Is there a relationship between disease duration and P-wave dispersion in patients with psoriasis?

Dear Editor

We have read with great enthusiasm the recently published article entitled ‘Electrocardiographic P-wave characteristics in patients with psoriasis vulgaris' by Bacaksız and co-workers (1). They concluded that Pmax and P-wave dispersion (PWD) were significantly higher in psoriasis patients than in controls (108.8 ± 21.3 ms versus 93.3 ± 13.0 ms, P < 0.01; 67.4 ± 22.9 ms versus 45.0 ± 19.6 ms, P < 0.01, respectively). Furthermore, Pmin was significantly lower in the psoriasis group (41.3 ± 12.3 ms versus 48.3 ± 14.3 ms, P = 0.04) (1). Recently, Ahlehoff et al. showed that psoriasis is associated with an increased risk of atrial fibrillation (AF) (2). Prolongation of PWD has been demonstrated to be an independent risk factor for the development of AF. Therefore, the subject is important in daily practice, and the study deserves further attention, keeping in mind its successful design and results.

Bacaksız et al. showed (1) that the Psoriasis Area and Severity Index (PASI) score was correlated with Pmax and PWD (P = 0.002 and P = 0.005, respectively). In addition, there was a significant positive correlation between hsCRP and PWD (r = 0.229, P = 0.001). It was speculated that although the exact mechanism still remains unclear, chronic inflammation may be responsible for the correlation between PASI score and PWD in these patients. Psoriasis is a chronic inflammatory disease, and the inflammation continues for the duration of the disease. Hence, a significant positive correlation between duration of the disease and PWD would be expected. We believe that an evaluation of the relationship between duration of the disease and PWD will help us to understand the increased frequency of AF in patients with psoriasis.

In addition, patients with coronary artery disease (CAD) were excluded in the study of Bacaksiz et al (1). Epidemiological studies in patients with severe psoriasis have revealed that there is an increased risk of cardiovascular mortality (3,4), and the cardiovascular disease risk has been found to be particularly high in young patients with a severe form of the disease (5,6). It has been postulated that premature occurrence of atherosclerosis is related to why psoriasis patients have an increased risk for developing cardiovascular disease. As we know, there is an important relationship between psoriasis and subclinical coronary atherosclerosis, independent of conventional cardiovascular disease risk factors (7-9). Bacaksız et al. (1) did not specify how CAD was excluded, but there might be some subclinical atherosclerosis in their patients. In a previous study, PWD was found to be more significant in patients with stable CAD than in patients with normal coronary angiograms and to be associated with severity of the disease as well (10). Therefore, it would have been helpful if Bacaksiz and co-workers had clearly identified these factors.