Testosterone Replacement Therapy Improves QTaVI in Hypogonadal Men with Spinal Cord Injury
La Fountaine MF, Wecht JM, Cirnigliaro CM, Kirshblum SC, Spungen AM, Bauman WA. Neuroendocrinology. 2013 Jan 23. [Epub ahead of print]

Source

VA RR&D Center of Excellence for the Medical Consequences of Spinal Cord Injury, James Peters VA, Medical Center, Bronx, N.Y., USA.

Abstract

Aim: To determine the effect of a 12-month intent-to-treat tesosterone replacement therapy (TRT) trial on QTa interval variability (QTaVI) in hypogonadal (HG) men with spinal cord injury (SCI). Method: A prospective, controlled, 12-month TRT trial was completed in twenty-two healthy, chronic, non-ambulatory men with SCI. Based on serum T concentration, subjects were designated as HG (≤11.3 nmol/l) or eugonadal (EG, ≥11.4 nmol/l). Digital 3-lead electrocardiograms were performed. Heart rate (RR), heart rate variability [(HRV), including total power (TP(RR)), low frequency (LF(RR)) and high freguency (HF(RR))], QTa, QTe, and RT intervals, QTC (Bazett), QTVN, and QTaVI were calculated and evaluated at baseline and 12 months. Lipoprotein profiles (triglycerides, total cholesterol, low density and high-density lipoproteins) were obtained at the respective time points. Results: Based on serum T concentration, 13 subjects were designated as HG and 11 EG. During the trial, there were no group differences for RR, QTa, QTe or RT intervals, QTC, TP(RR), HF(RR), or lipoproteins. The HG was older (p < 0.05) and LF(RR) was lower (p < 0.05) at baseline. At baseline, QTaVI was significantly greater in HG compared to EG [-0.17 (0.92) vs. -1.07 (0.90); p < 0.05]. After TRT, this group difference was no longer present [-0.44 (0.87) vs. -0.65 (0.85)] and the change in HG was significant (p < 0.05). Conclusion: Hypogonadism in men with SCI was associated with elevated QTaVI at baseline. After 12 months of physiological TRT, the QTaVI improved in association with raising T into the normal range. These findings occurred independently from the prolongation of the QT interval.