Bepridil produces prominent bradycardia-dependent QT prolongation in patients with structural heart disease.
The aim of the present study is to elucidate the effect of bepridil on heart rate-dependent QT prolongation in patients with or without structural heart disease. QT intervals and the preceding R-R intervals were randomly measured by 24-hour Holter electrocardiogram in 29 patients with symptomatic arrhythmias. The slope of the regression curve was used as a marker of bradycardia-dependent QT prolongation. The slope was not different in patients without structural heart disease (0.34 +/- 0.10) as compared with the apparently normal control subjects (0.32 +/- 0.057, n = 29), whereas it was larger than that in patients with structural heart disease (0.57 +/- 0.17; P < .01). Steep slopes (>0.43) were observed in 11 of the 14 patients with structural heart disease, whereas they were observed only in 1 patient without structural heart disease (P < .01). In conclusion, we need to pay attention to bradycardia-dependent QT prolongation by bepridil, especially when dealing with structural heart disease.
Sadanaga
Tsuneaki
T
Division of Cardiology, Yatsushiro General Hospital, Yatsushiro, Japan. kamefu@rb3.so-net.ne.jp <kamefu@rb3.so-net.ne.jp>
Ogawa
Satoshi
S
D000368:Aged; D015764:Bepridil / Q000009:adverse effects* / Q000627:therapeutic use*; D001919:Bradycardia / Q000139:chemically induced* / Q000175:diagnosis*; D009202:Cardiomyopathies / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000139:chemically induced* / Q000175:diagnosis*; D008297:Male; D014665:Vasodilator Agents / Q000009:adverse effects / Q000627:therapeutic use
D014665:Vasodilator Agents; D015764:Bepridil