Ventricular repolarization changes during thyrotropin releasing hormone test

We investigated the ventricular repolarization changes during thyrotropin-r eleasing hormone (TRH) test in 20 euthyroid healthy subjects. TSH elevation was observed in 14 subjects (age: 29 +/- 5 years). TSH increased at 20 min (baseline: 1.91 +/- 1.18 muU/ml vs. 20 min: 13.7 +/- 7.2 muU/ml, P < 0.000 1) and slightly decreased at 40 min (baseline vs. 40 min: 11.6 <plus/minus> 6.7 muU/ml P < 0.0001). Many dispersions prolonged at 20 and 40 min (P < 0 .05). At baseline, 20 and 40 min, positive linear correlations were observe d between TSH levels and TTd and TTcd, These data shows: that ventricular r epolarization and regional inhomogeneity of ventricular repolarization incr ease during the TRH test. Neural and receptor-mediated mechanisms on repola rization kinetics of myocardial cells may act on this effect. (C) 2001 Else vier Science Ireland Ltd. All rights reserved.