Testosterone replacement therapy improves QTaVI in hypogonadal men with spinal cord injury.
OBJECTIVE
To determine the effect of a 12-month intent-to-treat testosterone (T) replacement therapy (TRT) trial on QTa interval variability (QTaVI) in hypogonadal (HG) men with spinal cord injury (SCI).


METHODS
A prospective, controlled 12-month TRT trial was completed in 22 healthy, chronic, nonambulatory 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 [including total power (TPRR), low frequency (LFRR) and high frequency (HFRR)], QTa, QTe, and RT intervals, QTC (Bazett formula), QTVN, and QTaVI were calculated and evaluated at baseline and at 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 as EG. During the trial, there were no group differences for RR, QTa, QTe or RT intervals, QTC, TPRR, HFRR, or lipoproteins. The HG group was older (p < 0.05) and their LFRR was lower (p < 0.05) at baseline. At baseline, QTaVI was significantly greater in the HG group compared to the EG group [-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 the HG group was significant (p < 0.05).


CONCLUSIONS
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 of the prolongation of the QT interval.
VA RR&D Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY 10468, USA. michael.lafountaine @ va.gov
Michael F
MF
La Fountaine
Jill M
JM
Wecht
Christopher M
CM
Cirnigliaro
Steven C
SC
Kirshblum
Ann M
AM
Spungen
William A
WA
Bauman
D000328:Adult; D004562:Electrocardiography; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D020249:Hormone Replacement Therapy; D006801:Humans; D007006:Hypogonadism / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology; D013119:Spinal Cord Injuries / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D013739:Testosterone / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
D013739:Testosterone