Objective   To explore the feasibility and reliability to build a sinoatrial node damage model in canine induced by formaldehyde wet dressing.     Methods   Twenty dogs were randomly divided into 4 groups (5 in each group) by means of random number table: 2-hour

24-hour

1-week and 4-week groups after wet dressing. The sinoatrial node area of canine was damaged by wet dressing with 20% formaldehyde. Sinus node function was measured before

2 h after wet dressing and corresponding times of each group. Electrocardiogram (ECG) of body surface were recorded synchronically.     Results   Average wet dressing time was 6.2±2.6（3 to 12）min. Five dogs showed significantly decrease of heart rate (HR) (140±11 vs 89±6 beat/min

P0.01) after wet dressing without arrhythmia. Sinus arrhythmia

sinus arrest and premature atrial contraction appeared after wet dressing in 4 dogs

but regular sinus rhythm was observed quickly. In 11 dogs

P waves disappeared after wet dressing and their ECG displayed junctional rhythm. Among of them

4 dogs had sinus arrhythmia 24 h later with a significantly slower HR in comparison to those before wet dressing. HR of each group was significantly decreased than that of before wet dressing (P0.01)

while sinus node recovery time (SNRT) and corrected sinus node recovery time (CSNRT) were increased significantly.     Conclusion   Formaldehyde wet dressing can be used to establish sinoatrial node damage model in canine. This method is convenient and reliable relatively

and the change of electrophysiology resemble sick sinus syndrome.