Akademik Veri Yönetim Sistemi
Gazi Medical Journal, cilt.13, sa.3, ss.117-121, 2002 (Scopus)
Purpose: To investigate the effects of sildenafil citrate (Viagra) on heart rate variability and to find whether sildenafil citrate is a probable cause of lethal arrhythmias and sudden cardiac death. Methods: 50 patients with erectile dysfunction were evaluated with Holter monitorisation and the heart rate variability was determined over a period before and during oral sildenafil citrate therapy. Patients have taken 50-mg sildenafil-citrate one hour before sexual activity for 3 months. After 3 months patients used 50-mg/day-sildenafil citrate for four days before control holter monitorisation. All heart rate variability parameters, such as the standard deviation of the normal -to-normal (NN) intervals (SDNN), the standard deviation of the 5-min average of NN intervals (SDANN), the square root of squared successive differences in NN intervals (r-MSSD), the percentage of NN intervals with a cyclic length over 50 ms different from the previous interval (pNN50), in the time domains studied during 24 hours. Frequency domains such as low frequency (LF) showing sympathetic activity, high frequency (HF) showing parasympathetic activity, and total power (LF/HF ratio) values showing parasympathetic activity were studied during 24 hours. Results: SDNN values were not found to be significant when compared with the baseline SDNN. pNN50 was found to be statistically significant when compared with the baseline pNN50 (p <0.05). Moreover, increase in all day period values of r-MSSD, which is another indicator of parasympathetic activity, were found to be statistically significant (p<0.05). LF/HF were found to be decreased significantly when compared with the baseline values (p <0.05). Conclusion: Our results indicate that the reduced LF/HF ratio and increased pNN50 and r-MSSD values after sildenafil citrate treatment which shows parasympathetic activity may be a protective factor against lethal arrhythmias and sudden cardiac deaths as the increase in parasymphatic activity are known to be protective against these major complications. So we believe that sildenafil citrate may not be the cause of cardiovascular problems.