First diagnosis of colorectal or breast cancer and prevalence of atrial fibrillation.

Aim of the present study was to assess the prevalence of atrial fibrillation (AF) in patients with two different types of cancer. Recent epidemiologic and clinical studies support the hypothesis that AF is promoted and maintained by a broad spectrum of modulating factors. A total of 2,339 patients admitted to the Surgery Department of "Luigi Sacco Hospital, Milan," over the period 1987-2004 were eligible for the study. One thousand three hundred and seventeen patients were admitted consecutively with a first diagnosis of colorectal or breast cancer (cases). The remaining 1,022 were patients admitted to undergo non-neoplastic surgery (controls). Routine pre-surgery electrocardiogram available in patient charts was analysed by a cardiologist who was not aware of the present study to evaluate the presence of atrial fibrillation or other arrhythmias. Overall, AF was present in 3.6% cases and 1.6% controls. This corresponded to at least two times higher likelihood of having AF in cases compared to controls. Prevalence of AF increased with age both in cases and controls. Our study describes an increased prevalence of AF in two different types of cancer. Autonomic, endocrine, coagulation, and inflammatory alterations were previously described in both AF and cancer, and can provide the physiopathological basis to our clinical observation.

[Atrial fibrillation as a complication of colorectal tumors]. / La fibrillazione atriale come complicanza del tumore del colon.

We undertook a study to provide a quantitative basis to the clinical observation of an unexpected high frequency of atrial fibrillation in patients with colorectal cancer. In our study we considered a total of 1463 patients admitted during a period of 12 years (1987-1998) to the Department of Surgery of our Hospital for surgical treatment of colorectal cancer (case group: mean age 66 years) or non-neoplastic diseases including inguinal hernia, cholelithiasis, varicose veins and hemorrhoids (control group: mean age 65.6 years). We found a three times higher likelihood of having atrial fibrillation in patients with first diagnosis of colorectal cancer compared to controls. Logistic analysis was used to exclude an effect of age. Our study suggests that atrial fibrillation could be considered a non metastatic effect of colorectal cancer. Several pathophysiological mechanisms could explain this observation. A recent study, which reports a significant elevation of C-reactive protein in patients with atrial fibrillation, suggests that this arrhythmia could be promoted by a systemic inflammatory state. In conclusion, atrial fibrillation could be considered a pathological condition not only dependent to organic heart diseases; further studies are needed to evaluate the real impact of systemic inflammatory state or other non-cardiovascular diseases on the excess of mortality in the patients with atrial fibrillation.