Total radiation higher in obese patients undergoing radiofrequency ablation

Obese patients are exposed to greater doses of radiation during radiofrequency ablation for atrial fibrillation, a recent study has found.

The study included 144 patients (median age, 60 years; 21 percent female) who received radiofrequency ablation for atrial fibrillation. Most (n=68) of the participants were overweight, while 48 were obese and 34 were normal-weight. The primary endpoint was the cumulative end dose (ED), defined as the sum of doses received during the preprocedural computed tomography and during the ablation procedure.

Both overweight (p=0.2) and obese (p=0.007) patients received higher EDs, with a 23- and 75-percent difference relative to their normal-weight counterparts, respectively. Only the effect on obese patients was statistically significant.

“Impact of obesity on overall exposure to ionizing radiation, which was previously considered to be major with a dose increase of >300 percent for obese patients, seems finally revealed to be moderate,” said researchers.

Multivariate, generalized linear regression analysis found that body mass index was a significant predictor of overall ED received (β per additional kg/m², 0.27±0.11; p=0.009), as was X-ray time (β per additional minute, 0.27±0.10; p=0.004). Other univariate predictors such as sex, left atrial volume and the type of atrial fibrillation lost their significance after adjusting for covariates.

In addition, BMI was also a significant determinant of the success of the procedure (p=0.04), as were left atrial volume (p<0.001) and the type of atrial fibrillation.