[Association between incidence of idiopathic ventricular tachycardia and risk factors with short-term effects: a case-crossover study].

Objective: To explore the transient risks regarding idiopathic ventricular tachycardia (IVT).

Methods: A symmetric bidirectional case-crossover design was used to estimate the short-term risk of IVT. In the case-crossover design each case served as its own matched control while case-period were compared to two control-periods, 7 days before and after the case-period. Ninety-four subjects were recruited from People's Hospital of Jiangsu Province and Affiliated Hospital of Southeast University from Dec. 2007 to Nov. 2008. Generalized estimating equation, with binomial distributed dependent variable and logit link-function, was used to estimate OR and 95%CI.

Results: The risk factors that were associated with IVT would include: physical exertion (OR = 2.20, 95%CI: 1.51 - 3.19), in the state of anger (OR = 1.87, 95%CI: 1.07 - 3.27) sad feelings (OR = 3.58, 95%CI: 2.19 - 5.84), or agitation (OR = 3.06, 95%CI: 1.61 - 5.83) and having infection of some kind (OR = 2.25, 95%CI: 1.44 - 3.50).

Conclusion: Factors as physical Exertion, in the mood of anger, sadness agitation, having some kind of infection were related to IVT. Case-crossover design seemed to be able to identify the risk factors of IVT and its intensity.