Effects of adrenaline and potassium on QTc interval and QT dispersion in man

被引:54
作者
Lee, S
Harris, ND
Robinson, RT
Yeoh, L
Macdonald, IA
Heller, SR
机构
[1] Univ Sheffield, Ctr Clin Sci, No Gen Hosp, Div Clin Sci, Sheffield S5 7AU, S Yorkshire, England
[2] Univ Bath, Dept Med Sci, Bath BA2 7AY, Avon, England
[3] Queens Med Ctr, Sch Biomed Sci, Nottingham NG7 2UH, England
关键词
hypoglycaemia; hypokalaemia; QTc interval; sympatho-adrenal response;
D O I
10.1046/j.1365-2362.2003.01123.x
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Background Hypoglycaemia alters cardiac repolarization acutely, with increases in rate-corrected QT (QTc) interval and QT dispersion (QTd) on the electrocardiogram (ECG); such changes are related to the counterregulatory sympatho-adrenal response. Adrenaline produces both QTc lengthening and a fall in plasma potassium (K+) when infused into healthy volunteers. Hypokalaemia prolongs cardiac repolarization independently however, and therefore our aim was to determine whether adrenaline-induced repolarization changes are mediated directly or through lowered plasma K+. Materials and methods Ten healthy males were studied on two occasions. At both visits they received similar l- adrenaline infusions but on one occasion potassium was also administered; infusion rates were adjusted to maintain circulating K (+) at baseline. The QTc interval, QTd, peripheral physiological responses and plasma adrenaline and potassium concentrations were measured during both visits. Results The QTc interval and QTd increased both with and without potassium clamping. Without K+ replacement, mean (SE) QTc lengthened from 378 (5) ms to a final maximum value of 433 (10) ms, and QTd increased from 36 (5) ms to 69 (8) ms (both P < 0.001). During K (+) replacement, QTc duration at baseline and study end was 385 (7) ms and 423 (11) ms, respectively (P < 0.001), and QTd 38 was (4) ms and 63 (5) ms (P = 0.001). Conclusions These data suggest that disturbed cardiac repolarization as a result of increases in circulating adrenaline occurs independently of extracellular potassium. A direct effect of adrenaline upon the myocardium appears the most likely mechanism.
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收藏
页码:93 / 98
页数:6
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