Clinical suppression of bradycardia dependent premature ventricular contractions by the potassium channel opener nicorandil.
OBJECTIVE
To assess the clinical antiarrhythmic effect of nicorandil, a potassium channel opener; on premature ventricular contractions.


METHODS
The effect of oral nicorandil (15 to 60 mg daily for four weeks) on premature ventricular contractions was investigated in 20 patients (11 female, nine male, mean (SD) age 63 (17) years) who underwent 24 hour ambulatory ECG. Patients were classified into two groups based on the relation between the frequency of premature ventricular contractions and heart rate: (1) those with a positive correlation (n = 9); and (2) those with a bidirectional correlation (n = 11), characterised by an increased frequency of premature contractions at low heart rates and a decreased frequency at high heart rates.


RESULTS
Nicorandil reduced the frequency of premature ventricular contractions by 75% in five patients in group 2, but was not effective in any patient in group 1. The heart rate at which the frequency of premature ventricular contractions peaked was significantly lower in the five responders in group 2 than in the six non-responders (63.2 (3.7) v 76.3 (12.4) beats/min, p < 0.05).


CONCLUSIONS
Nicorandil may suppress premature ventricular contractions when they occur mainly at a low heart rate.
Takahashi
N
N
Department of Internal Medicine I, School of Medicine, Oita Medical University, Japan.
Ito
M
M
Saikawa
T
T
Arita
M
M
Fujino
T
T
Kagiyama
H
H
Fukumoto
T
T
Sakata
T
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000627:therapeutic use; D020108:Nicorandil; D018879:Ventricular Premature Complexes / Q000188:drug therapy* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D009536:Niacinamide; D020108:Nicorandil