Magnesium abolishes inadequate kinetics of frequency adaptation of the Q-aT interval in the presence of sotalol.

نویسندگان

  • G Stark
  • I Schwarzl
  • U Heiden
  • U Stark
  • H A Tritthart
چکیده

OBJECTIVE It has been well established that class III antiarrhythmic drugs can also induce ventricular arrhythmias. Marked changes in the QT interval are correlated with an increased dispersion of repolarization which is an important factor for the induction of ventricular arrhythmias. The aim of the present study was to investigate the effects of sotalol alone and in combination with MgSO4 and the Q-aT interval during abrupt changes in heart rate. METHODS The experiments were performed on isolated guinea-pig hearts perfused by the method of Langendorff. The rate adaptation of the Q-aT interval was estimated after abruptly changing the ventricular pacing rate from 220 to 180 ms and back to 220 ms. RESULTS In the presence of 10 microM sotalol, at a constant pacing cycle length of 220 ms, the QT interval was prolonged significantly (P < 0.01) from 152 +/- 4 to 166 +/- 3 ms (mean +/- s.e.m., n = 8 in each group). The addition of 3.4 mM MgSO4 caused a slight further prolongation of the QT interval. After abruptly shortening the pacing cycle length from 220 to 180 ms, the Q-aT interval shortened within 2 min by 11.3 +/- 0.5 ms with a time constant (tau) of 77 +/9 beats under control conditions, by 15.4 +/- 0.9 ms (P < 0.05 vs. control with tau = 52 +/- 7 beats (P < 0.05 vs. control) in the presence of sotalol, and by 13.1 +/- 1.2 ms with tau = 158 +/- 13 beats under the combination of sotalol (10 microM) and MgSO4 (3.4 mM). After abrupt shortening of the pacing cycle length the Q-aT interval of the first beat was shortened by 3.3 +/- 0.3 ms under control conditions, by 7.1 +/- 0.2 ms (P < 0.01 vs. control) under sotalol, and by 4.2 +/- 0.2 ms with the combination of sotalol and MgSO4. If the pacing cycle length was abruptly increased from 180 to 220 ms, the effects were comparable to those described above. CONCLUSIONS Sotalol led to inadequate kinetics of fate adaptation of the Q-aT interval indicated by a high amplitude of Q-aT interval change, especially within the first beat after abrupt change in the pacing rate. MgSO4 abolished this effect of sotalol. These findings suggest that MgSO4 could reduce sotalol-induced inadequate kinetics of rate adaptation and therefore also dispersion of repolarization, which may result in a reduction of sotalol-induced ventricular arrhythmias.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

The Frequency of IgM anti-Coxiella burnetii (Q fever) Antibodies among Slaughterhouse Workers in Kerman city, 2012

Background & Aim: Q fever is an important zoonotic disease caused by infection with Coxiella burnetii, a Gram negative, obligate intracellular bacterium classified within the order Legionellales. Farmers, veterinarians, abattoir workers and laboratory personnel are among persons at risk of Q fever. The aim of this study was to determine frequency of IgM anti-Coxiella burnetii antibodies in slau...

متن کامل

An evaluation of the impact of oral magnesium lactate on the corrected QT interval of patients receiving sotalol or dofetilide to prevent atrial or ventricular tachyarrhythmia recurrence.

BACKGROUND Intravenous magnesium reduces the QTc interval of patients receiving ibutilide. Whether oral magnesium can reduce the QTc interval associated with oral sotalol and dofetilide is not known. This study was undertaken to evaluate the impact of oral magnesium on the QTc interval and whether an inherent intracellular magnesium deficiency exists among patients with arrhythmias. METHODS P...

متن کامل

تاثیر تعداد وعده‌های غذایی در تامین مواد مغذی مورد نیاز نوجوانان

Background: Rapid tissue growth and development during puberty increases the need for energy and nutrients. On the other hand, the prevalence of obesity is accelerating among adolescents. Controversies exist regarding meal frequency, obesity and adequacy of nutrients in particular, a more frequent snacking pattern has been associated with overconsumption of calories in children and adolescents ...

متن کامل

Evaluation of the Efficiency of Double Aluminum-Magnesium Layered Nano-Hydroxide in Removal of Pharmaceuticals from Aquatic Solutions and Determination of Optimal Adsorption

Background: Antibiotics and their metabolites are known as dangerous non-degradable substances that potentially remain after the wastewater treatment process. Therefore, it is necessary to remove these compounds from aqueous solutions. This study aimed to use layered double nano-hydroxides to remove carbamazepine, cephalexin, and ciprofloxacin.   Methods: In this experimental study the charact...

متن کامل

Kinetics of ethylene polymerization over titanium-magnesium catalysts: The reasons for the observed second order of polymerization rate with respect to ethylene

The data on the effect of ethylene concentration on polymerization rate for several modifications of modern highly active titanium–magnesium catalysts TiCl4/MgCl2 are presented. These catalysts differ in titanium content and conditions of support preparation, activities, and the shape of kinetic curves. It is found that the observed order of polymerization rate with respect to ethylene in the r...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Cardiovascular research

دوره 35 1  شماره 

صفحات  -

تاریخ انتشار 1997