium-bromide (NIB) on QTd in wheezy infants. Methods: Twenty-nine children, under 2 years old, with the diagnosis of wheezy infant with acute exacerbation were enrolled in the study. Thirteen were treated by standard dose of NA therapy (0.15 mg/kg) and low doses of NAB (0.075 mg/kg) plus NIB (250 μg/dose) therapy was given to the remaining subjects. Respiratory distress score, 02 saturation and side effects were studied and QTd were measured from the standard electrocardiograms at baseline and after treatment. Significant improvement was achieved in clinical score and oxygenation of both groups. Result: The evaluation of the corrected QTd (QTcd) showed that there was no significant difference between pretreatment values of both groups (p>0.05). However, while there was no statistically significant difference in the pre and post-treatment values of QTcd of infants treated with combination therapy, QTcd was found to be significantly increased in NAB group after treatment (p<0.05). Conclusion: Our results suggest that, while clinical improvement is same, the increase of the QT dispersion is more prominent with the use of standard dose of NAB compared to low dose NAB plus NIB therapy. So, low dose of β2 agonist in combination with anticholinergic agents may much safer than the use of standard dose of β2 agonists alone in regard to preventing the possibility of arrythmogenic effects in wheezy infants with acute exacerbation.