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Chronotropic effects of cilostazol, a new antithrombotic agent, in patients with bradyarrhythmias
H Atarashi1, Y Endoh, H Saitoh
1First Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
Insights
Cilostazol, a phosphodiesterase inhibitor, effectively increased heart rate in patients with symptomatic bradyarrhythmias. This study found beneficial chronotropic effects, particularly in those with bradycardic atrial fibrillation and sick sinus syndrome.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Bradyarrhythmias pose a significant clinical challenge, often leading to symptoms and reduced quality of life.
- The chronotropic effects of phosphodiesterase inhibitors in patients with bradyarrhythmias are not well-established.
Purpose of the Study:
- To investigate the potential beneficial chronotropic effects of the oral phosphodiesterase inhibitor, cilostazol.
- To evaluate cilostazol's impact on heart rate in patients diagnosed with symptomatic bradyarrhythmias.
Main Methods:
- Twenty patients with symptomatic bradyarrhythmias (bradycardic atrial fibrillation, sick sinus syndrome, Wenckebach-type AV block) were enrolled.
- 24-hour Holter monitoring was conducted before and after two weeks of daily 200 mg oral cilostazol administration.
Main Results:
- Cilostazol significantly increased the 24-hour total heart-beat count (p < 0.0001).
- The minimal heart rate increased significantly (p < 0.0001), and the maximal RR interval decreased significantly (p = 0.0001).
- Adverse effects were minimal, with only two patients reporting headaches.
Conclusions:
- Cilostazol demonstrates a beneficial positive chronotropic effect in patients suffering from bradyarrhythmias.
- The drug appears particularly effective in patients with bradycardic atrial fibrillation and sick sinus syndrome.
Abstract:
Whether phosphodiesterase inhibitors increase the heart rate in patients with bradyarrhythmias is not known. We attempted to determine whether the oral phosphodiesterase inhibitor cilostazol exhibits beneficial chronotropic effects in patients with symptomatic bradyarrhythmias. Twenty patients comprising eight with bradycardic atrial fibrillation, eight with sick sinus syndrome, and four with Wenckebach-type atrioventricular block, whose 24-h total heart-beat count was < or =70,000 beats and whose maximal RR interval was > or =2.5 s, were enrolled. Holter recordings (24-h) were made before and 2 weeks after oral daily administration of 200 mg of cilostazol. Cilostazol increased the 24-h total heart-beat count from 77,429 +/- 11,168 to 107,981 +/- 13,536 (95% confidence interval, 24,605-36,497; p < 0.0001), the minimal heart rate from 33 +/- 9 47 +/- 13 beats/min (95% confidence interval, 9-19 beats/min; p < 0.0001), and the maximal RR interval from 3,149 +/- 1,018 to 2,087 +/- 601 ms (95% confidence interval, -1,517 to -608 ms; p = 0.0001). Only two patients had headaches as adverse effects. In conclusion, cilostazol had a beneficial positive chronotropic effect in patients with bradyarrhythmias, especially with bradycardic atrial fibrillation and sick sinus syndrome.